xref: /linux/drivers/scsi/hosts.c (revision 2624f124b3b5d550ab2fbef7ee3bc0e1fed09722) 
1 /*
2  *  hosts.c Copyright (C) 1992 Drew Eckhardt
3  *          Copyright (C) 1993, 1994, 1995 Eric Youngdale
4  *          Copyright (C) 2002-2003 Christoph Hellwig
5  *
6  *  mid to lowlevel SCSI driver interface
7  *      Initial versions: Drew Eckhardt
8  *      Subsequent revisions: Eric Youngdale
9  *
10  *  <drew@colorado.edu>
11  *
12  *  Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
13  *  Added QLOGIC QLA1280 SCSI controller kernel host support.
14  *     August 4, 1999 Fred Lewis, Intel DuPont
15  *
16  *  Updated to reflect the new initialization scheme for the higher
17  *  level of scsi drivers (sd/sr/st)
18  *  September 17, 2000 Torben Mathiasen <tmm@image.dk>
19  *
20  *  Restructured scsi_host lists and associated functions.
21  *  September 04, 2002 Mike Anderson (andmike@us.ibm.com)
22  */
23 
24 #include <linux/module.h>
25 #include <linux/blkdev.h>
26 #include <linux/kernel.h>
27 #include <linux/kthread.h>
28 #include <linux/string.h>
29 #include <linux/mm.h>
30 #include <linux/init.h>
31 #include <linux/completion.h>
32 #include <linux/transport_class.h>
33 
34 #include <scsi/scsi_device.h>
35 #include <scsi/scsi_host.h>
36 #include <scsi/scsi_transport.h>
37 
38 #include "scsi_priv.h"
39 #include "scsi_logging.h"
40 
41 
42 static int scsi_host_next_hn;		/* host_no for next new host */
43 
44 
45 static void scsi_host_cls_release(struct class_device *class_dev)
46 {
47 	put_device(&class_to_shost(class_dev)->shost_gendev);
48 }
49 
50 static struct class shost_class = {
51 	.name		= "scsi_host",
52 	.release	= scsi_host_cls_release,
53 };
54 
55 /**
56  *	scsi_host_set_state - Take the given host through the host
57  *		state model.
58  *	@shost:	scsi host to change the state of.
59  *	@state:	state to change to.
60  *
61  *	Returns zero if unsuccessful or an error if the requested
62  *	transition is illegal.
63  **/
64 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
65 {
66 	enum scsi_host_state oldstate = shost->shost_state;
67 
68 	if (state == oldstate)
69 		return 0;
70 
71 	switch (state) {
72 	case SHOST_CREATED:
73 		/* There are no legal states that come back to
74 		 * created.  This is the manually initialised start
75 		 * state */
76 		goto illegal;
77 
78 	case SHOST_RUNNING:
79 		switch (oldstate) {
80 		case SHOST_CREATED:
81 		case SHOST_RECOVERY:
82 			break;
83 		default:
84 			goto illegal;
85 		}
86 		break;
87 
88 	case SHOST_RECOVERY:
89 		switch (oldstate) {
90 		case SHOST_RUNNING:
91 			break;
92 		default:
93 			goto illegal;
94 		}
95 		break;
96 
97 	case SHOST_CANCEL:
98 		switch (oldstate) {
99 		case SHOST_CREATED:
100 		case SHOST_RUNNING:
101 			break;
102 		default:
103 			goto illegal;
104 		}
105 		break;
106 
107 	case SHOST_DEL:
108 		switch (oldstate) {
109 		case SHOST_CANCEL:
110 			break;
111 		default:
112 			goto illegal;
113 		}
114 		break;
115 
116 	}
117 	shost->shost_state = state;
118 	return 0;
119 
120  illegal:
121 	SCSI_LOG_ERROR_RECOVERY(1,
122 				dev_printk(KERN_ERR, &shost->shost_gendev,
123 					   "Illegal host state transition"
124 					   "%s->%s\n",
125 					   scsi_host_state_name(oldstate),
126 					   scsi_host_state_name(state)));
127 	return -EINVAL;
128 }
129 EXPORT_SYMBOL(scsi_host_set_state);
130 
131 /**
132  * scsi_remove_host - remove a scsi host
133  * @shost:	a pointer to a scsi host to remove
134  **/
135 void scsi_remove_host(struct Scsi_Host *shost)
136 {
137 	down(&shost->scan_mutex);
138 	scsi_host_set_state(shost, SHOST_CANCEL);
139 	up(&shost->scan_mutex);
140 	scsi_forget_host(shost);
141 	scsi_proc_host_rm(shost);
142 
143 	scsi_host_set_state(shost, SHOST_DEL);
144 
145 	transport_unregister_device(&shost->shost_gendev);
146 	class_device_unregister(&shost->shost_classdev);
147 	device_del(&shost->shost_gendev);
148 }
149 EXPORT_SYMBOL(scsi_remove_host);
150 
151 /**
152  * scsi_add_host - add a scsi host
153  * @shost:	scsi host pointer to add
154  * @dev:	a struct device of type scsi class
155  *
156  * Return value:
157  * 	0 on success / != 0 for error
158  **/
159 int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
160 {
161 	struct scsi_host_template *sht = shost->hostt;
162 	int error = -EINVAL;
163 
164 	printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
165 			sht->info ? sht->info(shost) : sht->name);
