xref: /titanic_41/usr/src/uts/common/os/sunmdi.c (revision 40e5e17b3361b3eea56a9723071c406894a20b78)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 #pragma ident	"%Z%%M%	%I%	%E% SMI"
26 
27 /*
28  * Multipath driver interface (MDI) implementation; see mdi_impl.h for a more
29  * detailed discussion of the overall mpxio architecture.
30  *
31  * Default locking order:
32  *
33  * _NOTE(LOCK_ORDER(mdi_mutex, mdi_vhci:vh_phci_mutex);
34  * _NOTE(LOCK_ORDER(mdi_mutex, mdi_vhci:vh_client_mutex);
35  * _NOTE(LOCK_ORDER(mdi_vhci:vh_phci_mutex, mdi_phci::ph_mutex);
36  * _NOTE(LOCK_ORDER(mdi_vhci:vh_client_mutex, mdi_client::ct_mutex);
37  * _NOTE(LOCK_ORDER(mdi_phci::ph_mutex mdi_pathinfo::pi_mutex))
38  * _NOTE(LOCK_ORDER(mdi_phci::ph_mutex mdi_client::ct_mutex))
39  * _NOTE(LOCK_ORDER(mdi_client::ct_mutex mdi_pathinfo::pi_mutex))
40  */
41 
42 #include <sys/note.h>
43 #include <sys/types.h>
44 #include <sys/varargs.h>
45 #include <sys/param.h>
46 #include <sys/errno.h>
47 #include <sys/uio.h>
48 #include <sys/buf.h>
49 #include <sys/modctl.h>
50 #include <sys/open.h>
51 #include <sys/kmem.h>
52 #include <sys/poll.h>
53 #include <sys/conf.h>
54 #include <sys/bootconf.h>
55 #include <sys/cmn_err.h>
56 #include <sys/stat.h>
57 #include <sys/ddi.h>
58 #include <sys/sunddi.h>
59 #include <sys/ddipropdefs.h>
60 #include <sys/sunndi.h>
61 #include <sys/ndi_impldefs.h>
62 #include <sys/promif.h>
63 #include <sys/sunmdi.h>
64 #include <sys/mdi_impldefs.h>
65 #include <sys/taskq.h>
66 #include <sys/epm.h>
67 #include <sys/sunpm.h>
68 #include <sys/modhash.h>
69 #include <sys/disp.h>
70 #include <sys/autoconf.h>
71 #include <sys/sysmacros.h>
72 
73 #ifdef	DEBUG
74 #include <sys/debug.h>
75 int	mdi_debug = 1;
76 int	mdi_debug_logonly = 0;
77 #define	MDI_DEBUG(level, stmnt) \
78 	    if (mdi_debug >= (level)) i_mdi_log stmnt
79 static void i_mdi_log(int, dev_info_t *, const char *fmt, ...);
80 #else	/* !DEBUG */
81 #define	MDI_DEBUG(level, stmnt)
82 #endif	/* DEBUG */
83 
84 extern pri_t	minclsyspri;
85 extern int	modrootloaded;
86 
87 /*
88  * Global mutex:
89  * Protects vHCI list and structure members.
90  */
91 kmutex_t	mdi_mutex;
92 
93 /*
94  * Registered vHCI class driver lists
95  */
96 int		mdi_vhci_count;
97 mdi_vhci_t	*mdi_vhci_head;
98 mdi_vhci_t	*mdi_vhci_tail;
99 
100 /*
101  * Client Hash Table size
102  */
103 static int	mdi_client_table_size = CLIENT_HASH_TABLE_SIZE;
104 
105 /*
106  * taskq interface definitions
107  */
108 #define	MDI_TASKQ_N_THREADS	8
109 #define	MDI_TASKQ_PRI		minclsyspri
110 #define	MDI_TASKQ_MINALLOC	(4*mdi_taskq_n_threads)
111 #define	MDI_TASKQ_MAXALLOC	(500*mdi_taskq_n_threads)
112 
113 taskq_t				*mdi_taskq;
114 static uint_t			mdi_taskq_n_threads = MDI_TASKQ_N_THREADS;
115 
116 #define	TICKS_PER_SECOND	(drv_usectohz(1000000))
117 
118 /*
119  * The data should be "quiet" for this interval (in seconds) before the
120  * vhci cached data is flushed to the disk.
121  */
122 static int mdi_vhcache_flush_delay = 10;
123 
124 /* number of seconds the vhcache flush daemon will sleep idle before exiting */
125 static int mdi_vhcache_flush_daemon_idle_time = 60;
126 
127 /*
128  * MDI falls back to discovery of all paths when a bus_config_one fails.
129  * The following parameters can be used to tune this operation.
130  *
131  * mdi_path_discovery_boot
132  *	Number of times path discovery will be attempted during early boot.
133  *	Probably there is no reason to ever set this value to greater than one.
134  *
135  * mdi_path_discovery_postboot
136  *	Number of times path discovery will be attempted after early boot.
137  *	Set it to a minimum of two to allow for discovery of iscsi paths which
138  *	may happen very late during booting.
139  *
140  * mdi_path_discovery_interval
141  *	Minimum number of seconds MDI will wait between successive discovery
142  *	of all paths. Set it to -1 to disable discovery of all paths.
143  */
144 static int mdi_path_discovery_boot = 1;
145 static int mdi_path_discovery_postboot = 2;
146 static int mdi_path_discovery_interval = 10;
147 
148 /*
149  * number of seconds the asynchronous configuration thread will sleep idle
150  * before exiting.
151  */
152 static int mdi_async_config_idle_time = 600;
153 
154 static int mdi_bus_config_cache_hash_size = 256;
155 
156 /* turns off multithreaded configuration for certain operations */
157 static int mdi_mtc_off = 0;
158 
159 /*
160  * MDI component property name/value string definitions
161  */
162 const char 		*mdi_component_prop = "mpxio-component";
163 const char		*mdi_component_prop_vhci = "vhci";
164 const char		*mdi_component_prop_phci = "phci";
165 const char		*mdi_component_prop_client = "client";
166 
167 /*
168  * MDI client global unique identifier property name
169  */
170 const char		*mdi_client_guid_prop = "client-guid";
171 
172 /*
173  * MDI client load balancing property name/value string definitions
174  */
175 const char		*mdi_load_balance = "load-balance";
176 const char		*mdi_load_balance_none = "none";
177 const char		*mdi_load_balance_rr = "round-robin";
178 const char		*mdi_load_balance_lba = "logical-block";
179 
180 /*
181  * Obsolete vHCI class definition; to be removed after Leadville update
182  */
183 const char *mdi_vhci_class_scsi = MDI_HCI_CLASS_SCSI;
184 
185 static char vhci_greeting[] =
186 	"\tThere already exists one vHCI driver for class %s\n"
187 	"\tOnly one vHCI driver for each class is allowed\n";
188 
189 /*
190  * Static function prototypes
191  */
192 static int		i_mdi_phci_offline(dev_info_t *, uint_t);
193 static int		i_mdi_client_offline(dev_info_t *, uint_t);
194 static int		i_mdi_phci_pre_detach(dev_info_t *, ddi_detach_cmd_t);
195 static void		i_mdi_phci_post_detach(dev_info_t *,
196 			    ddi_detach_cmd_t, int);
197 static int		i_mdi_client_pre_detach(dev_info_t *,
198 			    ddi_detach_cmd_t);
199 static void		i_mdi_client_post_detach(dev_info_t *,
200 			    ddi_detach_cmd_t, int);
201 static void		i_mdi_pm_hold_pip(mdi_pathinfo_t *);
202 static void		i_mdi_pm_rele_pip(mdi_pathinfo_t *);
203 static int 		i_mdi_lba_lb(mdi_client_t *ct,
204 			    mdi_pathinfo_t **ret_pip, struct buf *buf);
205 static void		i_mdi_pm_hold_client(mdi_client_t *, int);
206 static void		i_mdi_pm_rele_client(mdi_client_t *, int);
207 static void		i_mdi_pm_reset_client(mdi_client_t *);
208 static int		i_mdi_power_all_phci(mdi_client_t *);
209 static void		i_mdi_log_sysevent(dev_info_t *, char *, char *);
210 
211 
212 /*
213  * Internal mdi_pathinfo node functions
214  */
215 static void		i_mdi_pi_kstat_destroy(mdi_pathinfo_t *);
216 
217 static mdi_vhci_t	*i_mdi_vhci_class2vhci(char *);
218 static mdi_vhci_t	*i_devi_get_vhci(dev_info_t *);
219 static mdi_phci_t	*i_devi_get_phci(dev_info_t *);
220 static void		i_mdi_phci_lock(mdi_phci_t *, mdi_pathinfo_t *);
221 static void		i_mdi_phci_unlock(mdi_phci_t *);
222 static mdi_pathinfo_t	*i_mdi_pi_alloc(mdi_phci_t *, char *, mdi_client_t *);
223 static void		i_mdi_phci_add_path(mdi_phci_t *, mdi_pathinfo_t *);
224 static void		i_mdi_client_add_path(mdi_client_t *, mdi_pathinfo_t *);
225 static void		i_mdi_pi_free(mdi_phci_t *ph, mdi_pathinfo_t *,
226 			    mdi_client_t *);
227 static void		i_mdi_phci_remove_path(mdi_phci_t *, mdi_pathinfo_t *);
228 static void		i_mdi_client_remove_path(mdi_client_t *,
229 			    mdi_pathinfo_t *);
230 
231 static int		i_mdi_pi_state_change(mdi_pathinfo_t *,
232 			    mdi_pathinfo_state_t, int);
233 static int		i_mdi_pi_offline(mdi_pathinfo_t *, int);
234 static dev_info_t	*i_mdi_devinfo_create(mdi_vhci_t *, char *, char *,
235 			    char **, int);
236 static dev_info_t	*i_mdi_devinfo_find(mdi_vhci_t *, char *, char *);
237 static int		i_mdi_devinfo_remove(dev_info_t *, dev_info_t *, int);
238 static int		i_mdi_is_child_present(dev_info_t *, dev_info_t *);
239 static mdi_client_t	*i_mdi_client_alloc(mdi_vhci_t *, char *, char *);
240 static void		i_mdi_client_enlist_table(mdi_vhci_t *, mdi_client_t *);
241 static void		i_mdi_client_delist_table(mdi_vhci_t *, mdi_client_t *);
242 static mdi_client_t	*i_mdi_client_find(mdi_vhci_t *, char *, char *);
243 static void		i_mdi_client_update_state(mdi_client_t *);
244 static int		i_mdi_client_compute_state(mdi_client_t *,
245 			    mdi_phci_t *);
246 static void		i_mdi_client_lock(mdi_client_t *, mdi_pathinfo_t *);
247 static void		i_mdi_client_unlock(mdi_client_t *);
248 static int		i_mdi_client_free(mdi_vhci_t *, mdi_client_t *);
249 static mdi_client_t	*i_devi_get_client(dev_info_t *);
250 /*
251  * NOTE: this will be removed once the NWS files are changed to use the new
252  * mdi_{enable,disable}_path interfaces
253  */
254 static int		i_mdi_pi_enable_disable(dev_info_t *, dev_info_t *,
255 				int, int);
256 static mdi_pathinfo_t 	*i_mdi_enable_disable_path(mdi_pathinfo_t *pip,
257 				mdi_vhci_t *vh, int flags, int op);
258 /*
259  * Failover related function prototypes
260  */
261 static int		i_mdi_failover(void *);
262 
263 /*
264  * misc internal functions
265  */
266 static int		i_mdi_get_hash_key(char *);
267 static int		i_map_nvlist_error_to_mdi(int);
268 static void		i_mdi_report_path_state(mdi_client_t *,
269 			    mdi_pathinfo_t *);
270 
271 static void		setup_vhci_cache(mdi_vhci_t *);
272 static int		destroy_vhci_cache(mdi_vhci_t *);
273 static int		stop_vhcache_async_threads(mdi_vhci_config_t *);
274 static boolean_t	stop_vhcache_flush_thread(void *, int);
275 static void		free_string_array(char **, int);
276 static void		free_vhcache_phci(mdi_vhcache_phci_t *);
277 static void		free_vhcache_pathinfo(mdi_vhcache_pathinfo_t *);
278 static void		free_vhcache_client(mdi_vhcache_client_t *);
279 static int		mainnvl_to_vhcache(mdi_vhci_cache_t *, nvlist_t *);
280 static nvlist_t		*vhcache_to_mainnvl(mdi_vhci_cache_t *);
281 static void		vhcache_phci_add(mdi_vhci_config_t *, mdi_phci_t *);
282 static void		vhcache_phci_remove(mdi_vhci_config_t *, mdi_phci_t *);
283 static void		vhcache_pi_add(mdi_vhci_config_t *,
284 			    struct mdi_pathinfo *);
285 static void		vhcache_pi_remove(mdi_vhci_config_t *,
286 			    struct mdi_pathinfo *);
287 static void		free_phclient_path_list(mdi_phys_path_t *);
288 static void		sort_vhcache_paths(mdi_vhcache_client_t *);
289 static int		flush_vhcache(mdi_vhci_config_t *, int);
290 static void		vhcache_dirty(mdi_vhci_config_t *);
291 static void		free_async_client_config(mdi_async_client_config_t *);
292 static void		single_threaded_vhconfig_enter(mdi_vhci_config_t *);
293 static void		single_threaded_vhconfig_exit(mdi_vhci_config_t *);
294 static nvlist_t		*read_on_disk_vhci_cache(char *);
295 extern int		fread_nvlist(char *, nvlist_t **);
296 extern int		fwrite_nvlist(char *, nvlist_t *);
297 
298 /* called once when first vhci registers with mdi */
299 static void
300 i_mdi_init()
301 {
302 	static int initialized = 0;
303 
304 	if (initialized)
305 		return;
306 	initialized = 1;
307 
308 	mutex_init(&mdi_mutex, NULL, MUTEX_DEFAULT, NULL);
309 	/*
310 	 * Create our taskq resources
311 	 */
312 	mdi_taskq = taskq_create("mdi_taskq", mdi_taskq_n_threads,
313 	    MDI_TASKQ_PRI, MDI_TASKQ_MINALLOC, MDI_TASKQ_MAXALLOC,
314 	    TASKQ_PREPOPULATE | TASKQ_CPR_SAFE);
315 	ASSERT(mdi_taskq != NULL);	/* taskq_create never fails */
316 }
317 
318 /*
319  * mdi_get_component_type():
320  *		Return mpxio component type
321  * Return Values:
322  *		MDI_COMPONENT_NONE
323  *		MDI_COMPONENT_VHCI
324  *		MDI_COMPONENT_PHCI
325  *		MDI_COMPONENT_CLIENT
326  * XXX This doesn't work under multi-level MPxIO and should be
327  *	removed when clients migrate mdi_component_is_*() interfaces.
328  */
329 int
330 mdi_get_component_type(dev_info_t *dip)
331 {
332 	return (DEVI(dip)->devi_mdi_component);
333 }
334 
335 /*
336  * mdi_vhci_register():
337  *		Register a vHCI module with the mpxio framework
338  *		mdi_vhci_register() is called by vHCI drivers to register the
339  *		'class_driver' vHCI driver and its MDI entrypoints with the
340  *		mpxio framework.  The vHCI driver must call this interface as
341  *		part of its attach(9e) handler.
342  *		Competing threads may try to attach mdi_vhci_register() as
343  *		the vHCI drivers are loaded and attached as a result of pHCI
344  *		driver instance registration (mdi_phci_register()) with the
345  *		framework.
346  * Return Values:
347  *		MDI_SUCCESS
348  *		MDI_FAILURE
349  */
350 /*ARGSUSED*/
351 int
352 mdi_vhci_register(char *class, dev_info_t *vdip, mdi_vhci_ops_t *vops,
353     int flags)
354 {
355 	mdi_vhci_t		*vh = NULL;
356 
357 	ASSERT(vops->vo_revision == MDI_VHCI_OPS_REV);
358 	ASSERT(DEVI_BUSY_OWNED(ddi_get_parent(vdip)));
359 
360 	i_mdi_init();
361 
362 	mutex_enter(&mdi_mutex);
363 	/*
364 	 * Scan for already registered vhci
365 	 */
366 	for (vh = mdi_vhci_head; vh != NULL; vh = vh->vh_next) {
367 		if (strcmp(vh->vh_class, class) == 0) {
368 			/*
369 			 * vHCI has already been created.  Check for valid
370 			 * vHCI ops registration.  We only support one vHCI
371 			 * module per class
372 			 */
373 			if (vh->vh_ops != NULL) {
374 				mutex_exit(&mdi_mutex);
375 				cmn_err(CE_NOTE, vhci_greeting, class);
376 				return (MDI_FAILURE);
377 			}
378 			break;
379 		}
380 	}
381 
382 	/*
383 	 * if not yet created, create the vHCI component
384 	 */
385 	if (vh == NULL) {
386 		struct client_hash	*hash = NULL;
387 		char			*load_balance;
388 
389 		/*
390 		 * Allocate and initialize the mdi extensions
391 		 */
392 		vh = kmem_zalloc(sizeof (mdi_vhci_t), KM_SLEEP);
393 		hash = kmem_zalloc(mdi_client_table_size * sizeof (*hash),
394 		    KM_SLEEP);
395 		vh->vh_client_table = hash;
396 		vh->vh_class = kmem_zalloc(strlen(class) + 1, KM_SLEEP);
397 		(void) strcpy(vh->vh_class, class);
398 		vh->vh_lb = LOAD_BALANCE_RR;
399 		if (ddi_prop_lookup_string(DDI_DEV_T_ANY, vdip,
400 		    0, LOAD_BALANCE_PROP, &load_balance) == DDI_SUCCESS) {
401 			if (strcmp(load_balance, LOAD_BALANCE_PROP_NONE) == 0) {
402 				vh->vh_lb = LOAD_BALANCE_NONE;
403 			} else if (strcmp(load_balance, LOAD_BALANCE_PROP_LBA)
404 				    == 0) {
405 				vh->vh_lb = LOAD_BALANCE_LBA;
406 			}
407 			ddi_prop_free(load_balance);
408 		}
409 
410 		mutex_init(&vh->vh_phci_mutex, NULL, MUTEX_DEFAULT, NULL);
411 		mutex_init(&vh->vh_client_mutex, NULL, MUTEX_DEFAULT, NULL);
412 
413 		/*
414 		 * Store the vHCI ops vectors
415 		 */
416 		vh->vh_dip = vdip;
417 		vh->vh_ops = vops;
418 
419 		setup_vhci_cache(vh);
420 
421 		if (mdi_vhci_head == NULL) {
422 			mdi_vhci_head = vh;
423 		}
424 		if (mdi_vhci_tail) {
425 			mdi_vhci_tail->vh_next = vh;
426 		}
427 		mdi_vhci_tail = vh;
428 		mdi_vhci_count++;
429 	}
430 
431 	/*
432 	 * Claim the devfs node as a vhci component
433 	 */
434 	DEVI(vdip)->devi_mdi_component |= MDI_COMPONENT_VHCI;
435 
436 	/*
437 	 * Initialize our back reference from dev_info node
438 	 */
439 	DEVI(vdip)->devi_mdi_xhci = (caddr_t)vh;
440 	mutex_exit(&mdi_mutex);
441 	return (MDI_SUCCESS);
442 }
443 
444 /*
445  * mdi_vhci_unregister():
446  *		Unregister a vHCI module from mpxio framework
447  *		mdi_vhci_unregister() is called from the detach(9E) entrypoint
448  * 		of a vhci to unregister it from the framework.
449  * Return Values:
450  *		MDI_SUCCESS
451  *		MDI_FAILURE
452  */
453 /*ARGSUSED*/
454 int
455 mdi_vhci_unregister(dev_info_t *vdip, int flags)
456 {
457 	mdi_vhci_t	*found, *vh, *prev = NULL;
458 
459 	ASSERT(DEVI_BUSY_OWNED(ddi_get_parent(vdip)));
460 
461 	/*
462 	 * Check for invalid VHCI
463 	 */
464 	if ((vh = i_devi_get_vhci(vdip)) == NULL)
465 		return (MDI_FAILURE);
466 
467 	/*
468 	 * Scan the list of registered vHCIs for a match
469 	 */
470 	mutex_enter(&mdi_mutex);
471 	for (found = mdi_vhci_head; found != NULL; found = found->vh_next) {
472 		if (found == vh)
473 			break;
474 		prev = found;
475 	}
476 
477 	if (found == NULL) {
478 		mutex_exit(&mdi_mutex);
479 		return (MDI_FAILURE);
480 	}
481 
482 	/*
483 	 * Check the vHCI, pHCI and client count. All the pHCIs and clients
484 	 * should have been unregistered, before a vHCI can be
485 	 * unregistered.
486 	 */
487 	MDI_VHCI_PHCI_LOCK(vh);
488 	if (vh->vh_refcnt || vh->vh_phci_count || vh->vh_client_count) {
489 		MDI_VHCI_PHCI_UNLOCK(vh);
490 		mutex_exit(&mdi_mutex);
491 		return (MDI_FAILURE);
492 	}
493 	MDI_VHCI_PHCI_UNLOCK(vh);
494 
495 	if (destroy_vhci_cache(vh) != MDI_SUCCESS) {
496 		mutex_exit(&mdi_mutex);
497 		return (MDI_FAILURE);
498 	}
499 
500 	/*
501 	 * Remove the vHCI from the global list
502 	 */
503 	if (vh == mdi_vhci_head) {
504 		mdi_vhci_head = vh->vh_next;
505 	} else {
506 		prev->vh_next = vh->vh_next;
507 	}
508 	if (vh == mdi_vhci_tail) {
509 		mdi_vhci_tail = prev;
510 	}
511 	mdi_vhci_count--;
512 	mutex_exit(&mdi_mutex);
513 
514 	vh->vh_ops = NULL;
515 	DEVI(vdip)->devi_mdi_component &= ~MDI_COMPONENT_VHCI;
516 	DEVI(vdip)->devi_mdi_xhci = NULL;
517 	kmem_free(vh->vh_class, strlen(vh->vh_class)+1);
518 	kmem_free(vh->vh_client_table,
519 	    mdi_client_table_size * sizeof (struct client_hash));
520 	mutex_destroy(&vh->vh_phci_mutex);
521 	mutex_destroy(&vh->vh_client_mutex);
522 
523 	kmem_free(vh, sizeof (mdi_vhci_t));
524 	return (MDI_SUCCESS);
525 }
526 
527 /*
528  * i_mdi_vhci_class2vhci():
529  *		Look for a matching vHCI module given a vHCI class name
530  * Return Values:
531  *		Handle to a vHCI component
532  *		NULL
533  */
534 static mdi_vhci_t *
535 i_mdi_vhci_class2vhci(char *class)
536 {
537 	mdi_vhci_t	*vh = NULL;
538 
539 	ASSERT(!MUTEX_HELD(&mdi_mutex));
540 
541 	mutex_enter(&mdi_mutex);
542 	for (vh = mdi_vhci_head; vh != NULL; vh = vh->vh_next) {
543 		if (strcmp(vh->vh_class, class) == 0) {
544 			break;
545 		}
546 	}
547 	mutex_exit(&mdi_mutex);
548 	return (vh);
549 }
550 
551 /*
552  * i_devi_get_vhci():
553  *		Utility function to get the handle to a vHCI component
554  * Return Values:
555  *		Handle to a vHCI component
556  *		NULL
557  */
558 mdi_vhci_t *
559 i_devi_get_vhci(dev_info_t *vdip)
560 {
561 	mdi_vhci_t	*vh = NULL;
562 	if (MDI_VHCI(vdip)) {
563 		vh = (mdi_vhci_t *)DEVI(vdip)->devi_mdi_xhci;
564 	}
565 	return (vh);
566 }
567 
568 /*
569  * mdi_phci_register():
570  *		Register a pHCI module with mpxio framework
571  *		mdi_phci_register() is called by pHCI drivers to register with
572  *		the mpxio framework and a specific 'class_driver' vHCI.  The
573  *		pHCI driver must call this interface as part of its attach(9e)
574  *		handler.
575  * Return Values:
576  *		MDI_SUCCESS
577  *		MDI_FAILURE
578  */
579 /*ARGSUSED*/
580 int
581 mdi_phci_register(char *class, dev_info_t *pdip, int flags)
582 {
583 	mdi_phci_t		*ph;
584 	mdi_vhci_t		*vh;
585 	char			*data;
586 	char			*pathname;
587 
588 	/*
589 	 * Some subsystems, like fcp, perform pHCI registration from a
590 	 * different thread than the one doing the pHCI attach(9E) - the
591 	 * driver attach code is waiting for this other thread to complete.
592 	 * This means we can only ASSERT DEVI_BUSY_CHANGING of parent
593 	 * (indicating that some thread has done an ndi_devi_enter of parent)
594 	 * not DEVI_BUSY_OWNED (which would indicate that we did the enter).
595 	 */
596 	ASSERT(DEVI_BUSY_CHANGING(ddi_get_parent(pdip)));
597 
598 	pathname = kmem_zalloc(MAXPATHLEN, KM_SLEEP);
599 	(void) ddi_pathname(pdip, pathname);
600 
601 	/*
602 	 * Check for mpxio-disable property. Enable mpxio if the property is
603 	 * missing or not set to "yes".
604 	 * If the property is set to "yes" then emit a brief message.
605 	 */
606 	if ((ddi_prop_lookup_string(DDI_DEV_T_ANY, pdip, 0, "mpxio-disable",
607 	    &data) == DDI_SUCCESS)) {
608 		if (strcmp(data, "yes") == 0) {
609 			MDI_DEBUG(1, (CE_CONT, pdip,
610 			    "?%s (%s%d) multipath capabilities "
611 			    "disabled via %s.conf.\n", pathname,
612 			    ddi_driver_name(pdip), ddi_get_instance(pdip),
613 			    ddi_driver_name(pdip)));
614 			ddi_prop_free(data);
615 			kmem_free(pathname, MAXPATHLEN);
616 			return (MDI_FAILURE);
617 		}
618 		ddi_prop_free(data);
619 	}
620 
621 	kmem_free(pathname, MAXPATHLEN);
622 
623 	/*
624 	 * Search for a matching vHCI
625 	 */
626 	vh = (mdi_vhci_t *)i_mdi_vhci_class2vhci(class);
627 	if (vh == NULL) {
628 		return (MDI_FAILURE);
629 	}
630 
631 	ph = kmem_zalloc(sizeof (mdi_phci_t), KM_SLEEP);
632 	mutex_init(&ph->ph_mutex, NULL, MUTEX_DEFAULT, NULL);
633 	ph->ph_dip = pdip;
634 	ph->ph_vhci = vh;
635 	ph->ph_next = NULL;
636 	ph->ph_unstable = 0;
637 	ph->ph_vprivate = 0;
638 	cv_init(&ph->ph_unstable_cv, NULL, CV_DRIVER, NULL);
639 
640 	MDI_PHCI_LOCK(ph);
641 	MDI_PHCI_SET_POWER_UP(ph);
642 	MDI_PHCI_UNLOCK(ph);
643 	DEVI(pdip)->devi_mdi_component |= MDI_COMPONENT_PHCI;
644 	DEVI(pdip)->devi_mdi_xhci = (caddr_t)ph;
645 
646 	vhcache_phci_add(vh->vh_config, ph);
647 
648 	MDI_VHCI_PHCI_LOCK(vh);
649 	if (vh->vh_phci_head == NULL) {
650 		vh->vh_phci_head = ph;
651 	}
652 	if (vh->vh_phci_tail) {
653 		vh->vh_phci_tail->ph_next = ph;
654 	}
655 	vh->vh_phci_tail = ph;
656 	vh->vh_phci_count++;
657 	MDI_VHCI_PHCI_UNLOCK(vh);
658 
659 	i_mdi_log_sysevent(pdip, class, ESC_DDI_INITIATOR_REGISTER);
660 	return (MDI_SUCCESS);
661 }
662 
663 /*
664  * mdi_phci_unregister():
665  *		Unregister a pHCI module from mpxio framework
666  *		mdi_phci_unregister() is called by the pHCI drivers from their
667  *		detach(9E) handler to unregister their instances from the
668  *		framework.
669  * Return Values:
670  *		MDI_SUCCESS
671  *		MDI_FAILURE
672  */
673 /*ARGSUSED*/
674 int
675 mdi_phci_unregister(dev_info_t *pdip, int flags)
676 {
677 	mdi_vhci_t		*vh;
678 	mdi_phci_t		*ph;
679 	mdi_phci_t		*tmp;
680 	mdi_phci_t		*prev = NULL;
681 
682 	ASSERT(DEVI_BUSY_CHANGING(ddi_get_parent(pdip)));
683 
684 	ph = i_devi_get_phci(pdip);
685 	if (ph == NULL) {
686 		MDI_DEBUG(1, (CE_WARN, pdip,
687 		    "!pHCI unregister: Not a valid pHCI"));
688 		return (MDI_FAILURE);
689 	}
690 
691 	vh = ph->ph_vhci;
692 	ASSERT(vh != NULL);
693 	if (vh == NULL) {
694 		MDI_DEBUG(1, (CE_WARN, pdip,
695 		    "!pHCI unregister: Not a valid vHCI"));
696 		return (MDI_FAILURE);
697 	}
698 
699 	MDI_VHCI_PHCI_LOCK(vh);
700 	tmp = vh->vh_phci_head;
701 	while (tmp) {
702 		if (tmp == ph) {
703 			break;
704 		}
705 		prev = tmp;
706 		tmp = tmp->ph_next;
707 	}
708 
709 	if (ph == vh->vh_phci_head) {
710 		vh->vh_phci_head = ph->ph_next;
711 	} else {
712 		prev->ph_next = ph->ph_next;
713 	}
714 
715 	if (ph == vh->vh_phci_tail) {
716 		vh->vh_phci_tail = prev;
717 	}
718 
719 	vh->vh_phci_count--;
720 	MDI_VHCI_PHCI_UNLOCK(vh);
721 
722 	i_mdi_log_sysevent(pdip, ph->ph_vhci->vh_class,
723 	    ESC_DDI_INITIATOR_UNREGISTER);
724 	vhcache_phci_remove(vh->vh_config, ph);
725 	cv_destroy(&ph->ph_unstable_cv);
726 	mutex_destroy(&ph->ph_mutex);
727 	kmem_free(ph, sizeof (mdi_phci_t));
728 	DEVI(pdip)->devi_mdi_component &= ~MDI_COMPONENT_PHCI;
729 	DEVI(pdip)->devi_mdi_xhci = NULL;
730 	return (MDI_SUCCESS);
731 }
732 
733 /*
734  * i_devi_get_phci():
735  * 		Utility function to return the phci extensions.
736  */
737 static mdi_phci_t *
738 i_devi_get_phci(dev_info_t *pdip)
739 {
740 	mdi_phci_t	*ph = NULL;
741 	if (MDI_PHCI(pdip)) {
742 		ph = (mdi_phci_t *)DEVI(pdip)->devi_mdi_xhci;
743 	}
744 	return (ph);
745 }
746 
747 /*
748  * Single thread mdi entry into devinfo node for modifying its children.
749  * If necessary we perform an ndi_devi_enter of the vHCI before doing
750  * an ndi_devi_enter of 'dip'.  We maintain circular in two parts: one
751  * for the vHCI and one for the pHCI.
752  */
753 void
754 mdi_devi_enter(dev_info_t *phci_dip, int *circular)
755 {
756 	dev_info_t	*vdip;
757 	int		vcircular, pcircular;
758 
759 	/* Verify calling context */
760 	ASSERT(MDI_PHCI(phci_dip));
761 	vdip = mdi_devi_get_vdip(phci_dip);
762 	ASSERT(vdip);			/* A pHCI always has a vHCI */
763 
764 	/*
765 	 * If pHCI is detaching then the framework has already entered the
766 	 * vHCI on a threads that went down the code path leading to
767 	 * detach_node().  This framework enter of the vHCI during pHCI
768 	 * detach is done to avoid deadlock with vHCI power management
769 	 * operations which enter the vHCI and the enter down the path
770 	 * to the pHCI. If pHCI is detaching then we piggyback this calls
771 	 * enter of the vHCI on frameworks vHCI enter that has already
772 	 * occurred - this is OK because we know that the framework thread
773 	 * doing detach is waiting for our completion.
774 	 *
775 	 * We should DEVI_IS_DETACHING under an enter of the parent to avoid
776 	 * race with detach - but we can't do that because the framework has
777 	 * already entered the parent, so we have some complexity instead.
778 	 */
779 	for (;;) {
780 		if (ndi_devi_tryenter(vdip, &vcircular)) {
781 			ASSERT(vcircular != -1);
782 			if (DEVI_IS_DETACHING(phci_dip)) {
783 				ndi_devi_exit(vdip, vcircular);
784 				vcircular = -1;
785 			}
786 			break;
787 		} else if (DEVI_IS_DETACHING(phci_dip)) {
788 			vcircular = -1;
789 			break;
790 		} else {
791 			delay(1);
792 		}
793 	}
794 
795 	ndi_devi_enter(phci_dip, &pcircular);
796 	*circular = (vcircular << 16) | (pcircular & 0xFFFF);
797 }
798 
799 /*
800  * Release mdi_devi_enter or successful mdi_devi_tryenter.
801  */
802 void
803 mdi_devi_exit(dev_info_t *phci_dip, int circular)
804 {
805 	dev_info_t	*vdip;
806 	int		vcircular, pcircular;
807 
808 	/* Verify calling context */
809 	ASSERT(MDI_PHCI(phci_dip));
810 	vdip = mdi_devi_get_vdip(phci_dip);
811 	ASSERT(vdip);			/* A pHCI always has a vHCI */
812 
813 	/* extract two circular recursion values from single int */
814 	pcircular = (short)(circular & 0xFFFF);
815 	vcircular = (short)((circular >> 16) & 0xFFFF);
816 
817 	ndi_devi_exit(phci_dip, pcircular);
818 	if (vcircular != -1)
819 		ndi_devi_exit(vdip, vcircular);
820 }
821 
822 /*
823  * The functions mdi_devi_exit_phci() and mdi_devi_enter_phci() are used
824  * around a pHCI drivers calls to mdi_pi_online/offline, after holding
825  * the pathinfo node via mdi_hold_path/mdi_rele_path, to avoid deadlock
826  * with vHCI power management code during path online/offline.  Each
827  * mdi_devi_exit_phci must have a matching mdi_devi_enter_phci, and both must
828  * occur within the scope of an active mdi_devi_enter that establishes the
829  * circular value.
830  */
831 void
832 mdi_devi_exit_phci(dev_info_t *phci_dip, int circular)
833 {
834 	int		pcircular;
835 
836 	/* Verify calling context */
837 	ASSERT(MDI_PHCI(phci_dip));
838 
839 	pcircular = (short)(circular & 0xFFFF);
840 	ndi_devi_exit(phci_dip, pcircular);
841 }
842 
843 void
844 mdi_devi_enter_phci(dev_info_t *phci_dip, int *circular)
845 {
846 	int		pcircular;
847 
848 	/* Verify calling context */
849 	ASSERT(MDI_PHCI(phci_dip));
850 
851 	ndi_devi_enter(phci_dip, &pcircular);
852 
853 	/* verify matching mdi_devi_exit_phci/mdi_devi_enter_phci use */
854 	ASSERT(pcircular == ((short)(*circular & 0xFFFF)));
855 }
856 
857 /*
858  * mdi_devi_get_vdip():
859  *		given a pHCI dip return vHCI dip
860  */
861 dev_info_t *
862 mdi_devi_get_vdip(dev_info_t *pdip)
863 {
864 	mdi_phci_t	*ph;
865 
866 	ph = i_devi_get_phci(pdip);
867 	if (ph && ph->ph_vhci)
868 		return (ph->ph_vhci->vh_dip);
869 	return (NULL);
870 }
871 
872 /*
873  * mdi_devi_pdip_entered():
874  *		Return 1 if we are vHCI and have done an ndi_devi_enter
875  *		of a pHCI
876  */
877 int
878 mdi_devi_pdip_entered(dev_info_t *vdip)
879 {
880 	mdi_vhci_t	*vh;
881 	mdi_phci_t	*ph;
882 
883 	vh = i_devi_get_vhci(vdip);
884 	if (vh == NULL)
885 		return (0);
886 
887 	MDI_VHCI_PHCI_LOCK(vh);
888 	ph = vh->vh_phci_head;
889 	while (ph) {
890 		if (ph->ph_dip && DEVI_BUSY_OWNED(ph->ph_dip)) {
891 			MDI_VHCI_PHCI_UNLOCK(vh);
892 			return (1);
893 		}
894 		ph = ph->ph_next;
895 	}
896 	MDI_VHCI_PHCI_UNLOCK(vh);
897 	return (0);
898 }
899 
900 /*
901  * mdi_phci_path2devinfo():
902  * 		Utility function to search for a valid phci device given
903  *		the devfs pathname.
904  */
905 dev_info_t *
906 mdi_phci_path2devinfo(dev_info_t *vdip, caddr_t pathname)
907 {
908 	char		*temp_pathname;
909 	mdi_vhci_t	*vh;
910 	mdi_phci_t	*ph;
911 	dev_info_t 	*pdip = NULL;
912 
913 	vh = i_devi_get_vhci(vdip);
914 	ASSERT(vh != NULL);
915 
916 	if (vh == NULL) {
917 		/*
918 		 * Invalid vHCI component, return failure
919 		 */
920 		return (NULL);
921 	}
922 
923 	temp_pathname = kmem_zalloc(MAXPATHLEN, KM_SLEEP);
924 	MDI_VHCI_PHCI_LOCK(vh);
925 	ph = vh->vh_phci_head;
926 	while (ph != NULL) {
927 		pdip = ph->ph_dip;
928 		ASSERT(pdip != NULL);
929 		*temp_pathname = '\0';
930 		(void) ddi_pathname(pdip, temp_pathname);
931 		if (strcmp(temp_pathname, pathname) == 0) {
932 			break;
933 		}
934 		ph = ph->ph_next;
935 	}
936 	if (ph == NULL) {
937 		pdip = NULL;
938 	}
939 	MDI_VHCI_PHCI_UNLOCK(vh);
940 	kmem_free(temp_pathname, MAXPATHLEN);
941 	return (pdip);
942 }
943 
944 /*
945  * mdi_phci_get_path_count():
946  * 		get number of path information nodes associated with a given
947  *		pHCI device.
948  */
949 int
950 mdi_phci_get_path_count(dev_info_t *pdip)
951 {
952 	mdi_phci_t	*ph;
953 	int		count = 0;
954 
955 	ph = i_devi_get_phci(pdip);
956 	if (ph != NULL) {
957 		count = ph->ph_path_count;
958 	}
959 	return (count);
960 }
961 
962 /*
963  * i_mdi_phci_lock():
964  *		Lock a pHCI device
965  * Return Values:
966  *		None
967  * Note:
968  *		The default locking order is:
969  *		_NOTE(LOCK_ORDER(mdi_phci::ph_mutex mdi_pathinfo::pi_mutex))
970  *		But there are number of situations where locks need to be
971  *		grabbed in reverse order.  This routine implements try and lock
972  *		mechanism depending on the requested parameter option.
973  */
974 static void
975 i_mdi_phci_lock(mdi_phci_t *ph, mdi_pathinfo_t *pip)
976 {
977 	if (pip) {
978 		/* Reverse locking is requested. */
979 		while (MDI_PHCI_TRYLOCK(ph) == 0) {
980 			/*
981 			 * tryenter failed. Try to grab again
982 			 * after a small delay
983 			 */
984 			MDI_PI_HOLD(pip);
985 			MDI_PI_UNLOCK(pip);
986 			delay(1);
987 			MDI_PI_LOCK(pip);
988 			MDI_PI_RELE(pip);
989 		}
990 	} else {
991 		MDI_PHCI_LOCK(ph);
992 	}
993 }
994 
995 /*
996  * i_mdi_phci_unlock():
997  *		Unlock the pHCI component
998  */
999 static void
1000 i_mdi_phci_unlock(mdi_phci_t *ph)
1001 {
1002 	MDI_PHCI_UNLOCK(ph);
1003 }
1004 
1005 /*
1006  * i_mdi_devinfo_create():
1007  *		create client device's devinfo node
1008  * Return Values:
1009  *		dev_info
1010  *		NULL
1011  * Notes:
1012  */
1013 static dev_info_t *
1014 i_mdi_devinfo_create(mdi_vhci_t *vh, char *name, char *guid,
1015 	char **compatible, int ncompatible)
1016 {
1017 	dev_info_t *cdip = NULL;
1018 
1019 	ASSERT(MDI_VHCI_CLIENT_LOCKED(vh));
1020 
1021 	/* Verify for duplicate entry */
1022 	cdip = i_mdi_devinfo_find(vh, name, guid);
1023 	ASSERT(cdip == NULL);
1024 	if (cdip) {
1025 		cmn_err(CE_WARN,
1026 		    "i_mdi_devinfo_create: client dip %p already exists",
1027 			(void *)cdip);
1028 	}
1029 
1030 	ndi_devi_alloc_sleep(vh->vh_dip, name, DEVI_SID_NODEID, &cdip);
1031 	if (cdip == NULL)
1032 		goto fail;
1033 
1034 	/*
1035 	 * Create component type and Global unique identifier
1036 	 * properties
1037 	 */
1038 	if (ndi_prop_update_string(DDI_DEV_T_NONE, cdip,
1039 	    MDI_CLIENT_GUID_PROP, guid) != DDI_PROP_SUCCESS) {
1040 		goto fail;
1041 	}
1042 
1043 	/* Decorate the node with compatible property */
1044 	if (compatible &&
1045 	    (ndi_prop_update_string_array(DDI_DEV_T_NONE, cdip,
1046 	    "compatible", compatible, ncompatible) != DDI_PROP_SUCCESS)) {
1047 		goto fail;
1048 	}
1049 
1050 	return (cdip);
1051 
1052 fail:
1053 	if (cdip) {
1054 		(void) ndi_prop_remove_all(cdip);
1055 		(void) ndi_devi_free(cdip);
1056 	}
1057 	return (NULL);
1058 }
1059 
1060 /*
1061  * i_mdi_devinfo_find():
1062  *		Find a matching devinfo node for given client node name
1063  *		and its guid.
1064  * Return Values:
1065  *		Handle to a dev_info node or NULL
1066  */
1067 static dev_info_t *
1068 i_mdi_devinfo_find(mdi_vhci_t *vh, caddr_t name, char *guid)
1069 {
1070 	char			*data;
1071 	dev_info_t 		*cdip = NULL;
1072 	dev_info_t 		*ndip = NULL;
1073 	int			circular;
1074 
1075 	ndi_devi_enter(vh->vh_dip, &circular);
1076 	ndip = (dev_info_t *)DEVI(vh->vh_dip)->devi_child;
1077 	while ((cdip = ndip) != NULL) {
1078 		ndip = (dev_info_t *)DEVI(cdip)->devi_sibling;
1079 
1080 		if (strcmp(DEVI(cdip)->devi_node_name, name)) {
1081 			continue;
1082 		}
1083 
1084 		if (ddi_prop_lookup_string(DDI_DEV_T_ANY, cdip,
1085 		    DDI_PROP_DONTPASS, MDI_CLIENT_GUID_PROP,
1086 		    &data) != DDI_PROP_SUCCESS) {
1087 			continue;
1088 		}
1089 
1090 		if (strcmp(data, guid) != 0) {
1091 			ddi_prop_free(data);
1092 			continue;
1093 		}
1094 		ddi_prop_free(data);
1095 		break;
1096 	}
1097 	ndi_devi_exit(vh->vh_dip, circular);
1098 	return (cdip);
1099 }
1100 
1101 /*
1102  * i_mdi_devinfo_remove():
1103  *		Remove a client device node
1104  */
1105 static int
1106 i_mdi_devinfo_remove(dev_info_t *vdip, dev_info_t *cdip, int flags)
1107 {
1108 	int	rv = MDI_SUCCESS;
1109 
1110 	if (i_mdi_is_child_present(vdip, cdip) == MDI_SUCCESS ||
1111 	    (flags & MDI_CLIENT_FLAGS_DEV_NOT_SUPPORTED)) {
1112 		rv = ndi_devi_offline(cdip, NDI_DEVI_REMOVE);
1113 		if (rv != NDI_SUCCESS) {
1114 			MDI_DEBUG(1, (CE_NOTE, NULL, "!i_mdi_devinfo_remove:"
1115 			    " failed. cdip = %p\n", (void *)cdip));
1116 		}
1117 		/*
1118 		 * Convert to MDI error code
1119 		 */
1120 		switch (rv) {
1121 		case NDI_SUCCESS:
1122 			rv = MDI_SUCCESS;
1123 			break;
1124 		case NDI_BUSY:
1125 			rv = MDI_BUSY;
1126 			break;
1127 		default:
1128 			rv = MDI_FAILURE;
1129 			break;
1130 		}
1131 	}
1132 	return (rv);
1133 }
1134 
1135 /*
1136  * i_devi_get_client()
1137  *		Utility function to get mpxio component extensions
1138  */
1139 static mdi_client_t *
1140 i_devi_get_client(dev_info_t *cdip)
1141 {
1142 	mdi_client_t	*ct = NULL;
1143 
1144 	if (MDI_CLIENT(cdip)) {
1145 		ct = (mdi_client_t *)DEVI(cdip)->devi_mdi_client;
1146 	}
1147 	return (ct);
1148 }
1149 
1150 /*
1151  * i_mdi_is_child_present():
1152  *		Search for the presence of client device dev_info node
1153  */
1154 static int
1155 i_mdi_is_child_present(dev_info_t *vdip, dev_info_t *cdip)
1156 {
1157 	int		rv = MDI_FAILURE;
1158 	struct dev_info	*dip;
1159 	int		circular;
1160 
1161 	ndi_devi_enter(vdip, &circular);
1162 	dip = DEVI(vdip)->devi_child;
1163 	while (dip) {
1164 		if (dip == DEVI(cdip)) {
1165 			rv = MDI_SUCCESS;
1166 			break;
1167 		}
1168 		dip = dip->devi_sibling;
1169 	}
1170 	ndi_devi_exit(vdip, circular);
1171 	return (rv);
1172 }
1173 
1174 
1175 /*
1176  * i_mdi_client_lock():
1177  *		Grab client component lock
1178  * Return Values:
1179  *		None
1180  * Note:
1181  *		The default locking order is:
1182  *		_NOTE(LOCK_ORDER(mdi_client::ct_mutex mdi_pathinfo::pi_mutex))
1183  *		But there are number of situations where locks need to be
1184  *		grabbed in reverse order.  This routine implements try and lock
1185  *		mechanism depending on the requested parameter option.
1186  */
1187 static void
1188 i_mdi_client_lock(mdi_client_t *ct, mdi_pathinfo_t *pip)
1189 {
1190 	if (pip) {
1191 		/*
1192 		 * Reverse locking is requested.
1193 		 */
1194 		while (MDI_CLIENT_TRYLOCK(ct) == 0) {
1195 			/*
1196 			 * tryenter failed. Try to grab again
1197 			 * after a small delay
1198 			 */
1199 			MDI_PI_HOLD(pip);
1200 			MDI_PI_UNLOCK(pip);
1201 			delay(1);
1202 			MDI_PI_LOCK(pip);
1203 			MDI_PI_RELE(pip);
1204 		}
1205 	} else {
1206 		MDI_CLIENT_LOCK(ct);
1207 	}
1208 }
1209 
1210 /*
1211  * i_mdi_client_unlock():
1212  *		Unlock a client component
1213  */
1214 static void
1215 i_mdi_client_unlock(mdi_client_t *ct)
1216 {
1217 	MDI_CLIENT_UNLOCK(ct);
1218 }
1219 
1220 /*
1221  * i_mdi_client_alloc():
1222  * 		Allocate and initialize a client structure.  Caller should
1223  *		hold the vhci client lock.
1224  * Return Values:
1225  *		Handle to a client component
1226  */
1227 /*ARGSUSED*/
1228 static mdi_client_t *
1229 i_mdi_client_alloc(mdi_vhci_t *vh, char *name, char *lguid)
1230 {
1231 	mdi_client_t	*ct;
1232 
1233 	ASSERT(MDI_VHCI_CLIENT_LOCKED(vh));
1234 
1235 	/*
1236 	 * Allocate and initialize a component structure.
1237 	 */
1238 	ct = kmem_zalloc(sizeof (*ct), KM_SLEEP);
1239 	mutex_init(&ct->ct_mutex, NULL, MUTEX_DEFAULT, NULL);
1240 	ct->ct_hnext = NULL;
1241 	ct->ct_hprev = NULL;
1242 	ct->ct_dip = NULL;
1243 	ct->ct_vhci = vh;
1244 	ct->ct_drvname = kmem_alloc(strlen(name) + 1, KM_SLEEP);
1245 	(void) strcpy(ct->ct_drvname, name);
1246 	ct->ct_guid = kmem_alloc(strlen(lguid) + 1, KM_SLEEP);
1247 	(void) strcpy(ct->ct_guid, lguid);
1248 	ct->ct_cprivate = NULL;
1249 	ct->ct_vprivate = NULL;
1250 	ct->ct_flags = 0;
1251 	ct->ct_state = MDI_CLIENT_STATE_FAILED;
1252 	MDI_CLIENT_LOCK(ct);
1253 	MDI_CLIENT_SET_OFFLINE(ct);
1254 	MDI_CLIENT_SET_DETACH(ct);
1255 	MDI_CLIENT_SET_POWER_UP(ct);
1256 	MDI_CLIENT_UNLOCK(ct);
1257 	ct->ct_failover_flags = 0;
1258 	ct->ct_failover_status = 0;
1259 	cv_init(&ct->ct_failover_cv, NULL, CV_DRIVER, NULL);
1260 	ct->ct_unstable = 0;
1261 	cv_init(&ct->ct_unstable_cv, NULL, CV_DRIVER, NULL);
1262 	cv_init(&ct->ct_powerchange_cv, NULL, CV_DRIVER, NULL);
1263 	ct->ct_lb = vh->vh_lb;
1264 	ct->ct_lb_args =  kmem_zalloc(sizeof (client_lb_args_t), KM_SLEEP);
1265 	ct->ct_lb_args->region_size = LOAD_BALANCE_DEFAULT_REGION_SIZE;
1266 	ct->ct_path_count = 0;
1267 	ct->ct_path_head = NULL;
1268 	ct->ct_path_tail = NULL;
1269 	ct->ct_path_last = NULL;
1270 
1271 	/*
1272 	 * Add this client component to our client hash queue
1273 	 */
1274 	i_mdi_client_enlist_table(vh, ct);
1275 	return (ct);
1276 }
1277 
1278 /*
1279  * i_mdi_client_enlist_table():
1280  *		Attach the client device to the client hash table. Caller
1281  *		should hold the vhci client lock.
1282  */
1283 static void
1284 i_mdi_client_enlist_table(mdi_vhci_t *vh, mdi_client_t *ct)
1285 {
1286 	int 			index;
1287 	struct client_hash	*head;
1288 
1289 	ASSERT(MDI_VHCI_CLIENT_LOCKED(vh));
1290 
1291 	index = i_mdi_get_hash_key(ct->ct_guid);
1292 	head = &vh->vh_client_table[index];
1293 	ct->ct_hnext = (mdi_client_t *)head->ct_hash_head;
1294 	head->ct_hash_head = ct;
1295 	head->ct_hash_count++;
1296 	vh->vh_client_count++;
1297 }
1298 
1299 /*
1300  * i_mdi_client_delist_table():
1301  *		Attach the client device to the client hash table.
1302  *		Caller should hold the vhci client lock.
1303  */
1304 static void
1305 i_mdi_client_delist_table(mdi_vhci_t *vh, mdi_client_t *ct)
1306 {
1307 	int			index;
1308 	char			*guid;
1309 	struct client_hash 	*head;
1310 	mdi_client_t		*next;
1311 	mdi_client_t		*last;
1312 
1313 	ASSERT(MDI_VHCI_CLIENT_LOCKED(vh));
1314 
1315 	guid = ct->ct_guid;
1316 	index = i_mdi_get_hash_key(guid);
1317 	head = &vh->vh_client_table[index];
1318 
1319 	last = NULL;
1320 	next = (mdi_client_t *)head->ct_hash_head;
1321 	while (next != NULL) {
1322 		if (next == ct) {
1323 			break;
1324 		}
1325 		last = next;
1326 		next = next->ct_hnext;
1327 	}
1328 
1329 	if (next) {
1330 		head->ct_hash_count--;
1331 		if (last == NULL) {
1332 			head->ct_hash_head = ct->ct_hnext;
1333 		} else {
1334 			last->ct_hnext = ct->ct_hnext;
1335 		}
1336 		ct->ct_hnext = NULL;
1337 		vh->vh_client_count--;
1338 	}
1339 }
1340 
1341 
1342 /*
1343  * i_mdi_client_free():
1344  *		Free a client component
1345  */
1346 static int
1347 i_mdi_client_free(mdi_vhci_t *vh, mdi_client_t *ct)
1348 {
1349 	int		rv = MDI_SUCCESS;
1350 	int		flags = ct->ct_flags;
1351 	dev_info_t	*cdip;
1352 	dev_info_t	*vdip;
1353 
1354 	ASSERT(MDI_VHCI_CLIENT_LOCKED(vh));
1355 
1356 	vdip = vh->vh_dip;
1357 	cdip = ct->ct_dip;
1358 
1359 	(void) ndi_prop_remove(DDI_DEV_T_NONE, cdip, MDI_CLIENT_GUID_PROP);
1360 	DEVI(cdip)->devi_mdi_component &= ~MDI_COMPONENT_CLIENT;
1361 	DEVI(cdip)->devi_mdi_client = NULL;
1362 
1363 	/*
1364 	 * Clear out back ref. to dev_info_t node
1365 	 */
1366 	ct->ct_dip = NULL;
1367 
1368 	/*
1369 	 * Remove this client from our hash queue
1370 	 */
1371 	i_mdi_client_delist_table(vh, ct);
1372 
1373 	/*
1374 	 * Uninitialize and free the component
1375 	 */
1376 	kmem_free(ct->ct_drvname, strlen(ct->ct_drvname) + 1);
1377 	kmem_free(ct->ct_guid, strlen(ct->ct_guid) + 1);
1378 	kmem_free(ct->ct_lb_args, sizeof (client_lb_args_t));
1379 	cv_destroy(&ct->ct_failover_cv);
1380 	cv_destroy(&ct->ct_unstable_cv);
1381 	cv_destroy(&ct->ct_powerchange_cv);
1382 	mutex_destroy(&ct->ct_mutex);
1383 	kmem_free(ct, sizeof (*ct));
1384 
1385 	if (cdip != NULL) {
1386 		MDI_VHCI_CLIENT_UNLOCK(vh);
1387 		(void) i_mdi_devinfo_remove(vdip, cdip, flags);
1388 		MDI_VHCI_CLIENT_LOCK(vh);
1389 	}
1390 	return (rv);
1391 }
1392 
1393 /*
1394  * i_mdi_client_find():
1395  * 		Find the client structure corresponding to a given guid
1396  *		Caller should hold the vhci client lock.
1397  */
1398 static mdi_client_t *
1399 i_mdi_client_find(mdi_vhci_t *vh, char *cname, char *guid)
1400 {
1401 	int			index;
1402 	struct client_hash	*head;
1403 	mdi_client_t		*ct;
1404 
1405 	ASSERT(MDI_VHCI_CLIENT_LOCKED(vh));
1406 
1407 	index = i_mdi_get_hash_key(guid);
1408 	head = &vh->vh_client_table[index];
1409 
1410 	ct = head->ct_hash_head;
1411 	while (ct != NULL) {
1412 		if (strcmp(ct->ct_guid, guid) == 0 &&
1413 		    (cname == NULL || strcmp(ct->ct_drvname, cname) == 0)) {
1414 			break;
1415 		}
1416 		ct = ct->ct_hnext;
1417 	}
1418 	return (ct);
1419 }
1420 
1421 /*
1422  * i_mdi_client_update_state():
1423  *		Compute and update client device state
1424  * Notes:
1425  *		A client device can be in any of three possible states:
1426  *
1427  *		MDI_CLIENT_STATE_OPTIMAL - Client in optimal state with more
1428  *		one online/standby paths. Can tolerate failures.
1429  *		MDI_CLIENT_STATE_DEGRADED - Client device in degraded state with
1430  *		no alternate paths available as standby. A failure on the online
1431  *		would result in loss of access to device data.
1432  *		MDI_CLIENT_STATE_FAILED - Client device in failed state with
1433  *		no paths available to access the device.
1434  */
1435 static void
1436 i_mdi_client_update_state(mdi_client_t *ct)
1437 {
1438 	int state;
1439 
1440 	ASSERT(MDI_CLIENT_LOCKED(ct));
1441 	state = i_mdi_client_compute_state(ct, NULL);
1442 	MDI_CLIENT_SET_STATE(ct, state);
1443 }
1444 
1445 /*
1446  * i_mdi_client_compute_state():
1447  *		Compute client device state
1448  *
1449  *		mdi_phci_t *	Pointer to pHCI structure which should
1450  *				while computing the new value.  Used by
1451  *				i_mdi_phci_offline() to find the new
1452  *				client state after DR of a pHCI.
1453  */
1454 static int
1455 i_mdi_client_compute_state(mdi_client_t *ct, mdi_phci_t *ph)
1456 {
1457 	int		state;
1458 	int		online_count = 0;
1459 	int		standby_count = 0;
1460 	mdi_pathinfo_t	*pip, *next;
1461 
1462 	ASSERT(MDI_CLIENT_LOCKED(ct));
1463 	pip = ct->ct_path_head;
1464 	while (pip != NULL) {
1465 		MDI_PI_LOCK(pip);
1466 		next = (mdi_pathinfo_t *)MDI_PI(pip)->pi_client_link;
1467 		if (MDI_PI(pip)->pi_phci == ph) {
1468 			MDI_PI_UNLOCK(pip);
1469 			pip = next;
1470 			continue;
1471 		}
1472 
1473 		if ((MDI_PI(pip)->pi_state & MDI_PATHINFO_STATE_MASK)
1474 				== MDI_PATHINFO_STATE_ONLINE)
1475 			online_count++;
1476 		else if ((MDI_PI(pip)->pi_state & MDI_PATHINFO_STATE_MASK)
1477 				== MDI_PATHINFO_STATE_STANDBY)
1478 			standby_count++;
1479 		MDI_PI_UNLOCK(pip);
1480 		pip = next;
1481 	}
1482 
1483 	if (online_count == 0) {
1484 		if (standby_count == 0) {
1485 			state = MDI_CLIENT_STATE_FAILED;
1486 			MDI_DEBUG(2, (CE_NOTE, NULL, "!client state: failed"
1487 			    " ct = %p\n", (void *)ct));
1488 		} else if (standby_count == 1) {
1489 			state = MDI_CLIENT_STATE_DEGRADED;
1490 		} else {
1491 			state = MDI_CLIENT_STATE_OPTIMAL;
1492 		}
1493 	} else if (online_count == 1) {
1494 		if (standby_count == 0) {
1495 			state = MDI_CLIENT_STATE_DEGRADED;
1496 		} else {
1497 			state = MDI_CLIENT_STATE_OPTIMAL;
1498 		}
1499 	} else {
1500 		state = MDI_CLIENT_STATE_OPTIMAL;
1501 	}
1502 	return (state);
1503 }
1504 
1505 /*
1506  * i_mdi_client2devinfo():
1507  *		Utility function
1508  */
1509 dev_info_t *
1510 i_mdi_client2devinfo(mdi_client_t *ct)
1511 {
1512 	return (ct->ct_dip);
1513 }
1514 
1515 /*
1516  * mdi_client_path2_devinfo():
1517  * 		Given the parent devinfo and child devfs pathname, search for
1518  *		a valid devfs node handle.
1519  */
1520 dev_info_t *
1521 mdi_client_path2devinfo(dev_info_t *vdip, char *pathname)
1522 {
1523 	dev_info_t 	*cdip = NULL;
1524 	dev_info_t 	*ndip = NULL;
1525 	char		*temp_pathname;
1526 	int		circular;
1527 
1528 	/*
1529 	 * Allocate temp buffer
1530 	 */
1531 	temp_pathname = kmem_zalloc(MAXPATHLEN, KM_SLEEP);
1532 
1533 	/*
1534 	 * Lock parent against changes
1535 	 */
1536 	ndi_devi_enter(vdip, &circular);
1537 	ndip = (dev_info_t *)DEVI(vdip)->devi_child;
1538 	while ((cdip = ndip) != NULL) {
1539 		ndip = (dev_info_t *)DEVI(cdip)->devi_sibling;
1540 
1541 		*temp_pathname = '\0';
1542 		(void) ddi_pathname(cdip, temp_pathname);
1543 		if (strcmp(temp_pathname, pathname) == 0) {
1544 			break;
1545 		}
1546 	}
1547 	/*
1548 	 * Release devinfo lock
1549 	 */
1550 	ndi_devi_exit(vdip, circular);
1551 
1552 	/*
1553 	 * Free the temp buffer
1554 	 */
1555 	kmem_free(temp_pathname, MAXPATHLEN);
1556 	return (cdip);
1557 }
1558 
1559 /*
1560  * mdi_client_get_path_count():
1561  * 		Utility function to get number of path information nodes
1562  *		associated with a given client device.
1563  */
1564 int
1565 mdi_client_get_path_count(dev_info_t *cdip)
1566 {
1567 	mdi_client_t	*ct;
1568 	int		count = 0;
1569 
1570 	ct = i_devi_get_client(cdip);
1571 	if (ct != NULL) {
1572 		count = ct->ct_path_count;
1573 	}
1574 	return (count);
1575 }
1576 
1577 
1578 /*
1579  * i_mdi_get_hash_key():
1580  * 		Create a hash using strings as keys
1581  *
1582  */
1583 static int
1584 i_mdi_get_hash_key(char *str)
1585 {
1586 	uint32_t	g, hash = 0;
1587 	char		*p;
1588 
1589 	for (p = str; *p != '\0'; p++) {
1590 		g = *p;
1591 		hash += g;
1592 	}
1593 	return (hash % (CLIENT_HASH_TABLE_SIZE - 1));
1594 }
1595 
1596 /*
1597  * mdi_get_lb_policy():
1598  * 		Get current load balancing policy for a given client device
1599  */
1600 client_lb_t
1601 mdi_get_lb_policy(dev_info_t *cdip)
1602 {
1603 	client_lb_t	lb = LOAD_BALANCE_NONE;
1604 	mdi_client_t	*ct;
1605 
1606 	ct = i_devi_get_client(cdip);
1607 	if (ct != NULL) {
1608 		lb = ct->ct_lb;
1609 	}
1610 	return (lb);
1611 }
1612 
1613 /*
1614  * mdi_set_lb_region_size():
1615  * 		Set current region size for the load-balance
1616  */
1617 int
1618 mdi_set_lb_region_size(dev_info_t *cdip, int region_size)
1619 {
1620 	mdi_client_t	*ct;
1621 	int		rv = MDI_FAILURE;
1622 
1623 	ct = i_devi_get_client(cdip);
1624 	if (ct != NULL && ct->ct_lb_args != NULL) {
1625 		ct->ct_lb_args->region_size = region_size;
1626 		rv = MDI_SUCCESS;
1627 	}
1628 	return (rv);
1629 }
1630 
1631 /*
1632  * mdi_Set_lb_policy():
1633  * 		Set current load balancing policy for a given client device
1634  */
1635 int
1636 mdi_set_lb_policy(dev_info_t *cdip, client_lb_t lb)
1637 {
1638 	mdi_client_t	*ct;
1639 	int		rv = MDI_FAILURE;
1640 
1641 	ct = i_devi_get_client(cdip);
1642 	if (ct != NULL) {
1643 		ct->ct_lb = lb;
1644 		rv = MDI_SUCCESS;
1645 	}
1646 	return (rv);
1647 }
1648 
1649 /*
1650  * mdi_failover():
1651  *		failover function called by the vHCI drivers to initiate
1652  *		a failover operation.  This is typically due to non-availability
1653  *		of online paths to route I/O requests.  Failover can be
1654  *		triggered through user application also.
1655  *
1656  *		The vHCI driver calls mdi_failover() to initiate a failover
1657  *		operation. mdi_failover() calls back into the vHCI driver's
1658  *		vo_failover() entry point to perform the actual failover
1659  *		operation.  The reason for requiring the vHCI driver to
1660  *		initiate failover by calling mdi_failover(), instead of directly
1661  *		executing vo_failover() itself, is to ensure that the mdi
1662  *		framework can keep track of the client state properly.
1663  *		Additionally, mdi_failover() provides as a convenience the
1664  *		option of performing the failover operation synchronously or
1665  *		asynchronously
1666  *
1667  *		Upon successful completion of the failover operation, the
1668  *		paths that were previously ONLINE will be in the STANDBY state,
1669  *		and the newly activated paths will be in the ONLINE state.
1670  *
1671  *		The flags modifier determines whether the activation is done
1672  *		synchronously: MDI_FAILOVER_SYNC
1673  * Return Values:
1674  *		MDI_SUCCESS
1675  *		MDI_FAILURE
1676  *		MDI_BUSY
1677  */
1678 /*ARGSUSED*/
1679 int
1680 mdi_failover(dev_info_t *vdip, dev_info_t *cdip, int flags)
1681 {
1682 	int			rv;
1683 	mdi_client_t		*ct;
1684 
1685 	ct = i_devi_get_client(cdip);
1686 	ASSERT(ct != NULL);
1687 	if (ct == NULL) {
1688 		/* cdip is not a valid client device. Nothing more to do. */
1689 		return (MDI_FAILURE);
1690 	}
1691 
1692 	MDI_CLIENT_LOCK(ct);
1693 
1694 	if (MDI_CLIENT_IS_PATH_FREE_IN_PROGRESS(ct)) {
1695 		/* A path to the client is being freed */
1696 		MDI_CLIENT_UNLOCK(ct);
1697 		return (MDI_BUSY);
1698 	}
1699 
1700 
1701 	if (MDI_CLIENT_IS_FAILED(ct)) {
1702 		/*
1703 		 * Client is in failed state. Nothing more to do.
1704 		 */
1705 		MDI_CLIENT_UNLOCK(ct);
1706 		return (MDI_FAILURE);
1707 	}
1708 
1709 	if (MDI_CLIENT_IS_FAILOVER_IN_PROGRESS(ct)) {
1710 		/*
1711 		 * Failover is already in progress; return BUSY
1712 		 */
1713 		MDI_CLIENT_UNLOCK(ct);
1714 		return (MDI_BUSY);
1715 	}
1716 	/*
1717 	 * Make sure that mdi_pathinfo node state changes are processed.
1718 	 * We do not allow failovers to progress while client path state
1719 	 * changes are in progress
1720 	 */
1721 	if (ct->ct_unstable) {
1722 		if (flags == MDI_FAILOVER_ASYNC) {
1723 			MDI_CLIENT_UNLOCK(ct);
1724 			return (MDI_BUSY);
1725 		} else {
1726 			while (ct->ct_unstable)
1727 				cv_wait(&ct->ct_unstable_cv, &ct->ct_mutex);
1728 		}
1729 	}
1730 
1731 	/*
1732 	 * Client device is in stable state. Before proceeding, perform sanity
1733 	 * checks again.
1734 	 */
1735 	if ((MDI_CLIENT_IS_DETACHED(ct)) || (MDI_CLIENT_IS_FAILED(ct)) ||
1736 	    (!i_ddi_devi_attached(ct->ct_dip))) {
1737 		/*
1738 		 * Client is in failed state. Nothing more to do.
1739 		 */
1740 		MDI_CLIENT_UNLOCK(ct);
1741 		return (MDI_FAILURE);
1742 	}
1743 
1744 	/*
1745 	 * Set the client state as failover in progress.
1746 	 */
1747 	MDI_CLIENT_SET_FAILOVER_IN_PROGRESS(ct);
1748 	ct->ct_failover_flags = flags;
1749 	MDI_CLIENT_UNLOCK(ct);
1750 
1751 	if (flags == MDI_FAILOVER_ASYNC) {
1752 		/*
1753 		 * Submit the initiate failover request via CPR safe
1754 		 * taskq threads.
1755 		 */
1756 		(void) taskq_dispatch(mdi_taskq, (task_func_t *)i_mdi_failover,
1757 		    ct, KM_SLEEP);
1758 		return (MDI_ACCEPT);
1759 	} else {
1760 		/*
1761 		 * Synchronous failover mode.  Typically invoked from the user
1762 		 * land.
1763 		 */
1764 		rv = i_mdi_failover(ct);
1765 	}
1766 	return (rv);
1767 }
1768 
1769 /*
1770  * i_mdi_failover():
1771  *		internal failover function. Invokes vHCI drivers failover
1772  *		callback function and process the failover status
1773  * Return Values:
1774  *		None
1775  *
1776  * Note: A client device in failover state can not be detached or freed.
1777  */
1778 static int
1779 i_mdi_failover(void *arg)
1780 {
1781 	int		rv = MDI_SUCCESS;
1782 	mdi_client_t	*ct = (mdi_client_t *)arg;
1783 	mdi_vhci_t	*vh = ct->ct_vhci;
1784 
1785 	ASSERT(!MDI_CLIENT_LOCKED(ct));
1786 
1787 	if (vh->vh_ops->vo_failover != NULL) {
1788 		/*
1789 		 * Call vHCI drivers callback routine
1790 		 */
1791 		rv = (*vh->vh_ops->vo_failover)(vh->vh_dip, ct->ct_dip,
1792 		    ct->ct_failover_flags);
1793 	}
1794 
1795 	MDI_CLIENT_LOCK(ct);
1796 	MDI_CLIENT_CLEAR_FAILOVER_IN_PROGRESS(ct);
1797 
1798 	/*
1799 	 * Save the failover return status
1800 	 */
1801 	ct->ct_failover_status = rv;
1802 
1803 	/*
1804 	 * As a result of failover, client status would have been changed.
1805 	 * Update the client state and wake up anyone waiting on this client
1806 	 * device.
1807 	 */
1808 	i_mdi_client_update_state(ct);
1809 
1810 	cv_broadcast(&ct->ct_failover_cv);
1811 	MDI_CLIENT_UNLOCK(ct);
1812 	return (rv);
1813 }
1814 
1815 /*
1816  * Load balancing is logical block.
1817  * IOs within the range described by region_size
1818  * would go on the same path. This would improve the
1819  * performance by cache-hit on some of the RAID devices.
1820  * Search only for online paths(At some point we
1821  * may want to balance across target ports).
1822  * If no paths are found then default to round-robin.
1823  */
1824 static int
1825 i_mdi_lba_lb(mdi_client_t *ct, mdi_pathinfo_t **ret_pip, struct buf *bp)
1826 {
1827 	int		path_index = -1;
1828 	int		online_path_count = 0;
1829 	int		online_nonpref_path_count = 0;
1830 	int 		region_size = ct->ct_lb_args->region_size;
1831 	mdi_pathinfo_t	*pip;
1832 	mdi_pathinfo_t	*next;
1833 	int		preferred, path_cnt;
1834 
1835 	pip = ct->ct_path_head;
1836 	while (pip) {
1837 		MDI_PI_LOCK(pip);
1838 		if (MDI_PI(pip)->pi_state ==
1839 		    MDI_PATHINFO_STATE_ONLINE && MDI_PI(pip)->pi_preferred) {
1840 			online_path_count++;
1841 		} else if (MDI_PI(pip)->pi_state ==
1842 		    MDI_PATHINFO_STATE_ONLINE && !MDI_PI(pip)->pi_preferred) {
1843 			online_nonpref_path_count++;
1844 		}
1845 		next = (mdi_pathinfo_t *)
1846 		    MDI_PI(pip)->pi_client_link;
1847 		MDI_PI_UNLOCK(pip);
1848 		pip = next;
1849 	}
1850 	/* if found any online/preferred then use this type */
1851 	if (online_path_count > 0) {
1852 		path_cnt = online_path_count;
1853 		preferred = 1;
1854 	} else if (online_nonpref_path_count > 0) {
1855 		path_cnt = online_nonpref_path_count;
1856 		preferred = 0;
1857 	} else {
1858 		path_cnt = 0;
1859 	}
1860 	if (path_cnt) {
1861 		path_index = (bp->b_blkno >> region_size) % path_cnt;
1862 		pip = ct->ct_path_head;
1863 		while (pip && path_index != -1) {
1864 			MDI_PI_LOCK(pip);
1865 			if (path_index == 0 &&
1866 			    (MDI_PI(pip)->pi_state ==
1867 			    MDI_PATHINFO_STATE_ONLINE) &&
1868 				MDI_PI(pip)->pi_preferred == preferred) {
1869 				MDI_PI_HOLD(pip);
1870 				MDI_PI_UNLOCK(pip);
1871 				*ret_pip = pip;
1872 				return (MDI_SUCCESS);
1873 			}
1874 			path_index --;
1875 			next = (mdi_pathinfo_t *)
1876 			    MDI_PI(pip)->pi_client_link;
1877 			MDI_PI_UNLOCK(pip);
1878 			pip = next;
1879 		}
1880 		if (pip == NULL) {
1881 			MDI_DEBUG(4, (CE_NOTE, NULL,
1882 			    "!lba %llx, no pip !!\n",
1883 				bp->b_lblkno));
1884 		} else {
1885 			MDI_DEBUG(4, (CE_NOTE, NULL,
1886 			    "!lba %llx, no pip for path_index, "
1887 			    "pip %p\n", bp->b_lblkno, (void *)pip));
1888 		}
1889 	}
1890 	return (MDI_FAILURE);
1891 }
1892 
1893 /*
1894  * mdi_select_path():
1895  *		select a path to access a client device.
1896  *
1897  *		mdi_select_path() function is called by the vHCI drivers to
1898  *		select a path to route the I/O request to.  The caller passes
1899  *		the block I/O data transfer structure ("buf") as one of the
1900  *		parameters.  The mpxio framework uses the buf structure
1901  *		contents to maintain per path statistics (total I/O size /
1902  *		count pending).  If more than one online paths are available to
1903  *		select, the framework automatically selects a suitable path
1904  *		for routing I/O request. If a failover operation is active for
1905  *		this client device the call shall be failed with MDI_BUSY error
1906  *		code.
1907  *
1908  *		By default this function returns a suitable path in online
1909  *		state based on the current load balancing policy.  Currently
1910  *		we support LOAD_BALANCE_NONE (Previously selected online path
1911  *		will continue to be used till the path is usable) and
1912  *		LOAD_BALANCE_RR (Online paths will be selected in a round
1913  *		robin fashion), LOAD_BALANCE_LB(Online paths will be selected
1914  *		based on the logical block).  The load balancing
1915  *		through vHCI drivers configuration file (driver.conf).
1916  *
1917  *		vHCI drivers may override this default behavior by specifying
1918  *		appropriate flags.  If start_pip is specified (non NULL) is
1919  *		used as start point to walk and find the next appropriate path.
1920  *		The following values are currently defined:
1921  *		MDI_SELECT_ONLINE_PATH (to select an ONLINE path) and/or
1922  *		MDI_SELECT_STANDBY_PATH (to select an STANDBY path).
1923  *
1924  *		The non-standard behavior is used by the scsi_vhci driver,
1925  *		whenever it has to use a STANDBY/FAULTED path.  Eg. during
1926  *		attach of client devices (to avoid an unnecessary failover
1927  *		when the STANDBY path comes up first), during failover
1928  *		(to activate a STANDBY path as ONLINE).
1929  *
1930  *		The selected path is returned in a a mdi_hold_path() state
1931  *		(pi_ref_cnt). Caller should release the hold by calling
1932  *		mdi_rele_path().
1933  *
1934  * Return Values:
1935  *		MDI_SUCCESS	- Completed successfully
1936  *		MDI_BUSY 	- Client device is busy failing over
1937  *		MDI_NOPATH	- Client device is online, but no valid path are
1938  *				  available to access this client device
1939  *		MDI_FAILURE	- Invalid client device or state
1940  *		MDI_DEVI_ONLINING
1941  *				- Client device (struct dev_info state) is in
1942  *				  onlining state.
1943  */
1944 
1945 /*ARGSUSED*/
1946 int
1947 mdi_select_path(dev_info_t *cdip, struct buf *bp, int flags,
1948     mdi_pathinfo_t *start_pip, mdi_pathinfo_t **ret_pip)
1949 {
1950 	mdi_client_t	*ct;
1951 	mdi_pathinfo_t	*pip;
1952 	mdi_pathinfo_t	*next;
1953 	mdi_pathinfo_t	*head;
1954 	mdi_pathinfo_t	*start;
1955 	client_lb_t	lbp;	/* load balancing policy */
1956 	int		sb = 1;	/* standard behavior */
1957 	int		preferred = 1;	/* preferred path */
1958 	int		cond, cont = 1;
1959 	int		retry = 0;
1960 
1961 	if (flags != 0) {
1962 		/*
1963 		 * disable default behavior
1964 		 */
1965 		sb = 0;
1966 	}
1967 
1968 	*ret_pip = NULL;
1969 	ct = i_devi_get_client(cdip);
1970 	if (ct == NULL) {
1971 		/* mdi extensions are NULL, Nothing more to do */
1972 		return (MDI_FAILURE);
1973 	}
1974 
1975 	MDI_CLIENT_LOCK(ct);
1976 
1977 	if (sb) {
1978 		if (MDI_CLIENT_IS_FAILED(ct)) {
1979 			/*
1980 			 * Client is not ready to accept any I/O requests.
1981 			 * Fail this request.
1982 			 */
1983 			MDI_DEBUG(2, (CE_NOTE, cdip, "!mdi_select_path: "
1984 			    "client state offline ct = %p\n", (void *)ct));
1985 			MDI_CLIENT_UNLOCK(ct);
1986 			return (MDI_FAILURE);
1987 		}
1988 
1989 		if (MDI_CLIENT_IS_FAILOVER_IN_PROGRESS(ct)) {
1990 			/*
1991 			 * Check for Failover is in progress. If so tell the
1992 			 * caller that this device is busy.
1993 			 */
1994 			MDI_DEBUG(2, (CE_NOTE, cdip, "!mdi_select_path: "
1995 			    "client failover in progress ct = %p\n",
1996 			    (void *)ct));
1997 			MDI_CLIENT_UNLOCK(ct);
1998 			return (MDI_BUSY);
1999 		}
2000 
2001 		/*
2002 		 * Check to see whether the client device is attached.
2003 		 * If not so, let the vHCI driver manually select a path
2004 		 * (standby) and let the probe/attach process to continue.
2005 		 */
2006 		if (MDI_CLIENT_IS_DETACHED(ct) || !i_ddi_devi_attached(cdip)) {
2007 			MDI_DEBUG(4, (CE_NOTE, cdip, "!Devi is onlining "
2008 			    "ct = %p\n", (void *)ct));
2009 			MDI_CLIENT_UNLOCK(ct);
2010 			return (MDI_DEVI_ONLINING);
2011 		}
2012 	}
2013 
2014 	/*
2015 	 * Cache in the client list head.  If head of the list is NULL
2016 	 * return MDI_NOPATH
2017 	 */
2018 	head = ct->ct_path_head;
2019 	if (head == NULL) {
2020 		MDI_CLIENT_UNLOCK(ct);
2021 		return (MDI_NOPATH);
2022 	}
2023 
2024 	/*
2025 	 * for non default behavior, bypass current
2026 	 * load balancing policy and always use LOAD_BALANCE_RR
2027 	 * except that the start point will be adjusted based
2028 	 * on the provided start_pip
2029 	 */
2030 	lbp = sb ? ct->ct_lb : LOAD_BALANCE_RR;
2031 
2032 	switch (lbp) {
2033 	case LOAD_BALANCE_NONE:
2034 		/*
2035 		 * Load balancing is None  or Alternate path mode
2036 		 * Start looking for a online mdi_pathinfo node starting from
2037 		 * last known selected path
2038 		 */
2039 		preferred = 1;
2040 		pip = (mdi_pathinfo_t *)ct->ct_path_last;
2041 		if (pip == NULL) {
2042 			pip = head;
2043 		}
2044 		start = pip;
2045 		do {
2046 			MDI_PI_LOCK(pip);
2047 			/*
2048 			 * No need to explicitly check if the path is disabled.
2049 			 * Since we are checking for state == ONLINE and the
2050 			 * same veriable is used for DISABLE/ENABLE information.
2051 			 */
2052 			if ((MDI_PI(pip)->pi_state  ==
2053 				MDI_PATHINFO_STATE_ONLINE) &&
2054 				preferred == MDI_PI(pip)->pi_preferred) {
2055 				/*
2056 				 * Return the path in hold state. Caller should
2057 				 * release the lock by calling mdi_rele_path()
2058 				 */
2059 				MDI_PI_HOLD(pip);
2060 				MDI_PI_UNLOCK(pip);
2061 				ct->ct_path_last = pip;
2062 				*ret_pip = pip;
2063 				MDI_CLIENT_UNLOCK(ct);
2064 				return (MDI_SUCCESS);
2065 			}
2066 
2067 			/*
2068 			 * Path is busy.
2069 			 */
2070 			if (MDI_PI_IS_DRV_DISABLE_TRANSIENT(pip) ||
2071 			    MDI_PI_IS_TRANSIENT(pip))
2072 				retry = 1;
2073 			/*
2074 			 * Keep looking for a next available online path
2075 			 */
2076 			next = (mdi_pathinfo_t *)MDI_PI(pip)->pi_client_link;
2077 			if (next == NULL) {
2078 				next = head;
2079 			}
2080 			MDI_PI_UNLOCK(pip);
2081 			pip = next;
2082 			if (start == pip && preferred) {
2083 				preferred = 0;
2084 			} else if (start == pip && !preferred) {
2085 				cont = 0;
2086 			}
2087 		} while (cont);
2088 		break;
2089 
2090 	case LOAD_BALANCE_LBA:
2091 		/*
2092 		 * Make sure we are looking
2093 		 * for an online path. Otherwise, if it is for a STANDBY
2094 		 * path request, it will go through and fetch an ONLINE
2095 		 * path which is not desirable.
2096 		 */
2097 		if ((ct->ct_lb_args != NULL) &&
2098 			    (ct->ct_lb_args->region_size) && bp &&
2099 				(sb || (flags == MDI_SELECT_ONLINE_PATH))) {
2100 			if (i_mdi_lba_lb(ct, ret_pip, bp)
2101 				    == MDI_SUCCESS) {
2102 				MDI_CLIENT_UNLOCK(ct);
2103 				return (MDI_SUCCESS);
2104 			}
2105 		}
2106 		/*  FALLTHROUGH */
2107 	case LOAD_BALANCE_RR:
2108 		/*
2109 		 * Load balancing is Round Robin. Start looking for a online
2110 		 * mdi_pathinfo node starting from last known selected path
2111 		 * as the start point.  If override flags are specified,
2112 		 * process accordingly.
2113 		 * If the search is already in effect(start_pip not null),
2114 		 * then lets just use the same path preference to continue the
2115 		 * traversal.
2116 		 */
2117 
2118 		if (start_pip != NULL) {
2119 			preferred = MDI_PI(start_pip)->pi_preferred;
2120 		} else {
2121 			preferred = 1;
2122 		}
2123 
2124 		start = sb ? (mdi_pathinfo_t *)ct->ct_path_last : start_pip;
2125 		if (start == NULL) {
2126 			pip = head;
2127 		} else {
2128 			pip = (mdi_pathinfo_t *)MDI_PI(start)->pi_client_link;
2129 			if (pip == NULL) {
2130 				if (!sb) {
2131 					if (preferred == 0) {
2132 						/*
2133 						 * Looks like we have completed
2134 						 * the traversal as preferred
2135 						 * value is 0. Time to bail out.
2136 						 */
2137 						*ret_pip = NULL;
2138 						MDI_CLIENT_UNLOCK(ct);
2139 						return (MDI_NOPATH);
2140 					} else {
2141 						/*
2142 						 * Looks like we reached the
2143 						 * end of the list. Lets enable
2144 						 * traversal of non preferred
2145 						 * paths.
2146 						 */
2147 						preferred = 0;
2148 					}
2149 				}
2150 				pip = head;
2151 			}
2152 		}
2153 		start = pip;
2154 		do {
2155 			MDI_PI_LOCK(pip);
2156 			if (sb) {
2157 				cond = ((MDI_PI(pip)->pi_state ==
2158 				    MDI_PATHINFO_STATE_ONLINE &&
2159 					MDI_PI(pip)->pi_preferred ==
2160 						preferred) ? 1 : 0);
2161 			} else {
2162 				if (flags == MDI_SELECT_ONLINE_PATH) {
2163 					cond = ((MDI_PI(pip)->pi_state ==
2164 					    MDI_PATHINFO_STATE_ONLINE &&
2165 						MDI_PI(pip)->pi_preferred ==
2166 						preferred) ? 1 : 0);
2167 				} else if (flags == MDI_SELECT_STANDBY_PATH) {
2168 					cond = ((MDI_PI(pip)->pi_state ==
2169 					    MDI_PATHINFO_STATE_STANDBY &&
2170 						MDI_PI(pip)->pi_preferred ==
2171 						preferred) ? 1 : 0);
2172 				} else if (flags == (MDI_SELECT_ONLINE_PATH |
2173 				    MDI_SELECT_STANDBY_PATH)) {
2174 					cond = (((MDI_PI(pip)->pi_state ==
2175 					    MDI_PATHINFO_STATE_ONLINE ||
2176 					    (MDI_PI(pip)->pi_state ==
2177 					    MDI_PATHINFO_STATE_STANDBY)) &&
2178 						MDI_PI(pip)->pi_preferred ==
2179 						preferred) ? 1 : 0);
2180 				} else if (flags ==
2181 					(MDI_SELECT_STANDBY_PATH |
2182 					MDI_SELECT_ONLINE_PATH |
2183 					MDI_SELECT_USER_DISABLE_PATH)) {
2184 					cond = (((MDI_PI(pip)->pi_state ==
2185 					    MDI_PATHINFO_STATE_ONLINE ||
2186 					    (MDI_PI(pip)->pi_state ==
2187 					    MDI_PATHINFO_STATE_STANDBY) ||
2188 						(MDI_PI(pip)->pi_state ==
2189 					    (MDI_PATHINFO_STATE_ONLINE|
2190 					    MDI_PATHINFO_STATE_USER_DISABLE)) ||
2191 						(MDI_PI(pip)->pi_state ==
2192 					    (MDI_PATHINFO_STATE_STANDBY |
2193 					    MDI_PATHINFO_STATE_USER_DISABLE)))&&
2194 						MDI_PI(pip)->pi_preferred ==
2195 						preferred) ? 1 : 0);
2196 				} else {
2197 					cond = 0;
2198 				}
2199 			}
2200 			/*
2201 			 * No need to explicitly check if the path is disabled.
2202 			 * Since we are checking for state == ONLINE and the
2203 			 * same veriable is used for DISABLE/ENABLE information.
2204 			 */
2205 			if (cond) {
2206 				/*
2207 				 * Return the path in hold state. Caller should
2208 				 * release the lock by calling mdi_rele_path()
2209 				 */
2210 				MDI_PI_HOLD(pip);
2211 				MDI_PI_UNLOCK(pip);
2212 				if (sb)
2213 					ct->ct_path_last = pip;
2214 				*ret_pip = pip;
2215 				MDI_CLIENT_UNLOCK(ct);
2216 				return (MDI_SUCCESS);
2217 			}
2218 			/*
2219 			 * Path is busy.
2220 			 */
2221 			if (MDI_PI_IS_DRV_DISABLE_TRANSIENT(pip) ||
2222 			    MDI_PI_IS_TRANSIENT(pip))
2223 				retry = 1;
2224 
2225 			/*
2226 			 * Keep looking for a next available online path
2227 			 */
2228 do_again:
2229 			next = (mdi_pathinfo_t *)MDI_PI(pip)->pi_client_link;
2230 			if (next == NULL) {
2231 				if (!sb) {
2232 					if (preferred == 1) {
2233 						/*
2234 						 * Looks like we reached the
2235 						 * end of the list. Lets enable
2236 						 * traversal of non preferred
2237 						 * paths.
2238 						 */
2239 						preferred = 0;
2240 						next = head;
2241 					} else {
2242 						/*
2243 						 * We have done both the passes
2244 						 * Preferred as well as for
2245 						 * Non-preferred. Bail out now.
2246 						 */
2247 						cont = 0;
2248 					}
2249 				} else {
2250 					/*
2251 					 * Standard behavior case.
2252 					 */
2253 					next = head;
2254 				}
2255 			}
2256 			MDI_PI_UNLOCK(pip);
2257 			if (cont == 0) {
2258 				break;
2259 			}
2260 			pip = next;
2261 
2262 			if (!sb) {
2263 				/*
2264 				 * We need to handle the selection of
2265 				 * non-preferred path in the following
2266 				 * case:
2267 				 *
2268 				 * +------+   +------+   +------+   +-----+
2269 				 * | A : 1| - | B : 1| - | C : 0| - |NULL |
2270 				 * +------+   +------+   +------+   +-----+
2271 				 *
2272 				 * If we start the search with B, we need to
2273 				 * skip beyond B to pick C which is non -
2274 				 * preferred in the second pass. The following
2275 				 * test, if true, will allow us to skip over
2276 				 * the 'start'(B in the example) to select
2277 				 * other non preferred elements.
2278 				 */
2279 				if ((start_pip != NULL) && (start_pip == pip) &&
2280 				    (MDI_PI(start_pip)->pi_preferred
2281 				    != preferred)) {
2282 					/*
2283 					 * try again after going past the start
2284 					 * pip
2285 					 */
2286 					MDI_PI_LOCK(pip);
2287 					goto do_again;
2288 				}
2289 			} else {
2290 				/*
2291 				 * Standard behavior case
2292 				 */
2293 				if (start == pip && preferred) {
2294 					/* look for nonpreferred paths */
2295 					preferred = 0;
2296 				} else if (start == pip && !preferred) {
2297 					/*
2298 					 * Exit condition
2299 					 */
2300 					cont = 0;
2301 				}
2302 			}
2303 		} while (cont);
2304 		break;
2305 	}
2306 
2307 	MDI_CLIENT_UNLOCK(ct);
2308 	if (retry == 1) {
2309 		return (MDI_BUSY);
2310 	} else {
2311 		return (MDI_NOPATH);
2312 	}
2313 }
2314 
2315 /*
2316  * For a client, return the next available path to any phci
2317  *
2318  * Note:
2319  *		Caller should hold the branch's devinfo node to get a consistent
2320  *		snap shot of the mdi_pathinfo nodes.