166 
167 	if (!shost->can_queue) {
168 		printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
169 				sht->name);
170 		goto out;
171 	}
172 
173 	if (!shost->shost_gendev.parent)
174 		shost->shost_gendev.parent = dev ? dev : &platform_bus;
175 
176 	error = device_add(&shost->shost_gendev);
177 	if (error)
178 		goto out;
179 
180 	scsi_host_set_state(shost, SHOST_RUNNING);
181 	get_device(shost->shost_gendev.parent);
182 
183 	error = class_device_add(&shost->shost_classdev);
184 	if (error)
185 		goto out_del_gendev;
186 
187 	get_device(&shost->shost_gendev);
188 
189 	if (shost->transportt->host_size &&
190 	    (shost->shost_data = kmalloc(shost->transportt->host_size,
191 					 GFP_KERNEL)) == NULL)
192 		goto out_del_classdev;
193 
194 	if (shost->transportt->create_work_queue) {
195 		snprintf(shost->work_q_name, KOBJ_NAME_LEN, "scsi_wq_%d",
196 			shost->host_no);
197 		shost->work_q = create_singlethread_workqueue(
198 					shost->work_q_name);
199 		if (!shost->work_q)
200 			goto out_free_shost_data;
201 	}
202 
203 	error = scsi_sysfs_add_host(shost);
204 	if (error)
205 		goto out_destroy_host;
206 
207 	scsi_proc_host_add(shost);
208 	return error;
209 
210  out_destroy_host:
211 	if (shost->work_q)
212 		destroy_workqueue(shost->work_q);
213  out_free_shost_data:
214 	kfree(shost->shost_data);
215  out_del_classdev:
216 	class_device_del(&shost->shost_classdev);
217  out_del_gendev:
218 	device_del(&shost->shost_gendev);
219  out:
220 	return error;
221 }
222 EXPORT_SYMBOL(scsi_add_host);
223 
224 static void scsi_host_dev_release(struct device *dev)
225 {
226 	struct Scsi_Host *shost = dev_to_shost(dev);
227 	struct device *parent = dev->parent;
228 
229 	if (shost->ehandler)
230 		kthread_stop(shost->ehandler);
231 	if (shost->work_q)
232 		destroy_workqueue(shost->work_q);
233 
234 	scsi_proc_hostdir_rm(shost->hostt);
235 	scsi_destroy_command_freelist(shost);
236 	kfree(shost->shost_data);
237 
238 	if (parent)
239 		put_device(parent);
240 	kfree(shost);
241 }
242 
243 /**
244  * scsi_host_alloc - register a scsi host adapter instance.
245  * @sht:	pointer to scsi host template
246  * @privsize:	extra bytes to allocate for driver
247  *
248  * Note:
249  * 	Allocate a new Scsi_Host and perform basic initialization.
250  * 	The host is not published to the scsi midlayer until scsi_add_host
251  * 	is called.
252  *
253  * Return value:
254  * 	Pointer to a new Scsi_Host
255  **/
256 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
257 {
258 	struct Scsi_Host *shost;
259 	int gfp_mask = GFP_KERNEL, rval;
260 
261 	if (sht->unchecked_isa_dma && privsize)
262 		gfp_mask |= __GFP_DMA;
263 
264         /* Check to see if this host has any error handling facilities */
265         if (!sht->eh_strategy_handler && !sht->eh_abort_handler &&
266 	    !sht->eh_device_reset_handler && !sht->eh_bus_reset_handler &&
267             !sht->eh_host_reset_handler) {
268 		printk(KERN_ERR "ERROR: SCSI host `%s' has no error handling\n"
269 				"ERROR: This is not a safe way to run your "
270 				        "SCSI host\n"
271 				"ERROR: The error handling must be added to "
272 				"this driver\n", sht->proc_name);
273 		dump_stack();
274         }
275 
276 	shost = kmalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
277 	if (!shost)
278 		return NULL;
279 	memset(shost, 0, sizeof(struct Scsi_Host) + privsize);
280 
281 	spin_lock_init(&shost->default_lock);
282 	scsi_assign_lock(shost, &shost->default_lock);
283 	shost->shost_state = SHOST_CREATED;
284 	INIT_LIST_HEAD(&shost->__devices);
285 	INIT_LIST_HEAD(&shost->__targets);
286 	INIT_LIST_HEAD(&shost->eh_cmd_q);
287 	INIT_LIST_HEAD(&shost->starved_list);
288 	init_waitqueue_head(&shost->host_wait);
289 
290 	init_MUTEX(&shost->scan_mutex);
291 
292 	shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
293 	shost->dma_channel = 0xff;
294 
295 	/* These three are default values which can be overridden */
296 	shost->max_channel = 0;
297 	shost->max_id = 8;
298 	shost->max_lun = 8;
299 
300 	/* Give each shost a default transportt */
301 	shost->transportt = &blank_transport_template;
302 
303 	/*
304 	 * All drivers right now should be able to handle 12 byte
305 	 * commands.  Every so often there are requests for 16 byte
306 	 * commands, but individual low-level drivers need to certify that
307 	 * they actually do something sensible with such commands.