2321  *
2322  *		Please note that even the list is stable the mdi_pathinfo
2323  *		node state and properties are volatile.  The caller should lock
2324  *		and unlock the nodes by calling mdi_pi_lock() and
2325  *		mdi_pi_unlock() functions to get a stable properties.
2326  *
2327  *		If there is a need to use the nodes beyond the hold of the
2328  *		devinfo node period (For ex. I/O), then mdi_pathinfo node
2329  *		need to be held against unexpected removal by calling
2330  *		mdi_hold_path() and should be released by calling
2331  *		mdi_rele_path() on completion.
2332  */
2333 mdi_pathinfo_t *
2334 mdi_get_next_phci_path(dev_info_t *ct_dip, mdi_pathinfo_t *pip)
2335 {
2336 	mdi_client_t *ct;
2337 
2338 	if (!MDI_CLIENT(ct_dip))
2339 		return (NULL);
2340 
2341 	/*
2342 	 * Walk through client link
2343 	 */
2344 	ct = (mdi_client_t *)DEVI(ct_dip)->devi_mdi_client;
2345 	ASSERT(ct != NULL);
2346 
2347 	if (pip == NULL)
2348 		return ((mdi_pathinfo_t *)ct->ct_path_head);
2349 
2350 	return ((mdi_pathinfo_t *)MDI_PI(pip)->pi_client_link);
2351 }
2352 
2353 /*
2354  * For a phci, return the next available path to any client
2355  * Note: ditto mdi_get_next_phci_path()
2356  */
2357 mdi_pathinfo_t *
2358 mdi_get_next_client_path(dev_info_t *ph_dip, mdi_pathinfo_t *pip)
2359 {
2360 	mdi_phci_t *ph;
2361 
2362 	if (!MDI_PHCI(ph_dip))
2363 		return (NULL);
2364 
2365 	/*
2366 	 * Walk through pHCI link
2367 	 */
2368 	ph = (mdi_phci_t *)DEVI(ph_dip)->devi_mdi_xhci;
2369 	ASSERT(ph != NULL);
2370 
2371 	if (pip == NULL)
2372 		return ((mdi_pathinfo_t *)ph->ph_path_head);
2373 
2374 	return ((mdi_pathinfo_t *)MDI_PI(pip)->pi_phci_link);
2375 }
2376 
2377 /*
2378  * mdi_hold_path():
2379  *		Hold the mdi_pathinfo node against unwanted unexpected free.
2380  * Return Values:
2381  *		None
2382  */
2383 void
2384 mdi_hold_path(mdi_pathinfo_t *pip)
2385 {
2386 	if (pip) {
2387 		MDI_PI_LOCK(pip);
2388 		MDI_PI_HOLD(pip);
2389 		MDI_PI_UNLOCK(pip);
2390 	}
2391 }
2392 
2393 
2394 /*
2395  * mdi_rele_path():
2396  *		Release the mdi_pathinfo node which was selected
2397  *		through mdi_select_path() mechanism or manually held by
2398  *		calling mdi_hold_path().
2399  * Return Values:
2400  *		None
2401  */
2402 void
2403 mdi_rele_path(mdi_pathinfo_t *pip)
2404 {
2405 	if (pip) {
2406 		MDI_PI_LOCK(pip);
2407 		MDI_PI_RELE(pip);
2408 		if (MDI_PI(pip)->pi_ref_cnt == 0) {
2409 			cv_broadcast(&MDI_PI(pip)->pi_ref_cv);
2410 		}
2411 		MDI_PI_UNLOCK(pip);
2412 	}
2413 }
2414 
2415 /*
2416  * mdi_pi_lock():
2417  * 		Lock the mdi_pathinfo node.
2418  * Note:
2419  *		The caller should release the lock by calling mdi_pi_unlock()
2420  */
2421 void
2422 mdi_pi_lock(mdi_pathinfo_t *pip)
2423 {
2424 	ASSERT(pip != NULL);
2425 	if (pip) {
2426 		MDI_PI_LOCK(pip);
2427 	}
2428 }
2429 
2430 
2431 /*
2432  * mdi_pi_unlock():
2433  * 		Unlock the mdi_pathinfo node.
2434  * Note:
2435  *		The mdi_pathinfo node should have been locked with mdi_pi_lock()
2436  */
2437 void
2438 mdi_pi_unlock(mdi_pathinfo_t *pip)
2439 {
2440 	ASSERT(pip != NULL);
2441 	if (pip) {
2442 		MDI_PI_UNLOCK(pip);
2443 	}
2444 }
2445 
2446 /*
2447  * mdi_pi_find():
2448  *		Search the list of mdi_pathinfo nodes attached to the
2449  *		pHCI/Client device node whose path address matches "paddr".
2450  *		Returns a pointer to the mdi_pathinfo node if a matching node is
2451  *		found.
2452  * Return Values:
2453  *		mdi_pathinfo node handle
2454  *		NULL
2455  * Notes:
2456  *		Caller need not hold any locks to call this function.
2457  */
2458 mdi_pathinfo_t *
2459 mdi_pi_find(dev_info_t *pdip, char *caddr, char *paddr)
2460 {
2461 	mdi_phci_t		*ph;
2462 	mdi_vhci_t		*vh;
2463 	mdi_client_t		*ct;
2464 	mdi_pathinfo_t		*pip = NULL;
2465 
2466 	MDI_DEBUG(2, (CE_NOTE, pdip, "!mdi_pi_find: %s %s",
2467 	    caddr ? caddr : "NULL", paddr ? paddr : "NULL"));
2468 	if ((pdip == NULL) || (paddr == NULL)) {
2469 		return (NULL);
2470 	}
2471 	ph = i_devi_get_phci(pdip);
2472 	if (ph == NULL) {
2473 		/*
2474 		 * Invalid pHCI device, Nothing more to do.
2475 		 */
2476 		MDI_DEBUG(2, (CE_WARN, pdip,
2477 		    "!mdi_pi_find: invalid phci"));
2478 		return (NULL);
2479 	}
2480 
2481 	vh = ph->ph_vhci;
2482 	if (vh == NULL) {
2483 		/*
2484 		 * Invalid vHCI device, Nothing more to do.
2485 		 */
2486 		MDI_DEBUG(2, (CE_WARN, pdip,
2487 		    "!mdi_pi_find: invalid vhci"));
2488 		return (NULL);
2489 	}
2490 
2491 	/*
2492 	 * Look for pathinfo node identified by paddr.
2493 	 */
2494 	if (caddr == NULL) {
2495 		/*
2496 		 * Find a mdi_pathinfo node under pHCI list for a matching
2497 		 * unit address.
2498 		 */
2499 		MDI_PHCI_LOCK(ph);
2500 		if (MDI_PHCI_IS_OFFLINE(ph)) {
2501 			MDI_DEBUG(2, (CE_WARN, pdip,
2502 			    "!mdi_pi_find: offline phci %p", (void *)ph));
2503 			MDI_PHCI_UNLOCK(ph);
2504 			return (NULL);
2505 		}
2506 		pip = (mdi_pathinfo_t *)ph->ph_path_head;
2507 
2508 		while (pip != NULL) {
2509 			if (strcmp(MDI_PI(pip)->pi_addr, paddr) == 0) {
2510 				break;
2511 			}
2512 			pip = (mdi_pathinfo_t *)MDI_PI(pip)->pi_phci_link;
2513 		}
2514 		MDI_PHCI_UNLOCK(ph);
2515 		MDI_DEBUG(2, (CE_NOTE, pdip, "!mdi_pi_find: found %p",
2516 		    (void *)pip));
2517 		return (pip);
2518 	}
2519 
2520 	/*
2521 	 * XXX - Is the rest of the code in this function really necessary?
2522 	 * The consumers of mdi_pi_find() can search for the desired pathinfo
2523 	 * node by calling mdi_pi_find(pdip, NULL, paddr). Irrespective of
2524 	 * whether the search is based on the pathinfo nodes attached to
2525 	 * the pHCI or the client node, the result will be the same.
2526 	 */
2527 
2528 	/*
2529 	 * Find the client device corresponding to 'caddr'
2530 	 */
2531 	MDI_VHCI_CLIENT_LOCK(vh);
2532 
2533 	/*
2534 	 * XXX - Passing NULL to the following function works as long as the
2535 	 * the client addresses (caddr) are unique per vhci basis.
2536 	 */
2537 	ct = i_mdi_client_find(vh, NULL, caddr);
2538 	if (ct == NULL) {
2539 		/*
2540 		 * Client not found, Obviously mdi_pathinfo node has not been
2541 		 * created yet.
2542 		 */
2543 		MDI_VHCI_CLIENT_UNLOCK(vh);
2544 		MDI_DEBUG(2, (CE_NOTE, pdip, "!mdi_pi_find: client not "
2545 		    "found for caddr %s", caddr ? caddr : "NULL"));
2546 		return (NULL);
2547 	}
2548 
2549 	/*
2550 	 * Hold the client lock and look for a mdi_pathinfo node with matching
2551 	 * pHCI and paddr
2552 	 */
2553 	MDI_CLIENT_LOCK(ct);
2554 
2555 	/*
2556 	 * Release the global mutex as it is no more needed. Note: We always
2557 	 * respect the locking order while acquiring.
2558 	 */
2559 	MDI_VHCI_CLIENT_UNLOCK(vh);
2560 
2561 	pip = (mdi_pathinfo_t *)ct->ct_path_head;
2562 	while (pip != NULL) {
2563 		/*
2564 		 * Compare the unit address
2565 		 */
2566 		if ((MDI_PI(pip)->pi_phci == ph) &&
2567 		    strcmp(MDI_PI(pip)->pi_addr, paddr) == 0) {
2568 			break;
2569 		}
2570 		pip = (mdi_pathinfo_t *)MDI_PI(pip)->pi_client_link;
2571 	}
2572 	MDI_CLIENT_UNLOCK(ct);
2573 	MDI_DEBUG(2, (CE_NOTE, pdip, "!mdi_pi_find: found:: %p", (void *)pip));
2574 	return (pip);
2575 }
2576 
2577 /*
2578  * mdi_pi_alloc():
2579  *		Allocate and initialize a new instance of a mdi_pathinfo node.
2580  *		The mdi_pathinfo node returned by this function identifies a
2581  *		unique device path is capable of having properties attached
2582  *		and passed to mdi_pi_online() to fully attach and online the
2583  *		path and client device node.
2584  *		The mdi_pathinfo node returned by this function must be
2585  *		destroyed using mdi_pi_free() if the path is no longer
2586  *		operational or if the caller fails to attach a client device
2587  *		node when calling mdi_pi_online(). The framework will not free
2588  *		the resources allocated.
2589  *		This function can be called from both interrupt and kernel
2590  *		contexts.  DDI_NOSLEEP flag should be used while calling
2591  *		from interrupt contexts.
2592  * Return Values:
2593  *		MDI_SUCCESS
2594  *		MDI_FAILURE
2595  *		MDI_NOMEM
2596  */
2597 /*ARGSUSED*/
2598 int
2599 mdi_pi_alloc_compatible(dev_info_t *pdip, char *cname, char *caddr, char *paddr,
2600     char **compatible, int ncompatible, int flags, mdi_pathinfo_t **ret_pip)
2601 {
2602 	mdi_vhci_t	*vh;
2603 	mdi_phci_t	*ph;
2604 	mdi_client_t	*ct;
2605 	mdi_pathinfo_t	*pip = NULL;
2606 	dev_info_t	*cdip;
2607 	int		rv = MDI_NOMEM;
2608 	int		path_allocated = 0;
2609 
2610 	MDI_DEBUG(2, (CE_NOTE, pdip, "!mdi_pi_alloc_compatible: %s %s %s",
2611 	    cname ? cname : "NULL", caddr ? caddr : "NULL",
2612 	    paddr ? paddr : "NULL"));
2613 
2614 	if (pdip == NULL || cname == NULL || caddr == NULL || paddr == NULL ||
2615 	    ret_pip == NULL) {
2616 		/* Nothing more to do */
2617 		return (MDI_FAILURE);
2618 	}
2619 
2620 	*ret_pip = NULL;
2621 
2622 	/* No allocations on detaching pHCI */
2623 	if (DEVI_IS_DETACHING(pdip)) {
2624 		/* Invalid pHCI device, return failure */
2625 		MDI_DEBUG(1, (CE_WARN, pdip,
2626 		    "!mdi_pi_alloc: detaching pHCI=%p", (void *)pdip));
2627 		return (MDI_FAILURE);
2628 	}
2629 
2630 	ph = i_devi_get_phci(pdip);
2631 	ASSERT(ph != NULL);
2632 	if (ph == NULL) {
2633 		/* Invalid pHCI device, return failure */
2634 		MDI_DEBUG(1, (CE_WARN, pdip,
2635 		    "!mdi_pi_alloc: invalid pHCI=%p", (void *)pdip));
2636 		return (MDI_FAILURE);
2637 	}
2638 
2639 	MDI_PHCI_LOCK(ph);
2640 	vh = ph->ph_vhci;
2641 	if (vh == NULL) {
2642 		/* Invalid vHCI device, return failure */
2643 		MDI_DEBUG(1, (CE_WARN, pdip,
2644 		    "!mdi_pi_alloc: invalid vHCI=%p", (void *)pdip));
2645 		MDI_PHCI_UNLOCK(ph);
2646 		return (MDI_FAILURE);
2647 	}
2648 
2649 	if (MDI_PHCI_IS_READY(ph) == 0) {
2650 		/*
2651 		 * Do not allow new node creation when pHCI is in
2652 		 * offline/suspended states
2653 		 */
2654 		MDI_DEBUG(1, (CE_WARN, pdip,
2655 		    "mdi_pi_alloc: pHCI=%p is not ready", (void *)ph));
2656 		MDI_PHCI_UNLOCK(ph);
2657 		return (MDI_BUSY);
2658 	}
2659 	MDI_PHCI_UNSTABLE(ph);
2660 	MDI_PHCI_UNLOCK(ph);
2661 
2662 	/* look for a matching client, create one if not found */
2663 	MDI_VHCI_CLIENT_LOCK(vh);
2664 	ct = i_mdi_client_find(vh, cname, caddr);
2665 	if (ct == NULL) {
2666 		ct = i_mdi_client_alloc(vh, cname, caddr);
2667 		ASSERT(ct != NULL);
2668 	}
2669 
2670 	if (ct->ct_dip == NULL) {
2671 		/*
2672 		 * Allocate a devinfo node
2673 		 */
2674 		ct->ct_dip = i_mdi_devinfo_create(vh, cname, caddr,
2675 		    compatible, ncompatible);
2676 		if (ct->ct_dip == NULL) {
2677 			(void) i_mdi_client_free(vh, ct);
2678 			goto fail;
2679 		}
2680 	}
2681 	cdip = ct->ct_dip;
2682 
2683 	DEVI(cdip)->devi_mdi_component |= MDI_COMPONENT_CLIENT;
2684 	DEVI(cdip)->devi_mdi_client = (caddr_t)ct;
2685 
2686 	MDI_CLIENT_LOCK(ct);
2687 	pip = (mdi_pathinfo_t *)ct->ct_path_head;
2688 	while (pip != NULL) {
2689 		/*
2690 		 * Compare the unit address
2691 		 */
2692 		if ((MDI_PI(pip)->pi_phci == ph) &&
2693 		    strcmp(MDI_PI(pip)->pi_addr, paddr) == 0) {
2694 			break;
2695 		}
2696 		pip = (mdi_pathinfo_t *)MDI_PI(pip)->pi_client_link;
2697 	}
2698 	MDI_CLIENT_UNLOCK(ct);
2699 
2700 	if (pip == NULL) {
2701 		/*
2702 		 * This is a new path for this client device.  Allocate and
2703 		 * initialize a new pathinfo node
2704 		 */
2705 		pip = i_mdi_pi_alloc(ph, paddr, ct);
2706 		ASSERT(pip != NULL);
2707 		path_allocated = 1;
2708 	}
2709 	rv = MDI_SUCCESS;
2710 
2711 fail:
2712 	/*
2713 	 * Release the global mutex.
2714 	 */
2715 	MDI_VHCI_CLIENT_UNLOCK(vh);
2716 
2717 	/*
2718 	 * Mark the pHCI as stable
2719 	 */
2720 	MDI_PHCI_LOCK(ph);
2721 	MDI_PHCI_STABLE(ph);
2722 	MDI_PHCI_UNLOCK(ph);
2723 	*ret_pip = pip;
2724 
2725 	MDI_DEBUG(2, (CE_NOTE, pdip,
2726 	    "!mdi_pi_alloc_compatible: alloc %p", (void *)pip));
2727 
2728 	if (path_allocated)
2729 		vhcache_pi_add(vh->vh_config, MDI_PI(pip));
2730 
2731 	return (rv);
2732 }
2733 
2734 /*ARGSUSED*/
2735 int
2736 mdi_pi_alloc(dev_info_t *pdip, char *cname, char *caddr, char *paddr,
2737     int flags, mdi_pathinfo_t **ret_pip)
2738 {
2739 	return (mdi_pi_alloc_compatible(pdip, cname, caddr, paddr, NULL, 0,
2740 	    flags, ret_pip));
2741 }
2742 
2743 /*
2744  * i_mdi_pi_alloc():
2745  *		Allocate a mdi_pathinfo node and add to the pHCI path list
2746  * Return Values:
2747  *		mdi_pathinfo
2748  */
2749 /*ARGSUSED*/
2750 static mdi_pathinfo_t *
2751 i_mdi_pi_alloc(mdi_phci_t *ph, char *paddr, mdi_client_t *ct)
2752 {
2753 	mdi_pathinfo_t	*pip;
2754 	int		ct_circular;
2755 	int		ph_circular;
2756 	int		se_flag;
2757 	int		kmem_flag;
2758 
2759 	ASSERT(MDI_VHCI_CLIENT_LOCKED(ph->ph_vhci));
2760 
2761 	pip = kmem_zalloc(sizeof (struct mdi_pathinfo), KM_SLEEP);
2762 	mutex_init(&MDI_PI(pip)->pi_mutex, NULL, MUTEX_DEFAULT, NULL);
2763 	MDI_PI(pip)->pi_state = MDI_PATHINFO_STATE_INIT |
2764 	    MDI_PATHINFO_STATE_TRANSIENT;
2765 
2766 	if (MDI_PHCI_IS_USER_DISABLED(ph))
2767 		MDI_PI_SET_USER_DISABLE(pip);
2768 
2769 	if (MDI_PHCI_IS_DRV_DISABLED_TRANSIENT(ph))
2770 		MDI_PI_SET_DRV_DISABLE_TRANS(pip);
2771 
2772 	if (MDI_PHCI_IS_DRV_DISABLED(ph))
2773 		MDI_PI_SET_DRV_DISABLE(pip);
2774 
2775 	MDI_PI(pip)->pi_old_state = MDI_PATHINFO_STATE_INIT;
2776 	cv_init(&MDI_PI(pip)->pi_state_cv, NULL, CV_DEFAULT, NULL);
2777 	MDI_PI(pip)->pi_client = ct;
2778 	MDI_PI(pip)->pi_phci = ph;
2779 	MDI_PI(pip)->pi_addr = kmem_alloc(strlen(paddr) + 1, KM_SLEEP);
2780 	(void) strcpy(MDI_PI(pip)->pi_addr, paddr);
2781 	(void) nvlist_alloc(&MDI_PI(pip)->pi_prop, NV_UNIQUE_NAME, KM_SLEEP);
2782 	ASSERT(MDI_PI(pip)->pi_prop != NULL);
2783 	MDI_PI(pip)->pi_pprivate = NULL;
2784 	MDI_PI(pip)->pi_cprivate = NULL;
2785 	MDI_PI(pip)->pi_vprivate = NULL;
2786 	MDI_PI(pip)->pi_client_link = NULL;
2787 	MDI_PI(pip)->pi_phci_link = NULL;
2788 	MDI_PI(pip)->pi_ref_cnt = 0;
2789 	MDI_PI(pip)->pi_kstats = NULL;
2790 	MDI_PI(pip)->pi_preferred = 1;
2791 	cv_init(&MDI_PI(pip)->pi_ref_cv, NULL, CV_DEFAULT, NULL);
2792 
2793 	/*
2794 	 * Lock both dev_info nodes against changes in parallel.
2795 	 *
2796 	 * The ndi_devi_enter(Client), is atypical since the client is a leaf.
2797 	 * This atypical operation is done to synchronize pathinfo nodes
2798 	 * during devinfo snapshot (see di_register_pip) by 'pretending' that
2799 	 * the pathinfo nodes are children of the Client.
2800 	 */
2801 	ndi_devi_enter(ct->ct_dip, &ct_circular);
2802 	ndi_devi_enter(ph->ph_dip, &ph_circular);
2803 
2804 	i_mdi_phci_add_path(ph, pip);
2805 	i_mdi_client_add_path(ct, pip);
2806 
2807 	ndi_devi_exit(ph->ph_dip, ph_circular);
2808 	ndi_devi_exit(ct->ct_dip, ct_circular);
2809 
2810 	/* determine interrupt context */
2811 	se_flag = (servicing_interrupt()) ? SE_NOSLEEP : SE_SLEEP;
2812 	kmem_flag = (se_flag == SE_SLEEP) ? KM_SLEEP : KM_NOSLEEP;
2813 
2814 	i_ddi_di_cache_invalidate(kmem_flag);
2815 
2816 	return (pip);
2817 }
2818 
2819 /*
2820  * i_mdi_phci_add_path():
2821  * 		Add a mdi_pathinfo node to pHCI list.
2822  * Notes:
2823  *		Caller should per-pHCI mutex
2824  */
2825 static void
2826 i_mdi_phci_add_path(mdi_phci_t *ph, mdi_pathinfo_t *pip)
2827 {
2828 	ASSERT(DEVI_BUSY_OWNED(ph->ph_dip));
2829 
2830 	MDI_PHCI_LOCK(ph);
2831 	if (ph->ph_path_head == NULL) {
2832 		ph->ph_path_head = pip;
2833 	} else {
2834 		MDI_PI(ph->ph_path_tail)->pi_phci_link = MDI_PI(pip);
2835 	}
2836 	ph->ph_path_tail = pip;
2837 	ph->ph_path_count++;
2838 	MDI_PHCI_UNLOCK(ph);
2839 }
2840 
2841 /*
2842  * i_mdi_client_add_path():
2843  *		Add mdi_pathinfo node to client list
2844  */
2845 static void
2846 i_mdi_client_add_path(mdi_client_t *ct, mdi_pathinfo_t *pip)
2847 {
2848 	ASSERT(DEVI_BUSY_OWNED(ct->ct_dip));
2849 
2850 	MDI_CLIENT_LOCK(ct);
2851 	if (ct->ct_path_head == NULL) {
2852 		ct->ct_path_head = pip;
2853 	} else {
2854 		MDI_PI(ct->ct_path_tail)->pi_client_link = MDI_PI(pip);
2855 	}
2856 	ct->ct_path_tail = pip;
2857 	ct->ct_path_count++;
2858 	MDI_CLIENT_UNLOCK(ct);
2859 }
2860 
2861 /*
2862  * mdi_pi_free():
2863  *		Free the mdi_pathinfo node and also client device node if this
2864  *		is the last path to the device
2865  * Return Values:
2866  *		MDI_SUCCESS
2867  *		MDI_FAILURE
2868  *		MDI_BUSY
2869  */
2870 /*ARGSUSED*/
2871 int
2872 mdi_pi_free(mdi_pathinfo_t *pip, int flags)
2873 {
2874 	int		rv = MDI_SUCCESS;
2875 	mdi_vhci_t	*vh;
2876 	mdi_phci_t	*ph;
2877 	mdi_client_t	*ct;
2878 	int		(*f)();
2879 	int		client_held = 0;
2880 
2881 	MDI_PI_LOCK(pip);
2882 	ph = MDI_PI(pip)->pi_phci;
2883 	ASSERT(ph != NULL);
2884 	if (ph == NULL) {
2885 		/*
2886 		 * Invalid pHCI device, return failure
2887 		 */
2888 		MDI_DEBUG(1, (CE_WARN, NULL,
2889 		    "!mdi_pi_free: invalid pHCI pip=%p", (void *)pip));
2890 		MDI_PI_UNLOCK(pip);
2891 		return (MDI_FAILURE);
2892 	}
2893 
2894 	vh = ph->ph_vhci;
2895 	ASSERT(vh != NULL);
2896 	if (vh == NULL) {
2897 		/* Invalid pHCI device, return failure */
2898 		MDI_DEBUG(1, (CE_WARN, NULL,
2899 		    "!mdi_pi_free: invalid vHCI pip=%p", (void *)pip));
2900 		MDI_PI_UNLOCK(pip);
2901 		return (MDI_FAILURE);
2902 	}
2903 
2904 	ct = MDI_PI(pip)->pi_client;
2905 	ASSERT(ct != NULL);
2906 	if (ct == NULL) {
2907 		/*
2908 		 * Invalid Client device, return failure
2909 		 */
2910 		MDI_DEBUG(1, (CE_WARN, NULL,
2911 		    "!mdi_pi_free: invalid client pip=%p", (void *)pip));
2912 		MDI_PI_UNLOCK(pip);
2913 		return (MDI_FAILURE);
2914 	}
2915 
2916 	/*
2917 	 * Check to see for busy condition.  A mdi_pathinfo can only be freed
2918 	 * if the node state is either offline or init and the reference count
2919 	 * is zero.
2920 	 */
2921 	if (!(MDI_PI_IS_OFFLINE(pip) || MDI_PI_IS_INIT(pip) ||
2922 	    MDI_PI_IS_INITING(pip))) {
2923 		/*
2924 		 * Node is busy
2925 		 */
2926 		MDI_DEBUG(1, (CE_WARN, ct->ct_dip,
2927 		    "!mdi_pi_free: pathinfo node is busy pip=%p", (void *)pip));
2928 		MDI_PI_UNLOCK(pip);
2929 		return (MDI_BUSY);
2930 	}
2931 
2932 	while (MDI_PI(pip)->pi_ref_cnt != 0) {
2933 		/*
2934 		 * Give a chance for pending I/Os to complete.
2935 		 */
2936 		MDI_DEBUG(1, (CE_NOTE, ct->ct_dip, "!mdi_pi_free: "
2937 		    "%d cmds still pending on path: %p\n",
2938 		    MDI_PI(pip)->pi_ref_cnt, (void *)pip));
2939 		if (cv_timedwait(&MDI_PI(pip)->pi_ref_cv,
2940 		    &MDI_PI(pip)->pi_mutex,
2941 		    ddi_get_lbolt() + drv_usectohz(60 * 1000000)) == -1) {
2942 			/*
2943 			 * The timeout time reached without ref_cnt being zero
2944 			 * being signaled.
2945 			 */
2946 			MDI_DEBUG(1, (CE_NOTE, ct->ct_dip,
2947 			    "!mdi_pi_free: "
2948 			    "Timeout reached on path %p without the cond\n",
2949 			    (void *)pip));
2950 			MDI_DEBUG(1, (CE_NOTE, ct->ct_dip,
2951 			    "!mdi_pi_free: "
2952 			    "%d cmds still pending on path: %p\n",
2953 			    MDI_PI(pip)->pi_ref_cnt, (void *)pip));
2954 			MDI_PI_UNLOCK(pip);
2955 			return (MDI_BUSY);
2956 		}
2957 	}
2958 	if (MDI_PI(pip)->pi_pm_held) {
2959 		client_held = 1;
2960 	}
2961 	MDI_PI_UNLOCK(pip);
2962 
2963 	vhcache_pi_remove(vh->vh_config, MDI_PI(pip));
2964 
2965 	MDI_CLIENT_LOCK(ct);
2966 
2967 	/* Prevent further failovers till MDI_VHCI_CLIENT_LOCK is held */
2968 	MDI_CLIENT_SET_PATH_FREE_IN_PROGRESS(ct);
2969 
2970 	/*
2971 	 * Wait till failover is complete before removing this node.
2972 	 */
2973 	while (MDI_CLIENT_IS_FAILOVER_IN_PROGRESS(ct))
2974 		cv_wait(&ct->ct_failover_cv, &ct->ct_mutex);
2975 
2976 	MDI_CLIENT_UNLOCK(ct);
2977 	MDI_VHCI_CLIENT_LOCK(vh);
2978 	MDI_CLIENT_LOCK(ct);
2979 	MDI_CLIENT_CLEAR_PATH_FREE_IN_PROGRESS(ct);
2980 
2981 	if (!MDI_PI_IS_INITING(pip)) {
2982 		f = vh->vh_ops->vo_pi_uninit;
2983 		if (f != NULL) {
2984 			rv = (*f)(vh->vh_dip, pip, 0);
2985 		}
2986 	}
2987 	/*
2988 	 * If vo_pi_uninit() completed successfully.
2989 	 */
2990 	if (rv == MDI_SUCCESS) {
2991 		if (client_held) {
2992 			MDI_DEBUG(4, (CE_NOTE, ct->ct_dip, "mdi_pi_free "
2993 			    "i_mdi_pm_rele_client\n"));
2994 			i_mdi_pm_rele_client(ct, 1);
2995 		}
2996 		i_mdi_pi_free(ph, pip, ct);
2997 		if (ct->ct_path_count == 0) {
2998 			/*
2999 			 * Client lost its last path.
3000 			 * Clean up the client device
3001 			 */
3002 			MDI_CLIENT_UNLOCK(ct);
3003 			(void) i_mdi_client_free(ct->ct_vhci, ct);
3004 			MDI_VHCI_CLIENT_UNLOCK(vh);
3005 			return (rv);
3006 		}
3007 	}
3008 	MDI_CLIENT_UNLOCK(ct);
3009 	MDI_VHCI_CLIENT_UNLOCK(vh);
3010 
3011 	if (rv == MDI_FAILURE)
3012 		vhcache_pi_add(vh->vh_config, MDI_PI(pip));
3013 
3014 	return (rv);
3015 }
3016 
3017 /*
3018  * i_mdi_pi_free():
3019  *		Free the mdi_pathinfo node
3020  */
3021 static void
3022 i_mdi_pi_free(mdi_phci_t *ph, mdi_pathinfo_t *pip, mdi_client_t *ct)
3023 {
3024 	int	ct_circular;
3025 	int	ph_circular;
3026 	int	se_flag;
3027 	int	kmem_flag;
3028 
3029 	ASSERT(MDI_CLIENT_LOCKED(ct));
3030 
3031 	/*
3032 	 * remove any per-path kstats
3033 	 */
3034 	i_mdi_pi_kstat_destroy(pip);
3035 
3036 	/* See comments in i_mdi_pi_alloc() */
3037 	ndi_devi_enter(ct->ct_dip, &ct_circular);
3038 	ndi_devi_enter(ph->ph_dip, &ph_circular);
3039 
3040 	i_mdi_client_remove_path(ct, pip);
3041 	i_mdi_phci_remove_path(ph, pip);
3042 
3043 	ndi_devi_exit(ph->ph_dip, ph_circular);
3044 	ndi_devi_exit(ct->ct_dip, ct_circular);
3045 
3046 	/* determine interrupt context */
3047 	se_flag = (servicing_interrupt()) ? SE_NOSLEEP : SE_SLEEP;
3048 	kmem_flag = (se_flag == SE_SLEEP) ? KM_SLEEP : KM_NOSLEEP;
3049 
3050 	i_ddi_di_cache_invalidate(kmem_flag);
3051 
3052 	mutex_destroy(&MDI_PI(pip)->pi_mutex);
3053 	cv_destroy(&MDI_PI(pip)->pi_state_cv);
3054 	cv_destroy(&MDI_PI(pip)->pi_ref_cv);
3055 	if (MDI_PI(pip)->pi_addr) {
3056 		kmem_free(MDI_PI(pip)->pi_addr,
3057 		    strlen(MDI_PI(pip)->pi_addr) + 1);
3058 		MDI_PI(pip)->pi_addr = NULL;
3059 	}
3060 
3061 	if (MDI_PI(pip)->pi_prop) {
3062 		(void) nvlist_free(MDI_PI(pip)->pi_prop);
3063 		MDI_PI(pip)->pi_prop = NULL;
3064 	}
3065 	kmem_free(pip, sizeof (struct mdi_pathinfo));
3066 }
3067 
3068 
3069 /*
3070  * i_mdi_phci_remove_path():
3071  * 		Remove a mdi_pathinfo node from pHCI list.
3072  * Notes:
3073  *		Caller should hold per-pHCI mutex
3074  */
3075 static void
3076 i_mdi_phci_remove_path(mdi_phci_t *ph, mdi_pathinfo_t *pip)
3077 {
3078 	mdi_pathinfo_t	*prev = NULL;
3079 	mdi_pathinfo_t	*path = NULL;
3080 
3081 	ASSERT(DEVI_BUSY_OWNED(ph->ph_dip));
3082 
3083 	MDI_PHCI_LOCK(ph);
3084 	path = ph->ph_path_head;
3085 	while (path != NULL) {
3086 		if (path == pip) {
3087 			break;
3088 		}
3089 		prev = path;
3090 		path = (mdi_pathinfo_t *)MDI_PI(path)->pi_phci_link;
3091 	}
3092 
3093 	if (path) {
3094 		ph->ph_path_count--;
3095 		if (prev) {
3096 			MDI_PI(prev)->pi_phci_link = MDI_PI(path)->pi_phci_link;
3097 		} else {
3098 			ph->ph_path_head =
3099 			    (mdi_pathinfo_t *)MDI_PI(path)->pi_phci_link;
3100 		}
3101 		if (ph->ph_path_tail == path) {
3102 			ph->ph_path_tail = prev;
3103 		}
3104 	}
3105 
3106 	/*
3107 	 * Clear the pHCI link
3108 	 */
3109 	MDI_PI(pip)->pi_phci_link = NULL;
3110 	MDI_PI(pip)->pi_phci = NULL;
3111 	MDI_PHCI_UNLOCK(ph);
3112 }
3113 
3114 /*
3115  * i_mdi_client_remove_path():
3116  * 		Remove a mdi_pathinfo node from client path list.
3117  */
3118 static void
3119 i_mdi_client_remove_path(mdi_client_t *ct, mdi_pathinfo_t *pip)
3120 {
3121 	mdi_pathinfo_t	*prev = NULL;
3122 	mdi_pathinfo_t	*path;
3123 
3124 	ASSERT(DEVI_BUSY_OWNED(ct->ct_dip));
3125 
3126 	ASSERT(MDI_CLIENT_LOCKED(ct));
3127 	path = ct->ct_path_head;
3128 	while (path != NULL) {
3129 		if (path == pip) {
3130 			break;
3131 		}
3132 		prev = path;
3133 		path = (mdi_pathinfo_t *)MDI_PI(path)->pi_client_link;
3134 	}
3135 
3136 	if (path) {
3137 		ct->ct_path_count--;
3138 		if (prev) {
3139 			MDI_PI(prev)->pi_client_link =
3140 			    MDI_PI(path)->pi_client_link;
3141 		} else {
3142 			ct->ct_path_head =
3143 			    (mdi_pathinfo_t *)MDI_PI(path)->pi_client_link;
3144 		}
3145 		if (ct->ct_path_tail == path) {
3146 			ct->ct_path_tail = prev;
3147 		}
3148 		if (ct->ct_path_last == path) {
3149 			ct->ct_path_last = ct->ct_path_head;
3150 		}
3151 	}
3152 	MDI_PI(pip)->pi_client_link = NULL;
3153 	MDI_PI(pip)->pi_client = NULL;
3154 }
3155 
3156 /*
3157  * i_mdi_pi_state_change():
3158  *		online a mdi_pathinfo node
3159  *
3160  * Return Values:
3161  *		MDI_SUCCESS
3162  *		MDI_FAILURE
3163  */
3164 /*ARGSUSED*/
3165 static int
3166 i_mdi_pi_state_change(mdi_pathinfo_t *pip, mdi_pathinfo_state_t state, int flag)
3167 {
3168 	int		rv = MDI_SUCCESS;
3169 	mdi_vhci_t	*vh;
3170 	mdi_phci_t	*ph;
3171 	mdi_client_t	*ct;
3172 	int		(*f)();
3173 	dev_info_t	*cdip;
3174 
3175 	MDI_PI_LOCK(pip);
3176 
3177 	ph = MDI_PI(pip)->pi_phci;
3178 	ASSERT(ph);
3179 	if (ph == NULL) {
3180 		/*
3181 		 * Invalid pHCI device, fail the request
3182 		 */
3183 		MDI_PI_UNLOCK(pip);
3184 		MDI_DEBUG(1, (CE_WARN, NULL,
3185 		    "!mdi_pi_state_change: invalid phci pip=%p", (void *)pip));
3186 		return (MDI_FAILURE);
3187 	}
3188 
3189 	vh = ph->ph_vhci;
3190 	ASSERT(vh);
3191 	if (vh == NULL) {
3192 		/*
3193 		 * Invalid vHCI device, fail the request
3194 		 */
3195 		MDI_PI_UNLOCK(pip);
3196 		MDI_DEBUG(1, (CE_WARN, NULL,
3197 		    "!mdi_pi_state_change: invalid vhci pip=%p", (void *)pip));
3198 		return (MDI_FAILURE);
3199 	}
3200 
3201 	ct = MDI_PI(pip)->pi_client;
3202 	ASSERT(ct != NULL);
3203 	if (ct == NULL) {
3204 		/*
3205 		 * Invalid client device, fail the request
3206 		 */
3207 		MDI_PI_UNLOCK(pip);
3208 		MDI_DEBUG(1, (CE_WARN, NULL,
3209 		    "!mdi_pi_state_change: invalid client pip=%p",
3210 		    (void *)pip));
3211 		return (MDI_FAILURE);
3212 	}
3213 
3214 	/*
3215 	 * If this path has not been initialized yet, Callback vHCI driver's
3216 	 * pathinfo node initialize entry point
3217 	 */
3218 
3219 	if (MDI_PI_IS_INITING(pip)) {
3220 		MDI_PI_UNLOCK(pip);
3221 		f = vh->vh_ops->vo_pi_init;
3222 		if (f != NULL) {
3223 			rv = (*f)(vh->vh_dip, pip, 0);
3224 			if (rv != MDI_SUCCESS) {
3225 				MDI_DEBUG(1, (CE_WARN, ct->ct_dip,
3226 				    "!vo_pi_init: failed vHCI=0x%p, pip=0x%p",
3227 				    (void *)vh, (void *)pip));
3228 				return (MDI_FAILURE);
3229 			}
3230 		}
3231 		MDI_PI_LOCK(pip);
3232 		MDI_PI_CLEAR_TRANSIENT(pip);
3233 	}
3234 
3235 	/*
3236 	 * Do not allow state transition when pHCI is in offline/suspended
3237 	 * states
3238 	 */
3239 	i_mdi_phci_lock(ph, pip);
3240 	if (MDI_PHCI_IS_READY(ph) == 0) {
3241 		MDI_DEBUG(1, (CE_WARN, ct->ct_dip,
3242 		    "!mdi_pi_state_change: pHCI not ready, pHCI=%p",
3243 		    (void *)ph));
3244 		MDI_PI_UNLOCK(pip);
3245 		i_mdi_phci_unlock(ph);
3246 		return (MDI_BUSY);
3247 	}
3248 	MDI_PHCI_UNSTABLE(ph);
3249 	i_mdi_phci_unlock(ph);
3250 
3251 	/*
3252 	 * Check if mdi_pathinfo state is in transient state.
3253 	 * If yes, offlining is in progress and wait till transient state is
3254 	 * cleared.
3255 	 */
3256 	if (MDI_PI_IS_TRANSIENT(pip)) {
3257 		while (MDI_PI_IS_TRANSIENT(pip)) {
3258 			cv_wait(&MDI_PI(pip)->pi_state_cv,
3259 			    &MDI_PI(pip)->pi_mutex);
3260 		}
3261 	}
3262 
3263 	/*
3264 	 * Grab the client lock in reverse order sequence and release the
3265 	 * mdi_pathinfo mutex.
3266 	 */
3267 	i_mdi_client_lock(ct, pip);
3268 	MDI_PI_UNLOCK(pip);
3269 
3270 	/*
3271 	 * Wait till failover state is cleared
3272 	 */
3273 	while (MDI_CLIENT_IS_FAILOVER_IN_PROGRESS(ct))
3274 		cv_wait(&ct->ct_failover_cv, &ct->ct_mutex);
3275 
3276 	/*
3277 	 * Mark the mdi_pathinfo node state as transient
3278 	 */
3279 	MDI_PI_LOCK(pip);
3280 	switch (state) {
3281 	case MDI_PATHINFO_STATE_ONLINE:
3282 		MDI_PI_SET_ONLINING(pip);
3283 		break;
3284 
3285 	case MDI_PATHINFO_STATE_STANDBY:
3286 		MDI_PI_SET_STANDBYING(pip);
3287 		break;
3288 
3289 	case MDI_PATHINFO_STATE_FAULT:
3290 		/*
3291 		 * Mark the pathinfo state as FAULTED
3292 		 */
3293 		MDI_PI_SET_FAULTING(pip);
3294 		MDI_PI_ERRSTAT(pip, MDI_PI_HARDERR);
3295 		break;
3296 
3297 	case MDI_PATHINFO_STATE_OFFLINE:
3298 		/*
3299 		 * ndi_devi_offline() cannot hold pip or ct locks.
3300 		 */
3301 		MDI_PI_UNLOCK(pip);
3302 		/*
3303 		 * Don't offline the client dev_info node unless we have
3304 		 * no available paths left at all.
3305 		 */
3306 		cdip = ct->ct_dip;
3307 		if ((flag & NDI_DEVI_REMOVE) &&
3308 		    (MDI_CLIENT_STATE(ct) == MDI_CLIENT_STATE_DEGRADED) &&
3309 		    (ct->ct_path_count == 1)) {
3310 			i_mdi_client_unlock(ct);
3311 			rv = ndi_devi_offline(cdip, 0);
3312 			if (rv != NDI_SUCCESS) {
3313 				/*
3314 				 * Convert to MDI error code
3315 				 */
3316 				switch (rv) {
3317 				case NDI_BUSY:
3318 					rv = MDI_BUSY;
3319 					break;
3320 				default:
3321 					rv = MDI_FAILURE;
3322 					break;
3323 				}
3324 				goto state_change_exit;
3325 			} else {
3326 				i_mdi_client_lock(ct, NULL);
3327 			}
3328 		}
3329 		/*
3330 		 * Mark the mdi_pathinfo node state as transient
3331 		 */
3332 		MDI_PI_LOCK(pip);
3333 		MDI_PI_SET_OFFLINING(pip);
3334 		break;
3335 	}
3336 	MDI_PI_UNLOCK(pip);
3337 	MDI_CLIENT_UNSTABLE(ct);
3338 	i_mdi_client_unlock(ct);
3339 
3340 	f = vh->vh_ops->vo_pi_state_change;
3341 	if (f != NULL)
3342 		rv = (*f)(vh->vh_dip, pip, state, 0, flag);
3343 
3344 	MDI_CLIENT_LOCK(ct);
3345 	MDI_PI_LOCK(pip);
3346 	if (rv == MDI_NOT_SUPPORTED) {
3347 		MDI_CLIENT_SET_DEV_NOT_SUPPORTED(ct);
3348 	}
3349 	if (rv != MDI_SUCCESS) {
3350 		MDI_DEBUG(2, (CE_WARN, ct->ct_dip,
3351 		    "!vo_pi_state_change: failed rv = %x", rv));
3352 	}
3353 	if (MDI_PI_IS_TRANSIENT(pip)) {
3354 		if (rv == MDI_SUCCESS) {
3355 			MDI_PI_CLEAR_TRANSIENT(pip);
3356 		} else {
3357 			MDI_PI(pip)->pi_state = MDI_PI_OLD_STATE(pip);
3358 		}
3359 	}
3360 
3361 	/*
3362 	 * Wake anyone waiting for this mdi_pathinfo node
3363 	 */
3364 	cv_broadcast(&MDI_PI(pip)->pi_state_cv);
3365 	MDI_PI_UNLOCK(pip);
3366 
3367 	/*
3368 	 * Mark the client device as stable
3369 	 */
3370 	MDI_CLIENT_STABLE(ct);
3371 	if (rv == MDI_SUCCESS) {
3372 		if (ct->ct_unstable == 0) {
3373 			cdip = ct->ct_dip;
3374 
3375 			/*
3376 			 * Onlining the mdi_pathinfo node will impact the
3377 			 * client state Update the client and dev_info node
3378 			 * state accordingly
3379 			 */
3380 			rv = NDI_SUCCESS;
3381 			i_mdi_client_update_state(ct);
3382 			switch (MDI_CLIENT_STATE(ct)) {
3383 			case MDI_CLIENT_STATE_OPTIMAL:
3384 			case MDI_CLIENT_STATE_DEGRADED:
3385 				if (cdip && !i_ddi_devi_attached(cdip) &&
3386 				    ((state == MDI_PATHINFO_STATE_ONLINE) ||
3387 				    (state == MDI_PATHINFO_STATE_STANDBY))) {
3388 
3389 					/*
3390 					 * Must do ndi_devi_online() through
3391 					 * hotplug thread for deferred
3392 					 * attach mechanism to work
3393 					 */
3394 					MDI_CLIENT_UNLOCK(ct);
3395 					rv = ndi_devi_online(cdip, 0);
3396 					MDI_CLIENT_LOCK(ct);
3397 					if ((rv != NDI_SUCCESS) &&
3398 					    (MDI_CLIENT_STATE(ct) ==
3399 					    MDI_CLIENT_STATE_DEGRADED)) {
3400 						/*
3401 						 * ndi_devi_online failed.
3402 						 * Reset client flags to
3403 						 * offline.
3404 						 */
3405 						MDI_DEBUG(1, (CE_WARN, cdip,
3406 						    "!ndi_devi_online: failed "
3407 						    " Error: %x", rv));
3408 						MDI_CLIENT_SET_OFFLINE(ct);
3409 					}
3410 					if (rv != NDI_SUCCESS) {
3411 						/* Reset the path state */
3412 						MDI_PI_LOCK(pip);
3413 						MDI_PI(pip)->pi_state =
3414 						    MDI_PI_OLD_STATE(pip);
3415 						MDI_PI_UNLOCK(pip);
3416 					}
3417 				}
3418 				break;
3419 
3420 			case MDI_CLIENT_STATE_FAILED:
3421 				/*
3422 				 * This is the last path case for
3423 				 * non-user initiated events.
3424 				 */
3425 				if (((flag & NDI_DEVI_REMOVE) == 0) &&
3426 				    cdip && (i_ddi_node_state(cdip) >=
3427 				    DS_INITIALIZED)) {
3428 					MDI_CLIENT_UNLOCK(ct);
3429 					rv = ndi_devi_offline(cdip, 0);
3430 					MDI_CLIENT_LOCK(ct);
3431 
3432 					if (rv != NDI_SUCCESS) {
3433 						/*
3434 						 * ndi_devi_offline failed.
3435 						 * Reset client flags to
3436 						 * online as the path could not
3437 						 * be offlined.
3438 						 */
3439 						MDI_DEBUG(1, (CE_WARN, cdip,
3440 						    "!ndi_devi_offline: failed "
3441 						    " Error: %x", rv));
3442 						MDI_CLIENT_SET_ONLINE(ct);
3443 					}
3444 				}
3445 				break;
3446 			}
3447 			/*
3448 			 * Convert to MDI error code
3449 			 */
3450 			switch (rv) {
3451 			case NDI_SUCCESS:
3452 				MDI_CLIENT_SET_REPORT_DEV_NEEDED(ct);
3453 				i_mdi_report_path_state(ct, pip);
3454 				rv = MDI_SUCCESS;
3455 				break;
3456 			case NDI_BUSY:
3457 				rv = MDI_BUSY;
3458 				break;
3459 			default:
3460 				rv = MDI_FAILURE;
3461 				break;
3462 			}
3463 		}
3464 	}
3465 	MDI_CLIENT_UNLOCK(ct);
3466 
3467 state_change_exit:
3468 	/*
3469 	 * Mark the pHCI as stable again.
3470 	 */
3471 	MDI_PHCI_LOCK(ph);
3472 	MDI_PHCI_STABLE(ph);
3473 	MDI_PHCI_UNLOCK(ph);
3474 	return (rv);
3475 }
3476 
3477 /*
3478  * mdi_pi_online():
3479  *		Place the path_info node in the online state.  The path is
3480  *		now available to be selected by mdi_select_path() for
3481  *		transporting I/O requests to client devices.
3482  * Return Values:
3483  *		MDI_SUCCESS
3484  *		MDI_FAILURE
3485  */
3486 int
3487 mdi_pi_online(mdi_pathinfo_t *pip, int flags)
3488 {
3489 	mdi_client_t	*ct = MDI_PI(pip)->pi_client;
3490 	int		client_held = 0;
3491 	int		rv;
3492 
3493 	ASSERT(ct != NULL);
3494 	rv = i_mdi_pi_state_change(pip, MDI_PATHINFO_STATE_ONLINE, flags);
3495 	if (rv != MDI_SUCCESS)
3496 		return (rv);
3497 
3498 	MDI_PI_LOCK(pip);
3499 	if (MDI_PI(pip)->pi_pm_held == 0) {
3500 		MDI_DEBUG(4, (CE_NOTE, ct->ct_dip, "mdi_pi_online "
3501 		    "i_mdi_pm_hold_pip %p\n", (void *)pip));
3502 		i_mdi_pm_hold_pip(pip);
3503 		client_held = 1;
3504 	}
3505 	MDI_PI_UNLOCK(pip);
3506 
3507 	if (client_held) {
3508 		MDI_CLIENT_LOCK(ct);
3509 		if (ct->ct_power_cnt == 0) {
3510 			rv = i_mdi_power_all_phci(ct);
3511 		}
3512 
3513 		MDI_DEBUG(4, (CE_NOTE, ct->ct_dip, "mdi_pi_online "
3514 		    "i_mdi_pm_hold_client %p\n", (void *)ct));
3515 		i_mdi_pm_hold_client(ct, 1);
3516 		MDI_CLIENT_UNLOCK(ct);
3517 	}
3518 
3519 	return (rv);
3520 }
3521 
3522 /*
3523  * mdi_pi_standby():
3524  *		Place the mdi_pathinfo node in standby state
3525  *
3526  * Return Values:
3527  *		MDI_SUCCESS
3528  *		MDI_FAILURE
3529  */
3530 int
3531 mdi_pi_standby(mdi_pathinfo_t *pip, int flags)
3532 {
3533 	return (i_mdi_pi_state_change(pip, MDI_PATHINFO_STATE_STANDBY, flags));
3534 }
3535 
3536 /*
3537  * mdi_pi_fault():
3538  *		Place the mdi_pathinfo node in fault'ed state
3539  * Return Values:
3540  *		MDI_SUCCESS
3541  *		MDI_FAILURE
3542  */
3543 int
3544 mdi_pi_fault(mdi_pathinfo_t *pip, int flags)
3545 {
3546 	return (i_mdi_pi_state_change(pip, MDI_PATHINFO_STATE_FAULT, flags));
3547 }
3548 
3549 /*
3550  * mdi_pi_offline():
3551  *		Offline a mdi_pathinfo node.
3552  * Return Values:
3553  *		MDI_SUCCESS
3554  *		MDI_FAILURE
3555  */
3556 int
3557 mdi_pi_offline(mdi_pathinfo_t *pip, int flags)
3558 {
3559 	int	ret, client_held = 0;
3560 	mdi_client_t	*ct;
3561 
3562 	ret = i_mdi_pi_state_change(pip, MDI_PATHINFO_STATE_OFFLINE, flags);
3563 
3564 	if (ret == MDI_SUCCESS) {
3565 		MDI_PI_LOCK(pip);
3566 		if (MDI_PI(pip)->pi_pm_held) {
3567 			client_held = 1;
3568 		}
3569 		MDI_PI_UNLOCK(pip);
3570 
3571 		if (client_held) {
3572 			ct = MDI_PI(pip)->pi_client;
3573 			MDI_CLIENT_LOCK(ct);
3574 			MDI_DEBUG(4, (CE_NOTE, ct->ct_dip,
3575 			    "mdi_pi_offline i_mdi_pm_rele_client\n"));
3576 			i_mdi_pm_rele_client(ct, 1);
3577 			MDI_CLIENT_UNLOCK(ct);
3578 		}
3579 	}
3580 
3581 	return (ret);
3582 }
3583 
3584 /*
3585  * i_mdi_pi_offline():
3586  *		Offline a mdi_pathinfo node and call the vHCI driver's callback
3587  */
3588 static int
3589 i_mdi_pi_offline(mdi_pathinfo_t *pip, int flags)
3590 {
3591 	dev_info_t	*vdip = NULL;
3592 	mdi_vhci_t	*vh = NULL;
3593 	mdi_client_t	*ct = NULL;
3594 	int		(*f)();
3595 	int		rv;
3596 
3597 	MDI_PI_LOCK(pip);
3598 	ct = MDI_PI(pip)->pi_client;
3599 	ASSERT(ct != NULL);
3600 
3601 	while (MDI_PI(pip)->pi_ref_cnt != 0) {
3602 		/*
3603 		 * Give a chance for pending I/Os to complete.
3604 		 */
3605 		MDI_DEBUG(1, (CE_NOTE, ct->ct_dip, "!i_mdi_pi_offline: "
3606 		    "%d cmds still pending on path: %p\n",
3607 		    MDI_PI(pip)->pi_ref_cnt, (void *)pip));
3608 		if (cv_timedwait(&MDI_PI(pip)->pi_ref_cv,
3609 		    &MDI_PI(pip)->pi_mutex,
3610 		    ddi_get_lbolt() + drv_usectohz(60 * 1000000)) == -1) {
3611 			/*
3612 			 * The timeout time reached without ref_cnt being zero
3613 			 * being signaled.
3614 			 */
3615 			MDI_DEBUG(1, (CE_NOTE, ct->ct_dip, "!i_mdi_pi_offline: "
3616 			    "Timeout reached on path %p without the cond\n",
3617 			    (void *)pip));
3618 			MDI_DEBUG(1, (CE_NOTE, ct->ct_dip, "!i_mdi_pi_offline: "
3619 			    "%d cmds still pending on path: %p\n",
3620 			    MDI_PI(pip)->pi_ref_cnt, (void *)pip));
3621 		}
3622 	}
3623 	vh = ct->ct_vhci;
3624 	vdip = vh->vh_dip;
3625 
3626 	/*
3627 	 * Notify vHCI that has registered this event
3628 	 */
3629 	ASSERT(vh->vh_ops);
3630 	f = vh->vh_ops->vo_pi_state_change;
3631 
3632 	if (f != NULL) {
3633 		MDI_PI_UNLOCK(pip);
3634 		if ((rv = (*f)(vdip, pip, MDI_PATHINFO_STATE_OFFLINE, 0,
3635 		    flags)) != MDI_SUCCESS) {
3636 			MDI_DEBUG(1, (CE_WARN, ct->ct_dip,
3637 			    "!vo_path_offline failed "
3638 			    "vdip %p, pip %p", (void *)vdip, (void *)pip));
3639 		}
3640 		MDI_PI_LOCK(pip);
3641 	}
3642 
3643 	/*
3644 	 * Set the mdi_pathinfo node state and clear the transient condition
3645 	 */
3646 	MDI_PI_SET_OFFLINE(pip);
3647 	cv_broadcast(&MDI_PI(pip)->pi_state_cv);
3648 	MDI_PI_UNLOCK(pip);
3649 
3650 	MDI_CLIENT_LOCK(ct);
3651 	if (rv == MDI_SUCCESS) {
3652 		if (ct->ct_unstable == 0) {
3653 			dev_info_t	*cdip = ct->ct_dip;
3654 
3655 			/*
3656 			 * Onlining the mdi_pathinfo node will impact the
3657 			 * client state Update the client and dev_info node
3658 			 * state accordingly
3659 			 */
3660 			i_mdi_client_update_state(ct);
3661 			rv = NDI_SUCCESS;
3662 			if (MDI_CLIENT_STATE(ct) == MDI_CLIENT_STATE_FAILED) {
3663 				if (cdip &&
3664 				    (i_ddi_node_state(cdip) >=
3665 				    DS_INITIALIZED)) {
3666 					MDI_CLIENT_UNLOCK(ct);
3667 					rv = ndi_devi_offline(cdip, 0);
3668 					MDI_CLIENT_LOCK(ct);
3669 					if (rv != NDI_SUCCESS) {
3670 						/*
3671 						 * ndi_devi_offline failed.
3672 						 * Reset client flags to
3673 						 * online.
3674 						 */
3675 						MDI_DEBUG(4, (CE_WARN, cdip,
3676 						    "!ndi_devi_offline: failed "
3677 						    " Error: %x", rv));
3678 						MDI_CLIENT_SET_ONLINE(ct);
3679 					}
3680 				}
3681 			}
3682 			/*
3683 			 * Convert to MDI error code
3684 			 */
3685 			switch (rv) {
3686 			case NDI_SUCCESS:
3687 				rv = MDI_SUCCESS;
3688 				break;
3689 			case NDI_BUSY:
3690 				rv = MDI_BUSY;
3691 				break;
3692 			default:
3693 				rv = MDI_FAILURE;
3694 				break;
3695 			}
3696 		}
3697 		MDI_CLIENT_SET_REPORT_DEV_NEEDED(ct);
3698 		i_mdi_report_path_state(ct, pip);
3699 	}
3700 
3701 	MDI_CLIENT_UNLOCK(ct);
3702 
3703 	/*
3704 	 * Change in the mdi_pathinfo node state will impact the client state
3705 	 */
3706 	MDI_DEBUG(2, (CE_NOTE, NULL, "!i_mdi_pi_offline ct = %p pip = %p",
3707 	    (void *)ct, (void *)pip));
3708 	return (rv);
3709 }
3710 
3711 
3712 /*
3713  * mdi_pi_get_addr():
3714  *		Get the unit address associated with a mdi_pathinfo node
3715  *
3716  * Return Values:
3717  *		char *
3718  */
3719 char *
3720 mdi_pi_get_addr(mdi_pathinfo_t *pip)
3721 {
3722 	if (pip == NULL)
3723 		return (NULL);
3724 
3725 	return (MDI_PI(pip)->pi_addr);
3726 }
3727 
3728 /*
3729  * mdi_pi_get_client():
3730  *		Get the client devinfo associated with a mdi_pathinfo node
3731  *
3732  * Return Values:
3733  *		Handle to client device dev_info node
3734  */
3735 dev_info_t *
3736 mdi_pi_get_client(mdi_pathinfo_t *pip)
3737 {
3738 	dev_info_t	*dip = NULL;
3739 	if (pip) {
3740 		dip = MDI_PI(pip)->pi_client->ct_dip;
3741 	}
3742 	return (dip);
3743 }
3744 
3745 /*
3746  * mdi_pi_get_phci():
3747  *		Get the pHCI devinfo associated with the mdi_pathinfo node
3748  * Return Values:
3749  *		Handle to dev_info node
3750  */
3751 dev_info_t *
3752 mdi_pi_get_phci(mdi_pathinfo_t *pip)
3753 {
3754 	dev_info_t	*dip = NULL;
3755 	if (pip) {
3756 		dip = MDI_PI(pip)->pi_phci->ph_dip;
3757 	}
3758 	return (dip);
3759 }
3760 
3761 /*
3762  * mdi_pi_get_client_private():
3763  *		Get the client private information associated with the
3764  *		mdi_pathinfo node
3765  */
3766 void *
3767 mdi_pi_get_client_private(mdi_pathinfo_t *pip)
3768 {
3769 	void *cprivate = NULL;
3770 	if (pip) {
3771 		cprivate = MDI_PI(pip)->pi_cprivate;
3772 	}
3773 	return (cprivate);
3774 }
3775 
3776 /*
3777  * mdi_pi_set_client_private():
3778  *		Set the client private information in the mdi_pathinfo node
3779  */
3780 void
3781 mdi_pi_set_client_private(mdi_pathinfo_t *pip, void *priv)
3782 {
3783 	if (pip) {
3784 		MDI_PI(pip)->pi_cprivate = priv;
3785 	}
3786 }
3787 
3788 /*
3789  * mdi_pi_get_phci_private():
3790  *		Get the pHCI private information associated with the
3791  *		mdi_pathinfo node
3792  */
3793 caddr_t
3794 mdi_pi_get_phci_private(mdi_pathinfo_t *pip)
3795 {
3796 	caddr_t	pprivate = NULL;
3797 	if (pip) {
3798 		pprivate = MDI_PI(pip)->pi_pprivate;
3799 	}
3800 	return (pprivate);
3801 }
3802 
3803 /*
3804  * mdi_pi_set_phci_private():
3805  *		Set the pHCI private information in the mdi_pathinfo node
3806  */
3807 void
3808 mdi_pi_set_phci_private(mdi_pathinfo_t *pip, caddr_t priv)
3809 {
3810 	if (pip) {
3811 		MDI_PI(pip)->pi_pprivate = priv;
3812 	}
3813 }
3814 
3815 /*
3816  * mdi_pi_get_state():
3817  *		Get the mdi_pathinfo node state. Transient states are internal
3818  *		and not provided to the users
3819  */
3820 mdi_pathinfo_state_t
3821 mdi_pi_get_state(mdi_pathinfo_t *pip)
3822 {
3823 	mdi_pathinfo_state_t    state = MDI_PATHINFO_STATE_INIT;
3824 
3825 	if (pip) {
3826 		if (MDI_PI_IS_TRANSIENT(pip)) {
3827 			/*
3828 			 * mdi_pathinfo is in state transition.  Return the
3829 			 * last good state.
3830 			 */
3831 			state = MDI_PI_OLD_STATE(pip);
3832 		} else {
3833 			state = MDI_PI_STATE(pip);
3834 		}
3835 	}
3836 	return (state);
3837 }
3838 
3839 /*
3840  * Note that the following function needs to be the new interface for
3841  * mdi_pi_get_state when mpxio gets integrated to ON.
3842  */
3843 int
3844 mdi_pi_get_state2(mdi_pathinfo_t *pip, mdi_pathinfo_state_t *state,
3845 		uint32_t *ext_state)
3846 {
3847 	*state = MDI_PATHINFO_STATE_INIT;
3848 
3849 	if (pip) {
3850 		if (MDI_PI_IS_TRANSIENT(pip)) {
3851 			/*
3852 			 * mdi_pathinfo is in state transition.  Return the
3853 			 * last good state.
3854 			 */
3855 			*state = MDI_PI_OLD_STATE(pip);
3856 			*ext_state = MDI_PI_OLD_EXT_STATE(pip);
3857 		} else {
3858 			*state = MDI_PI_STATE(pip);
3859 			*ext_state = MDI_PI_EXT_STATE(pip);
3860 		}
3861 	}
3862 	return (MDI_SUCCESS);
3863 }
3864 
3865 /*
3866  * mdi_pi_get_preferred:
3867  *	Get the preferred path flag
3868  */
3869 int
3870 mdi_pi_get_preferred(mdi_pathinfo_t *pip)
3871 {
3872 	if (pip) {
3873 		return (MDI_PI(pip)->pi_preferred);
3874 	}
3875 	return (0);
3876 }
3877 
3878 /*
3879  * mdi_pi_set_preferred:
3880  *	Set the preferred path flag
3881  */
3882 void
3883 mdi_pi_set_preferred(mdi_pathinfo_t *pip, int preferred)
3884 {
3885 	if (pip) {
3886 		MDI_PI(pip)->pi_preferred = preferred;
3887 	}
3888 }
3889 
3890 /*
3891  * mdi_pi_set_state():
3892  *		Set the mdi_pathinfo node state
3893  */
3894 void
3895 mdi_pi_set_state(mdi_pathinfo_t *pip, mdi_pathinfo_state_t state)
3896 {
3897 	uint32_t	ext_state;
3898 
3899 	if (pip) {
3900 		ext_state = MDI_PI(pip)->pi_state & MDI_PATHINFO_EXT_STATE_MASK;
3901 		MDI_PI(pip)->pi_state = state;
3902 		MDI_PI(pip)->pi_state |= ext_state;
3903 	}
3904 }
3905 
3906 /*
3907  * Property functions:
3908  */
3909 int
3910 i_map_nvlist_error_to_mdi(int val)
3911 {
3912 	int rv;
3913 
3914 	switch (val) {
3915 	case 0:
3916 		rv = DDI_PROP_SUCCESS;
3917 		break;
3918 	case EINVAL:
3919 	case ENOTSUP:
3920 		rv = DDI_PROP_INVAL_ARG;
3921 		break;
3922 	case ENOMEM:
3923 		rv = DDI_PROP_NO_MEMORY;
3924 		break;
3925 	default:
3926 		rv = DDI_PROP_NOT_FOUND;
3927 		break;
3928 	}
3929 	return (rv);
3930 }
3931 
3932 /*
3933  * mdi_pi_get_next_prop():
3934  * 		Property walk function.  The caller should hold mdi_pi_lock()
3935  *		and release by calling mdi_pi_unlock() at the end of walk to
3936  *		get a consistent value.
3937  */
3938 nvpair_t *
3939 mdi_pi_get_next_prop(mdi_pathinfo_t *pip, nvpair_t *prev)
3940 {
3941 	if ((pip == NULL) || (MDI_PI(pip)->pi_prop == NULL)) {
3942 		return (NULL);
3943 	}
3944 	ASSERT(MDI_PI_LOCKED(pip));
3945 	return (nvlist_next_nvpair(MDI_PI(pip)->pi_prop, prev));
3946 }
3947 
3948 /*
3949  * mdi_prop_remove():
3950  * 		Remove the named property from the named list.
3951  */
3952 int
3953 mdi_prop_remove(mdi_pathinfo_t *pip, char *name)
3954 {
3955 	if (pip == NULL) {
3956 		return (DDI_PROP_NOT_FOUND);
3957 	}
3958 	ASSERT(!MDI_PI_LOCKED(pip));
3959 	MDI_PI_LOCK(pip);
3960 	if (MDI_PI(pip)->pi_prop == NULL) {
3961 		MDI_PI_UNLOCK(pip);
3962 		return (DDI_PROP_NOT_FOUND);
3963 	}
3964 	if (name) {
3965 		(void) nvlist_remove_all(MDI_PI(pip)->pi_prop, name);
3966 	} else {
3967 		char		nvp_name[MAXNAMELEN];
3968 		nvpair_t	*nvp;
3969 		nvp = nvlist_next_nvpair(MDI_PI(pip)->pi_prop, NULL);
3970 		while (nvp) {
3971 			nvpair_t	*next;
3972 			next = nvlist_next_nvpair(MDI_PI(pip)->pi_prop, nvp);
3973 			(void) snprintf(nvp_name, MAXNAMELEN, "%s",
3974 			    nvpair_name(nvp));
3975 			(void) nvlist_remove_all(MDI_PI(pip)->pi_prop,
3976 			    nvp_name);
3977 			nvp = next;
3978 		}
3979 	}
3980 	MDI_PI_UNLOCK(pip);
3981 	return (DDI_PROP_SUCCESS);
3982 }
3983 
3984 /*
3985  * mdi_prop_size():
3986  * 		Get buffer size needed to pack the property data.
3987  * 		Caller should hold the mdi_pathinfo_t lock to get a consistent
3988  *		buffer size.
3989  */
3990 int
3991 mdi_prop_size(mdi_pathinfo_t *pip, size_t *buflenp)
3992 {
3993 	int	rv;
3994 	size_t	bufsize;
3995 
3996 	*buflenp = 0;
3997 	if ((pip == NULL) || (MDI_PI(pip)->pi_prop == NULL)) {
3998 		return (DDI_PROP_NOT_FOUND);
3999 	}
4000 	ASSERT(MDI_PI_LOCKED(pip));
4001 	rv = nvlist_size(MDI_PI(pip)->pi_prop,
4002 	    &bufsize, NV_ENCODE_NATIVE);
4003 	*buflenp = bufsize;
4004 	return (i_map_nvlist_error_to_mdi(rv));
4005 }
4006 
4007 /*
4008  * mdi_prop_pack():
4009  * 		pack the property list.  The caller should hold the
4010  *		mdi_pathinfo_t node to get a consistent data
4011  */
4012 int
4013 mdi_prop_pack(mdi_pathinfo_t *pip, char **bufp, uint_t buflen)
4014 {
4015 	int	rv;
4016 	size_t	bufsize;
4017 
4018 	if ((pip == NULL) || MDI_PI(pip)->pi_prop == NULL) {
4019 		return (DDI_PROP_NOT_FOUND);
4020 	}
4021 
4022 	ASSERT(MDI_PI_LOCKED(pip));
4023 
4024 	bufsize = buflen;
4025 	rv = nvlist_pack(MDI_PI(pip)->pi_prop, bufp, (size_t *)&bufsize,
4026 	    NV_ENCODE_NATIVE, KM_SLEEP);
4027 
4028 	return (i_map_nvlist_error_to_mdi(rv));
4029 }
4030 
4031 /*
4032  * mdi_prop_update_byte():
4033  *		Create/Update a byte property
4034  */
4035 int
4036 mdi_prop_update_byte(mdi_pathinfo_t *pip, char *name, uchar_t data)
4037 {
4038 	int rv;
4039 
4040 	if (pip == NULL) {
4041 		return (DDI_PROP_INVAL_ARG);
4042 	}
4043 	ASSERT(!MDI_PI_LOCKED(pip));
4044 	MDI_PI_LOCK(pip);
4045 	if (MDI_PI(pip)->pi_prop == NULL) {
4046 		MDI_PI_UNLOCK(pip);
4047 		return (DDI_PROP_NOT_FOUND);
4048 	}
4049 	rv = nvlist_add_byte(MDI_PI(pip)->pi_prop, name, data);
4050 	MDI_PI_UNLOCK(pip);
4051 	return (i_map_nvlist_error_to_mdi(rv));
4052 }
4053 
4054 /*
4055  * mdi_prop_update_byte_array():
4056  *		Create/Update a byte array property
4057  */
4058 int
4059 mdi_prop_update_byte_array(mdi_pathinfo_t *pip, char *name, uchar_t *data,
4060     uint_t nelements)
4061 {
4062 	int rv;
4063 
4064 	if (pip == NULL) {
4065 		return (DDI_PROP_INVAL_ARG);
4066 	}
4067 	ASSERT(!MDI_PI_LOCKED(pip));
4068 	MDI_PI_LOCK(pip);
4069 	if (MDI_PI(pip)->pi_prop == NULL) {
4070 		MDI_PI_UNLOCK(pip);
4071 		return (DDI_PROP_NOT_FOUND);
4072 	}
4073 	rv = nvlist_add_byte_array(MDI_PI(pip)->pi_prop, name, data, nelements);
4074 	MDI_PI_UNLOCK(pip);
4075 	return (i_map_nvlist_error_to_mdi(rv));
4076 }
4077 
4078 /*
4079  * mdi_prop_update_int():
4080  *		Create/Update a 32 bit integer property
4081  */
4082 int
4083 mdi_prop_update_int(mdi_pathinfo_t *pip, char *name, int data)
4084 {
4085 	int rv;
4086 
4087 	if (pip == NULL) {
4088 		return (DDI_PROP_INVAL_ARG);
4089 	}
4090 	ASSERT(!MDI_PI_LOCKED(pip));
4091 	MDI_PI_LOCK(pip);
4092 	if (MDI_PI(pip)->pi_prop == NULL) {
4093 		MDI_PI_UNLOCK(pip);
4094 		return (DDI_PROP_NOT_FOUND);
4095 	}
4096 	rv = nvlist_add_int32(MDI_PI(pip)->pi_prop, name, (int32_t)data);
4097 	MDI_PI_UNLOCK(pip);
4098 	return (i_map_nvlist_error_to_mdi(rv));
4099 }
4100 
4101 /*
4102  * mdi_prop_update_int64():
4103  *		Create/Update a 64 bit integer property
4104  */
4105 int
4106 mdi_prop_update_int64(mdi_pathinfo_t *pip, char *name, int64_t data)
4107 {
4108 	int rv;
4109 
4110 	if (pip == NULL) {
4111 		return (DDI_PROP_INVAL_ARG);
4112 	}
4113 	ASSERT(!MDI_PI_LOCKED(pip));
4114 	MDI_PI_LOCK(pip);
4115 	if (MDI_PI(pip)->pi_prop == NULL) {
4116 		MDI_PI_UNLOCK(pip);
4117 		return (DDI_PROP_NOT_FOUND);
4118 	}
4119 	rv = nvlist_add_int64(MDI_PI(pip)->pi_prop, name, data);
4120 	MDI_PI_UNLOCK(pip);
4121 	return (i_map_nvlist_error_to_mdi(rv));
4122 }
4123 
4124 /*
4125  * mdi_prop_update_int_array():
4126  *		Create/Update a int array property
4127  */
4128 int
4129 mdi_prop_update_int_array(mdi_pathinfo_t *pip, char *name, int *data,
4130 	    uint_t nelements)
4131 {
4132 	int rv;
4133 
4134 	if (pip == NULL) {
4135 		return (DDI_PROP_INVAL_ARG);
4136 	}
4137 	ASSERT(!MDI_PI_LOCKED(pip));
4138 	MDI_PI_LOCK(pip);
4139 	if (MDI_PI(pip)->pi_prop == NULL) {
4140 		MDI_PI_UNLOCK(pip);
4141 		return (DDI_PROP_NOT_FOUND);
4142 	}
4143 	rv = nvlist_add_int32_array(MDI_PI(pip)->pi_prop, name, (int32_t *)data,
4144 	    nelements);
4145 	MDI_PI_UNLOCK(pip);
4146 	return (i_map_nvlist_error_to_mdi(rv));
4147 }
4148 
4149 /*
4150  * mdi_prop_update_string():
4151  *		Create/Update a string property
4152  */
4153 int
4154 mdi_prop_update_string(mdi_pathinfo_t *pip, char *name, char *data)
4155 {
4156 	int rv;
4157 
4158 	if (pip == NULL) {
4159 		return (DDI_PROP_INVAL_ARG);
4160 	}
4161 	ASSERT(!MDI_PI_LOCKED(pip));
4162 	MDI_PI_LOCK(pip);
4163 	if (MDI_PI(pip)->pi_prop == NULL) {
4164 		MDI_PI_UNLOCK(pip);
4165 		return (DDI_PROP_NOT_FOUND);
4166 	}
4167 	rv = nvlist_add_string(MDI_PI(pip)->pi_prop, name, data);
4168 	MDI_PI_UNLOCK(pip);
4169 	return (i_map_nvlist_error_to_mdi(rv));
4170 }
4171 
4172 /*
4173  * mdi_prop_update_string_array():
4174  *		Create/Update a string array property
4175  */
4176 int
4177 mdi_prop_update_string_array(mdi_pathinfo_t *pip, char *name, char **data,
4178     uint_t nelements)
4179 {
4180 	int rv;
4181 
4182 	if (pip == NULL) {
4183 		return (DDI_PROP_INVAL_ARG);
4184 	}
4185 	ASSERT(!MDI_PI_LOCKED(pip));
4186 	MDI_PI_LOCK(pip);
4187 	if (MDI_PI(pip)->pi_prop == NULL) {
4188 		MDI_PI_UNLOCK(pip);
4189 		return (DDI_PROP_NOT_FOUND);
4190 	}
4191 	rv = nvlist_add_string_array(MDI_PI(pip)->pi_prop, name, data,
4192 	    nelements);
4193 	MDI_PI_UNLOCK(pip);
4194 	return (i_map_nvlist_error_to_mdi(rv));
4195 }
4196 
4197 /*
4198  * mdi_prop_lookup_byte():
4199  * 		Look for byte property identified by name.  The data returned
4200  *		is the actual property and valid as long as mdi_pathinfo_t node
4201  *		is alive.
4202  */
4203 int
4204 mdi_prop_lookup_byte(mdi_pathinfo_t *pip, char *name, uchar_t *data)
4205 {
4206 	int rv;
4207 
4208 	if ((pip == NULL) || (MDI_PI(pip)->pi_prop == NULL)) {
4209 		return (DDI_PROP_NOT_FOUND);
4210 	}
4211 	rv = nvlist_lookup_byte(MDI_PI(pip)->pi_prop, name, data);
4212 	return (i_map_nvlist_error_to_mdi(rv));
4213 }
4214 
4215 
4216 /*
4217  * mdi_prop_lookup_byte_array():
4218  * 		Look for byte array property identified by name.  The data
4219  *		returned is the actual property and valid as long as
4220  *		mdi_pathinfo_t node is alive.
4221  */
4222 int
4223 mdi_prop_lookup_byte_array(mdi_pathinfo_t *pip, char *name, uchar_t **data,
4224     uint_t *nelements)
4225 {
4226 	int rv;
4227 
4228 	if ((pip == NULL) || (MDI_PI(pip)->pi_prop == NULL)) {
4229 		return (DDI_PROP_NOT_FOUND);
4230 	}
4231 	rv = nvlist_lookup_byte_array(MDI_PI(pip)->pi_prop, name, data,
4232 	    nelements);
4233 	return (i_map_nvlist_error_to_mdi(rv));
4234 }
4235 
4236 /*
4237  * mdi_prop_lookup_int():
4238  * 		Look for int property identified by name.  The data returned
4239  *		is the actual property and valid as long as mdi_pathinfo_t
4240  *		node is alive.
4241  */
4242 int
4243 mdi_prop_lookup_int(mdi_pathinfo_t *pip, char *name, int *data)
4244 {
4245 	int rv;
4246 
4247 	if ((pip == NULL) || (MDI_PI(pip)->pi_prop == NULL)) {
4248 		return (DDI_PROP_NOT_FOUND);
4249 	}
4250 	rv = nvlist_lookup_int32(MDI_PI(pip)->pi_prop, name, (int32_t *)data);
4251 	return (i_map_nvlist_error_to_mdi(rv));
4252 }
4253 
4254 /*
4255  * mdi_prop_lookup_int64():
4256  * 		Look for int64 property identified by name.  The data returned
4257  *		is the actual property and valid as long as mdi_pathinfo_t node
4258  *		is alive.
4259  */
4260 int
4261 mdi_prop_lookup_int64(mdi_pathinfo_t *pip, char *name, int64_t *data)
4262 {
4263 	int rv;
4264 	if ((pip == NULL) || (MDI_PI(pip)->pi_prop == NULL)) {
4265 		return (DDI_PROP_NOT_FOUND);
4266 	}
4267 	rv = nvlist_lookup_int64(MDI_PI(pip)->pi_prop, name, data);
4268 	return (i_map_nvlist_error_to_mdi(rv));
4269 }
4270 
4271 /*
4272  * mdi_prop_lookup_int_array():
4273  * 		Look for int array property identified by name.  The data
4274  *		returned is the actual property and valid as long as
4275  *		mdi_pathinfo_t node is alive.
4276  */
4277 int
4278 mdi_prop_lookup_int_array(mdi_pathinfo_t *pip, char *name, int **data,
4279     uint_t *nelements)
4280 {
4281 	int rv;
4282 
4283 	if ((pip == NULL) || (MDI_PI(pip)->pi_prop == NULL)) {
4284 		return (DDI_PROP_NOT_FOUND);
4285 	}
4286 	rv = nvlist_lookup_int32_array(MDI_PI(pip)->pi_prop, name,
4287 	    (int32_t **)data, nelements);
4288 	return (i_map_nvlist_error_to_mdi(rv));
4289 }
4290 
4291 /*
4292  * mdi_prop_lookup_string():
4293  * 		Look for string property identified by name.  The data
4294  *		returned is the actual property and valid as long as
4295  *		mdi_pathinfo_t node is alive.
4296  */
4297 int
4298 mdi_prop_lookup_string(mdi_pathinfo_t *pip, char *name, char **data)
4299 {
4300 	int rv;
4301 
4302 	if ((pip == NULL) || (MDI_PI(pip)->pi_prop == NULL)) {
4303 		return (DDI_PROP_NOT_FOUND);
4304 	}
4305 	rv = nvlist_lookup_string(MDI_PI(pip)->pi_prop, name, data);
4306 	return (i_map_nvlist_error_to_mdi(rv));
4307 }
4308 
4309 /*
4310  * mdi_prop_lookup_string_array():
4311  * 		Look for string array property identified by name.  The data
4312  *		returned is the actual property and valid as long as
4313  *		mdi_pathinfo_t node is alive.
4314  */
4315 int
4316 mdi_prop_lookup_string_array(mdi_pathinfo_t *pip, char *name, char ***data,
4317     uint_t *nelements)
4318 {
4319 	int rv;
4320 
4321 	if ((pip == NULL) || (MDI_PI(pip)->pi_prop == NULL)) {
4322 		return (DDI_PROP_NOT_FOUND);
4323 	}
4324 	rv = nvlist_lookup_string_array(MDI_PI(pip)->pi_prop, name, data,
4325 	    nelements);
4326 	return (i_map_nvlist_error_to_mdi(rv));
4327 }
4328 
4329 /*
4330  * mdi_prop_free():
4331  * 		Symmetrical function to ddi_prop_free(). nvlist_lookup_xx()
4332  *		functions return the pointer to actual property data and not a
4333  *		copy of it.  So the data returned is valid as long as
4334  *		mdi_pathinfo_t node is valid.
4335  */
4336 /*ARGSUSED*/
4337 int
4338 mdi_prop_free(void *data)
4339 {
4340 	return (DDI_PROP_SUCCESS);
4341 }
4342 
4343 /*ARGSUSED*/
4344 static void
4345 i_mdi_report_path_state(mdi_client_t *ct, mdi_pathinfo_t *pip)
4346 {
4347 	char		*phci_path, *ct_path;
4348 	char		*ct_status;
4349 	char		*status;
4350 	dev_info_t	*dip = ct->ct_dip;
4351 	char		lb_buf[64];
4352 
4353 	ASSERT(MDI_CLIENT_LOCKED(ct));
4354 	if ((dip == NULL) || (ddi_get_instance(dip) == -1) ||
4355 	    (MDI_CLIENT_IS_REPORT_DEV_NEEDED(ct) == 0)) {
4356 		return;
4357 	}
4358 	if (MDI_CLIENT_STATE(ct) == MDI_CLIENT_STATE_OPTIMAL) {
4359 		ct_status = "optimal";
4360 	} else if (MDI_CLIENT_STATE(ct) == MDI_CLIENT_STATE_DEGRADED) {
4361 		ct_status = "degraded";
4362 	} else if (MDI_CLIENT_STATE(ct) == MDI_CLIENT_STATE_FAILED) {
4363 		ct_status = "failed";
4364 	} else {
4365 		ct_status = "unknown";
4366 	}
4367 
4368 	if (MDI_PI_IS_OFFLINE(pip)) {
4369 		status = "offline";
4370 	} else if (MDI_PI_IS_ONLINE(pip)) {
4371 		status = "online";
4372 	} else if (MDI_PI_IS_STANDBY(pip)) {
4373 		status = "standby";
4374 	} else if (MDI_PI_IS_FAULT(pip)) {
4375 		status = "faulted";
4376 	} else {
4377 		status = "unknown";
4378 	}
4379 
4380 	if (ct->ct_lb == LOAD_BALANCE_LBA) {
4381 		(void) snprintf(lb_buf, sizeof (lb_buf),
4382 		    "%s, region-size: %d", mdi_load_balance_lba,
4383 			ct->ct_lb_args->region_size);
4384 	} else if (ct->ct_lb == LOAD_BALANCE_NONE) {
4385 		(void) snprintf(lb_buf, sizeof (lb_buf),
4386 		    "%s", mdi_load_balance_none);
4387 	} else {
4388 		(void) snprintf(lb_buf, sizeof (lb_buf), "%s",
4389 		    mdi_load_balance_rr);
4390 	}
4391 
4392 	if (dip) {
4393 		ct_path = kmem_alloc(MAXPATHLEN, KM_SLEEP);
4394 		phci_path = kmem_alloc(MAXPATHLEN, KM_SLEEP);
4395 		cmn_err(CE_CONT, "?%s (%s%d) multipath status: %s, "
4396 		    "path %s (%s%d) to target address: %s is %s"
4397 		    " Load balancing: %s\n",
4398 		    ddi_pathname(dip, ct_path), ddi_driver_name(dip),
4399 		    ddi_get_instance(dip), ct_status,
4400 		    ddi_pathname(MDI_PI(pip)->pi_phci->ph_dip, phci_path),
4401 		    ddi_driver_name(MDI_PI(pip)->pi_phci->ph_dip),
4402 		    ddi_get_instance(MDI_PI(pip)->pi_phci->ph_dip),
4403 		    MDI_PI(pip)->pi_addr, status, lb_buf);
4404 		kmem_free(phci_path, MAXPATHLEN);
4405 		kmem_free(ct_path, MAXPATHLEN);
4406 		MDI_CLIENT_CLEAR_REPORT_DEV_NEEDED(ct);
4407 	}
4408 }
4409 
4410 #ifdef	DEBUG
4411 /*
4412  * i_mdi_log():
4413  *		Utility function for error message management
4414  *
4415  */
4416 /*PRINTFLIKE3*/
4417 static void
4418 i_mdi_log(int level, dev_info_t *dip, const char *fmt, ...)
4419 {
4420 	char		name[MAXNAMELEN];
4421 	char		buf[MAXNAMELEN];
4422 	char		*bp;
4423 	va_list		ap;
4424 	int		log_only = 0;
4425 	int		boot_only = 0;
4426 	int		console_only = 0;
4427 
4428 	if (dip) {
4429 		(void) snprintf(name, MAXNAMELEN, "%s%d: ",
4430 		    ddi_node_name(dip), ddi_get_instance(dip));
4431 	} else {
4432 		name[0] = 0;
4433 	}
4434 
4435 	va_start(ap, fmt);
4436 	(void) vsnprintf(buf, MAXNAMELEN, fmt, ap);
4437 	va_end(ap);
4438 
4439 	switch (buf[0]) {
4440 	case '!':
4441 		bp = &buf[1];
4442 		log_only = 1;
4443 		break;
4444 	case '?':
4445 		bp = &buf[1];
4446 		boot_only = 1;
4447 		break;
4448 	case '^':
4449 		bp = &buf[1];
4450 		console_only = 1;
4451 		break;
4452 	default:
4453 		bp = buf;
4454 		break;
4455 	}
4456 	if (mdi_debug_logonly) {
4457 		log_only = 1;
4458 		boot_only = 0;
4459 		console_only = 0;
4460 	}
4461 
4462 	switch (level) {
4463 	case CE_NOTE:
4464 		level = CE_CONT;
4465 		/* FALLTHROUGH */
4466 	case CE_CONT:
4467 	case CE_WARN:
4468 	case CE_PANIC:
4469 		if (boot_only) {
4470 			cmn_err(level, "?mdi: %s%s", name, bp);
4471 		} else if (console_only) {
4472 			cmn_err(level, "^mdi: %s%s", name, bp);
4473 		} else if (log_only) {
4474 			cmn_err(level, "!mdi: %s%s", name, bp);
4475 		} else {
4476 			cmn_err(level, "mdi: %s%s", name, bp);
4477 		}
4478 		break;
4479 	default:
4480 		cmn_err(level, "mdi: %s%s", name, bp);
4481 		break;
4482 	}
4483 }
4484 #endif	/* DEBUG */
4485 
4486 void
4487 i_mdi_client_online(dev_info_t *ct_dip)
4488 {
4489 	mdi_client_t	*ct;
4490 
4491 	/*
4492 	 * Client online notification. Mark client state as online
4493 	 * restore our binding with dev_info node
4494 	 */
4495 	ct = i_devi_get_client(ct_dip);
4496 	ASSERT(ct != NULL);
4497 	MDI_CLIENT_LOCK(ct);
4498 	MDI_CLIENT_SET_ONLINE(ct);
4499 	/* catch for any memory leaks */
4500 	ASSERT((ct->ct_dip == NULL) || (ct->ct_dip == ct_dip));
4501 	ct->ct_dip = ct_dip;
4502 
4503 	if (ct->ct_power_cnt == 0)
4504 		(void) i_mdi_power_all_phci(ct);
4505 
4506 	MDI_DEBUG(4, (CE_NOTE, ct_dip, "i_mdi_client_online "
4507 	    "i_mdi_pm_hold_client %p\n", (void *)ct));
4508 	i_mdi_pm_hold_client(ct, 1);
4509 
4510 	MDI_CLIENT_UNLOCK(ct);
4511 }
4512 
4513 void
4514 i_mdi_phci_online(dev_info_t *ph_dip)
4515 {
4516 	mdi_phci_t	*ph;
4517 
4518 	/* pHCI online notification. Mark state accordingly */
4519 	ph = i_devi_get_phci(ph_dip);
4520 	ASSERT(ph != NULL);
4521 	MDI_PHCI_LOCK(ph);
4522 	MDI_PHCI_SET_ONLINE(ph);
4523 	MDI_PHCI_UNLOCK(ph);
4524 }
4525 
4526 /*
4527  * mdi_devi_online():
4528  * 		Online notification from NDI framework on pHCI/client
4529  *		device online.
4530  * Return Values:
4531  *		NDI_SUCCESS
4532  *		MDI_FAILURE
4533  */
4534 /*ARGSUSED*/
4535 int
4536 mdi_devi_online(dev_info_t *dip, uint_t flags)
4537 {
4538 	if (MDI_PHCI(dip)) {
4539 		i_mdi_phci_online(dip);
4540 	}
4541 
4542 	if (MDI_CLIENT(dip)) {
4543 		i_mdi_client_online(dip);
4544 	}
4545 	return (NDI_SUCCESS);
4546 }
4547 
4548 /*
4549  * mdi_devi_offline():
4550  * 		Offline notification from NDI framework on pHCI/Client device
4551  *		offline.
4552  *
4553  * Return Values:
4554  *		NDI_SUCCESS
4555  *		NDI_FAILURE
4556  */
4557 /*ARGSUSED*/
4558 int
4559 mdi_devi_offline(dev_info_t *dip, uint_t flags)
4560 {
4561 	int		rv = NDI_SUCCESS;
4562 
4563 	if (MDI_CLIENT(dip)) {
4564 		rv = i_mdi_client_offline(dip, flags);
4565 		if (rv != NDI_SUCCESS)
4566 			return (rv);
4567 	}
4568 
4569 	if (MDI_PHCI(dip)) {
4570 		rv = i_mdi_phci_offline(dip, flags);
4571 
4572 		if ((rv != NDI_SUCCESS) && MDI_CLIENT(dip)) {
4573 			/* set client back online */
4574 			i_mdi_client_online(dip);
4575 		}
4576 	}
4577 
4578 	return (rv);
4579 }
4580 
4581 /*ARGSUSED*/
4582 static int
4583 i_mdi_phci_offline(dev_info_t *dip, uint_t flags)
4584 {
4585 	int		rv = NDI_SUCCESS;
4586 	mdi_phci_t	*ph;
4587 	mdi_client_t	*ct;
4588 	mdi_pathinfo_t	*pip;
4589 	mdi_pathinfo_t	*next;
4590 	mdi_pathinfo_t	*failed_pip = NULL;
4591 	dev_info_t	*cdip;
4592 
4593 	/*
4594 	 * pHCI component offline notification
4595 	 * Make sure that this pHCI instance is free to be offlined.
4596 	 * If it is OK to proceed, Offline and remove all the child
4597 	 * mdi_pathinfo nodes.  This process automatically offlines
4598 	 * corresponding client devices, for which this pHCI provides
4599 	 * critical services.
4600 	 */
4601 	ph = i_devi_get_phci(dip);
4602 	MDI_DEBUG(2, (CE_NOTE, dip, "!mdi_phci_offline called %p %p\n",
4603 	    (void *)dip, (void *)ph));
4604 	if (ph == NULL) {
4605 		return (rv);
4606 	}
4607 
4608 	MDI_PHCI_LOCK(ph);
4609 
4610 	if (MDI_PHCI_IS_OFFLINE(ph)) {
4611 		MDI_DEBUG(1, (CE_WARN, dip, "!pHCI %p already offlined",
4612 		    (void *)ph));
4613 		MDI_PHCI_UNLOCK(ph);
4614 		return (NDI_SUCCESS);
4615 	}
4616 
4617 	/*
4618 	 * Check to see if the pHCI can be offlined
4619 	 */
4620 	if (ph->ph_unstable) {
4621 		MDI_DEBUG(1, (CE_WARN, dip,
4622 		    "!One or more target devices are in transient "
4623 		    "state. This device can not be removed at "
4624 		    "this moment. Please try again later."));
4625 		MDI_PHCI_UNLOCK(ph);
4626 		return (NDI_BUSY);
4627 	}
4628 
4629 	pip = ph->ph_path_head;
4630 	while (pip != NULL) {
4631 		MDI_PI_LOCK(pip);
4632 		next = (mdi_pathinfo_t *)MDI_PI(pip)->pi_phci_link;
4633 
4634 		/*
4635 		 * The mdi_pathinfo state is OK. Check the client state.
4636 		 * If failover in progress fail the pHCI from offlining
4637 		 */
4638 		ct = MDI_PI(pip)->pi_client;
4639 		i_mdi_client_lock(ct, pip);
4640 		if ((MDI_CLIENT_IS_FAILOVER_IN_PROGRESS(ct)) ||
4641 		    (ct->ct_unstable)) {
4642 			/*
4643 			 * Failover is in progress, Fail the DR
4644 			 */
4645 			MDI_DEBUG(1, (CE_WARN, dip,
4646 			    "!pHCI device (%s%d) is Busy. %s",
4647 			    ddi_driver_name(dip), ddi_get_instance(dip),
4648 			    "This device can not be removed at "
4649 			    "this moment. Please try again later."));
4650 			MDI_PI_UNLOCK(pip);
4651 			i_mdi_client_unlock(ct);
4652 			MDI_PHCI_UNLOCK(ph);
4653 			return (NDI_BUSY);
4654 		}
4655 		MDI_PI_UNLOCK(pip);
4656 
4657 		/*
4658 		 * Check to see of we are removing the last path of this
4659 		 * client device...
4660 		 */
4661 		cdip = ct->ct_dip;
4662 		if (cdip && (i_ddi_node_state(cdip) >= DS_INITIALIZED) &&
4663 		    (i_mdi_client_compute_state(ct, ph) ==
4664 		    MDI_CLIENT_STATE_FAILED)) {
4665 			i_mdi_client_unlock(ct);
4666 			MDI_PHCI_UNLOCK(ph);
4667 			if (ndi_devi_offline(cdip, 0) != NDI_SUCCESS) {
4668 				/*
4669 				 * ndi_devi_offline() failed.
4670 				 * This pHCI provides the critical path
4671 				 * to one or more client devices.
4672 				 * Return busy.
4673 				 */
4674 				MDI_PHCI_LOCK(ph);
4675 				MDI_DEBUG(1, (CE_WARN, dip,
4676 				    "!pHCI device (%s%d) is Busy. %s",
4677 				    ddi_driver_name(dip), ddi_get_instance(dip),
4678 				    "This device can not be removed at "
4679 				    "this moment. Please try again later."));
4680 				failed_pip = pip;
4681 				break;
4682 			} else {
4683 				MDI_PHCI_LOCK(ph);
4684 				pip = next;
4685 			}
4686 		} else {
4687 			i_mdi_client_unlock(ct);
4688 			pip = next;
4689 		}
4690 	}
4691 
4692 	if (failed_pip) {
4693 		pip = ph->ph_path_head;
4694 		while (pip != failed_pip) {
4695 			MDI_PI_LOCK(pip);
4696 			next = (mdi_pathinfo_t *)MDI_PI(pip)->pi_phci_link;
4697 			ct = MDI_PI(pip)->pi_client;
4698 			i_mdi_client_lock(ct, pip);
4699 			cdip = ct->ct_dip;
4700 			switch (MDI_CLIENT_STATE(ct)) {
4701 			case MDI_CLIENT_STATE_OPTIMAL:
4702 			case MDI_CLIENT_STATE_DEGRADED:
4703 				if (cdip) {
4704 					MDI_PI_UNLOCK(pip);
4705 					i_mdi_client_unlock(ct);
4706 					MDI_PHCI_UNLOCK(ph);
4707 					(void) ndi_devi_online(cdip, 0);
4708 					MDI_PHCI_LOCK(ph);
4709 					pip = next;
4710 					continue;
4711 				}
4712 				break;
4713 
4714 			case MDI_CLIENT_STATE_FAILED:
4715 				if (cdip) {
4716 					MDI_PI_UNLOCK(pip);
4717 					i_mdi_client_unlock(ct);
4718 					MDI_PHCI_UNLOCK(ph);
4719 					(void) ndi_devi_offline(cdip, 0);
4720 					MDI_PHCI_LOCK(ph);
4721 					pip = next;
4722 					continue;
4723 				}
4724 				break;
4725 			}
4726 			MDI_PI_UNLOCK(pip);
4727 			i_mdi_client_unlock(ct);
4728 			pip = next;
4729 		}
4730 		MDI_PHCI_UNLOCK(ph);
4731 		return (NDI_BUSY);
4732 	}
4733 
4734 	/*
4735 	 * Mark the pHCI as offline
4736 	 */
4737 	MDI_PHCI_SET_OFFLINE(ph);
4738 
4739 	/*
4740 	 * Mark the child mdi_pathinfo nodes as transient
4741 	 */
4742 	pip = ph->ph_path_head;
4743 	while (pip != NULL) {
4744 		MDI_PI_LOCK(pip);
4745 		next = (mdi_pathinfo_t *)MDI_PI(pip)->pi_phci_link;
4746 		MDI_PI_SET_OFFLINING(pip);
4747 		MDI_PI_UNLOCK(pip);
4748 		pip = next;
4749 	}
4750 	MDI_PHCI_UNLOCK(ph);
4751 	/*
4752 	 * Give a chance for any pending commands to execute
4753 	 */
4754 	delay(1);
4755 	MDI_PHCI_LOCK(ph);
4756 	pip = ph->ph_path_head;
4757 	while (pip != NULL) {
4758 		next = (mdi_pathinfo_t *)MDI_PI(pip)->pi_phci_link;
4759 		(void) i_mdi_pi_offline(pip, flags);
4760 		MDI_PI_LOCK(pip);
4761 		ct = MDI_PI(pip)->pi_client;
4762 		if (!MDI_PI_IS_OFFLINE(pip)) {
4763 			MDI_DEBUG(1, (CE_WARN, dip,
4764 			    "!pHCI device (%s%d) is Busy. %s",
4765 			    ddi_driver_name(dip), ddi_get_instance(dip),
4766 			    "This device can not be removed at "
4767 			    "this moment. Please try again later."));
4768 			MDI_PI_UNLOCK(pip);
4769 			MDI_PHCI_SET_ONLINE(ph);
4770 			MDI_PHCI_UNLOCK(ph);
4771 			return (NDI_BUSY);
4772 		}
4773 		MDI_PI_UNLOCK(pip);
4774 		pip = next;
4775 	}
4776 	MDI_PHCI_UNLOCK(ph);
4777 
4778 	return (rv);
4779 }
4780 
4781 /*ARGSUSED*/
4782 static int
4783 i_mdi_client_offline(dev_info_t *dip, uint_t flags)
4784 {
4785 	int		rv = NDI_SUCCESS;
4786 	mdi_client_t	*ct;
4787 
4788 	/*
4789 	 * Client component to go offline.  Make sure that we are
4790 	 * not in failing over state and update client state
4791 	 * accordingly
4792 	 */
4793 	ct = i_devi_get_client(dip);
4794 	MDI_DEBUG(2, (CE_NOTE, dip, "!i_mdi_client_offline called %p %p\n",
4795 	    (void *)dip, (void *)ct));
4796 	if (ct != NULL) {
4797 		MDI_CLIENT_LOCK(ct);
4798 		if (ct->ct_unstable) {
4799 			/*
4800 			 * One or more paths are in transient state,
4801 			 * Dont allow offline of a client device
4802 			 */
4803 			MDI_DEBUG(1, (CE_WARN, dip,
4804 			    "!One or more paths to this device is "
4805 			    "in transient state. This device can not "
4806 			    "be removed at this moment. "
4807 			    "Please try again later."));
4808 			MDI_CLIENT_UNLOCK(ct);
4809 			return (NDI_BUSY);
4810 		}
4811 		if (MDI_CLIENT_IS_FAILOVER_IN_PROGRESS(ct)) {
4812 			/*
4813 			 * Failover is in progress, Dont allow DR of
4814 			 * a client device
4815 			 */
4816 			MDI_DEBUG(1, (CE_WARN, dip,
4817 			    "!Client device (%s%d) is Busy. %s",
4818 			    ddi_driver_name(dip), ddi_get_instance(dip),
4819 			    "This device can not be removed at "
4820 			    "this moment. Please try again later."));
4821 			MDI_CLIENT_UNLOCK(ct);
4822 			return (NDI_BUSY);
4823 		}
4824 		MDI_CLIENT_SET_OFFLINE(ct);
4825 
4826 		/*
4827 		 * Unbind our relationship with the dev_info node
4828 		 */
4829 		if (flags & NDI_DEVI_REMOVE) {
4830 			ct->ct_dip = NULL;
4831 		}
4832 		MDI_CLIENT_UNLOCK(ct);
4833 	}
4834 	return (rv);
4835 }
4836 
4837 /*
4838  * mdi_pre_attach():
4839  *		Pre attach() notification handler
4840  */
4841 /*ARGSUSED*/
4842 int
4843 mdi_pre_attach(dev_info_t *dip, ddi_attach_cmd_t cmd)
4844 {
4845 	/* don't support old DDI_PM_RESUME */
4846 	if ((DEVI(dip)->devi_mdi_component != MDI_COMPONENT_NONE) &&
4847 	    (cmd == DDI_PM_RESUME))
4848 		return (DDI_FAILURE);
4849 
4850 	return (DDI_SUCCESS);
4851 }
4852 
4853 /*
4854  * mdi_post_attach():
4855  *		Post attach() notification handler
4856  */
4857 /*ARGSUSED*/
4858 void
4859 mdi_post_attach(dev_info_t *dip, ddi_attach_cmd_t cmd, int error)
4860 {
4861 	mdi_phci_t	*ph;
4862 	mdi_client_t	*ct;
4863 	mdi_vhci_t	*vh;
4864 
4865 	if (MDI_PHCI(dip)) {
4866 		ph = i_devi_get_phci(dip);
4867 		ASSERT(ph != NULL);
4868 
4869 		MDI_PHCI_LOCK(ph);
4870 		switch (cmd) {
4871 		case DDI_ATTACH:
4872 			MDI_DEBUG(2, (CE_NOTE, dip,
4873 			    "!pHCI post_attach: called %p\n", (void *)ph));
4874 			if (error == DDI_SUCCESS) {
4875 				MDI_PHCI_SET_ATTACH(ph);
4876 			} else {
4877 				MDI_DEBUG(1, (CE_NOTE, dip,
4878 				    "!pHCI post_attach: failed error=%d\n",
4879 				    error));
4880 				MDI_PHCI_SET_DETACH(ph);
4881 			}
4882 			break;
4883 
4884 		case DDI_RESUME:
4885 			MDI_DEBUG(2, (CE_NOTE, dip,
4886 			    "!pHCI post_resume: called %p\n", (void *)ph));
4887 			if (error == DDI_SUCCESS) {
4888 				MDI_PHCI_SET_RESUME(ph);
4889 			} else {
4890 				MDI_DEBUG(1, (CE_NOTE, dip,
4891 				    "!pHCI post_resume: failed error=%d\n",
4892 				    error));
4893 				MDI_PHCI_SET_SUSPEND(ph);
4894 			}
4895 			break;
4896 		}
4897 		MDI_PHCI_UNLOCK(ph);
4898 	}
4899 
4900 	if (MDI_CLIENT(dip)) {
4901 		ct = i_devi_get_client(dip);
4902 		ASSERT(ct != NULL);
4903 
4904 		MDI_CLIENT_LOCK(ct);
4905 		switch (cmd) {
4906 		case DDI_ATTACH:
4907 			MDI_DEBUG(2, (CE_NOTE, dip,
4908 			    "!Client post_attach: called %p\n", (void *)ct));
4909 			if (error != DDI_SUCCESS) {
4910 				MDI_DEBUG(1, (CE_NOTE, dip,
4911 				    "!Client post_attach: failed error=%d\n",
4912 				    error));
4913 				MDI_CLIENT_SET_DETACH(ct);
4914 				MDI_DEBUG(4, (CE_WARN, dip,
4915 				    "mdi_post_attach i_mdi_pm_reset_client\n"));
4916 				i_mdi_pm_reset_client(ct);
4917 				break;
4918 			}
4919 
4920 			/*
4921 			 * Client device has successfully attached, inform
4922 			 * the vhci.
4923 			 */
4924 			vh = ct->ct_vhci;
4925 			if (vh->vh_ops->vo_client_attached)
4926 				(*vh->vh_ops->vo_client_attached)(dip);
4927 
4928 			MDI_CLIENT_SET_ATTACH(ct);
4929 			break;
4930 
4931 		case DDI_RESUME:
4932 			MDI_DEBUG(2, (CE_NOTE, dip,
4933 			    "!Client post_attach: called %p\n", (void *)ct));
4934 			if (error == DDI_SUCCESS) {
4935 				MDI_CLIENT_SET_RESUME(ct);
4936 			} else {
4937 				MDI_DEBUG(1, (CE_NOTE, dip,
4938 				    "!Client post_resume: failed error=%d\n",
4939 				    error));
4940 				MDI_CLIENT_SET_SUSPEND(ct);
4941 			}
4942 			break;
4943 		}
4944 		MDI_CLIENT_UNLOCK(ct);
4945 	}
4946 }
4947 
4948 /*
4949  * mdi_pre_detach():
4950  *		Pre detach notification handler
4951  */
4952 /*ARGSUSED*/
4953 int
4954 mdi_pre_detach(dev_info_t *dip, ddi_detach_cmd_t cmd)
4955 {
4956 	int rv = DDI_SUCCESS;
4957 
4958 	if (MDI_CLIENT(dip)) {
4959 		(void) i_mdi_client_pre_detach(dip, cmd);
4960 	}
4961 
4962 	if (MDI_PHCI(dip)) {
4963 		rv = i_mdi_phci_pre_detach(dip, cmd);
4964 	}
4965 
4966 	return (rv);
4967 }
4968 
4969 /*ARGSUSED*/
4970 static int
4971 i_mdi_phci_pre_detach(dev_info_t *dip, ddi_detach_cmd_t cmd)
4972 {
4973 	int		rv = DDI_SUCCESS;
4974 	mdi_phci_t	*ph;
4975 	mdi_client_t	*ct;
4976 	mdi_pathinfo_t	*pip;
4977 	mdi_pathinfo_t	*failed_pip = NULL;
4978 	mdi_pathinfo_t	*next;
4979 
4980 	ph = i_devi_get_phci(dip);
4981 	if (ph == NULL) {
4982 		return (rv);
4983 	}
4984 
4985 	MDI_PHCI_LOCK(ph);
4986 	switch (cmd) {
4987 	case DDI_DETACH:
4988 		MDI_DEBUG(2, (CE_NOTE, dip,
4989 		    "!pHCI pre_detach: called %p\n", (void *)ph));
4990 		if (!MDI_PHCI_IS_OFFLINE(ph)) {
4991 			/*
4992 			 * mdi_pathinfo nodes are still attached to
4993 			 * this pHCI. Fail the detach for this pHCI.
4994 			 */
4995 			MDI_DEBUG(2, (CE_WARN, dip,
4996 			    "!pHCI pre_detach: "
4997 			    "mdi_pathinfo nodes are still attached "
4998 			    "%p\n", (void *)ph));
4999 			rv = DDI_FAILURE;
5000 			break;
5001 		}
5002 		MDI_PHCI_SET_DETACH(ph);
5003 		break;
5004 
5005 	case DDI_SUSPEND:
5006 		/*
5007 		 * pHCI is getting suspended.  Since mpxio client
5008 		 * devices may not be suspended at this point, to avoid
5009 		 * a potential stack overflow, it is important to suspend
5010 		 * client devices before pHCI can be suspended.
5011 		 */
5012 
5013 		MDI_DEBUG(2, (CE_NOTE, dip,
5014 		    "!pHCI pre_suspend: called %p\n", (void *)ph));
5015 		/*
5016 		 * Suspend all the client devices accessible through this pHCI
5017 		 */
5018 		pip = ph->ph_path_head;
5019 		while (pip != NULL && rv == DDI_SUCCESS) {
5020 			dev_info_t *cdip;
5021 			MDI_PI_LOCK(pip);
5022 			next =
5023 			    (mdi_pathinfo_t *)MDI_PI(pip)->pi_phci_link;
5024 			ct = MDI_PI(pip)->pi_client;
5025 			i_mdi_client_lock(ct, pip);
5026 			cdip = ct->ct_dip;
5027 			MDI_PI_UNLOCK(pip);
5028 			if ((MDI_CLIENT_IS_DETACHED(ct) == 0) &&
5029 			    MDI_CLIENT_IS_SUSPENDED(ct) == 0) {
5030 				i_mdi_client_unlock(ct);
5031 				if ((rv = devi_detach(cdip, DDI_SUSPEND)) !=
5032 				    DDI_SUCCESS) {
5033 					/*
5034 					 * Suspend of one of the client
5035 					 * device has failed.
5036 					 */
5037 					MDI_DEBUG(1, (CE_WARN, dip,
5038 					    "!Suspend of device (%s%d) failed.",
5039 					    ddi_driver_name(cdip),
5040 					    ddi_get_instance(cdip)));
5041 					failed_pip = pip;
5042 					break;
5043 				}
5044 			} else {
5045 				i_mdi_client_unlock(ct);
5046 			}
5047 			pip = next;
5048 		}
5049 
5050 		if (rv == DDI_SUCCESS) {
5051 			/*
5052 			 * Suspend of client devices is complete. Proceed
5053 			 * with pHCI suspend.
5054 			 */
5055 			MDI_PHCI_SET_SUSPEND(ph);
5056 		} else {
5057 			/*
5058 			 * Revert back all the suspended client device states
5059 			 * to converse.
5060 			 */
5061 			pip = ph->ph_path_head;
5062 			while (pip != failed_pip) {
5063 				dev_info_t *cdip;
5064 				MDI_PI_LOCK(pip);
5065 				next =
5066 				    (mdi_pathinfo_t *)MDI_PI(pip)->pi_phci_link;
5067 				ct = MDI_PI(pip)->pi_client;
5068 				i_mdi_client_lock(ct, pip);
5069 				cdip = ct->ct_dip;
5070 				MDI_PI_UNLOCK(pip);
5071 				if (MDI_CLIENT_IS_SUSPENDED(ct)) {
5072 					i_mdi_client_unlock(ct);
5073 					(void) devi_attach(cdip, DDI_RESUME);
5074 				} else {
5075 					i_mdi_client_unlock(ct);
5076 				}
5077 				pip = next;
5078 			}
5079 		}
5080 		break;
5081 
5082 	default:
5083 		rv = DDI_FAILURE;
5084 		break;
5085 	}
5086 	MDI_PHCI_UNLOCK(ph);
5087 	return (rv);
5088 }
5089 
5090 /*ARGSUSED*/
5091 static int
5092 i_mdi_client_pre_detach(dev_info_t *dip, ddi_detach_cmd_t cmd)
5093 {
5094 	int		rv = DDI_SUCCESS;
5095 	mdi_client_t	*ct;
5096 
5097 	ct = i_devi_get_client(dip);
5098 	if (ct == NULL) {
5099 		return (rv);
5100 	}
5101 
5102 	MDI_CLIENT_LOCK(ct);
5103 	switch (cmd) {
5104 	case DDI_DETACH:
5105 		MDI_DEBUG(2, (CE_NOTE, dip,
5106 		    "!Client pre_detach: called %p\n", (void *)ct));
5107 		MDI_CLIENT_SET_DETACH(ct);
5108 		break;
5109 
5110 	case DDI_SUSPEND:
5111 		MDI_DEBUG(2, (CE_NOTE, dip,
5112 		    "!Client pre_suspend: called %p\n", (void *)ct));
5113 		MDI_CLIENT_SET_SUSPEND(ct);
5114 		break;
5115 
5116 	default:
5117 		rv = DDI_FAILURE;
5118 		break;
5119 	}
5120 	MDI_CLIENT_UNLOCK(ct);
5121 	return (rv);
5122 }
5123 
5124 /*
5125  * mdi_post_detach():
5126  *		Post detach notification handler
5127  */
5128 /*ARGSUSED*/
5129 void
5130 mdi_post_detach(dev_info_t *dip, ddi_detach_cmd_t cmd, int error)
5131 {
5132 	/*
5133 	 * Detach/Suspend of mpxio component failed. Update our state
5134 	 * too
5135 	 */
5136 	if (MDI_PHCI(dip))
5137 		i_mdi_phci_post_detach(dip, cmd, error);
5138 
5139 	if (MDI_CLIENT(dip))
5140 		i_mdi_client_post_detach(dip, cmd, error);
5141 }
5142 
5143 /*ARGSUSED*/
5144 static void
5145 i_mdi_phci_post_detach(dev_info_t *dip, ddi_detach_cmd_t cmd, int error)
5146 {
5147 	mdi_phci_t	*ph;
5148 
5149 	/*
5150 	 * Detach/Suspend of phci component failed. Update our state
5151 	 * too
5152 	 */
5153 	ph = i_devi_get_phci(dip);
5154 	if (ph == NULL) {
5155 		return;
5156 	}
5157 
5158 	MDI_PHCI_LOCK(ph);
5159 	/*
5160 	 * Detach of pHCI failed. Restore back converse
5161 	 * state
5162 	 */
5163 	switch (cmd) {
5164 	case DDI_DETACH:
5165 		MDI_DEBUG(2, (CE_NOTE, dip,
5166 		    "!pHCI post_detach: called %p\n", (void *)ph));
5167 		if (error != DDI_SUCCESS)
5168 			MDI_PHCI_SET_ATTACH(ph);
5169 		break;
5170 
5171 	case DDI_SUSPEND:
5172 		MDI_DEBUG(2, (CE_NOTE, dip,
5173 		    "!pHCI post_suspend: called %p\n", (void *)ph));
5174 		if (error != DDI_SUCCESS)
5175 			MDI_PHCI_SET_RESUME(ph);
5176 		break;
5177 	}
5178 	MDI_PHCI_UNLOCK(ph);
5179 }
5180 
5181 /*ARGSUSED*/
5182 static void
5183 i_mdi_client_post_detach(dev_info_t *dip, ddi_detach_cmd_t cmd, int error)
5184 {
5185 	mdi_client_t	*ct;
5186 
5187 	ct = i_devi_get_client(dip);
5188 	if (ct == NULL) {
5189 		return;
5190 	}
5191 	MDI_CLIENT_LOCK(ct);
5192 	/*
5193 	 * Detach of Client failed. Restore back converse
5194 	 * state
5195 	 */
5196 	switch (cmd) {
5197 	case DDI_DETACH:
5198 		MDI_DEBUG(2, (CE_NOTE, dip,
5199 		    "!Client post_detach: called %p\n", (void *)ct));
5200 		if (DEVI_IS_ATTACHING(ct->ct_dip)) {
5201 			MDI_DEBUG(4, (CE_NOTE, dip, "i_mdi_client_post_detach "
5202 			    "i_mdi_pm_rele_client\n"));
5203 			i_mdi_pm_rele_client(ct, ct->ct_path_count);
5204 		} else {
5205 			MDI_DEBUG(4, (CE_NOTE, dip, "i_mdi_client_post_detach "
5206 			    "i_mdi_pm_reset_client\n"));
5207 			i_mdi_pm_reset_client(ct);
5208 		}
5209 		if (error != DDI_SUCCESS)
5210 			MDI_CLIENT_SET_ATTACH(ct);
5211 		break;
5212 
5213 	case DDI_SUSPEND:
5214 		MDI_DEBUG(2, (CE_NOTE, dip,
5215 		    "!Client post_suspend: called %p\n", (void *)ct));
5216 		if (error != DDI_SUCCESS)
5217 			MDI_CLIENT_SET_RESUME(ct);
5218 		break;
5219 	}
5220 	MDI_CLIENT_UNLOCK(ct);
5221 }
5222 
5223 int
5224 mdi_pi_kstat_exists(mdi_pathinfo_t *pip)
5225 {
5226 	return (MDI_PI(pip)->pi_kstats ? 1 : 0);
5227 }
5228 
5229 /*
5230  * create and install per-path (client - pHCI) statistics
5231  * I/O stats supported: nread, nwritten, reads, and writes
5232  * Error stats - hard errors, soft errors, & transport errors
5233  */
5234 int
5235 mdi_pi_kstat_create(mdi_pathinfo_t *pip, char *ksname)
5236 {
5237 	kstat_t			*kiosp, *kerrsp;
5238 	struct pi_errs		*nsp;
5239 	struct mdi_pi_kstats	*mdi_statp;
5240 
5241 	if (MDI_PI(pip)->pi_kstats != NULL)
5242 		return (MDI_SUCCESS);
5243 
5244 	if ((kiosp = kstat_create("mdi", 0, ksname, "iopath",
5245 	    KSTAT_TYPE_IO, 1, KSTAT_FLAG_PERSISTENT)) == NULL) {
5246 		return (MDI_FAILURE);
5247 	}
5248 
5249 	(void) strcat(ksname, ",err");
5250 	kerrsp = kstat_create("mdi", 0, ksname, "iopath_errors",
5251 	    KSTAT_TYPE_NAMED,
5252 	    sizeof (struct pi_errs) / sizeof (kstat_named_t), 0);
5253 	if (kerrsp == NULL) {
5254 		kstat_delete(kiosp);
5255 		return (MDI_FAILURE);
5256 	}
5257 
5258 	nsp = (struct pi_errs *)kerrsp->ks_data;
5259 	kstat_named_init(&nsp->pi_softerrs, "Soft Errors", KSTAT_DATA_UINT32);
5260 	kstat_named_init(&nsp->pi_harderrs, "Hard Errors", KSTAT_DATA_UINT32);
5261 	kstat_named_init(&nsp->pi_transerrs, "Transport Errors",
5262 	    KSTAT_DATA_UINT32);
5263 	kstat_named_init(&nsp->pi_icnt_busy, "Interconnect Busy",
5264 	    KSTAT_DATA_UINT32);
5265 	kstat_named_init(&nsp->pi_icnt_errors, "Interconnect Errors",
5266 	    KSTAT_DATA_UINT32);
5267 	kstat_named_init(&nsp->pi_phci_rsrc, "pHCI No Resources",
5268 	    KSTAT_DATA_UINT32);
5269 	kstat_named_init(&nsp->pi_phci_localerr, "pHCI Local Errors",
5270 	    KSTAT_DATA_UINT32);
5271 	kstat_named_init(&nsp->pi_phci_invstate, "pHCI Invalid State",
5272 	    KSTAT_DATA_UINT32);
5273 	kstat_named_init(&nsp->pi_failedfrom, "Failed From",
5274 	    KSTAT_DATA_UINT32);
5275 	kstat_named_init(&nsp->pi_failedto, "Failed To", KSTAT_DATA_UINT32);
5276 
5277 	mdi_statp = kmem_alloc(sizeof (*mdi_statp), KM_SLEEP);
5278 	mdi_statp->pi_kstat_ref = 1;
5279 	mdi_statp->pi_kstat_iostats = kiosp;
5280 	mdi_statp->pi_kstat_errstats = kerrsp;
5281 	kstat_install(kiosp);
5282 	kstat_install(kerrsp);
5283 	MDI_PI(pip)->pi_kstats = mdi_statp;
5284 	return (MDI_SUCCESS);
5285 }
5286 
5287 /*
5288  * destroy per-path properties
5289  */
5290 static void
5291 i_mdi_pi_kstat_destroy(mdi_pathinfo_t *pip)
5292 {
5293 
5294 	struct mdi_pi_kstats *mdi_statp;
5295 
5296 	if (MDI_PI(pip)->pi_kstats == NULL)
5297 		return;
5298 	if ((mdi_statp = MDI_PI(pip)->pi_kstats) == NULL)
5299 		return;
5300 
5301 	MDI_PI(pip)->pi_kstats = NULL;
5302 
5303 	/*
5304 	 * the kstat may be shared between multiple pathinfo nodes
5305 	 * decrement this pathinfo's usage, removing the kstats
5306 	 * themselves when the last pathinfo reference is removed.
5307 	 */
5308 	ASSERT(mdi_statp->pi_kstat_ref > 0);
5309 	if (--mdi_statp->pi_kstat_ref != 0)
5310 		return;
5311 
5312 	kstat_delete(mdi_statp->pi_kstat_iostats);
5313 	kstat_delete(mdi_statp->pi_kstat_errstats);
5314 	kmem_free(mdi_statp, sizeof (*mdi_statp));
5315 }
5316 
5317 /*
5318  * update I/O paths KSTATS
5319  */
5320 void
5321 mdi_pi_kstat_iosupdate(mdi_pathinfo_t *pip, struct buf *bp)
5322 {
5323 	kstat_t *iostatp;
5324 	size_t xfer_cnt;
5325 
5326 	ASSERT(pip != NULL);
5327 
5328 	/*
5329 	 * I/O can be driven across a path prior to having path
5330 	 * statistics available, i.e. probe(9e).
5331 	 */
5332 	if (bp != NULL && MDI_PI(pip)->pi_kstats != NULL) {
5333 		iostatp = MDI_PI(pip)->pi_kstats->pi_kstat_iostats;
5334 		xfer_cnt = bp->b_bcount - bp->b_resid;
5335 		if (bp->b_flags & B_READ) {
5336 			KSTAT_IO_PTR(iostatp)->reads++;
5337 			KSTAT_IO_PTR(iostatp)->nread += xfer_cnt;
5338 		} else {
5339 			KSTAT_IO_PTR(iostatp)->writes++;
5340 			KSTAT_IO_PTR(iostatp)->nwritten += xfer_cnt;
5341 		}
5342 	}
5343 }
5344 
5345 /*
5346  * Enable the path(specific client/target/initiator)
5347  * Enabling a path means that MPxIO may select the enabled path for routing
5348  * future I/O requests, subject to other path state constraints.
5349  */
5350 int
5351 mdi_pi_enable_path(mdi_pathinfo_t *pip, int flags)
5352 {
5353 	mdi_phci_t	*ph;
5354 
5355 	ph = i_devi_get_phci(mdi_pi_get_phci(pip));
5356 	if (ph == NULL) {
5357 		MDI_DEBUG(1, (CE_NOTE, NULL, "!mdi_pi_enable_path:"
5358 			" failed. pip: %p ph = NULL\n", (void *)pip));
5359 		return (MDI_FAILURE);
5360 	}
5361 
5362 	(void) i_mdi_enable_disable_path(pip, ph->ph_vhci, flags,
5363 		MDI_ENABLE_OP);
5364 	MDI_DEBUG(5, (CE_NOTE, NULL, "!mdi_pi_enable_path:"
5365 		" Returning success pip = %p. ph = %p\n",
5366 		(void *)pip, (void *)ph));
5367 	return (MDI_SUCCESS);
5368 
5369 }
5370 
5371 /*
5372  * Disable the path (specific client/target/initiator)
5373  * Disabling a path means that MPxIO will not select the disabled path for
5374  * routing any new I/O requests.
5375  */
5376 int
5377 mdi_pi_disable_path(mdi_pathinfo_t *pip, int flags)
5378 {
5379 	mdi_phci_t	*ph;
5380 
5381 	ph = i_devi_get_phci(mdi_pi_get_phci(pip));
5382 	if (ph == NULL) {
5383 		MDI_DEBUG(1, (CE_NOTE, NULL, "!mdi_pi_disable_path:"
5384 			" failed. pip: %p ph = NULL\n", (void *)pip));
5385 		return (MDI_FAILURE);
5386 	}
5387 
5388 	(void) i_mdi_enable_disable_path(pip,
5389 			ph->ph_vhci, flags, MDI_DISABLE_OP);
5390 	MDI_DEBUG(5, (CE_NOTE, NULL, "!mdi_pi_disable_path:"
5391 		"Returning success pip = %p. ph = %p",
5392 		(void *)pip, (void *)ph));
5393 	return (MDI_SUCCESS);
5394 }
5395 
5396 /*
5397  * disable the path to a particular pHCI (pHCI specified in the phci_path
5398  * argument) for a particular client (specified in the client_path argument).
5399  * Disabling a path means that MPxIO will not select the disabled path for
5400  * routing any new I/O requests.
5401  * NOTE: this will be removed once the NWS files are changed to use the new
5402  * mdi_{enable,disable}_path interfaces
5403  */
5404 int
5405 mdi_pi_disable(dev_info_t *cdip, dev_info_t *pdip, int flags)
5406 {
5407 	return (i_mdi_pi_enable_disable(cdip, pdip, flags, MDI_DISABLE_OP));
5408 }
5409 
5410 /*
5411  * Enable the path to a particular pHCI (pHCI specified in the phci_path
5412  * argument) for a particular client (specified in the client_path argument).
5413  * Enabling a path means that MPxIO may select the enabled path for routing
5414  * future I/O requests, subject to other path state constraints.
5415  * NOTE: this will be removed once the NWS files are changed to use the new
5416  * mdi_{enable,disable}_path interfaces
5417  */
5418 
5419 int
5420 mdi_pi_enable(dev_info_t *cdip, dev_info_t *pdip, int flags)
5421 {
5422 	return (i_mdi_pi_enable_disable(cdip, pdip, flags, MDI_ENABLE_OP));
5423 }
5424 
5425 /*
5426  * Common routine for doing enable/disable.
5427  */
5428 static mdi_pathinfo_t *
5429 i_mdi_enable_disable_path(mdi_pathinfo_t *pip, mdi_vhci_t *vh, int flags,
5430 		int op)
5431 {
5432 	int		sync_flag = 0;
5433 	int		rv;
5434 	mdi_pathinfo_t 	*next;
5435 	int		(*f)() = NULL;
5436 
5437 	f = vh->vh_ops->vo_pi_state_change;
5438 
5439 	sync_flag = (flags << 8) & 0xf00;
5440 
5441 	/*
5442 	 * Do a callback into the mdi consumer to let it
5443 	 * know that path is about to get enabled/disabled.
5444 	 */
5445 	if (f != NULL) {
5446 		rv = (*f)(vh->vh_dip, pip, 0,
5447 			MDI_PI_EXT_STATE(pip),
5448 			MDI_EXT_STATE_CHANGE | sync_flag |
5449 			op | MDI_BEFORE_STATE_CHANGE);
5450 		if (rv != MDI_SUCCESS) {
5451 			MDI_DEBUG(2, (CE_WARN, vh->vh_dip,
5452 			"!vo_pi_state_change: failed rv = %x", rv));
5453 		}
5454 	}
5455 	MDI_PI_LOCK(pip);
5456 	next = (mdi_pathinfo_t *)MDI_PI(pip)->pi_phci_link;
5457 
5458 	switch (flags) {
5459 		case USER_DISABLE:
5460 			if (op == MDI_DISABLE_OP) {
5461 				MDI_PI_SET_USER_DISABLE(pip);
5462 			} else {
5463 				MDI_PI_SET_USER_ENABLE(pip);
5464 			}
5465 			break;
5466 		case DRIVER_DISABLE:
5467 			if (op == MDI_DISABLE_OP) {
5468 				MDI_PI_SET_DRV_DISABLE(pip);
5469 			} else {
5470 				MDI_PI_SET_DRV_ENABLE(pip);
5471 			}
5472 			break;
5473 		case DRIVER_DISABLE_TRANSIENT:
5474 			if (op == MDI_DISABLE_OP && rv == MDI_SUCCESS) {
5475 				MDI_PI_SET_DRV_DISABLE_TRANS(pip);
5476 			} else {
5477 				MDI_PI_SET_DRV_ENABLE_TRANS(pip);
5478 			}
5479 			break;
5480 	}
5481 	MDI_PI_UNLOCK(pip);
5482 	/*
5483 	 * Do a callback into the mdi consumer to let it
5484 	 * know that path is now enabled/disabled.
5485 	 */
5486 	if (f != NULL) {
5487 		rv = (*f)(vh->vh_dip, pip, 0,
5488 			MDI_PI_EXT_STATE(pip),
5489 			MDI_EXT_STATE_CHANGE | sync_flag |
5490 			op | MDI_AFTER_STATE_CHANGE);
5491 		if (rv != MDI_SUCCESS) {
5492 			MDI_DEBUG(2, (CE_WARN, vh->vh_dip,
5493 			"!vo_pi_state_change: failed rv = %x", rv));
5494 		}
5495 	}
5496 	return (next);
5497 }
5498 
5499 /*
5500  * Common routine for doing enable/disable.
5501  * NOTE: this will be removed once the NWS files are changed to use the new
5502  * mdi_{enable,disable}_path has been putback
5503  */
5504 int
5505 i_mdi_pi_enable_disable(dev_info_t *cdip, dev_info_t *pdip, int flags, int op)
5506 {
5507 
5508 	mdi_phci_t	*ph;
5509 	mdi_vhci_t	*vh = NULL;
5510 	mdi_client_t	*ct;
5511 	mdi_pathinfo_t	*next, *pip;
5512 	int		found_it;
5513 
5514 	ph = i_devi_get_phci(pdip);
5515 	MDI_DEBUG(5, (CE_NOTE, NULL, "!i_mdi_pi_enable_disable: "
5516 		"Op = %d pdip = %p cdip = %p\n", op, (void *)pdip,
5517 		(void *)cdip));
5518 	if (ph == NULL) {
5519 		MDI_DEBUG(1, (CE_NOTE, NULL, "!i_mdi_pi_enable_disable:"
5520 			"Op %d failed. ph = NULL\n", op));
5521 		return (MDI_FAILURE);
5522 	}
5523 
5524 	if ((op != MDI_ENABLE_OP) && (op != MDI_DISABLE_OP)) {
5525 		MDI_DEBUG(1, (CE_NOTE, NULL, "!i_mdi_pi_enable_disable: "
5526 			"Op Invalid operation = %d\n", op));
5527 		return (MDI_FAILURE);
5528 	}
5529 
5530 	vh = ph->ph_vhci;
5531 
5532 	if (cdip == NULL) {
5533 		/*
5534 		 * Need to mark the Phci as enabled/disabled.
5535 		 */
5536 		MDI_DEBUG(3, (CE_NOTE, NULL, "!i_mdi_pi_enable_disable: "
5537 		"Op %d for the phci\n", op));
5538 		MDI_PHCI_LOCK(ph);
5539 		switch (flags) {
5540 			case USER_DISABLE:
5541 				if (op == MDI_DISABLE_OP) {
5542 					MDI_PHCI_SET_USER_DISABLE(ph);
5543 				} else {
5544 					MDI_PHCI_SET_USER_ENABLE(ph);
5545 				}
5546 				break;
5547 			case DRIVER_DISABLE:
5548 				if (op == MDI_DISABLE_OP) {
5549 					MDI_PHCI_SET_DRV_DISABLE(ph);
5550 				} else {
5551 					MDI_PHCI_SET_DRV_ENABLE(ph);
5552 				}
5553 				break;
5554 			case DRIVER_DISABLE_TRANSIENT:
5555 				if (op == MDI_DISABLE_OP) {
5556 					MDI_PHCI_SET_DRV_DISABLE_TRANSIENT(ph);
5557 				} else {
5558 					MDI_PHCI_SET_DRV_ENABLE_TRANSIENT(ph);
5559 				}
5560 				break;
5561 			default:
5562 				MDI_PHCI_UNLOCK(ph);
5563 				MDI_DEBUG(1, (CE_NOTE, NULL,
5564 				"!i_mdi_pi_enable_disable:"
5565 				" Invalid flag argument= %d\n", flags));
5566 		}
5567 
5568 		/*
5569 		 * Phci has been disabled. Now try to enable/disable
5570 		 * path info's to each client.
5571 		 */
5572 		pip = ph->ph_path_head;
5573 		while (pip != NULL) {
5574 			pip = i_mdi_enable_disable_path(pip, vh, flags, op);
5575 		}
5576 		MDI_PHCI_UNLOCK(ph);
5577 	} else {
5578 
5579 		/*
5580 		 * Disable a specific client.
5581 		 */
5582 		ct = i_devi_get_client(cdip);
5583 		if (ct == NULL) {
5584 			MDI_DEBUG(1, (CE_NOTE, NULL,
5585 			"!i_mdi_pi_enable_disable:"
5586 			" failed. ct = NULL operation = %d\n", op));
5587 			return (MDI_FAILURE);
5588 		}
5589 
5590 		MDI_CLIENT_LOCK(ct);
5591 		pip = ct->ct_path_head;
5592 		found_it = 0;
5593 		while (pip != NULL) {
5594 			MDI_PI_LOCK(pip);
5595 			next = (mdi_pathinfo_t *)MDI_PI(pip)->pi_client_link;
5596 			if (MDI_PI(pip)->pi_phci == ph) {
5597 				MDI_PI_UNLOCK(pip);
5598 				found_it = 1;
5599 				break;
5600 			}
5601 			MDI_PI_UNLOCK(pip);
5602 			pip = next;
5603 		}
5604 
5605 
5606 		MDI_CLIENT_UNLOCK(ct);
5607 		if (found_it == 0) {
5608 			MDI_DEBUG(1, (CE_NOTE, NULL,
5609 			"!i_mdi_pi_enable_disable:"
5610 			" failed. Could not find corresponding pip\n"));
5611 			return (MDI_FAILURE);
5612 		}
5613 
5614 		(void) i_mdi_enable_disable_path(pip, vh, flags, op);
5615 	}
5616 
5617 	MDI_DEBUG(5, (CE_NOTE, NULL, "!i_mdi_pi_enable_disable: "
5618 		"Op %d Returning success pdip = %p cdip = %p\n",
5619 		op, (void *)pdip, (void *)cdip));
5620 	return (MDI_SUCCESS);
5621 }
5622 
5623 /*
5624  * Ensure phci powered up
5625  */
5626 static void
5627 i_mdi_pm_hold_pip(mdi_pathinfo_t *pip)
5628 {
5629 	dev_info_t	*ph_dip;
5630 
5631 	ASSERT(pip != NULL);
5632 	ASSERT(MDI_PI_LOCKED(pip));
5633 
5634 	if (MDI_PI(pip)->pi_pm_held) {
5635 		return;
5636 	}
5637 
5638 	ph_dip = mdi_pi_get_phci(pip);
5639 	MDI_DEBUG(4, (CE_NOTE, ph_dip, "i_mdi_pm_hold_pip for %s%d %p\n",
5640 	    ddi_get_name(ph_dip), ddi_get_instance(ph_dip), (void *)pip));
5641 	if (ph_dip == NULL) {
5642 		return;
5643 	}
5644 
5645 	MDI_PI_UNLOCK(pip);
5646 	MDI_DEBUG(4, (CE_NOTE, ph_dip, "kidsupcnt was %d\n",
5647 	    DEVI(ph_dip)->devi_pm_kidsupcnt));
5648 
5649 	pm_hold_power(ph_dip);
5650 
5651 	MDI_DEBUG(4, (CE_NOTE, ph_dip, "kidsupcnt is %d\n",
5652 	    DEVI(ph_dip)->devi_pm_kidsupcnt));
5653 	MDI_PI_LOCK(pip);
5654 
5655 	/* If PM_GET_PM_INFO is NULL the pm_hold_power above was a noop */
5656 	if (DEVI(ph_dip)->devi_pm_info)
5657 		MDI_PI(pip)->pi_pm_held = 1;
5658 }
5659 
5660 /*
5661  * Allow phci powered down
5662  */
5663 static void
5664 i_mdi_pm_rele_pip(mdi_pathinfo_t *pip)
5665 {
5666 	dev_info_t	*ph_dip = NULL;
5667 
5668 	ASSERT(pip != NULL);
5669 	ASSERT(MDI_PI_LOCKED(pip));
5670 
5671 	if (MDI_PI(pip)->pi_pm_held == 0) {
5672 		return;
5673 	}
5674 
5675 	ph_dip = mdi_pi_get_phci(pip);
5676 	ASSERT(ph_dip != NULL);
5677 
5678 	MDI_PI_UNLOCK(pip);
5679 	MDI_DEBUG(4, (CE_NOTE, ph_dip, "i_mdi_pm_rele_pip for %s%d %p\n",
5680 	    ddi_get_name(ph_dip), ddi_get_instance(ph_dip), (void *)pip));
5681 
5682 	MDI_DEBUG(4, (CE_NOTE, ph_dip, "kidsupcnt was %d\n",
5683 	    DEVI(ph_dip)->devi_pm_kidsupcnt));
5684 	pm_rele_power(ph_dip);
5685 	MDI_DEBUG(4, (CE_NOTE, ph_dip, "kidsupcnt is %d\n",
5686 	    DEVI(ph_dip)->devi_pm_kidsupcnt));
5687 
5688 	MDI_PI_LOCK(pip);
5689 	MDI_PI(pip)->pi_pm_held = 0;
5690 }
5691 
5692 static void
5693 i_mdi_pm_hold_client(mdi_client_t *ct, int incr)
5694 {
5695 	ASSERT(MDI_CLIENT_LOCKED(ct));
5696 
5697 	ct->ct_power_cnt += incr;
5698 	MDI_DEBUG(4, (CE_NOTE, ct->ct_dip, "i_mdi_pm_hold_client %p "
5699 	    "ct_power_cnt = %d incr = %d\n", (void *)ct,
5700 	    ct->ct_power_cnt, incr));
5701 	ASSERT(ct->ct_power_cnt >= 0);
5702 }
5703 
5704 static void
5705 i_mdi_rele_all_phci(mdi_client_t *ct)
5706 {
5707 	mdi_pathinfo_t  *pip;
5708 
5709 	ASSERT(MDI_CLIENT_LOCKED(ct));
5710 	pip = (mdi_pathinfo_t *)ct->ct_path_head;
5711 	while (pip != NULL) {
5712 		mdi_hold_path(pip);
5713 		MDI_PI_LOCK(pip);
5714 		i_mdi_pm_rele_pip(pip);
5715 		MDI_PI_UNLOCK(pip);
5716 		mdi_rele_path(pip);
5717 		pip = (mdi_pathinfo_t *)MDI_PI(pip)->pi_client_link;
5718 	}
5719 }
5720 
5721 static void
5722 i_mdi_pm_rele_client(mdi_client_t *ct, int decr)
5723 {
5724 	ASSERT(MDI_CLIENT_LOCKED(ct));
5725 
5726 	if (i_ddi_devi_attached(ct->ct_dip)) {
5727 		ct->ct_power_cnt -= decr;
5728 		MDI_DEBUG(4, (CE_NOTE, ct->ct_dip, "i_mdi_pm_rele_client %p "
5729 		    "ct_power_cnt = %d decr = %d\n",
5730 		    (void *)ct, ct->ct_power_cnt, decr));
5731 	}
5732 
5733 	ASSERT(ct->ct_power_cnt >= 0);
5734 	if (ct->ct_power_cnt == 0) {
5735 		i_mdi_rele_all_phci(ct);
5736 		return;
5737 	}
5738 }
5739 
5740 static void
5741 i_mdi_pm_reset_client(mdi_client_t *ct)
5742 {
5743 	MDI_DEBUG(4, (CE_NOTE, ct->ct_dip, "i_mdi_pm_reset_client %p "
5744 	    "ct_power_cnt = %d\n", (void *)ct, ct->ct_power_cnt));
5745 	ASSERT(MDI_CLIENT_LOCKED(ct));
5746 	ct->ct_power_cnt = 0;
5747 	i_mdi_rele_all_phci(ct);
5748 	ct->ct_powercnt_config = 0;
5749 	ct->ct_powercnt_unconfig = 0;
5750 	ct->ct_powercnt_reset = 1;
5751 }
5752 
5753 static int
5754 i_mdi_power_one_phci(mdi_pathinfo_t *pip)
5755 {
5756 	int		ret;
5757 	dev_info_t	*ph_dip;
5758 
5759 	MDI_PI_LOCK(pip);
5760 	i_mdi_pm_hold_pip(pip);
5761 
5762 	ph_dip = mdi_pi_get_phci(pip);
5763 	MDI_PI_UNLOCK(pip);
5764 
5765 	/* bring all components of phci to full power */
5766 	MDI_DEBUG(4, (CE_NOTE, ph_dip, "i_mdi_power_one_phci "
5767 	    "pm_powerup for %s%d %p\n", ddi_get_name(ph_dip),
5768 	    ddi_get_instance(ph_dip), (void *)pip));
5769 
5770 	ret = pm_powerup(ph_dip);
5771 
5772 	if (ret == DDI_FAILURE) {
5773 		MDI_DEBUG(4, (CE_NOTE, ph_dip, "i_mdi_power_one_phci "
5774 		    "pm_powerup FAILED for %s%d %p\n",
5775 		    ddi_get_name(ph_dip), ddi_get_instance(ph_dip),
5776 		    (void *)pip));
5777 
5778 		MDI_PI_LOCK(pip);
5779 		i_mdi_pm_rele_pip(pip);
5780 		MDI_PI_UNLOCK(pip);
5781 		return (MDI_FAILURE);
5782 	}
5783 
5784 	return (MDI_SUCCESS);
5785 }
5786 
5787 static int
5788 i_mdi_power_all_phci(mdi_client_t *ct)
5789 {
5790 	mdi_pathinfo_t  *pip;
5791 	int		succeeded = 0;
5792 
5793 	ASSERT(MDI_CLIENT_LOCKED(ct));
5794 	pip = (mdi_pathinfo_t *)ct->ct_path_head;
5795 	while (pip != NULL) {
5796 		/*
5797 		 * Don't power if MDI_PATHINFO_STATE_FAULT
5798 		 * or MDI_PATHINFO_STATE_OFFLINE.
5799 		 */
5800 		if (MDI_PI_IS_INIT(pip) ||
5801 		    MDI_PI_IS_ONLINE(pip) || MDI_PI_IS_STANDBY(pip)) {
5802 			mdi_hold_path(pip);
5803 			MDI_CLIENT_UNLOCK(ct);
5804 			if (i_mdi_power_one_phci(pip) == MDI_SUCCESS)
5805 				succeeded = 1;
5806 
5807 			ASSERT(ct == MDI_PI(pip)->pi_client);
5808 			MDI_CLIENT_LOCK(ct);
5809 			mdi_rele_path(pip);
5810 		}
5811 		pip = (mdi_pathinfo_t *)MDI_PI(pip)->pi_client_link;
5812 	}
5813 
5814 	return (succeeded ? MDI_SUCCESS : MDI_FAILURE);
5815 }
5816 
5817 /*
5818  * mdi_bus_power():
5819  *		1. Place the phci(s) into powered up state so that
5820  *		   client can do power management
5821  *		2. Ensure phci powered up as client power managing
5822  * Return Values:
5823  *		MDI_SUCCESS
5824  *		MDI_FAILURE
5825  */
5826 int
5827 mdi_bus_power(dev_info_t *parent, void *impl_arg, pm_bus_power_op_t op,
5828     void *arg, void *result)
5829 {
5830 	int			ret = MDI_SUCCESS;
5831 	pm_bp_child_pwrchg_t	*bpc;
5832 	mdi_client_t		*ct;
5833 	dev_info_t		*cdip;
5834 	pm_bp_has_changed_t	*bphc;
5835 
5836 	/*
5837 	 * BUS_POWER_NOINVOL not supported
5838 	 */
5839 	if (op == BUS_POWER_NOINVOL)
5840 		return (MDI_FAILURE);
5841 
5842 	/*
5843 	 * ignore other OPs.
5844 	 * return quickly to save cou cycles on the ct processing
5845 	 */
5846 	switch (op) {
5847 	case BUS_POWER_PRE_NOTIFICATION:
5848 	case BUS_POWER_POST_NOTIFICATION:
5849 		bpc = (pm_bp_child_pwrchg_t *)arg;
5850 		cdip = bpc->bpc_dip;
5851 		break;
5852 	case BUS_POWER_HAS_CHANGED:
5853 		bphc = (pm_bp_has_changed_t *)arg;
5854 		cdip = bphc->bphc_dip;
5855 		break;
5856 	default:
5857 		return (pm_busop_bus_power(parent, impl_arg, op, arg, result));
5858 	}
5859 
5860 	ASSERT(MDI_CLIENT(cdip));
5861 
5862 	ct = i_devi_get_client(cdip);
5863 	if (ct == NULL)
5864 		return (MDI_FAILURE);
5865 
5866 	/*
5867 	 * wait till the mdi_pathinfo node state change are processed
5868 	 */
5869 	MDI_CLIENT_LOCK(ct);
5870 	switch (op) {
5871 	case BUS_POWER_PRE_NOTIFICATION:
5872 		MDI_DEBUG(4, (CE_NOTE, bpc->bpc_dip, "mdi_bus_power "
5873 		    "BUS_POWER_PRE_NOTIFICATION:"
5874 		    "%s@%s, olevel=%d, nlevel=%d, comp=%d\n",
5875 		    PM_NAME(bpc->bpc_dip), PM_ADDR(bpc->bpc_dip),
5876 		    bpc->bpc_olevel, bpc->bpc_nlevel, bpc->bpc_comp));
5877 
5878 		/* serialize power level change per client */
5879 		while (MDI_CLIENT_IS_POWER_TRANSITION(ct))
5880 			cv_wait(&ct->ct_powerchange_cv, &ct->ct_mutex);
5881 
5882 		MDI_CLIENT_SET_POWER_TRANSITION(ct);
5883 
5884 		if (ct->ct_power_cnt == 0) {
5885 			ret = i_mdi_power_all_phci(ct);
5886 		}
5887 
5888 		/*
5889 		 * if new_level > 0:
5890 		 *	- hold phci(s)
5891 		 *	- power up phci(s) if not already
5892 		 * ignore power down
5893 		 */
5894 		if (bpc->bpc_nlevel > 0) {
5895 			if (!DEVI_IS_ATTACHING(ct->ct_dip)) {
5896 				MDI_DEBUG(4, (CE_NOTE, bpc->bpc_dip,
5897 				    "mdi_bus_power i_mdi_pm_hold_client\n"));
5898 				i_mdi_pm_hold_client(ct, ct->ct_path_count);
5899 			}
5900 		}
5901 		break;
5902 	case BUS_POWER_POST_NOTIFICATION:
5903 		MDI_DEBUG(4, (CE_NOTE, bpc->bpc_dip, "mdi_bus_power "
5904 		    "BUS_POWER_POST_NOTIFICATION:"
5905 		    "%s@%s, olevel=%d, nlevel=%d, comp=%d result=%d\n",
5906 		    PM_NAME(bpc->bpc_dip), PM_ADDR(bpc->bpc_dip),
5907 		    bpc->bpc_olevel, bpc->bpc_nlevel, bpc->bpc_comp,
5908 		    *(int *)result));
5909 
5910 		if (*(int *)result == DDI_SUCCESS) {
5911 			if (bpc->bpc_nlevel > 0) {
5912 				MDI_CLIENT_SET_POWER_UP(ct);
5913 			} else {
5914 				MDI_CLIENT_SET_POWER_DOWN(ct);
5915 			}
5916 		}
5917 
5918 		/* release the hold we did in pre-notification */
5919 		if (bpc->bpc_nlevel > 0 && (*(int *)result != DDI_SUCCESS) &&
5920 		    !DEVI_IS_ATTACHING(ct->ct_dip)) {
5921 			MDI_DEBUG(4, (CE_NOTE, bpc->bpc_dip,
5922 			    "mdi_bus_power i_mdi_pm_rele_client\n"));
5923 			i_mdi_pm_rele_client(ct, ct->ct_path_count);
5924 		}
5925 
5926 		if (bpc->bpc_nlevel == 0 && (*(int *)result == DDI_SUCCESS)) {
5927 			/* another thread might started attaching */
5928 			if (DEVI_IS_ATTACHING(ct->ct_dip)) {
5929 				MDI_DEBUG(4, (CE_NOTE, bpc->bpc_dip,
5930 				    "mdi_bus_power i_mdi_pm_rele_client\n"));
5931 				i_mdi_pm_rele_client(ct, ct->ct_path_count);
5932 			/* detaching has been taken care in pm_post_unconfig */
5933 			} else if (!DEVI_IS_DETACHING(ct->ct_dip)) {
5934 				MDI_DEBUG(4, (CE_NOTE, bpc->bpc_dip,
5935 				    "mdi_bus_power i_mdi_pm_reset_client\n"));
5936 				i_mdi_pm_reset_client(ct);
5937 			}
5938 		}
5939 
5940 		MDI_CLIENT_CLEAR_POWER_TRANSITION(ct);
5941 		cv_broadcast(&ct->ct_powerchange_cv);
5942 
5943 		break;
5944 
5945 	/* need to do more */
5946 	case BUS_POWER_HAS_CHANGED:
5947 		MDI_DEBUG(4, (CE_NOTE, bphc->bphc_dip, "mdi_bus_power "
5948 		    "BUS_POWER_HAS_CHANGED:"
5949 		    "%s@%s, olevel=%d, nlevel=%d, comp=%d\n",
5950 		    PM_NAME(bphc->bphc_dip), PM_ADDR(bphc->bphc_dip),
5951 		    bphc->bphc_olevel, bphc->bphc_nlevel, bphc->bphc_comp));
5952 
5953 		if (bphc->bphc_nlevel > 0 &&
5954 		    bphc->bphc_nlevel > bphc->bphc_olevel) {
5955 			if (ct->ct_power_cnt == 0) {
5956 				ret = i_mdi_power_all_phci(ct);
5957 			}
5958 			MDI_DEBUG(4, (CE_NOTE, bphc->bphc_dip,
5959 			    "mdi_bus_power i_mdi_pm_hold_client\n"));
5960 			i_mdi_pm_hold_client(ct, ct->ct_path_count);
5961 		}
5962 
5963 		if (bphc->bphc_nlevel == 0 && bphc->bphc_olevel != -1) {
5964 			MDI_DEBUG(4, (CE_NOTE, bphc->bphc_dip,
5965 			    "mdi_bus_power i_mdi_pm_rele_client\n"));
5966 			i_mdi_pm_rele_client(ct, ct->ct_path_count);
5967 		}
5968 		break;
5969 	}
5970 
5971 	MDI_CLIENT_UNLOCK(ct);
5972 	return (ret);
5973 }
5974 
5975 static int
5976 i_mdi_pm_pre_config_one(dev_info_t *child)
5977 {
5978 	int		ret = MDI_SUCCESS;
5979 	mdi_client_t	*ct;
5980 
5981 	ct = i_devi_get_client(child);
5982 	if (ct == NULL)
5983 		return (MDI_FAILURE);
5984 
5985 	MDI_CLIENT_LOCK(ct);
5986 	while (MDI_CLIENT_IS_POWER_TRANSITION(ct))
5987 		cv_wait(&ct->ct_powerchange_cv, &ct->ct_mutex);
5988 
5989 	if (!MDI_CLIENT_IS_FAILED(ct)) {
5990 		MDI_CLIENT_UNLOCK(ct);
5991 		MDI_DEBUG(4, (CE_NOTE, child,
5992 		    "i_mdi_pm_pre_config_one already configured\n"));
5993 		return (MDI_SUCCESS);
5994 	}
5995 
5996 	if (ct->ct_powercnt_config) {
5997 		MDI_CLIENT_UNLOCK(ct);
5998 		MDI_DEBUG(4, (CE_NOTE, child,
5999 		    "i_mdi_pm_pre_config_one ALREADY held\n"));
6000 		return (MDI_SUCCESS);
6001 	}
6002 
6003 	if (ct->ct_power_cnt == 0) {
6004 		ret = i_mdi_power_all_phci(ct);
6005 	}
6006 	MDI_DEBUG(4, (CE_NOTE, child,
6007 	    "i_mdi_pm_pre_config_one i_mdi_pm_hold_client\n"));
6008 	i_mdi_pm_hold_client(ct, ct->ct_path_count);
6009 	ct->ct_powercnt_config = 1;
6010 	ct->ct_powercnt_reset = 0;
6011 	MDI_CLIENT_UNLOCK(ct);
6012 	return (ret);
6013 }
6014 
6015 static int
6016 i_mdi_pm_pre_config(dev_info_t *vdip, dev_info_t *child)
6017 {
6018 	int			ret = MDI_SUCCESS;
6019 	dev_info_t		*cdip;
6020 	int			circ;
6021 
6022 	ASSERT(MDI_VHCI(vdip));
6023 
6024 	/* ndi_devi_config_one */
6025 	if (child) {
6026 		ASSERT(DEVI_BUSY_OWNED(vdip));
6027 		return (i_mdi_pm_pre_config_one(child));
6028 	}
6029 
6030 	/* devi_config_common */
6031 	ndi_devi_enter(vdip, &circ);
6032 	cdip = ddi_get_child(vdip);
6033 	while (cdip) {
6034 		dev_info_t *next = ddi_get_next_sibling(cdip);
6035 
6036 		ret = i_mdi_pm_pre_config_one(cdip);
6037 		if (ret != MDI_SUCCESS)
6038 			break;
6039 		cdip = next;
6040 	}
6041 	ndi_devi_exit(vdip, circ);
6042 	return (ret);
6043 }
6044 
6045 static int
6046 i_mdi_pm_pre_unconfig_one(dev_info_t *child, int *held, int flags)
6047 {
6048 	int		ret = MDI_SUCCESS;
6049 	mdi_client_t	*ct;
6050 
6051 	ct = i_devi_get_client(child);
6052 	if (ct == NULL)
6053 		return (MDI_FAILURE);
6054 
6055 	MDI_CLIENT_LOCK(ct);
6056 	while (MDI_CLIENT_IS_POWER_TRANSITION(ct))
6057 		cv_wait(&ct->ct_powerchange_cv, &ct->ct_mutex);
6058 
6059 	if (!i_ddi_devi_attached(ct->ct_dip)) {
6060 		MDI_DEBUG(4, (CE_NOTE, child,
6061 		    "i_mdi_pm_pre_unconfig node detached already\n"));
6062 		MDI_CLIENT_UNLOCK(ct);
6063 		return (MDI_SUCCESS);
6064 	}
6065 
6066 	if (MDI_CLIENT_IS_POWERED_DOWN(ct) &&
6067 	    (flags & NDI_AUTODETACH)) {
6068 		MDI_DEBUG(4, (CE_NOTE, child,
6069 		    "i_mdi_pm_pre_unconfig auto-modunload\n"));
6070 		MDI_CLIENT_UNLOCK(ct);
6071 		return (MDI_FAILURE);
6072 	}
6073 
6074 	if (ct->ct_powercnt_unconfig) {
6075 		MDI_DEBUG(4, (CE_NOTE, child,
6076 		    "i_mdi_pm_pre_unconfig ct_powercnt_held\n"));
6077 		MDI_CLIENT_UNLOCK(ct);
6078 		*held = 1;
6079 		return (MDI_SUCCESS);
6080 	}
6081 
6082 	if (ct->ct_power_cnt == 0) {
6083 		ret = i_mdi_power_all_phci(ct);
6084 	}
6085 	MDI_DEBUG(4, (CE_NOTE, child,
6086 	    "i_mdi_pm_pre_unconfig i_mdi_pm_hold_client\n"));
6087 	i_mdi_pm_hold_client(ct, ct->ct_path_count);
6088 	ct->ct_powercnt_unconfig = 1;
6089 	ct->ct_powercnt_reset = 0;
6090 	MDI_CLIENT_UNLOCK(ct);
6091 	if (ret == MDI_SUCCESS)
6092 		*held = 1;
6093 	return (ret);
6094 }
6095 
6096 static int
6097 i_mdi_pm_pre_unconfig(dev_info_t *vdip, dev_info_t *child, int *held,
6098     int flags)
6099 {
6100 	int			ret = MDI_SUCCESS;
6101 	dev_info_t		*cdip;
6102 	int			circ;
6103 
6104 	ASSERT(MDI_VHCI(vdip));
6105 	*held = 0;
6106 
6107 	/* ndi_devi_unconfig_one */
6108 	if (child) {
6109 		ASSERT(DEVI_BUSY_OWNED(vdip));
6110 		return (i_mdi_pm_pre_unconfig_one(child, held, flags));
6111 	}
6112 
6113 	/* devi_unconfig_common */
6114 	ndi_devi_enter(vdip, &circ);
6115 	cdip = ddi_get_child(vdip);
6116 	while (cdip) {
6117 		dev_info_t *next = ddi_get_next_sibling(cdip);
6118 
6119 		ret = i_mdi_pm_pre_unconfig_one(cdip, held, flags);
6120 		cdip = next;
6121 	}
6122 	ndi_devi_exit(vdip, circ);
6123 
6124 	if (*held)
6125 		ret = MDI_SUCCESS;
6126 
6127 	return (ret);
6128 }
6129 
6130 static void
6131 i_mdi_pm_post_config_one(dev_info_t *child)
6132 {
6133 	mdi_client_t	*ct;
6134 
6135 	ct = i_devi_get_client(child);
6136 	if (ct == NULL)
6137 		return;
6138 
6139 	MDI_CLIENT_LOCK(ct);
6140 	while (MDI_CLIENT_IS_POWER_TRANSITION(ct))
6141 		cv_wait(&ct->ct_powerchange_cv, &ct->ct_mutex);
6142 
6143 	if (ct->ct_powercnt_reset || !ct->ct_powercnt_config) {
6144 		MDI_DEBUG(4, (CE_NOTE, child,
6145 		    "i_mdi_pm_post_config_one NOT configured\n"));
6146 		MDI_CLIENT_UNLOCK(ct);
6147 		return;
6148 	}
6149 
6150 	/* client has not been updated */
6151 	if (MDI_CLIENT_IS_FAILED(ct)) {
6152 		MDI_DEBUG(4, (CE_NOTE, child,
6153 		    "i_mdi_pm_post_config_one NOT configured\n"));
6154 		MDI_CLIENT_UNLOCK(ct);
6155 		return;
6156 	}
6157 
6158 	/* another thread might have powered it down or detached it */
6159 	if ((MDI_CLIENT_IS_POWERED_DOWN(ct) &&
6160 	    !DEVI_IS_ATTACHING(ct->ct_dip)) ||
6161 	    (!i_ddi_devi_attached(ct->ct_dip) &&
6162 	    !DEVI_IS_ATTACHING(ct->ct_dip))) {
6163 		MDI_DEBUG(4, (CE_NOTE, child,
6164 		    "i_mdi_pm_post_config i_mdi_pm_reset_client\n"));
6165 		i_mdi_pm_reset_client(ct);
6166 	} else {
6167 		mdi_pathinfo_t  *pip, *next;
6168 		int	valid_path_count = 0;
6169 
6170 		MDI_DEBUG(4, (CE_NOTE, child,
6171 		    "i_mdi_pm_post_config i_mdi_pm_rele_client\n"));
6172 		pip = ct->ct_path_head;
6173 		while (pip != NULL) {
6174 			MDI_PI_LOCK(pip);
6175 			next = (mdi_pathinfo_t *)MDI_PI(pip)->pi_client_link;
6176 			if (MDI_PI_IS_ONLINE(pip) || MDI_PI_IS_STANDBY(pip))
6177 				valid_path_count ++;
6178 			MDI_PI_UNLOCK(pip);
6179 			pip = next;
6180 		}
6181 		i_mdi_pm_rele_client(ct, valid_path_count);
6182 	}
6183 	ct->ct_powercnt_config = 0;
6184 	MDI_CLIENT_UNLOCK(ct);
6185 }
6186 
6187 static void
6188 i_mdi_pm_post_config(dev_info_t *vdip, dev_info_t *child)
6189 {
6190 	int		circ;
6191 	dev_info_t	*cdip;
6192 
6193 	ASSERT(MDI_VHCI(vdip));
6194 
6195 	/* ndi_devi_config_one */
6196 	if (child) {
6197 		ASSERT(DEVI_BUSY_OWNED(vdip));
6198 		i_mdi_pm_post_config_one(child);
6199 		return;
6200 	}
6201 
6202 	/* devi_config_common */
6203 	ndi_devi_enter(vdip, &circ);
6204 	cdip = ddi_get_child(vdip);
6205 	while (cdip) {
6206 		dev_info_t *next = ddi_get_next_sibling(cdip);
6207 
6208 		i_mdi_pm_post_config_one(cdip);
6209 		cdip = next;
6210 	}
6211 	ndi_devi_exit(vdip, circ);
6212 }
6213 
6214 static void
6215 i_mdi_pm_post_unconfig_one(dev_info_t *child)
6216 {
6217 	mdi_client_t	*ct;
6218 
6219 	ct = i_devi_get_client(child);
6220 	if (ct == NULL)
6221 		return;
6222 
6223 	MDI_CLIENT_LOCK(ct);
6224 	while (MDI_CLIENT_IS_POWER_TRANSITION(ct))
6225 		cv_wait(&ct->ct_powerchange_cv, &ct->ct_mutex);
6226 
6227 	if (!ct->ct_powercnt_unconfig || ct->ct_powercnt_reset) {
6228 		MDI_DEBUG(4, (CE_NOTE, child,
6229 		    "i_mdi_pm_post_unconfig NOT held\n"));
6230 		MDI_CLIENT_UNLOCK(ct);
6231 		return;
6232 	}
6233 
6234 	/* failure detaching or another thread just attached it */
6235 	if ((MDI_CLIENT_IS_POWERED_DOWN(ct) &&
6236 	    i_ddi_devi_attached(ct->ct_dip)) ||
6237 	    (!i_ddi_devi_attached(ct->ct_dip) &&
6238 	    !DEVI_IS_ATTACHING(ct->ct_dip))) {
6239 		MDI_DEBUG(4, (CE_NOTE, child,
6240 		    "i_mdi_pm_post_unconfig i_mdi_pm_reset_client\n"));
6241 		i_mdi_pm_reset_client(ct);
6242 	} else {
6243 		mdi_pathinfo_t  *pip, *next;
6244 		int	valid_path_count = 0;
6245 
6246 		MDI_DEBUG(4, (CE_NOTE, child,
6247 		    "i_mdi_pm_post_unconfig i_mdi_pm_rele_client\n"));
6248 		pip = ct->ct_path_head;
6249 		while (pip != NULL) {
6250 			MDI_PI_LOCK(pip);
6251 			next = (mdi_pathinfo_t *)MDI_PI(pip)->pi_client_link;
6252 			if (MDI_PI_IS_ONLINE(pip) || MDI_PI_IS_STANDBY(pip))
6253 				valid_path_count ++;
6254 			MDI_PI_UNLOCK(pip);
6255 			pip = next;
6256 		}
6257 		i_mdi_pm_rele_client(ct, valid_path_count);
6258 		ct->ct_powercnt_unconfig = 0;
6259 	}
6260 
6261 	MDI_CLIENT_UNLOCK(ct);
6262 }
6263 
6264 static void
6265 i_mdi_pm_post_unconfig(dev_info_t *vdip, dev_info_t *child, int held)
6266 {
6267 	int			circ;
6268 	dev_info_t		*cdip;
6269 
6270 	ASSERT(MDI_VHCI(vdip));
6271 
6272 	if (!held) {
6273 		MDI_DEBUG(4, (CE_NOTE, vdip,
6274 		    "i_mdi_pm_post_unconfig held = %d\n", held));
6275 		return;
6276 	}
6277 
6278 	if (child) {
6279 		ASSERT(DEVI_BUSY_OWNED(vdip));
6280 		i_mdi_pm_post_unconfig_one(child);
6281 		return;
6282 	}
6283 
6284 	ndi_devi_enter(vdip, &circ);
6285 	cdip = ddi_get_child(vdip);
6286 	while (cdip) {
6287 		dev_info_t *next = ddi_get_next_sibling(cdip);
6288 
6289 		i_mdi_pm_post_unconfig_one(cdip);
6290 		cdip = next;
6291 	}
6292 	ndi_devi_exit(vdip, circ);
6293 }
6294 
6295 int
6296 mdi_power(dev_info_t *vdip, mdi_pm_op_t op, void *args, char *devnm, int flags)
6297 {
6298 	int			circ, ret = MDI_SUCCESS;
6299 	dev_info_t		*client_dip = NULL;
6300 	mdi_client_t		*ct;
6301 
6302 	/*
6303 	 * Handling ndi_devi_config_one and ndi_devi_unconfig_one.
6304 	 * Power up pHCI for the named client device.
6305 	 * Note: Before the client is enumerated under vhci by phci,
6306 	 * client_dip can be NULL. Then proceed to power up all the
6307 	 * pHCIs.
6308 	 */
6309 	if (devnm != NULL) {
6310 		ndi_devi_enter(vdip, &circ);
6311 		client_dip = ndi_devi_findchild(vdip, devnm);
6312 	}
6313 
6314 	MDI_DEBUG(4, (CE_NOTE, vdip, "mdi_power op = %d %s %p\n",
6315 	    op, devnm ? devnm : "NULL", (void *)client_dip));
6316 
6317 	switch (op) {
6318 	case MDI_PM_PRE_CONFIG:
6319 		ret = i_mdi_pm_pre_config(vdip, client_dip);
6320 		break;
6321 
6322 	case MDI_PM_PRE_UNCONFIG:
6323 		ret = i_mdi_pm_pre_unconfig(vdip, client_dip, (int *)args,
6324 		    flags);
6325 		break;
6326 
6327 	case MDI_PM_POST_CONFIG:
6328 		i_mdi_pm_post_config(vdip, client_dip);
6329 		break;
6330 
6331 	case MDI_PM_POST_UNCONFIG:
6332 		i_mdi_pm_post_unconfig(vdip, client_dip, *(int *)args);
6333 		break;
6334 
6335 	case MDI_PM_HOLD_POWER:
6336 	case MDI_PM_RELE_POWER:
6337 		ASSERT(args);
6338 
6339 		client_dip = (dev_info_t *)args;
6340 		ASSERT(MDI_CLIENT(client_dip));
6341 
6342 		ct = i_devi_get_client(client_dip);
6343 		MDI_CLIENT_LOCK(ct);
6344 
6345 		if (op == MDI_PM_HOLD_POWER) {
6346 			if (ct->ct_power_cnt == 0) {
6347 				(void) i_mdi_power_all_phci(ct);
6348 				MDI_DEBUG(4, (CE_NOTE, client_dip,
6349 				    "mdi_power i_mdi_pm_hold_client\n"));
6350 				i_mdi_pm_hold_client(ct, ct->ct_path_count);
6351 			}
6352 		} else {
6353 			if (DEVI_IS_ATTACHING(ct->ct_dip)) {
6354 				MDI_DEBUG(4, (CE_NOTE, client_dip,
6355 				    "mdi_power i_mdi_pm_rele_client\n"));
6356 				i_mdi_pm_rele_client(ct, ct->ct_path_count);
6357 			} else {
6358 				MDI_DEBUG(4, (CE_NOTE, client_dip,
6359 				    "mdi_power i_mdi_pm_reset_client\n"));
6360 				i_mdi_pm_reset_client(ct);
6361 			}
6362 		}
6363 
6364 		MDI_CLIENT_UNLOCK(ct);
6365 		break;
6366 
6367 	default:
6368 		break;
6369 	}
6370 
6371 	if (devnm)
6372 		ndi_devi_exit(vdip, circ);
6373 
6374 	return (ret);
6375 }
6376 
6377 int
6378 mdi_component_is_vhci(dev_info_t *dip, const char **mdi_class)
6379 {
6380 	mdi_vhci_t *vhci;
6381 
6382 	if (!MDI_VHCI(dip))
6383 		return (MDI_FAILURE);
6384 
6385 	if (mdi_class) {
6386 		vhci = DEVI(dip)->devi_mdi_xhci;
6387 		ASSERT(vhci);
6388 		*mdi_class = vhci->vh_class;
6389 	}
6390 
6391 	return (MDI_SUCCESS);
6392 }
6393 
6394 int
6395 mdi_component_is_phci(dev_info_t *dip, const char **mdi_class)
6396 {
6397 	mdi_phci_t *phci;
6398 
6399 	if (!MDI_PHCI(dip))
6400 		return (MDI_FAILURE);
6401 
6402 	if (mdi_class) {
6403 		phci = DEVI(dip)->devi_mdi_xhci;
6404 		ASSERT(phci);
6405 		*mdi_class = phci->ph_vhci->vh_class;
6406 	}
6407 
6408 	return (MDI_SUCCESS);
6409 }
6410 
6411 int
6412 mdi_component_is_client(dev_info_t *dip, const char **mdi_class)
6413 {
6414 	mdi_client_t *client;
6415 
6416 	if (!MDI_CLIENT(dip))
6417 		return (MDI_FAILURE);
6418 
6419 	if (mdi_class) {
6420 		client = DEVI(dip)->devi_mdi_client;
6421 		ASSERT(client);
6422 		*mdi_class = client->ct_vhci->vh_class;
6423 	}
6424 
6425 	return (MDI_SUCCESS);
6426 }
6427 
6428 void *
6429 mdi_client_get_vhci_private(dev_info_t *dip)
6430 {
6431 	ASSERT(mdi_component_is_client(dip, NULL) == MDI_SUCCESS);
6432 	if (mdi_component_is_client(dip, NULL) == MDI_SUCCESS) {
6433 		mdi_client_t	*ct;
6434 		ct = i_devi_get_client(dip);
6435 		return (ct->ct_vprivate);
6436 	}
6437 	return (NULL);
6438 }
6439 
6440 void
6441 mdi_client_set_vhci_private(dev_info_t *dip, void *data)
6442 {
6443 	ASSERT(mdi_component_is_client(dip, NULL) == MDI_SUCCESS);
6444 	if (mdi_component_is_client(dip, NULL) == MDI_SUCCESS) {
6445 		mdi_client_t	*ct;
6446 		ct = i_devi_get_client(dip);
6447 		ct->ct_vprivate = data;
6448 	}
6449 }
6450 /*
6451  * mdi_pi_get_vhci_private():
6452  *		Get the vhci private information associated with the
6453  *		mdi_pathinfo node
6454  */
6455 void *
6456 mdi_pi_get_vhci_private(mdi_pathinfo_t *pip)
6457 {
6458 	caddr_t	vprivate = NULL;
6459 	if (pip) {
6460 		vprivate = MDI_PI(pip)->pi_vprivate;
6461 	}
6462 	return (vprivate);
6463 }
6464 
6465 /*
6466  * mdi_pi_set_vhci_private():
6467  *		Set the vhci private information in the mdi_pathinfo node
6468  */
6469 void
6470 mdi_pi_set_vhci_private(mdi_pathinfo_t *pip, void *priv)
6471 {
6472 	if (pip) {
6473 		MDI_PI(pip)->pi_vprivate = priv;
6474 	}
6475 }
6476 
6477 /*
6478  * mdi_phci_get_vhci_private():
6479  *		Get the vhci private information associated with the
6480  *		mdi_phci node
6481  */
6482 void *
6483 mdi_phci_get_vhci_private(dev_info_t *dip)
6484 {
6485 	ASSERT(mdi_component_is_phci(dip, NULL) == MDI_SUCCESS);
6486 	if (mdi_component_is_phci(dip, NULL) == MDI_SUCCESS) {
6487 		mdi_phci_t	*ph;
6488 		ph = i_devi_get_phci(dip);
6489 		return (ph->ph_vprivate);
6490 	}
6491 	return (NULL);
6492 }
6493 
6494 /*
6495  * mdi_phci_set_vhci_private():
6496  *		Set the vhci private information in the mdi_phci node
6497  */
6498 void
6499 mdi_phci_set_vhci_private(dev_info_t *dip, void *priv)
6500 {
6501 	ASSERT(mdi_component_is_phci(dip, NULL) == MDI_SUCCESS);
6502 	if (mdi_component_is_phci(dip, NULL) == MDI_SUCCESS) {
6503 		mdi_phci_t	*ph;
6504 		ph = i_devi_get_phci(dip);
6505 		ph->ph_vprivate = priv;
6506 	}
6507 }
6508 
6509 /*
6510  * List of vhci class names:
6511  * A vhci class name must be in this list only if the corresponding vhci
6512  * driver intends to use the mdi provided bus config implementation
6513  * (i.e., mdi_vhci_bus_config()).
6514  */
6515 static char *vhci_class_list[] = { MDI_HCI_CLASS_SCSI, MDI_HCI_CLASS_IB };
6516 #define	N_VHCI_CLASSES	(sizeof (vhci_class_list) / sizeof (char *))
6517 
6518 /*
6519  * During boot time, the on-disk vhci cache for every vhci class is read
6520  * in the form of an nvlist and stored here.
6521  */
6522 static nvlist_t *vhcache_nvl[N_VHCI_CLASSES];
6523 
6524 /* nvpair names in vhci cache nvlist */
6525 #define	MDI_VHCI_CACHE_VERSION	1
6526 #define	MDI_NVPNAME_VERSION	"version"
6527 #define	MDI_NVPNAME_PHCIS	"phcis"
6528 #define	MDI_NVPNAME_CTADDRMAP	"clientaddrmap"
6529 
6530 /*
6531  * Given vhci class name, return its on-disk vhci cache filename.
6532  * Memory for the returned filename which includes the full path is allocated
6533  * by this function.
6534  */
6535 static char *
6536 vhclass2vhcache_filename(char *vhclass)
6537 {
6538 	char *filename;
6539 	int len;
6540 	static char *fmt = "/etc/devices/mdi_%s_cache";
6541 
6542 	/*
6543 	 * fmt contains the on-disk vhci cache file name format;
6544 	 * for scsi_vhci the filename is "/etc/devices/mdi_scsi_vhci_cache".
6545 	 */
6546 
6547 	/* the -1 below is to account for "%s" in the format string */
6548 	len = strlen(fmt) + strlen(vhclass) - 1;
6549 	filename = kmem_alloc(len, KM_SLEEP);
6550 	(void) snprintf(filename, len, fmt, vhclass);
6551 	ASSERT(len == (strlen(filename) + 1));
6552 	return (filename);
6553 }
6554 
6555 /*
6556  * initialize the vhci cache related data structures and read the on-disk
6557  * vhci cached data into memory.
6558  */
6559 static void
6560 setup_vhci_cache(mdi_vhci_t *vh)
6561 {
6562 	mdi_vhci_config_t *vhc;
6563 	mdi_vhci_cache_t *vhcache;
6564 	int i;
6565 	nvlist_t *nvl = NULL;
6566 
6567 	vhc = kmem_zalloc(sizeof (mdi_vhci_config_t), KM_SLEEP);
6568 	vh->vh_config = vhc;
6569 	vhcache = &vhc->vhc_vhcache;
6570 
6571 	vhc->vhc_vhcache_filename = vhclass2vhcache_filename(vh->vh_class);
6572 
6573 	mutex_init(&vhc->vhc_lock, NULL, MUTEX_DEFAULT, NULL);
6574 	cv_init(&vhc->vhc_cv, NULL, CV_DRIVER, NULL);
6575 
6576 	rw_init(&vhcache->vhcache_lock, NULL, RW_DRIVER, NULL);
6577 
6578 	/*
6579 	 * Create string hash; same as mod_hash_create_strhash() except that
6580 	 * we use NULL key destructor.
6581 	 */
6582 	vhcache->vhcache_client_hash = mod_hash_create_extended(vh->vh_class,
6583 	    mdi_bus_config_cache_hash_size,
6584 	    mod_hash_null_keydtor, mod_hash_null_valdtor,
6585 	    mod_hash_bystr, NULL, mod_hash_strkey_cmp, KM_SLEEP);
6586 
6587 	/*
6588 	 * The on-disk vhci cache is read during booting prior to the
6589 	 * lights-out period by mdi_read_devices_files().
6590 	 */
6591 	for (i = 0; i < N_VHCI_CLASSES; i++) {
6592 		if (strcmp(vhci_class_list[i], vh->vh_class) == 0) {
6593 			nvl = vhcache_nvl[i];
6594 			vhcache_nvl[i] = NULL;
6595 			break;
6596 		}
6597 	}
6598 
6599 	/*
6600 	 * this is to cover the case of some one manually causing unloading
6601 	 * (or detaching) and reloading (or attaching) of a vhci driver.
6602 	 */
6603 	if (nvl == NULL && modrootloaded)
6604 		nvl = read_on_disk_vhci_cache(vh->vh_class);
6605 
6606 	if (nvl != NULL) {
6607 		rw_enter(&vhcache->vhcache_lock, RW_WRITER);
6608 		if (mainnvl_to_vhcache(vhcache, nvl) == MDI_SUCCESS)
6609 			vhcache->vhcache_flags |= MDI_VHCI_CACHE_SETUP_DONE;
6610 		else  {
6611 			cmn_err(CE_WARN,
6612 			    "%s: data file corrupted, will recreate\n",
6613 			    vhc->vhc_vhcache_filename);
6614 		}
6615 		rw_exit(&vhcache->vhcache_lock);
6616 		nvlist_free(nvl);
6617 	}
6618 
6619 	vhc->vhc_cbid = callb_add(stop_vhcache_flush_thread, vhc,
6620 	    CB_CL_UADMIN_PRE_VFS, "mdi_vhcache_flush");
6621 
6622 	vhc->vhc_path_discovery_boot = mdi_path_discovery_boot;
6623 	vhc->vhc_path_discovery_postboot = mdi_path_discovery_postboot;
6624 }
6625 
6626 /*
6627  * free all vhci cache related resources
6628  */
6629 static int
6630 destroy_vhci_cache(mdi_vhci_t *vh)
6631 {
6632 	mdi_vhci_config_t *vhc = vh->vh_config;
6633 	mdi_vhci_cache_t *vhcache = &vhc->vhc_vhcache;
6634 	mdi_vhcache_phci_t *cphci, *cphci_next;
6635 	mdi_vhcache_client_t *cct, *cct_next;
6636 	mdi_vhcache_pathinfo_t *cpi, *cpi_next;
6637 
6638 	if (stop_vhcache_async_threads(vhc) != MDI_SUCCESS)
6639 		return (MDI_FAILURE);
6640 
6641 	kmem_free(vhc->vhc_vhcache_filename,
6642 	    strlen(vhc->vhc_vhcache_filename) + 1);
6643 
6644 	mod_hash_destroy_strhash(vhcache->vhcache_client_hash);
6645 
6646 	for (cphci = vhcache->vhcache_phci_head; cphci != NULL;
6647 	    cphci = cphci_next) {
6648 		cphci_next = cphci->cphci_next;
6649 		free_vhcache_phci(cphci);
6650 	}
6651 
6652 	for (cct = vhcache->vhcache_client_head; cct != NULL; cct = cct_next) {
6653 		cct_next = cct->cct_next;
6654 		for (cpi = cct->cct_cpi_head; cpi != NULL; cpi = cpi_next) {
6655 			cpi_next = cpi->cpi_next;
6656 			free_vhcache_pathinfo(cpi);
6657 		}
6658 		free_vhcache_client(cct);
6659 	}
6660 
6661 	rw_destroy(&vhcache->vhcache_lock);
6662 
6663 	mutex_destroy(&vhc->vhc_lock);
6664 	cv_destroy(&vhc->vhc_cv);
6665 	kmem_free(vhc, sizeof (mdi_vhci_config_t));
6666 	return (MDI_SUCCESS);
6667 }
6668 
6669 /*
6670  * Stop all vhci cache related async threads and free their resources.
6671  */
6672 static int
6673 stop_vhcache_async_threads(mdi_vhci_config_t *vhc)
6674 {
6675 	mdi_async_client_config_t *acc, *acc_next;
6676 
6677 	mutex_enter(&vhc->vhc_lock);
6678 	vhc->vhc_flags |= MDI_VHC_EXIT;
6679 	ASSERT(vhc->vhc_acc_thrcount >= 0);
6680 	cv_broadcast(&vhc->vhc_cv);
6681 
6682 	while ((vhc->vhc_flags & MDI_VHC_VHCACHE_FLUSH_THREAD) ||
6683 	    vhc->vhc_acc_thrcount != 0) {
6684 		mutex_exit(&vhc->vhc_lock);
6685 		delay(1);
6686 		mutex_enter(&vhc->vhc_lock);
6687 	}
6688 
6689 	vhc->vhc_flags &= ~MDI_VHC_EXIT;
6690 
6691 	for (acc = vhc->vhc_acc_list_head; acc != NULL; acc = acc_next) {
6692 		acc_next = acc->acc_next;
6693 		free_async_client_config(acc);
6694 	}
6695 	vhc->vhc_acc_list_head = NULL;
6696 	vhc->vhc_acc_list_tail = NULL;
6697 	vhc->vhc_acc_count = 0;
6698 
6699 	if (vhc->vhc_flags & MDI_VHC_VHCACHE_DIRTY) {
6700 		vhc->vhc_flags &= ~MDI_VHC_VHCACHE_DIRTY;
6701 		mutex_exit(&vhc->vhc_lock);
6702 		if (flush_vhcache(vhc, 0) != MDI_SUCCESS) {
6703 			vhcache_dirty(vhc);
6704 			return (MDI_FAILURE);
6705 		}
6706 	} else
6707 		mutex_exit(&vhc->vhc_lock);
6708 
6709 	if (callb_delete(vhc->vhc_cbid) != 0)
6710 		return (MDI_FAILURE);
6711 
6712 	return (MDI_SUCCESS);
6713 }
6714 
6715 /*
6716  * Stop vhci cache flush thread
6717  */
6718 /* ARGSUSED */
6719 static boolean_t
6720 stop_vhcache_flush_thread(void *arg, int code)
6721 {
6722 	mdi_vhci_config_t *vhc = (mdi_vhci_config_t *)arg;
6723 
6724 	mutex_enter(&vhc->vhc_lock);
6725 	vhc->vhc_flags |= MDI_VHC_EXIT;
6726 	cv_broadcast(&vhc->vhc_cv);
6727 
6728 	while (vhc->vhc_flags & MDI_VHC_VHCACHE_FLUSH_THREAD) {
6729 		mutex_exit(&vhc->vhc_lock);
6730 		delay(1);
6731 		mutex_enter(&vhc->vhc_lock);
6732 	}
6733 
6734 	if (vhc->vhc_flags & MDI_VHC_VHCACHE_DIRTY) {
6735 		vhc->vhc_flags &= ~MDI_VHC_VHCACHE_DIRTY;
6736 		mutex_exit(&vhc->vhc_lock);
6737 		(void) flush_vhcache(vhc, 1);
6738 	} else
6739 		mutex_exit(&vhc->vhc_lock);
6740 
6741 	return (B_TRUE);
6742 }
6743 
6744 /*
6745  * Enqueue the vhcache phci (cphci) at the tail of the list
6746  */
6747 static void
6748 enqueue_vhcache_phci(mdi_vhci_cache_t *vhcache, mdi_vhcache_phci_t *cphci)
6749 {
6750 	cphci->cphci_next = NULL;
6751 	if (vhcache->vhcache_phci_head == NULL)
6752 		vhcache->vhcache_phci_head = cphci;
6753 	else
6754 		vhcache->vhcache_phci_tail->cphci_next = cphci;
6755 	vhcache->vhcache_phci_tail = cphci;
6756 }
6757 
6758 /*
6759  * Enqueue the vhcache pathinfo (cpi) at the tail of the list
6760  */
6761 static void
6762 enqueue_tail_vhcache_pathinfo(mdi_vhcache_client_t *cct,
6763     mdi_vhcache_pathinfo_t *cpi)
6764 {
6765 	cpi->cpi_next = NULL;
6766 	if (cct->cct_cpi_head == NULL)
6767 		cct->cct_cpi_head = cpi;
6768 	else
6769 		cct->cct_cpi_tail->cpi_next = cpi;
6770 	cct->cct_cpi_tail = cpi;
6771 }
6772 
6773 /*
6774  * Enqueue the vhcache pathinfo (cpi) at the correct location in the
6775  * ordered list. All cpis which do not have MDI_CPI_HINT_PATH_DOES_NOT_EXIST
6776  * flag set come at the beginning of the list. All cpis which have this
6777  * flag set come at the end of the list.
6778  */
6779 static void
6780 enqueue_vhcache_pathinfo(mdi_vhcache_client_t *cct,
6781     mdi_vhcache_pathinfo_t *newcpi)
6782 {
6783 	mdi_vhcache_pathinfo_t *cpi, *prev_cpi;
6784 
6785 	if (cct->cct_cpi_head == NULL ||
6786 	    (newcpi->cpi_flags & MDI_CPI_HINT_PATH_DOES_NOT_EXIST))
6787 		enqueue_tail_vhcache_pathinfo(cct, newcpi);
6788 	else {
6789 		for (cpi = cct->cct_cpi_head, prev_cpi = NULL; cpi != NULL &&
6790 		    !(cpi->cpi_flags & MDI_CPI_HINT_PATH_DOES_NOT_EXIST);
6791 		    prev_cpi = cpi, cpi = cpi->cpi_next)
6792 			;
6793 
6794 		if (prev_cpi == NULL)
6795 			cct->cct_cpi_head = newcpi;
6796 		else
6797 			prev_cpi->cpi_next = newcpi;
6798 
6799 		newcpi->cpi_next = cpi;
6800 
6801 		if (cpi == NULL)
6802 			cct->cct_cpi_tail = newcpi;
6803 	}
6804 }
6805 
6806 /*
6807  * Enqueue the vhcache client (cct) at the tail of the list
6808  */
6809 static void
6810 enqueue_vhcache_client(mdi_vhci_cache_t *vhcache,
6811     mdi_vhcache_client_t *cct)
6812 {
6813 	cct->cct_next = NULL;
6814 	if (vhcache->vhcache_client_head == NULL)
6815 		vhcache->vhcache_client_head = cct;
6816 	else
6817 		vhcache->vhcache_client_tail->cct_next = cct;
6818 	vhcache->vhcache_client_tail = cct;
6819 }
6820 
6821 static void
6822 free_string_array(char **str, int nelem)
6823 {
6824 	int i;
6825 
6826 	if (str) {
6827 		for (i = 0; i < nelem; i++) {
6828 			if (str[i])
6829 				kmem_free(str[i], strlen(str[i]) + 1);
6830 		}
6831 		kmem_free(str, sizeof (char *) * nelem);
6832 	}
6833 }
6834 
6835 static void
6836 free_vhcache_phci(mdi_vhcache_phci_t *cphci)
6837 {
6838 	kmem_free(cphci->cphci_path, strlen(cphci->cphci_path) + 1);
6839 	kmem_free(cphci, sizeof (*cphci));
6840 }
6841 
6842 static void
6843 free_vhcache_pathinfo(mdi_vhcache_pathinfo_t *cpi)
6844 {
6845 	kmem_free(cpi->cpi_addr, strlen(cpi->cpi_addr) + 1);
6846 	kmem_free(cpi, sizeof (*cpi));
6847 }
6848 
6849 static void
6850 free_vhcache_client(mdi_vhcache_client_t *cct)
6851 {
6852 	kmem_free(cct->cct_name_addr, strlen(cct->cct_name_addr) + 1);
6853 	kmem_free(cct, sizeof (*cct));
6854 }
6855 
6856 static char *
6857 vhcache_mknameaddr(char *ct_name, char *ct_addr, int *ret_len)
6858 {
6859 	char *name_addr;
6860 	int len;
6861 
6862 	len = strlen(ct_name) + strlen(ct_addr) + 2;
6863 	name_addr = kmem_alloc(len, KM_SLEEP);
6864 	(void) snprintf(name_addr, len, "%s@%s", ct_name, ct_addr);
6865 
6866 	if (ret_len)
6867 		*ret_len = len;
6868 	return (name_addr);
6869 }
6870 
6871 /*
6872  * Copy the contents of paddrnvl to vhci cache.
6873  * paddrnvl nvlist contains path information for a vhci client.
6874  * See the comment in mainnvl_to_vhcache() for the format of this nvlist.
6875  */
6876 static void
6877 paddrnvl_to_vhcache(nvlist_t *nvl, mdi_vhcache_phci_t *cphci_list[],
6878     mdi_vhcache_client_t *cct)
6879 {
6880 	nvpair_t *nvp = NULL;
6881 	mdi_vhcache_pathinfo_t *cpi;
6882 	uint_t nelem;
6883 	uint32_t *val;
6884 
6885 	while ((nvp = nvlist_next_nvpair(nvl, nvp)) != NULL) {
6886 		ASSERT(nvpair_type(nvp) == DATA_TYPE_UINT32_ARRAY);
6887 		cpi = kmem_zalloc(sizeof (*cpi), KM_SLEEP);
6888 		cpi->cpi_addr = i_ddi_strdup(nvpair_name(nvp), KM_SLEEP);
6889 		(void) nvpair_value_uint32_array(nvp, &val, &nelem);
6890 		ASSERT(nelem == 2);
6891 		cpi->cpi_cphci = cphci_list[val[0]];
6892 		cpi->cpi_flags = val[1];
6893 		enqueue_tail_vhcache_pathinfo(cct, cpi);
6894 	}
6895 }
6896 
6897 /*
6898  * Copy the contents of caddrmapnvl to vhci cache.
6899  * caddrmapnvl nvlist contains vhci client address to phci client address
6900  * mappings. See the comment in mainnvl_to_vhcache() for the format of
6901  * this nvlist.
6902  */
6903 static void
6904 caddrmapnvl_to_vhcache(mdi_vhci_cache_t *vhcache, nvlist_t *nvl,
6905     mdi_vhcache_phci_t *cphci_list[])
6906 {
6907 	nvpair_t *nvp = NULL;
6908 	nvlist_t *paddrnvl;
6909 	mdi_vhcache_client_t *cct;
6910 
6911 	while ((nvp = nvlist_next_nvpair(nvl, nvp)) != NULL) {
6912 		ASSERT(nvpair_type(nvp) == DATA_TYPE_NVLIST);
6913 		cct = kmem_zalloc(sizeof (*cct), KM_SLEEP);
6914 		cct->cct_name_addr = i_ddi_strdup(nvpair_name(nvp), KM_SLEEP);
6915 		(void) nvpair_value_nvlist(nvp, &paddrnvl);
6916 		paddrnvl_to_vhcache(paddrnvl, cphci_list, cct);
6917 		/* the client must contain at least one path */
6918 		ASSERT(cct->cct_cpi_head != NULL);
6919 
6920 		enqueue_vhcache_client(vhcache, cct);
6921 		(void) mod_hash_insert(vhcache->vhcache_client_hash,
6922 		    (mod_hash_key_t)cct->cct_name_addr, (mod_hash_val_t)cct);
6923 	}
6924 }
6925 
6926 /*
6927  * Copy the contents of the main nvlist to vhci cache.
6928  *
6929  * VHCI busconfig cached data is stored in the form of a nvlist on the disk.
6930  * The nvlist contains the mappings between the vhci client addresses and
6931  * their corresponding phci client addresses.
6932  *
6933  * The structure of the nvlist is as follows:
6934  *
6935  * Main nvlist:
6936  *	NAME		TYPE		DATA
6937  *	version		int32		version number
6938  *	phcis		string array	array of phci paths
6939  *	clientaddrmap	nvlist_t	c2paddrs_nvl (see below)
6940  *
6941  * structure of c2paddrs_nvl:
6942  *	NAME		TYPE		DATA
6943  *	caddr1		nvlist_t	paddrs_nvl1
6944  *	caddr2		nvlist_t	paddrs_nvl2
6945  *	...
6946  * where caddr1, caddr2, ... are vhci client name and addresses in the
6947  * form of "<clientname>@<clientaddress>".
6948  * (for example: "ssd@2000002037cd9f72");
6949  * paddrs_nvl1, paddrs_nvl2, .. are nvlists that contain path information.
6950  *
6951  * structure of paddrs_nvl:
6952  *	NAME		TYPE		DATA
6953  *	pi_addr1	uint32_array	(phci-id, cpi_flags)
6954  *	pi_addr2	uint32_array	(phci-id, cpi_flags)
6955  *	...
6956  * where pi_addr1, pi_addr2, ... are bus specific addresses of pathinfo nodes
6957  * (so called pi_addrs, for example: "w2100002037cd9f72,0");
6958  * phci-ids are integers that identify PHCIs to which the
6959  * the bus specific address belongs to. These integers are used as an index
6960  * into to the phcis string array in the main nvlist to get the PHCI path.
6961  */
6962 static int
6963 mainnvl_to_vhcache(mdi_vhci_cache_t *vhcache, nvlist_t *nvl)
6964 {
6965 	char **phcis, **phci_namep;
6966 	uint_t nphcis;
6967 	mdi_vhcache_phci_t *cphci, **cphci_list;
6968 	nvlist_t *caddrmapnvl;
6969 	int32_t ver;
6970 	int i;
6971 	size_t cphci_list_size;
6972 
6973 	ASSERT(RW_WRITE_HELD(&vhcache->vhcache_lock));
6974 
6975 	if (nvlist_lookup_int32(nvl, MDI_NVPNAME_VERSION, &ver) != 0 ||
6976 	    ver != MDI_VHCI_CACHE_VERSION)
6977 		return (MDI_FAILURE);
6978 
6979 	if (nvlist_lookup_string_array(nvl, MDI_NVPNAME_PHCIS, &phcis,
6980 	    &nphcis) != 0)
6981 		return (MDI_SUCCESS);
6982 
6983 	ASSERT(nphcis > 0);
6984 
6985 	cphci_list_size = sizeof (mdi_vhcache_phci_t *) * nphcis;
6986 	cphci_list = kmem_alloc(cphci_list_size, KM_SLEEP);
6987 	for (i = 0, phci_namep = phcis; i < nphcis; i++, phci_namep++) {
6988 		cphci = kmem_zalloc(sizeof (mdi_vhcache_phci_t), KM_SLEEP);
6989 		cphci->cphci_path = i_ddi_strdup(*phci_namep, KM_SLEEP);
6990 		enqueue_vhcache_phci(vhcache, cphci);
6991 		cphci_list[i] = cphci;
6992 	}
6993 
6994 	ASSERT(vhcache->vhcache_phci_head != NULL);
6995 
6996 	if (nvlist_lookup_nvlist(nvl, MDI_NVPNAME_CTADDRMAP, &caddrmapnvl) == 0)
6997 		caddrmapnvl_to_vhcache(vhcache, caddrmapnvl, cphci_list);
6998 
6999 	kmem_free(cphci_list, cphci_list_size);
7000 	return (MDI_SUCCESS);
7001 }
7002 
7003 /*
7004  * Build paddrnvl for the specified client using the information in the
7005  * vhci cache and add it to the caddrmapnnvl.
7006  * Returns 0 on success, errno on failure.
7007  */
7008 static int
7009 vhcache_to_paddrnvl(mdi_vhci_cache_t *vhcache, mdi_vhcache_client_t *cct,
7010     nvlist_t *caddrmapnvl)
7011 {
7012 	mdi_vhcache_pathinfo_t *cpi;
7013 	nvlist_t *nvl;
7014 	int err;
7015 	uint32_t val[2];
7016 
7017 	ASSERT(RW_LOCK_HELD(&vhcache->vhcache_lock));
7018 
7019 	if ((err = nvlist_alloc(&nvl, 0, KM_SLEEP)) != 0)
7020 		return (err);
7021 
7022 	for (cpi = cct->cct_cpi_head; cpi != NULL; cpi = cpi->cpi_next) {
7023 		val[0] = cpi->cpi_cphci->cphci_id;
7024 		val[1] = cpi->cpi_flags;
7025 		if ((err = nvlist_add_uint32_array(nvl, cpi->cpi_addr, val, 2))
7026 		    != 0)
7027 			goto out;
7028 	}
7029 
7030 	err = nvlist_add_nvlist(caddrmapnvl, cct->cct_name_addr, nvl);
7031 out:
7032 	nvlist_free(nvl);
7033 	return (err);
7034 }
7035 
7036 /*
7037  * Build caddrmapnvl using the information in the vhci cache
7038  * and add it to the mainnvl.
7039  * Returns 0 on success, errno on failure.
7040  */
7041 static int
7042 vhcache_to_caddrmapnvl(mdi_vhci_cache_t *vhcache, nvlist_t *mainnvl)
7043 {
7044 	mdi_vhcache_client_t *cct;
7045 	nvlist_t *nvl;
7046 	int err;
7047 
7048 	ASSERT(RW_LOCK_HELD(&vhcache->vhcache_lock));
7049 
7050 	if ((err = nvlist_alloc(&nvl, NV_UNIQUE_NAME, KM_SLEEP)) != 0)
7051 		return (err);
7052 
7053 	for (cct = vhcache->vhcache_client_head; cct != NULL;
7054 	    cct = cct->cct_next) {
7055 		if ((err = vhcache_to_paddrnvl(vhcache, cct, nvl)) != 0)
7056 			goto out;
7057 	}
7058 
7059 	err = nvlist_add_nvlist(mainnvl, MDI_NVPNAME_CTADDRMAP, nvl);
7060 out:
7061 	nvlist_free(nvl);
7062 	return (err);
7063 }
7064 
7065 /*
7066  * Build nvlist using the information in the vhci cache.
7067  * See the comment in mainnvl_to_vhcache() for the format of the nvlist.
7068  * Returns nvl on success, NULL on failure.
7069  */
7070 static nvlist_t *
7071 vhcache_to_mainnvl(mdi_vhci_cache_t *vhcache)
7072 {
7073 	mdi_vhcache_phci_t *cphci;
7074 	uint_t phci_count;
7075 	char **phcis;
7076 	nvlist_t *nvl;
7077 	int err, i;
7078 
7079 	if ((err = nvlist_alloc(&nvl, NV_UNIQUE_NAME, KM_SLEEP)) != 0) {
7080 		nvl = NULL;
7081 		goto out;
7082 	}
7083 
7084 	if ((err = nvlist_add_int32(nvl, MDI_NVPNAME_VERSION,
7085 	    MDI_VHCI_CACHE_VERSION)) != 0)
7086 		goto out;
7087 
7088 	rw_enter(&vhcache->vhcache_lock, RW_READER);
7089 	if (vhcache->vhcache_phci_head == NULL) {
7090 		rw_exit(&vhcache->vhcache_lock);
7091 		return (nvl);
7092 	}
7093 
7094 	phci_count = 0;
7095 	for (cphci = vhcache->vhcache_phci_head; cphci != NULL;
7096 	    cphci = cphci->cphci_next)
7097 		cphci->cphci_id = phci_count++;
7098 
7099 	/* build phci pathname list */
7100 	phcis = kmem_alloc(sizeof (char *) * phci_count, KM_SLEEP);
7101 	for (cphci = vhcache->vhcache_phci_head, i = 0; cphci != NULL;
7102 	    cphci = cphci->cphci_next, i++)
7103 		phcis[i] = i_ddi_strdup(cphci->cphci_path, KM_SLEEP);
7104 
7105 	err = nvlist_add_string_array(nvl, MDI_NVPNAME_PHCIS, phcis,
7106 	    phci_count);
7107 	free_string_array(phcis, phci_count);
7108 
7109 	if (err == 0 &&
7110 	    (err = vhcache_to_caddrmapnvl(vhcache, nvl)) == 0) {
7111 		rw_exit(&vhcache->vhcache_lock);
7112 		return (nvl);
7113 	}
7114 
7115 	rw_exit(&vhcache->vhcache_lock);
7116 out:
7117 	if (nvl)
7118 		nvlist_free(nvl);
7119 	return (NULL);
7120 }
7121 
7122 /*
7123  * Lookup vhcache phci structure for the specified phci path.
7124  */
7125 static mdi_vhcache_phci_t *
7126 lookup_vhcache_phci_by_name(mdi_vhci_cache_t *vhcache, char *phci_path)
7127 {
7128 	mdi_vhcache_phci_t *cphci;
7129 
7130 	ASSERT(RW_LOCK_HELD(&vhcache->vhcache_lock));
7131 
7132 	for (cphci = vhcache->vhcache_phci_head; cphci != NULL;
7133 	    cphci = cphci->cphci_next) {
7134 		if (strcmp(cphci->cphci_path, phci_path) == 0)
7135 			return (cphci);
7136 	}
7137 
7138 	return (NULL);
7139 }
7140 
7141 /*
7142  * Lookup vhcache phci structure for the specified phci.
7143  */
7144 static mdi_vhcache_phci_t *
7145 lookup_vhcache_phci_by_addr(mdi_vhci_cache_t *vhcache, mdi_phci_t *ph)
7146 {
7147 	mdi_vhcache_phci_t *cphci;
7148 
7149 	ASSERT(RW_LOCK_HELD(&vhcache->vhcache_lock));
7150 
7151 	for (cphci = vhcache->vhcache_phci_head; cphci != NULL;
7152 	    cphci = cphci->cphci_next) {
7153 		if (cphci->cphci_phci == ph)
7154 			return (cphci);
7155 	}
7156 
7157 	return (NULL);
7158 }
7159 
7160 /*
7161  * Add the specified phci to the vhci cache if not already present.
7162  */
7163 static void
7164 vhcache_phci_add(mdi_vhci_config_t *vhc, mdi_phci_t *ph)
7165 {
7166 	mdi_vhci_cache_t *vhcache = &vhc->vhc_vhcache;
7167 	mdi_vhcache_phci_t *cphci;
7168 	char *pathname;
7169 	int cache_updated;
7170 
7171 	rw_enter(&vhcache->vhcache_lock, RW_WRITER);
7172 
7173 	pathname = kmem_alloc(MAXPATHLEN, KM_SLEEP);
7174 	(void) ddi_pathname(ph->ph_dip, pathname);
7175 	if ((cphci = lookup_vhcache_phci_by_name(vhcache, pathname))
7176 	    != NULL) {
7177 		cphci->cphci_phci = ph;
7178 		cache_updated = 0;
7179 	} else {
7180 		cphci = kmem_zalloc(sizeof (*cphci), KM_SLEEP);
7181 		cphci->cphci_path = i_ddi_strdup(pathname, KM_SLEEP);
7182 		cphci->cphci_phci = ph;
7183 		enqueue_vhcache_phci(vhcache, cphci);
7184 		cache_updated = 1;
7185 	}
7186 
7187 	rw_exit(&vhcache->vhcache_lock);
7188 
7189 	/*
7190 	 * Since a new phci has been added, reset
7191 	 * vhc_path_discovery_cutoff_time to allow for discovery of paths
7192 	 * during next vhcache_discover_paths().
7193 	 */
7194 	mutex_enter(&vhc->vhc_lock);
7195 	vhc->vhc_path_discovery_cutoff_time = 0;
7196 	mutex_exit(&vhc->vhc_lock);
7197 
7198 	kmem_free(pathname, MAXPATHLEN);
7199 	if (cache_updated)
7200 		vhcache_dirty(vhc);
7201 }
7202 
7203 /*
7204  * Remove the reference to the specified phci from the vhci cache.
7205  */
7206 static void
7207 vhcache_phci_remove(mdi_vhci_config_t *vhc, mdi_phci_t *ph)
7208 {
7209 	mdi_vhci_cache_t *vhcache = &vhc->vhc_vhcache;
7210 	mdi_vhcache_phci_t *cphci;
7211 
7212 	rw_enter(&vhcache->vhcache_lock, RW_WRITER);
7213 	if ((cphci = lookup_vhcache_phci_by_addr(vhcache, ph)) != NULL) {
7214 		/* do not remove the actual mdi_vhcache_phci structure */
7215 		cphci->cphci_phci = NULL;
7216 	}
7217 	rw_exit(&vhcache->vhcache_lock);
7218 }
7219 
7220 static void
7221 init_vhcache_lookup_token(mdi_vhcache_lookup_token_t *dst,
7222     mdi_vhcache_lookup_token_t *src)
7223 {
7224 	if (src == NULL) {
7225 		dst->lt_cct = NULL;
7226 		dst->lt_cct_lookup_time = 0;
7227 	} else {
7228 		dst->lt_cct = src->lt_cct;
7229 		dst->lt_cct_lookup_time = src->lt_cct_lookup_time;
7230 	}
7231 }
7232 
7233 /*
7234  * Look up vhcache client for the specified client.
7235  */
7236 static mdi_vhcache_client_t *
7237 lookup_vhcache_client(mdi_vhci_cache_t *vhcache, char *ct_name, char *ct_addr,
7238     mdi_vhcache_lookup_token_t *token)
7239 {
7240 	mod_hash_val_t hv;
7241 	char *name_addr;
7242 	int len;
7243 
7244 	ASSERT(RW_LOCK_HELD(&vhcache->vhcache_lock));
7245 
7246 	/*
7247 	 * If no vhcache clean occurred since the last lookup, we can
7248 	 * simply return the cct from the last lookup operation.
7249 	 * It works because ccts are never freed except during the vhcache
7250 	 * cleanup operation.
7251 	 */
7252 	if (token != NULL &&
7253 	    vhcache->vhcache_clean_time < token->lt_cct_lookup_time)
7254 		return (token->lt_cct);
7255 
7256 	name_addr = vhcache_mknameaddr(ct_name, ct_addr, &len);
7257 	if (mod_hash_find(vhcache->vhcache_client_hash,
7258 	    (mod_hash_key_t)name_addr, &hv) == 0) {
7259 		if (token) {
7260 			token->lt_cct = (mdi_vhcache_client_t *)hv;
7261 			token->lt_cct_lookup_time = lbolt64;
7262 		}
7263 	} else {
7264 		if (token) {
7265 			token->lt_cct = NULL;
7266 			token->lt_cct_lookup_time = 0;
7267 		}
7268 		hv = NULL;
7269 	}
7270 	kmem_free(name_addr, len);
7271 	return ((mdi_vhcache_client_t *)hv);
7272 }
7273 
7274 /*
7275  * Add the specified path to the vhci cache if not already present.
7276  * Also add the vhcache client for the client corresponding to this path
7277  * if it doesn't already exist.
7278  */
7279 static void
7280 vhcache_pi_add(mdi_vhci_config_t *vhc, struct mdi_pathinfo *pip)
7281 {
7282 	mdi_vhci_cache_t *vhcache = &vhc->vhc_vhcache;
7283 	mdi_vhcache_client_t *cct;
7284 	mdi_vhcache_pathinfo_t *cpi;
7285 	mdi_phci_t *ph = pip->pi_phci;
7286 	mdi_client_t *ct = pip->pi_client;
7287 	int cache_updated = 0;
7288 
7289 	rw_enter(&vhcache->vhcache_lock, RW_WRITER);
7290 
7291 	/* if vhcache client for this pip doesn't already exist, add it */
7292 	if ((cct = lookup_vhcache_client(vhcache, ct->ct_drvname, ct->ct_guid,
7293 	    NULL)) == NULL) {
7294 		cct = kmem_zalloc(sizeof (*cct), KM_SLEEP);
7295 		cct->cct_name_addr = vhcache_mknameaddr(ct->ct_drvname,
7296 		    ct->ct_guid, NULL);
7297 		enqueue_vhcache_client(vhcache, cct);
7298 		(void) mod_hash_insert(vhcache->vhcache_client_hash,
7299 		    (mod_hash_key_t)cct->cct_name_addr, (mod_hash_val_t)cct);
7300 		cache_updated = 1;
7301 	}
7302 
7303 	for (cpi = cct->cct_cpi_head; cpi != NULL; cpi = cpi->cpi_next) {
7304 		if (cpi->cpi_cphci->cphci_phci == ph &&
7305 		    strcmp(cpi->cpi_addr, pip->pi_addr) == 0) {
7306 			cpi->cpi_pip = pip;
7307 			if (cpi->cpi_flags & MDI_CPI_HINT_PATH_DOES_NOT_EXIST) {
7308 				cpi->cpi_flags &=
7309 				    ~MDI_CPI_HINT_PATH_DOES_NOT_EXIST;
7310 				sort_vhcache_paths(cct);
7311 				cache_updated = 1;
7312 			}
7313 			break;
7314 		}
7315 	}
7316 
7317 	if (cpi == NULL) {
7318 		cpi = kmem_zalloc(sizeof (*cpi), KM_SLEEP);
7319 		cpi->cpi_addr = i_ddi_strdup(pip->pi_addr, KM_SLEEP);
7320 		cpi->cpi_cphci = lookup_vhcache_phci_by_addr(vhcache, ph);
7321 		ASSERT(cpi->cpi_cphci != NULL);
7322 		cpi->cpi_pip = pip;
7323 		enqueue_vhcache_pathinfo(cct, cpi);
7324 		cache_updated = 1;
7325 	}
7326 
7327 	rw_exit(&vhcache->vhcache_lock);
7328 
7329 	if (cache_updated)
7330 		vhcache_dirty(vhc);
7331 }
7332 
7333 /*
7334  * Remove the reference to the specified path from the vhci cache.
7335  */
7336 static void
7337 vhcache_pi_remove(mdi_vhci_config_t *vhc, struct mdi_pathinfo *pip)
7338 {
7339 	mdi_vhci_cache_t *vhcache = &vhc->vhc_vhcache;
7340 	mdi_client_t *ct = pip->pi_client;
7341 	mdi_vhcache_client_t *cct;
7342 	mdi_vhcache_pathinfo_t *cpi;
7343 
7344 	rw_enter(&vhcache->vhcache_lock, RW_WRITER);
7345 	if ((cct = lookup_vhcache_client(vhcache, ct->ct_drvname, ct->ct_guid,
7346 	    NULL)) != NULL) {
7347 		for (cpi = cct->cct_cpi_head; cpi != NULL;
7348 		    cpi = cpi->cpi_next) {
7349 			if (cpi->cpi_pip == pip) {
7350 				cpi->cpi_pip = NULL;
7351 				break;
7352 			}
7353 		}
7354 	}
7355 	rw_exit(&vhcache->vhcache_lock);
7356 }
7357 
7358 /*
7359  * Flush the vhci cache to disk.
7360  * Returns MDI_SUCCESS on success, MDI_FAILURE on failure.
7361  */
7362 static int
7363 flush_vhcache(mdi_vhci_config_t *vhc, int force_flag)
7364 {
7365 	nvlist_t *nvl;
7366 	int err;
7367 	int rv;
7368 
7369 	/*
7370 	 * It is possible that the system may shutdown before
7371 	 * i_ddi_io_initialized (during stmsboot for example). To allow for
7372 	 * flushing the cache in this case do not check for
7373 	 * i_ddi_io_initialized when force flag is set.
7374 	 */
7375 	if (force_flag == 0 && !i_ddi_io_initialized())
7376 		return (MDI_FAILURE);
7377 
7378 	if ((nvl = vhcache_to_mainnvl(&vhc->vhc_vhcache)) != NULL) {
7379 		err = fwrite_nvlist(vhc->vhc_vhcache_filename, nvl);
7380 		nvlist_free(nvl);
7381 	} else
7382 		err = EFAULT;
7383 
7384 	rv = MDI_SUCCESS;
7385 	mutex_enter(&vhc->vhc_lock);
7386 	if (err != 0) {
7387 		if (err == EROFS) {
7388 			vhc->vhc_flags |= MDI_VHC_READONLY_FS;
7389 			vhc->vhc_flags &= ~(MDI_VHC_VHCACHE_FLUSH_ERROR |
7390 			    MDI_VHC_VHCACHE_DIRTY);
7391 		} else {
7392 			if (!(vhc->vhc_flags & MDI_VHC_VHCACHE_FLUSH_ERROR)) {
7393 				cmn_err(CE_CONT, "%s: update failed\n",
7394 				    vhc->vhc_vhcache_filename);
7395 				vhc->vhc_flags |= MDI_VHC_VHCACHE_FLUSH_ERROR;
7396 			}
7397 			rv = MDI_FAILURE;
7398 		}
7399 	} else if (vhc->vhc_flags & MDI_VHC_VHCACHE_FLUSH_ERROR) {
7400 		cmn_err(CE_CONT,
7401 		    "%s: update now ok\n", vhc->vhc_vhcache_filename);
7402 		vhc->vhc_flags &= ~MDI_VHC_VHCACHE_FLUSH_ERROR;
7403 	}
7404 	mutex_exit(&vhc->vhc_lock);
7405 
7406 	return (rv);
7407 }
7408 
7409 /*
7410  * Call flush_vhcache() to flush the vhci cache at the scheduled time.
7411  * Exits itself if left idle for the idle timeout period.
7412  */
7413 static void
7414 vhcache_flush_thread(void *arg)
7415 {
7416 	mdi_vhci_config_t *vhc = (mdi_vhci_config_t *)arg;
7417 	clock_t idle_time, quit_at_ticks;
7418 	callb_cpr_t cprinfo;
7419 
7420 	/* number of seconds to sleep idle before exiting */
7421 	idle_time = mdi_vhcache_flush_daemon_idle_time * TICKS_PER_SECOND;
7422 
7423 	CALLB_CPR_INIT(&cprinfo, &vhc->vhc_lock, callb_generic_cpr,
7424 	    "mdi_vhcache_flush");
7425 	mutex_enter(&vhc->vhc_lock);
7426 	for (; ; ) {
7427 		while (!(vhc->vhc_flags & MDI_VHC_EXIT) &&
7428 		    (vhc->vhc_flags & MDI_VHC_VHCACHE_DIRTY)) {
7429 			if (ddi_get_lbolt() < vhc->vhc_flush_at_ticks) {
7430 				CALLB_CPR_SAFE_BEGIN(&cprinfo);
7431 				(void) cv_timedwait(&vhc->vhc_cv,
7432 				    &vhc->vhc_lock, vhc->vhc_flush_at_ticks);
7433 				CALLB_CPR_SAFE_END(&cprinfo, &vhc->vhc_lock);
7434 			} else {
7435 				vhc->vhc_flags &= ~MDI_VHC_VHCACHE_DIRTY;
7436 				mutex_exit(&vhc->vhc_lock);
7437 
7438 				if (flush_vhcache(vhc, 0) != MDI_SUCCESS)
7439 					vhcache_dirty(vhc);
7440 
7441 				mutex_enter(&vhc->vhc_lock);
7442 			}
7443 		}
7444 
7445 		quit_at_ticks = ddi_get_lbolt() + idle_time;
7446 
7447 		while (!(vhc->vhc_flags & MDI_VHC_EXIT) &&
7448 		    !(vhc->vhc_flags & MDI_VHC_VHCACHE_DIRTY) &&
7449 		    ddi_get_lbolt() < quit_at_ticks) {
7450 			CALLB_CPR_SAFE_BEGIN(&cprinfo);
7451 			(void) cv_timedwait(&vhc->vhc_cv, &vhc->vhc_lock,
7452 			    quit_at_ticks);
7453 			CALLB_CPR_SAFE_END(&cprinfo, &vhc->vhc_lock);
7454 		}
7455 
7456 		if ((vhc->vhc_flags & MDI_VHC_EXIT) ||
7457 		    !(vhc->vhc_flags & MDI_VHC_VHCACHE_DIRTY))
7458 			goto out;
7459 	}
7460 
7461 out:
7462 	vhc->vhc_flags &= ~MDI_VHC_VHCACHE_FLUSH_THREAD;
7463 	/* CALLB_CPR_EXIT releases the vhc->vhc_lock */
7464 	CALLB_CPR_EXIT(&cprinfo);
7465 }
7466 
7467 /*
7468  * Make vhci cache dirty and schedule flushing by vhcache flush thread.
7469  */
7470 static void
7471 vhcache_dirty(mdi_vhci_config_t *vhc)
7472 {
7473 	mdi_vhci_cache_t *vhcache = &vhc->vhc_vhcache;
7474 	int create_thread;
7475 
7476 	rw_enter(&vhcache->vhcache_lock, RW_READER);
7477 	/* do not flush cache until the cache is fully built */
7478 	if (!(vhcache->vhcache_flags & MDI_VHCI_CACHE_SETUP_DONE)) {
7479 		rw_exit(&vhcache->vhcache_lock);
7480 		return;
7481 	}
7482 	rw_exit(&vhcache->vhcache_lock);
7483 
7484 	mutex_enter(&vhc->vhc_lock);
7485 	if (vhc->vhc_flags & MDI_VHC_READONLY_FS) {
7486 		mutex_exit(&vhc->vhc_lock);
7487 		return;
7488 	}
7489 
7490 	vhc->vhc_flags |= MDI_VHC_VHCACHE_DIRTY;
7491 	vhc->vhc_flush_at_ticks = ddi_get_lbolt() +
7492 	    mdi_vhcache_flush_delay * TICKS_PER_SECOND;
7493 	if (vhc->vhc_flags & MDI_VHC_VHCACHE_FLUSH_THREAD) {
7494 		cv_broadcast(&vhc->vhc_cv);
7495 		create_thread = 0;
7496 	} else {
7497 		vhc->vhc_flags |= MDI_VHC_VHCACHE_FLUSH_THREAD;
7498 		create_thread = 1;
7499 	}
7500 	mutex_exit(&vhc->vhc_lock);
7501 
7502 	if (create_thread)
7503 		(void) thread_create(NULL, 0, vhcache_flush_thread, vhc,
7504 		    0, &p0, TS_RUN, minclsyspri);
7505 }
7506 
7507 /*
7508  * phci bus config structure - one for for each phci bus config operation that
7509  * we initiate on behalf of a vhci.
7510  */
7511 typedef struct mdi_phci_bus_config_s {
7512 	char *phbc_phci_path;
7513 	struct mdi_vhci_bus_config_s *phbc_vhbusconfig;	/* vhci bus config */
7514 	struct mdi_phci_bus_config_s *phbc_next;
7515 } mdi_phci_bus_config_t;
7516 
7517 /* vhci bus config structure - one for each vhci bus config operation */
7518 typedef struct mdi_vhci_bus_config_s {
7519 	ddi_bus_config_op_t vhbc_op;	/* bus config op */
7520 	major_t vhbc_op_major;		/* bus config op major */
7521 	uint_t vhbc_op_flags;		/* bus config op flags */
7522 	kmutex_t vhbc_lock;
7523 	kcondvar_t vhbc_cv;
7524 	int vhbc_thr_count;
7525 } mdi_vhci_bus_config_t;
7526 
7527 /*
7528  * bus config the specified phci
7529  */
7530 static void
7531 bus_config_phci(void *arg)
7532 {
7533 	mdi_phci_bus_config_t *phbc = (mdi_phci_bus_config_t *)arg;
7534 	mdi_vhci_bus_config_t *vhbc = phbc->phbc_vhbusconfig;
7535 	dev_info_t *ph_dip;
7536 
7537 	/*
7538 	 * first configure all path components upto phci and then configure
7539 	 * the phci children.
7540 	 */
7541 	if ((ph_dip = e_ddi_hold_devi_by_path(phbc->phbc_phci_path, 0))
7542 	    != NULL) {
7543 		if (vhbc->vhbc_op == BUS_CONFIG_DRIVER ||
7544 		    vhbc->vhbc_op == BUS_UNCONFIG_DRIVER) {
7545 			(void) ndi_devi_config_driver(ph_dip,
7546 			    vhbc->vhbc_op_flags,
7547 			    vhbc->vhbc_op_major);
7548 		} else
7549 			(void) ndi_devi_config(ph_dip,
7550 			    vhbc->vhbc_op_flags);
7551 
7552 		/* release the hold that e_ddi_hold_devi_by_path() placed */
7553 		ndi_rele_devi(ph_dip);
7554 	}
7555 
7556 	kmem_free(phbc->phbc_phci_path, strlen(phbc->phbc_phci_path) + 1);
7557 	kmem_free(phbc, sizeof (*phbc));
7558 
7559 	mutex_enter(&vhbc->vhbc_lock);
7560 	vhbc->vhbc_thr_count--;
7561 	if (vhbc->vhbc_thr_count == 0)
7562 		cv_broadcast(&vhbc->vhbc_cv);
7563 	mutex_exit(&vhbc->vhbc_lock);
7564 }
7565 
7566 /*
7567  * Bus config all phcis associated with the vhci in parallel.
7568  * op must be BUS_CONFIG_DRIVER or BUS_CONFIG_ALL.
7569  */
7570 static void
7571 bus_config_all_phcis(mdi_vhci_cache_t *vhcache, uint_t flags,
7572     ddi_bus_config_op_t op, major_t maj)
7573 {
7574 	mdi_phci_bus_config_t *phbc_head = NULL, *phbc, *phbc_next;
7575 	mdi_vhci_bus_config_t *vhbc;
7576 	mdi_vhcache_phci_t *cphci;
7577 
7578 	rw_enter(&vhcache->vhcache_lock, RW_READER);
7579 	if (vhcache->vhcache_phci_head == NULL) {
7580 		rw_exit(&vhcache->vhcache_lock);
7581 		return;
7582 	}
7583 
7584 	vhbc = kmem_zalloc(sizeof (*vhbc), KM_SLEEP);
7585 
7586 	for (cphci = vhcache->vhcache_phci_head; cphci != NULL;
7587 	    cphci = cphci->cphci_next) {
7588 		phbc = kmem_zalloc(sizeof (*phbc), KM_SLEEP);
7589 		phbc->phbc_phci_path = i_ddi_strdup(cphci->cphci_path,
7590 		    KM_SLEEP);
7591 		phbc->phbc_vhbusconfig = vhbc;
7592 		phbc->phbc_next = phbc_head;
7593 		phbc_head = phbc;
7594 		vhbc->vhbc_thr_count++;
7595 	}
7596 	rw_exit(&vhcache->vhcache_lock);
7597 
7598 	vhbc->vhbc_op = op;
7599 	vhbc->vhbc_op_major = maj;
7600 	vhbc->vhbc_op_flags = NDI_NO_EVENT |
7601 	    (flags & (NDI_CONFIG_REPROBE | NDI_DRV_CONF_REPROBE));
7602 	mutex_init(&vhbc->vhbc_lock, NULL, MUTEX_DEFAULT, NULL);
7603 	cv_init(&vhbc->vhbc_cv, NULL, CV_DRIVER, NULL);
7604 
7605 	/* now create threads to initiate bus config on all phcis in parallel */
7606 	for (phbc = phbc_head; phbc != NULL; phbc = phbc_next) {
7607 		phbc_next = phbc->phbc_next;
7608 		if (mdi_mtc_off)
7609 			bus_config_phci((void *)phbc);
7610 		else
7611 			(void) thread_create(NULL, 0, bus_config_phci, phbc,
7612 			    0, &p0, TS_RUN, minclsyspri);
7613 	}
7614 
7615 	mutex_enter(&vhbc->vhbc_lock);
7616 	/* wait until all threads exit */
7617 	while (vhbc->vhbc_thr_count > 0)
7618 		cv_wait(&vhbc->vhbc_cv, &vhbc->vhbc_lock);
7619 	mutex_exit(&vhbc->vhbc_lock);
7620 
7621 	mutex_destroy(&vhbc->vhbc_lock);
7622 	cv_destroy(&vhbc->vhbc_cv);
7623 	kmem_free(vhbc, sizeof (*vhbc));
7624 }
7625 
7626 /*
7627  * Single threaded version of bus_config_all_phcis()
7628  */
7629 static void
7630 st_bus_config_all_phcis(mdi_vhci_config_t *vhc, uint_t flags,
7631     ddi_bus_config_op_t op, major_t maj)
7632 {
7633 	mdi_vhci_cache_t *vhcache = &vhc->vhc_vhcache;
7634 
7635 	single_threaded_vhconfig_enter(vhc);
7636 	bus_config_all_phcis(vhcache, flags, op, maj);
7637 	single_threaded_vhconfig_exit(vhc);
7638 }
7639 
7640 /*
7641  * Perform BUS_CONFIG_ONE on the specified child of the phci.
7642  * The path includes the child component in addition to the phci path.
7643  */
7644 static int
7645 bus_config_one_phci_child(char *path)
7646 {
7647 	dev_info_t *ph_dip, *child;
7648 	char *devnm;
7649 	int rv = MDI_FAILURE;
7650 
7651 	/* extract the child component of the phci */
7652 	devnm = strrchr(path, '/');
7653 	*devnm++ = '\0';
7654 
7655 	/*
7656 	 * first configure all path components upto phci and then
7657 	 * configure the phci child.
7658 	 */
7659 	if ((ph_dip = e_ddi_hold_devi_by_path(path, 0)) != NULL) {
7660 		if (ndi_devi_config_one(ph_dip, devnm, &child, NDI_NO_EVENT) ==
7661 		    NDI_SUCCESS) {
7662 			/*
7663 			 * release the hold that ndi_devi_config_one() placed
7664 			 */
7665 			ndi_rele_devi(child);
7666 			rv = MDI_SUCCESS;
7667 		}
7668 
7669 		/* release the hold that e_ddi_hold_devi_by_path() placed */
7670 		ndi_rele_devi(ph_dip);
7671 	}
7672 
7673 	devnm--;
7674 	*devnm = '/';
7675 	return (rv);
7676 }
7677 
7678 /*
7679  * Build a list of phci client paths for the specified vhci client.
7680  * The list includes only those phci client paths which aren't configured yet.
7681  */
7682 static mdi_phys_path_t *
7683 build_phclient_path_list(mdi_vhcache_client_t *cct, char *ct_name)
7684 {
7685 	mdi_vhcache_pathinfo_t *cpi;
7686 	mdi_phys_path_t *pp_head = NULL, *pp_tail = NULL, *pp;
7687 	int config_path, len;
7688 
7689 	for (cpi = cct->cct_cpi_head; cpi != NULL; cpi = cpi->cpi_next) {
7690 		/*
7691 		 * include only those paths that aren't configured.
7692 		 */
7693 		config_path = 0;
7694 		if (cpi->cpi_pip == NULL)
7695 			config_path = 1;
7696 		else {
7697 			MDI_PI_LOCK(cpi->cpi_pip);
7698 			if (MDI_PI_IS_INIT(cpi->cpi_pip))
7699 				config_path = 1;
7700 			MDI_PI_UNLOCK(cpi->cpi_pip);
7701 		}
7702 
7703 		if (config_path) {
7704 			pp = kmem_alloc(sizeof (*pp), KM_SLEEP);
7705 			len = strlen(cpi->cpi_cphci->cphci_path) +
7706 			    strlen(ct_name) + strlen(cpi->cpi_addr) + 3;
7707 			pp->phys_path = kmem_alloc(len, KM_SLEEP);
7708 			(void) snprintf(pp->phys_path, len, "%s/%s@%s",
7709 			    cpi->cpi_cphci->cphci_path, ct_name,
7710 			    cpi->cpi_addr);
7711 			pp->phys_path_next = NULL;
7712 
7713 			if (pp_head == NULL)
7714 				pp_head = pp;
7715 			else
7716 				pp_tail->phys_path_next = pp;
7717 			pp_tail = pp;
7718 		}
7719 	}
7720 
7721 	return (pp_head);
7722 }
7723 
7724 /*
7725  * Free the memory allocated for phci client path list.
7726  */
7727 static void
7728 free_phclient_path_list(mdi_phys_path_t *pp_head)
7729 {
7730 	mdi_phys_path_t *pp, *pp_next;
7731 
7732 	for (pp = pp_head; pp != NULL; pp = pp_next) {
7733 		pp_next = pp->phys_path_next;
7734 		kmem_free(pp->phys_path, strlen(pp->phys_path) + 1);
7735 		kmem_free(pp, sizeof (*pp));
7736 	}
7737 }
7738 
7739 /*
7740  * Allocated async client structure and initialize with the specified values.
7741  */
7742 static mdi_async_client_config_t *
7743 alloc_async_client_config(char *ct_name, char *ct_addr,
7744     mdi_phys_path_t *pp_head, mdi_vhcache_lookup_token_t *tok)
7745 {
7746 	mdi_async_client_config_t *acc;
7747 
7748 	acc = kmem_alloc(sizeof (*acc), KM_SLEEP);
7749 	acc->acc_ct_name = i_ddi_strdup(ct_name, KM_SLEEP);
7750 	acc->acc_ct_addr = i_ddi_strdup(ct_addr, KM_SLEEP);
7751 	acc->acc_phclient_path_list_head = pp_head;
7752 	init_vhcache_lookup_token(&acc->acc_token, tok);
7753 	acc->acc_next = NULL;
7754 	return (acc);
7755 }
7756 
7757 /*
7758  * Free the memory allocated for the async client structure and their members.
7759  */
7760 static void
7761 free_async_client_config(mdi_async_client_config_t *acc)
7762 {
7763 	if (acc->acc_phclient_path_list_head)
7764 		free_phclient_path_list(acc->acc_phclient_path_list_head);
7765 	kmem_free(acc->acc_ct_name, strlen(acc->acc_ct_name) + 1);
7766 	kmem_free(acc->acc_ct_addr, strlen(acc->acc_ct_addr) + 1);
7767 	kmem_free(acc, sizeof (*acc));
7768 }
7769 
7770 /*
7771  * Sort vhcache pathinfos (cpis) of the specified client.
7772  * All cpis which do not have MDI_CPI_HINT_PATH_DOES_NOT_EXIST
7773  * flag set come at the beginning of the list. All cpis which have this
7774  * flag set come at the end of the list.
7775  */
7776 static void
7777 sort_vhcache_paths(mdi_vhcache_client_t *cct)
7778 {
7779 	mdi_vhcache_pathinfo_t *cpi, *cpi_next, *cpi_head;
7780 
7781 	cpi_head = cct->cct_cpi_head;
7782 	cct->cct_cpi_head = cct->cct_cpi_tail = NULL;
7783 	for (cpi = cpi_head; cpi != NULL; cpi = cpi_next) {
7784 		cpi_next = cpi->cpi_next;
7785 		enqueue_vhcache_pathinfo(cct, cpi);
7786 	}
7787 }
7788 
7789 /*
7790  * Verify whether MDI_CPI_HINT_PATH_DOES_NOT_EXIST flag setting is correct for
7791  * every vhcache pathinfo of the specified client. If not adjust the flag
7792  * setting appropriately.
7793  *
7794  * Note that MDI_CPI_HINT_PATH_DOES_NOT_EXIST flag is persisted in the
7795  * on-disk vhci cache. So every time this flag is updated the cache must be
7796  * flushed.
7797  */
7798 static void
7799 adjust_sort_vhcache_paths(mdi_vhci_config_t *vhc, char *ct_name, char *ct_addr,
7800     mdi_vhcache_lookup_token_t *tok)
7801 {
7802 	mdi_vhci_cache_t *vhcache = &vhc->vhc_vhcache;
7803 	mdi_vhcache_client_t *cct;
7804 	mdi_vhcache_pathinfo_t *cpi;
7805 
7806 	rw_enter(&vhcache->vhcache_lock, RW_READER);
7807 	if ((cct = lookup_vhcache_client(vhcache, ct_name, ct_addr, tok))
7808 	    == NULL) {
7809 		rw_exit(&vhcache->vhcache_lock);
7810 		return;
7811 	}
7812 
7813 	/*
7814 	 * to avoid unnecessary on-disk cache updates, first check if an
7815 	 * update is really needed. If no update is needed simply return.
7816 	 */
7817 	for (cpi = cct->cct_cpi_head; cpi != NULL; cpi = cpi->cpi_next) {
7818 		if ((cpi->cpi_pip != NULL &&
7819 		    (cpi->cpi_flags & MDI_CPI_HINT_PATH_DOES_NOT_EXIST)) ||
7820 		    (cpi->cpi_pip == NULL &&
7821 		    !(cpi->cpi_flags & MDI_CPI_HINT_PATH_DOES_NOT_EXIST))) {
7822 			break;
7823 		}
7824 	}
7825 	if (cpi == NULL) {
7826 		rw_exit(&vhcache->vhcache_lock);
7827 		return;
7828 	}
7829 
7830 	if (rw_tryupgrade(&vhcache->vhcache_lock) == 0) {
7831 		rw_exit(&vhcache->vhcache_lock);
7832 		rw_enter(&vhcache->vhcache_lock, RW_WRITER);
7833 		if ((cct = lookup_vhcache_client(vhcache, ct_name, ct_addr,
7834 		    tok)) == NULL) {
7835 			rw_exit(&vhcache->vhcache_lock);
7836 			return;
7837 		}
7838 	}
7839 
7840 	for (cpi = cct->cct_cpi_head; cpi != NULL; cpi = cpi->cpi_next) {
7841 		if (cpi->cpi_pip != NULL)
7842 			cpi->cpi_flags &= ~MDI_CPI_HINT_PATH_DOES_NOT_EXIST;
7843 		else
7844 			cpi->cpi_flags |= MDI_CPI_HINT_PATH_DOES_NOT_EXIST;
7845 	}
7846 	sort_vhcache_paths(cct);
7847 
7848 	rw_exit(&vhcache->vhcache_lock);
7849 	vhcache_dirty(vhc);
7850 }
7851 
7852 /*
7853  * Configure all specified paths of the client.
7854  */
7855 static void
7856 config_client_paths_sync(mdi_vhci_config_t *vhc, char *ct_name, char *ct_addr,
7857     mdi_phys_path_t *pp_head, mdi_vhcache_lookup_token_t *tok)
7858 {
7859 	mdi_phys_path_t *pp;
7860 
7861 	for (pp = pp_head; pp != NULL; pp = pp->phys_path_next)
7862 		(void) bus_config_one_phci_child(pp->phys_path);
7863 	adjust_sort_vhcache_paths(vhc, ct_name, ct_addr, tok);
7864 }
7865 
7866 /*
7867  * Dequeue elements from vhci async client config list and bus configure
7868  * their corresponding phci clients.
7869  */
7870 static void
7871 config_client_paths_thread(void *arg)
7872 {
7873 	mdi_vhci_config_t *vhc = (mdi_vhci_config_t *)arg;
7874 	mdi_async_client_config_t *acc;
7875 	clock_t quit_at_ticks;
7876 	clock_t idle_time = mdi_async_config_idle_time * TICKS_PER_SECOND;
7877 	callb_cpr_t cprinfo;
7878 
7879 	CALLB_CPR_INIT(&cprinfo, &vhc->vhc_lock, callb_generic_cpr,
7880 	    "mdi_config_client_paths");
7881 
7882 	for (; ; ) {
7883 		quit_at_ticks = ddi_get_lbolt() + idle_time;
7884 
7885 		mutex_enter(&vhc->vhc_lock);
7886 		while (!(vhc->vhc_flags & MDI_VHC_EXIT) &&
7887 		    vhc->vhc_acc_list_head == NULL &&
7888 		    ddi_get_lbolt() < quit_at_ticks) {
7889 			CALLB_CPR_SAFE_BEGIN(&cprinfo);
7890 			(void) cv_timedwait(&vhc->vhc_cv, &vhc->vhc_lock,
7891 			    quit_at_ticks);
7892 			CALLB_CPR_SAFE_END(&cprinfo, &vhc->vhc_lock);
7893 		}
7894 
7895 		if ((vhc->vhc_flags & MDI_VHC_EXIT) ||
7896 		    vhc->vhc_acc_list_head == NULL)
7897 			goto out;
7898 
7899 		acc = vhc->vhc_acc_list_head;
7900 		vhc->vhc_acc_list_head = acc->acc_next;
7901 		if (vhc->vhc_acc_list_head == NULL)
7902 			vhc->vhc_acc_list_tail = NULL;
7903 		vhc->vhc_acc_count--;
7904 		mutex_exit(&vhc->vhc_lock);
7905 
7906 		config_client_paths_sync(vhc, acc->acc_ct_name,
7907 		    acc->acc_ct_addr, acc->acc_phclient_path_list_head,
7908 		    &acc->acc_token);
7909 
7910 		free_async_client_config(acc);
7911 	}
7912 
7913 out:
7914 	vhc->vhc_acc_thrcount--;
7915 	/* CALLB_CPR_EXIT releases the vhc->vhc_lock */
7916 	CALLB_CPR_EXIT(&cprinfo);
7917 }
7918 
7919 /*
7920  * Arrange for all the phci client paths (pp_head) for the specified client
7921  * to be bus configured asynchronously by a thread.
7922  */
7923 static void
7924 config_client_paths_async(mdi_vhci_config_t *vhc, char *ct_name, char *ct_addr,
7925     mdi_phys_path_t *pp_head, mdi_vhcache_lookup_token_t *tok)
7926 {
7927 	mdi_async_client_config_t *acc, *newacc;
7928 	int create_thread;
7929 
7930 	if (pp_head == NULL)
7931 		return;
7932 
7933 	if (mdi_mtc_off) {
7934 		config_client_paths_sync(vhc, ct_name, ct_addr, pp_head, tok);
7935 		free_phclient_path_list(pp_head);
7936 		return;
7937 	}
7938 
7939 	newacc = alloc_async_client_config(ct_name, ct_addr, pp_head, tok);
7940 	ASSERT(newacc);
7941 
7942 	mutex_enter(&vhc->vhc_lock);
7943 	for (acc = vhc->vhc_acc_list_head; acc != NULL; acc = acc->acc_next) {
7944 		if (strcmp(ct_name, acc->acc_ct_name) == 0 &&
7945 		    strcmp(ct_addr, acc->acc_ct_addr) == 0) {
7946 			free_async_client_config(newacc);
7947 			mutex_exit(&vhc->vhc_lock);
7948 			return;
7949 		}
7950 	}
7951 
7952 	if (vhc->vhc_acc_list_head == NULL)
7953 		vhc->vhc_acc_list_head = newacc;
7954 	else
7955 		vhc->vhc_acc_list_tail->acc_next = newacc;
7956 	vhc->vhc_acc_list_tail = newacc;
7957 	vhc->vhc_acc_count++;
7958 	if (vhc->vhc_acc_count <= vhc->vhc_acc_thrcount) {
7959 		cv_broadcast(&vhc->vhc_cv);
7960 		create_thread = 0;
7961 	} else {
7962 		vhc->vhc_acc_thrcount++;
7963 		create_thread = 1;
7964 	}
7965 	mutex_exit(&vhc->vhc_lock);
7966 
7967 	if (create_thread)
7968 		(void) thread_create(NULL, 0, config_client_paths_thread, vhc,
7969 		    0, &p0, TS_RUN, minclsyspri);
7970 }
7971 
7972 /*
7973  * Return number of online paths for the specified client.
7974  */
7975 static int
7976 nonline_paths(mdi_vhcache_client_t *cct)
7977 {
7978 	mdi_vhcache_pathinfo_t *cpi;
7979 	int online_count = 0;
7980 
7981 	for (cpi = cct->cct_cpi_head; cpi != NULL; cpi = cpi->cpi_next) {
7982 		if (cpi->cpi_pip != NULL) {
7983 			MDI_PI_LOCK(cpi->cpi_pip);
7984 			if (cpi->cpi_pip->pi_state == MDI_PATHINFO_STATE_ONLINE)
7985 				online_count++;
7986 			MDI_PI_UNLOCK(cpi->cpi_pip);
7987 		}
7988 	}
7989 
7990 	return (online_count);
7991 }
7992 
7993 /*
7994  * Bus configure all paths for the specified vhci client.
7995  * If at least one path for the client is already online, the remaining paths
7996  * will be configured asynchronously. Otherwise, it synchronously configures
7997  * the paths until at least one path is online and then rest of the paths
7998  * will be configured asynchronously.
7999  */
8000 static void
8001 config_client_paths(mdi_vhci_config_t *vhc, char *ct_name, char *ct_addr)
8002 {
8003 	mdi_vhci_cache_t *vhcache = &vhc->vhc_vhcache;
8004 	mdi_phys_path_t *pp_head, *pp;
8005 	mdi_vhcache_client_t *cct;
8006 	mdi_vhcache_lookup_token_t tok;
8007 
8008 	ASSERT(RW_LOCK_HELD(&vhcache->vhcache_lock));
8009 
8010 	init_vhcache_lookup_token(&tok, NULL);
8011 
8012 	if (ct_name == NULL || ct_addr == NULL ||
8013 	    (cct = lookup_vhcache_client(vhcache, ct_name, ct_addr, &tok))
8014 	    == NULL ||
8015 	    (pp_head = build_phclient_path_list(cct, ct_name)) == NULL) {
8016 		rw_exit(&vhcache->vhcache_lock);
8017 		return;
8018 	}
8019 
8020 	/* if at least one path is online, configure the rest asynchronously */
8021 	if (nonline_paths(cct) > 0) {
8022 		rw_exit(&vhcache->vhcache_lock);
8023 		config_client_paths_async(vhc, ct_name, ct_addr, pp_head, &tok);
8024 		return;
8025 	}
8026 
8027 	rw_exit(&vhcache->vhcache_lock);
8028 
8029 	for (pp = pp_head; pp != NULL; pp = pp->phys_path_next) {
8030 		if (bus_config_one_phci_child(pp->phys_path) == MDI_SUCCESS) {
8031 			rw_enter(&vhcache->vhcache_lock, RW_READER);
8032 
8033 			if ((cct = lookup_vhcache_client(vhcache, ct_name,
8034 			    ct_addr, &tok)) == NULL) {
8035 				rw_exit(&vhcache->vhcache_lock);
8036 				goto out;
8037 			}
8038 
8039 			if (nonline_paths(cct) > 0 &&
8040 			    pp->phys_path_next != NULL) {
8041 				rw_exit(&vhcache->vhcache_lock);
8042 				config_client_paths_async(vhc, ct_name, ct_addr,
8043 				    pp->phys_path_next, &tok);
8044 				pp->phys_path_next = NULL;
8045 				goto out;
8046 			}
8047 
8048 			rw_exit(&vhcache->vhcache_lock);
8049 		}
8050 	}
8051 
8052 	adjust_sort_vhcache_paths(vhc, ct_name, ct_addr, &tok);
8053 out:
8054 	free_phclient_path_list(pp_head);
8055 }
8056 
8057 static void
8058 single_threaded_vhconfig_enter(mdi_vhci_config_t *vhc)
8059 {
8060 	mutex_enter(&vhc->vhc_lock);
8061 	while (vhc->vhc_flags & MDI_VHC_SINGLE_THREADED)
8062 		cv_wait(&vhc->vhc_cv, &vhc->vhc_lock);
8063 	vhc->vhc_flags |= MDI_VHC_SINGLE_THREADED;
8064 	mutex_exit(&vhc->vhc_lock);
8065 }
8066 
8067 static void
8068 single_threaded_vhconfig_exit(mdi_vhci_config_t *vhc)
8069 {
8070 	mutex_enter(&vhc->vhc_lock);
8071 	vhc->vhc_flags &= ~MDI_VHC_SINGLE_THREADED;
8072 	cv_broadcast(&vhc->vhc_cv);
8073 	mutex_exit(&vhc->vhc_lock);
8074 }
8075 
8076 typedef struct mdi_phci_driver_info {
8077 	char	*phdriver_name;	/* name of the phci driver */
8078 
8079 	/* set to non zero if the phci driver supports root device */
8080 	int	phdriver_root_support;
8081 } mdi_phci_driver_info_t;
8082 
8083 /*
8084  * vhci class and root support capability of a phci driver can be
8085  * specified using ddi-vhci-class and ddi-no-root-support properties in the
8086  * phci driver.conf file. The built-in tables below contain this information
8087  * for those phci drivers whose driver.conf files don't yet contain this info.
8088  *
8089  * All phci drivers expect iscsi have root device support.
8090  */
8091 static mdi_phci_driver_info_t scsi_phci_driver_list[] = {
8092 	{ "fp", 1 },
8093 	{ "iscsi", 0 },
8094 	{ "ibsrp", 1 }
8095 	};
8096 
8097 static mdi_phci_driver_info_t ib_phci_driver_list[] = { "tavor", 1 };
8098 
8099 static void *
8100 mdi_realloc(void *old_ptr, size_t old_size, size_t new_size)
8101 {
8102 	void *new_ptr;
8103 
8104 	new_ptr = kmem_zalloc(new_size, KM_SLEEP);
8105 	if (old_ptr) {
8106 		bcopy(old_ptr, new_ptr, MIN(old_size, new_size));
8107 		kmem_free(old_ptr, old_size);
8108 	}
8109 	return (new_ptr);
8110 }
8111 
8112 static void
8113 add_to_phci_list(char ***driver_list, int **root_support_list,
8114     int *cur_elements, int *max_elements, char *driver_name, int root_support)
8115 {
8116 	ASSERT(*cur_elements <= *max_elements);
8117 	if (*cur_elements == *max_elements) {
8118 		*max_elements += 10;
8119 		*driver_list = mdi_realloc(*driver_list,
8120 		    sizeof (char *) * (*cur_elements),
8121 		    sizeof (char *) * (*max_elements));
8122 		*root_support_list = mdi_realloc(*root_support_list,
8123 		    sizeof (int) * (*cur_elements),
8124 		    sizeof (int) * (*max_elements));
8125 	}
8126 	(*driver_list)[*cur_elements] = i_ddi_strdup(driver_name, KM_SLEEP);
8127 	(*root_support_list)[*cur_elements] = root_support;
8128 	(*cur_elements)++;
8129 }
8130 
8131 static void
8132 get_phci_driver_list(char *vhci_class, char ***driver_list,
8133     int **root_support_list, int *cur_elements, int *max_elements)
8134 {
8135 	mdi_phci_driver_info_t	*st_driver_list, *p;
8136 	int		st_ndrivers, root_support, i, j, driver_conf_count;
8137 	major_t		m;
8138 	struct devnames	*dnp;
8139 	ddi_prop_t	*propp;
8140 
8141 	*driver_list = NULL;
8142 	*root_support_list = NULL;
8143 	*cur_elements = 0;
8144 	*max_elements = 0;
8145 
8146 	/* add the phci drivers derived from the phci driver.conf files */
8147 	for (m = 0; m < devcnt; m++) {
8148 		dnp = &devnamesp[m];
8149 
8150 		if (dnp->dn_flags & DN_PHCI_DRIVER) {
8151 			LOCK_DEV_OPS(&dnp->dn_lock);
8152 			if (dnp->dn_global_prop_ptr != NULL &&
8153 			    (propp = i_ddi_prop_search(DDI_DEV_T_ANY,
8154 			    DDI_VHCI_CLASS, DDI_PROP_TYPE_STRING,
8155 			    &dnp->dn_global_prop_ptr->prop_list)) != NULL &&
8156 			    strcmp(propp->prop_val, vhci_class) == 0) {
8157 
8158 				root_support = (i_ddi_prop_search(DDI_DEV_T_ANY,
8159 				    DDI_NO_ROOT_SUPPORT, DDI_PROP_TYPE_INT,
8160 				    &dnp->dn_global_prop_ptr->prop_list)
8161 				    == NULL) ? 1 : 0;
8162 
8163 				add_to_phci_list(driver_list, root_support_list,
8164 				    cur_elements, max_elements, dnp->dn_name,
8165 				    root_support);
8166 
8167 				UNLOCK_DEV_OPS(&dnp->dn_lock);
8168 			} else
8169 				UNLOCK_DEV_OPS(&dnp->dn_lock);
8170 		}
8171 	}
8172 
8173 	driver_conf_count = *cur_elements;
8174 
8175 	/* add the phci drivers specified in the built-in tables */
8176 	if (strcmp(vhci_class, MDI_HCI_CLASS_SCSI) == 0) {
8177 		st_driver_list = scsi_phci_driver_list;
8178 		st_ndrivers = sizeof (scsi_phci_driver_list) /
8179 		    sizeof (mdi_phci_driver_info_t);
8180 	} else if (strcmp(vhci_class, MDI_HCI_CLASS_IB) == 0) {
8181 		st_driver_list = ib_phci_driver_list;
8182 		st_ndrivers = sizeof (ib_phci_driver_list) /
8183 		    sizeof (mdi_phci_driver_info_t);
8184 	} else {
8185 		st_driver_list = NULL;
8186 		st_ndrivers = 0;
8187 	}
8188 
8189 	for (i = 0, p = st_driver_list; i < st_ndrivers; i++, p++) {
8190 		/* add this phci driver if not already added before */
8191 		for (j = 0; j < driver_conf_count; j++) {
8192 			if (strcmp((*driver_list)[j], p->phdriver_name) == 0)
8193 				break;
8194 		}
8195 		if (j == driver_conf_count) {
8196 			add_to_phci_list(driver_list, root_support_list,
8197 			    cur_elements, max_elements, p->phdriver_name,
8198 			    p->phdriver_root_support);
8199 		}
8200 	}
8201 }
8202 
8203 /*
8204  * Attach the phci driver instances associated with the specified vhci class.
8205  * If root is mounted attach all phci driver instances.
8206  * If root is not mounted, attach the instances of only those phci
8207  * drivers that have the root support.
8208  */
8209 static void
8210 attach_phci_drivers(char *vhci_class)
8211 {
8212 	char	**driver_list, **p;
8213 	int	*root_support_list;
8214 	int	cur_elements, max_elements, i;
8215 	major_t	m;
8216 
8217 	get_phci_driver_list(vhci_class, &driver_list, &root_support_list,
8218 	    &cur_elements, &max_elements);
8219 
8220 	for (i = 0; i < cur_elements; i++) {
8221 		if (modrootloaded || root_support_list[i]) {
8222 			m = ddi_name_to_major(driver_list[i]);
8223 			if (m != (major_t)-1 && ddi_hold_installed_driver(m))
8224 				ddi_rele_driver(m);
8225 		}
8226 	}
8227 
8228 	if (driver_list) {
8229 		for (i = 0, p = driver_list; i < cur_elements; i++, p++)
8230 			kmem_free(*p, strlen(*p) + 1);
8231 		kmem_free(driver_list, sizeof (char *) * max_elements);
8232 		kmem_free(root_support_list, sizeof (int) * max_elements);
8233 	}
8234 }
8235 
8236 /*
8237  * Build vhci cache:
8238  *
8239  * Attach phci driver instances and then drive BUS_CONFIG_ALL on
8240  * the phci driver instances. During this process the cache gets built.
8241  *
8242  * Cache is built fully if the root is mounted.
8243  * If the root is not mounted, phci drivers that do not have root support
8244  * are not attached. As a result the cache is built partially. The entries
8245  * in the cache reflect only those phci drivers that have root support.
8246  */
8247 static int
8248 build_vhci_cache(mdi_vhci_t *vh)
8249 {
8250 	mdi_vhci_config_t *vhc = vh->vh_config;
8251 	mdi_vhci_cache_t *vhcache = &vhc->vhc_vhcache;
8252 
8253 	single_threaded_vhconfig_enter(vhc);
8254 
8255 	rw_enter(&vhcache->vhcache_lock, RW_READER);
8256 	if (vhcache->vhcache_flags & MDI_VHCI_CACHE_SETUP_DONE) {
8257 		rw_exit(&vhcache->vhcache_lock);
8258 		single_threaded_vhconfig_exit(vhc);
8259 		return (0);
8260 	}
8261 	rw_exit(&vhcache->vhcache_lock);
8262 
8263 	attach_phci_drivers(vh->vh_class);
8264 	bus_config_all_phcis(vhcache, NDI_DRV_CONF_REPROBE | NDI_NO_EVENT,
8265 	    BUS_CONFIG_ALL, (major_t)-1);
8266 
8267 	rw_enter(&vhcache->vhcache_lock, RW_WRITER);
8268 	vhcache->vhcache_flags |= MDI_VHCI_CACHE_SETUP_DONE;
8269 	rw_exit(&vhcache->vhcache_lock);
8270 
8271 	single_threaded_vhconfig_exit(vhc);
8272 	vhcache_dirty(vhc);
8273 	return (1);
8274 }
8275 
8276 /*
8277  * Determine if discovery of paths is needed.
8278  */
8279 static int
8280 vhcache_do_discovery(mdi_vhci_config_t *vhc)
8281 {
8282 	int rv = 1;
8283 
8284 	mutex_enter(&vhc->vhc_lock);
8285 	if (i_ddi_io_initialized() == 0) {
8286 		if (vhc->vhc_path_discovery_boot > 0) {
8287 			vhc->vhc_path_discovery_boot--;
8288 			goto out;
8289 		}
8290 	} else {
8291 		if (vhc->vhc_path_discovery_postboot > 0) {
8292 			vhc->vhc_path_discovery_postboot--;
8293 			goto out;
8294 		}
8295 	}
8296 
8297 	/*
8298 	 * Do full path discovery at most once per mdi_path_discovery_interval.
8299 	 * This is to avoid a series of full path discoveries when opening
8300 	 * stale /dev/[r]dsk links.
8301 	 */
8302 	if (mdi_path_discovery_interval != -1 &&
8303 	    lbolt64 >= vhc->vhc_path_discovery_cutoff_time)
8304 		goto out;
8305 
8306 	rv = 0;
8307 out:
8308 	mutex_exit(&vhc->vhc_lock);
8309 	return (rv);
8310 }
8311 
8312 /*
8313  * Discover all paths:
8314  *
8315  * Attach phci driver instances and then drive BUS_CONFIG_ALL on all the phci
8316  * driver instances. During this process all paths will be discovered.
8317  */
8318 static int
8319 vhcache_discover_paths(mdi_vhci_t *vh)
8320 {
8321 	mdi_vhci_config_t *vhc = vh->vh_config;
8322 	mdi_vhci_cache_t *vhcache = &vhc->vhc_vhcache;
8323 	int rv = 0;
8324 
8325 	single_threaded_vhconfig_enter(vhc);
8326 
8327 	if (vhcache_do_discovery(vhc)) {
8328 		attach_phci_drivers(vh->vh_class);
8329 		bus_config_all_phcis(vhcache, NDI_DRV_CONF_REPROBE |
8330 		    NDI_NO_EVENT, BUS_CONFIG_ALL, (major_t)-1);
8331 
8332 		mutex_enter(&vhc->vhc_lock);
8333 		vhc->vhc_path_discovery_cutoff_time = lbolt64 +
8334 		    mdi_path_discovery_interval * TICKS_PER_SECOND;
8335 		mutex_exit(&vhc->vhc_lock);
8336 		rv = 1;
8337 	}
8338 
8339 	single_threaded_vhconfig_exit(vhc);
8340 	return (rv);
8341 }
8342 
8343 /*
8344  * Generic vhci bus config implementation:
8345  *
8346  * Parameters
8347  *	vdip	vhci dip
8348  *	flags	bus config flags
8349  *	op	bus config operation
8350  *	The remaining parameters are bus config operation specific
8351  *
8352  * for BUS_CONFIG_ONE
8353  *	arg	pointer to name@addr
8354  *	child	upon successful return from this function, *child will be
8355  *		set to the configured and held devinfo child node of vdip.
8356  *	ct_addr	pointer to client address (i.e. GUID)
8357  *
8358  * for BUS_CONFIG_DRIVER
8359  *	arg	major number of the driver
8360  *	child and ct_addr parameters are ignored
8361  *
8362  * for BUS_CONFIG_ALL
8363  *	arg, child, and ct_addr parameters are ignored
8364  *
8365  * Note that for the rest of the bus config operations, this function simply
8366  * calls the framework provided default bus config routine.
8367  */
8368 int
8369 mdi_vhci_bus_config(dev_info_t *vdip, uint_t flags, ddi_bus_config_op_t op,
8370     void *arg, dev_info_t **child, char *ct_addr)
8371 {
8372 	mdi_vhci_t *vh = i_devi_get_vhci(vdip);
8373 	mdi_vhci_config_t *vhc = vh->vh_config;
8374 	mdi_vhci_cache_t *vhcache = &vhc->vhc_vhcache;
8375 	int rv = 0;
8376 	int params_valid = 0;
8377 	char *cp;
8378 
8379 	/*
8380 	 * To bus config vhcis we relay operation, possibly using another
8381 	 * thread, to phcis. The phci driver then interacts with MDI to cause
8382 	 * vhci child nodes to be enumerated under the vhci node.  Adding a
8383 	 * vhci child requires an ndi_devi_enter of the vhci. Since another
8384 	 * thread may be adding the child, to avoid deadlock we can't wait
8385 	 * for the relayed operations to complete if we have already entered
8386 	 * the vhci node.
8387 	 */
8388 	if (DEVI_BUSY_OWNED(vdip)) {
8389 		MDI_DEBUG(2, (CE_NOTE, vdip, "!MDI: vhci bus config: "
8390 		    "vhci dip is busy owned %p\n", (void *)vdip));
8391 		goto default_bus_config;
8392 	}
8393 
8394 	rw_enter(&vhcache->vhcache_lock, RW_READER);
8395 	if (!(vhcache->vhcache_flags & MDI_VHCI_CACHE_SETUP_DONE)) {
8396 		rw_exit(&vhcache->vhcache_lock);
8397 		rv = build_vhci_cache(vh);
8398 		rw_enter(&vhcache->vhcache_lock, RW_READER);
8399 	}
8400 
8401 	switch (op) {
8402 	case BUS_CONFIG_ONE:
8403 		if (arg != NULL && ct_addr != NULL) {
8404 			/* extract node name */
8405 			cp = (char *)arg;
8406 			while (*cp != '\0' && *cp != '@')
8407 				cp++;
8408 			if (*cp == '@') {
8409 				params_valid = 1;
8410 				*cp = '\0';
8411 				config_client_paths(vhc, (char *)arg, ct_addr);
8412 				/* config_client_paths() releases cache_lock */
8413 				*cp = '@';
8414 				break;
8415 			}
8416 		}
8417 
8418 		rw_exit(&vhcache->vhcache_lock);
8419 		break;
8420 
8421 	case BUS_CONFIG_DRIVER:
8422 		rw_exit(&vhcache->vhcache_lock);
8423 		if (rv == 0)
8424 			st_bus_config_all_phcis(vhc, flags, op,
8425 			    (major_t)(uintptr_t)arg);
8426 		break;
8427 
8428 	case BUS_CONFIG_ALL:
8429 		rw_exit(&vhcache->vhcache_lock);
8430 		if (rv == 0)
8431 			st_bus_config_all_phcis(vhc, flags, op, -1);
8432 		break;
8433 
8434 	default:
8435 		rw_exit(&vhcache->vhcache_lock);
8436 		break;
8437 	}
8438 
8439 
8440 default_bus_config:
8441 	/*
8442 	 * All requested child nodes are enumerated under the vhci.
8443 	 * Now configure them.
8444 	 */
8445 	if (ndi_busop_bus_config(vdip, flags, op, arg, child, 0) ==
8446 	    NDI_SUCCESS) {
8447 		return (MDI_SUCCESS);
8448 	} else if (op == BUS_CONFIG_ONE && rv == 0 && params_valid) {
8449 		/* discover all paths and try configuring again */
8450 		if (vhcache_discover_paths(vh) &&
8451 		    ndi_busop_bus_config(vdip, flags, op, arg, child, 0) ==
8452 		    NDI_SUCCESS)
8453 			return (MDI_SUCCESS);
8454 	}
8455 
8456 	return (MDI_FAILURE);
8457 }
8458 
8459 /*
8460  * Read the on-disk vhci cache into an nvlist for the specified vhci class.
8461  */
8462 static nvlist_t *
8463 read_on_disk_vhci_cache(char *vhci_class)
8464 {
8465 	nvlist_t *nvl;
8466 	int err;
8467 	char *filename;
8468 
8469 	filename = vhclass2vhcache_filename(vhci_class);
8470 
8471 	if ((err = fread_nvlist(filename, &nvl)) == 0) {
8472 		kmem_free(filename, strlen(filename) + 1);
8473 		return (nvl);
8474 	} else if (err == EIO)
8475 		cmn_err(CE_WARN, "%s: I/O error, will recreate\n", filename);
8476 	else if (err == EINVAL)
8477 		cmn_err(CE_WARN,
8478 		    "%s: data file corrupted, will recreate\n", filename);
8479 
8480 	kmem_free(filename, strlen(filename) + 1);
8481 	return (NULL);
8482 }
8483 
8484 /*
8485  * Read on-disk vhci cache into nvlists for all vhci classes.
8486  * Called during booting by i_ddi_read_devices_files().
8487  */
8488 void
8489 mdi_read_devices_files(void)
8490 {
8491 	int i;
8492 
8493 	for (i = 0; i < N_VHCI_CLASSES; i++)
8494 		vhcache_nvl[i] = read_on_disk_vhci_cache(vhci_class_list[i]);
8495 }
8496 
8497 /*
8498  * Remove all stale entries from vhci cache.
8499  */
8500 static void
8501 clean_vhcache(mdi_vhci_config_t *vhc)
8502 {
8503 	mdi_vhci_cache_t *vhcache = &vhc->vhc_vhcache;
8504 	mdi_vhcache_phci_t *cphci, *cphci_head, *cphci_next;
8505 	mdi_vhcache_client_t *cct, *cct_head, *cct_next;
8506 	mdi_vhcache_pathinfo_t *cpi, *cpi_head, *cpi_next;
8507 
8508 	rw_enter(&vhcache->vhcache_lock, RW_WRITER);
8509 
8510 	cct_head = vhcache->vhcache_client_head;
8511 	vhcache->vhcache_client_head = vhcache->vhcache_client_tail = NULL;
8512 	for (cct = cct_head; cct != NULL; cct = cct_next) {
8513 		cct_next = cct->cct_next;
8514 
8515 		cpi_head = cct->cct_cpi_head;
8516 		cct->cct_cpi_head = cct->cct_cpi_tail = NULL;
8517 		for (cpi = cpi_head; cpi != NULL; cpi = cpi_next) {
8518 			cpi_next = cpi->cpi_next;
8519 			if (cpi->cpi_pip != NULL) {
8520 				ASSERT(cpi->cpi_cphci->cphci_phci != NULL);
8521 				enqueue_tail_vhcache_pathinfo(cct, cpi);
8522 			} else
8523 				free_vhcache_pathinfo(cpi);
8524 		}
8525 
8526 		if (cct->cct_cpi_head != NULL)
8527 			enqueue_vhcache_client(vhcache, cct);
8528 		else {
8529 			(void) mod_hash_destroy(vhcache->vhcache_client_hash,
8530 			    (mod_hash_key_t)cct->cct_name_addr);
8531 			free_vhcache_client(cct);
8532 		}
8533 	}
8534 
8535 	cphci_head = vhcache->vhcache_phci_head;
8536 	vhcache->vhcache_phci_head = vhcache->vhcache_phci_tail = NULL;
8537 	for (cphci = cphci_head; cphci != NULL; cphci = cphci_next) {
8538 		cphci_next = cphci->cphci_next;
8539 		if (cphci->cphci_phci != NULL)
8540 			enqueue_vhcache_phci(vhcache, cphci);
8541 		else
8542 			free_vhcache_phci(cphci);
8543 	}
8544 
8545 	vhcache->vhcache_clean_time = lbolt64;
8546 	rw_exit(&vhcache->vhcache_lock);
8547 	vhcache_dirty(vhc);
8548 }
8549 
8550 /*
8551  * Remove all stale entries from vhci cache.
8552  * Called by i_ddi_clean_devices_files() during the execution of devfsadm -C
8553  */
8554 void
8555 mdi_clean_vhcache(void)
8556 {
8557 	mdi_vhci_t *vh;
8558 
8559 	mutex_enter(&mdi_mutex);
8560 	for (vh = mdi_vhci_head; vh != NULL; vh = vh->vh_next) {
8561 		vh->vh_refcnt++;
8562 		mutex_exit(&mdi_mutex);
8563 		clean_vhcache(vh->vh_config);
8564 		mutex_enter(&mdi_mutex);
8565 		vh->vh_refcnt--;
8566 	}
8567 	mutex_exit(&mdi_mutex);
8568 }
8569 
8570 /*
8571  * mdi_vhci_walk_clients():
8572  *		Walker routine to traverse client dev_info nodes
8573  * ddi_walk_devs(ddi_get_child(vdip), f, arg) returns the entire tree
8574  * below the client, including nexus devices, which we dont want.
8575  * So we just traverse the immediate siblings, starting from 1st client.
8576  */
8577 void
8578 mdi_vhci_walk_clients(dev_info_t *vdip,
8579     int (*f)(dev_info_t *, void *), void *arg)
8580 {
8581 	mdi_vhci_t	*vh = i_devi_get_vhci(vdip);
8582 	dev_info_t	*cdip;
8583 	mdi_client_t	*ct;
8584 
8585 	MDI_VHCI_CLIENT_LOCK(vh);
8586 	cdip = ddi_get_child(vdip);
8587 	while (cdip) {
8588 		ct = i_devi_get_client(cdip);
8589 		MDI_CLIENT_LOCK(ct);
8590 
8591 		if (((*f)(cdip, arg)) == DDI_WALK_CONTINUE)
8592 			cdip = ddi_get_next_sibling(cdip);
8593 		else
8594 			cdip = NULL;
8595 
8596 		MDI_CLIENT_UNLOCK(ct);
8597 	}
8598 	MDI_VHCI_CLIENT_UNLOCK(vh);
8599 }
8600 
8601 /*
8602  * mdi_vhci_walk_phcis():
8603  *		Walker routine to traverse phci dev_info nodes
8604  */
8605 void
8606 mdi_vhci_walk_phcis(dev_info_t *vdip,
8607     int (*f)(dev_info_t *, void *), void *arg)
8608 {
8609 	mdi_vhci_t	*vh = i_devi_get_vhci(vdip);
8610 	mdi_phci_t	*ph, *next;
8611 
8612 	MDI_VHCI_PHCI_LOCK(vh);
8613 	ph = vh->vh_phci_head;
8614 	while (ph) {
8615 		MDI_PHCI_LOCK(ph);
8616 
8617 		if (((*f)(ph->ph_dip, arg)) == DDI_WALK_CONTINUE)
8618 			next = ph->ph_next;
8619 		else
8620 			next = NULL;
8621 
8622 		MDI_PHCI_UNLOCK(ph);
8623 		ph = next;
8624 	}
8625 	MDI_VHCI_PHCI_UNLOCK(vh);
8626 }
8627 
8628 
8629 /*
8630  * mdi_walk_vhcis():
8631  *		Walker routine to traverse vhci dev_info nodes
8632  */
8633 void
8634 mdi_walk_vhcis(int (*f)(dev_info_t *, void *), void *arg)
8635 {
8636 	mdi_vhci_t	*vh = NULL;
8637 
8638 	mutex_enter(&mdi_mutex);
8639 	/*
8640 	 * Scan for already registered vhci
8641 	 */
8642 	for (vh = mdi_vhci_head; vh != NULL; vh = vh->vh_next) {
8643 		vh->vh_refcnt++;
8644 		mutex_exit(&mdi_mutex);
8645 		if (((*f)(vh->vh_dip, arg)) != DDI_WALK_CONTINUE) {
8646 			mutex_enter(&mdi_mutex);
8647 			vh->vh_refcnt--;
8648 			break;
8649 		} else {
8650 			mutex_enter(&mdi_mutex);
8651 			vh->vh_refcnt--;
8652 		}
8653 	}
8654 
8655 	mutex_exit(&mdi_mutex);
8656 }
8657 
8658 /*
8659  * i_mdi_log_sysevent():
8660  *		Logs events for pickup by syseventd
8661  */
8662 static void
8663 i_mdi_log_sysevent(dev_info_t *dip, char *ph_vh_class, char *subclass)
8664 {
8665 	char		*path_name;
8666 	nvlist_t	*attr_list;
8667 
8668 	if (nvlist_alloc(&attr_list, NV_UNIQUE_NAME_TYPE,
8669 	    KM_SLEEP) != DDI_SUCCESS) {
8670 		goto alloc_failed;
8671 	}
8672 
8673 	path_name = kmem_zalloc(MAXPATHLEN, KM_SLEEP);
8674 	(void) ddi_pathname(dip, path_name);
8675 
8676 	if (nvlist_add_string(attr_list, DDI_DRIVER_NAME,
8677 	    ddi_driver_name(dip)) != DDI_SUCCESS) {
8678 		goto error;
8679 	}
8680 
8681 	if (nvlist_add_int32(attr_list, DDI_DRIVER_MAJOR,
8682 	    (int32_t)ddi_driver_major(dip)) != DDI_SUCCESS) {
8683 		goto error;
8684 	}
8685 
8686 	if (nvlist_add_int32(attr_list, DDI_INSTANCE,
8687 	    (int32_t)ddi_get_instance(dip)) != DDI_SUCCESS) {
8688 		goto error;
8689 	}
8690 
8691 	if (nvlist_add_string(attr_list, DDI_PATHNAME,
8692 	    path_name) != DDI_SUCCESS) {
8693 		goto error;
8694 	}
8695 
8696 	if (nvlist_add_string(attr_list, DDI_CLASS,
8697 	    ph_vh_class) != DDI_SUCCESS) {
8698 		goto error;
8699 	}
8700 
8701 	(void) ddi_log_sysevent(dip, DDI_VENDOR_SUNW, EC_DDI, subclass,
8702 	    attr_list, NULL, DDI_SLEEP);
8703 
8704 error:
8705 	kmem_free(path_name, MAXPATHLEN);
8706 	nvlist_free(attr_list);
8707 	return;
8708 
8709 alloc_failed:
8710 	MDI_DEBUG(1, (CE_WARN, dip,
8711 	    "!i_mdi_log_sysevent: Unable to send sysevent"));
8712 }
8713 
8714 char **
8715 mdi_get_phci_driver_list(char *vhci_class, int	*ndrivers)
8716 {
8717 	char	**driver_list, **ret_driver_list = NULL;
8718 	int	*root_support_list;
8719 	int	cur_elements, max_elements;
8720 
8721 	get_phci_driver_list(vhci_class, &driver_list, &root_support_list,
8722 	    &cur_elements, &max_elements);
8723 
8724 
8725 	if (driver_list) {
8726 		kmem_free(root_support_list, sizeof (int) * max_elements);
8727 		ret_driver_list = mdi_realloc(driver_list, sizeof (char *)
8728 		    * max_elements, sizeof (char *) * cur_elements);
8729 	}
8730 	*ndrivers = cur_elements;
8731 
8732 	return (ret_driver_list);
8733 
8734 }
8735 
8736 void
8737 mdi_free_phci_driver_list(char **driver_list, int ndrivers)
8738 {
8739 	char	**p;
8740 	int	i;
8741 
8742 	if (driver_list) {
8743 		for (i = 0, p = driver_list; i < ndrivers; i++, p++)
8744 			kmem_free(*p, strlen(*p) + 1);
8745 		kmem_free(driver_list, sizeof (char *) * ndrivers);
8746 	}
8747 }
8748