308 	 */
309 	shost->max_cmd_len = 12;
310 	shost->hostt = sht;
311 	shost->this_id = sht->this_id;
312 	shost->can_queue = sht->can_queue;
313 	shost->sg_tablesize = sht->sg_tablesize;
314 	shost->cmd_per_lun = sht->cmd_per_lun;
315 	shost->unchecked_isa_dma = sht->unchecked_isa_dma;
316 	shost->use_clustering = sht->use_clustering;
317 	shost->ordered_flush = sht->ordered_flush;
318 	shost->ordered_tag = sht->ordered_tag;
319 
320 	/*
321 	 * hosts/devices that do queueing must support ordered tags
322 	 */
323 	if (shost->can_queue > 1 && shost->ordered_flush) {
324 		printk(KERN_ERR "scsi: ordered flushes don't support queueing\n");
325 		shost->ordered_flush = 0;
326 	}
327 
328 	if (sht->max_host_blocked)
329 		shost->max_host_blocked = sht->max_host_blocked;
330 	else
331 		shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
332 
333 	/*
334 	 * If the driver imposes no hard sector transfer limit, start at
335 	 * machine infinity initially.
336 	 */
337 	if (sht->max_sectors)
338 		shost->max_sectors = sht->max_sectors;
339 	else
340 		shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
341 
342 	/*
343 	 * assume a 4GB boundary, if not set
344 	 */
345 	if (sht->dma_boundary)
346 		shost->dma_boundary = sht->dma_boundary;
347 	else
348 		shost->dma_boundary = 0xffffffff;
349 
350 	rval = scsi_setup_command_freelist(shost);
351 	if (rval)
352 		goto fail_kfree;
353 
354 	device_initialize(&shost->shost_gendev);
355 	snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
356 		shost->host_no);
357 	shost->shost_gendev.release = scsi_host_dev_release;
358 
359 	class_device_initialize(&shost->shost_classdev);
360 	shost->shost_classdev.dev = &shost->shost_gendev;
361 	shost->shost_classdev.class = &shost_class;
362 	snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
363 		  shost->host_no);
364 
365 	shost->ehandler = kthread_run(scsi_error_handler, shost,
366 			"scsi_eh_%d", shost->host_no);
367 	if (IS_ERR(shost->ehandler)) {
368 		rval = PTR_ERR(shost->ehandler);
369 		goto fail_destroy_freelist;
370 	}
371 
372 	scsi_proc_hostdir_add(shost->hostt);
373 	return shost;
374 
375  fail_destroy_freelist:
376 	scsi_destroy_command_freelist(shost);
377  fail_kfree:
378 	kfree(shost);
379 	return NULL;
380 }
381 EXPORT_SYMBOL(scsi_host_alloc);
382 
383 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
384 {
385 	struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
386 
387 	if (!sht->detect) {
388 		printk(KERN_WARNING "scsi_register() called on new-style "
389 				    "template for driver %s\n", sht->name);
390 		dump_stack();
391 	}
392 
393 	if (shost)
394 		list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
395 	return shost;
396 }
397 EXPORT_SYMBOL(scsi_register);
398 
399 void scsi_unregister(struct Scsi_Host *shost)
400 {
401 	list_del(&shost->sht_legacy_list);
402 	scsi_host_put(shost);
403 }
404 EXPORT_SYMBOL(scsi_unregister);
405 
406 /**
407  * scsi_host_lookup - get a reference to a Scsi_Host by host no
408  *
409  * @hostnum:	host number to locate
410  *
411  * Return value:
412  *	A pointer to located Scsi_Host or NULL.
413  **/
414 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
415 {
416 	struct class *class = &shost_class;
417 	struct class_device *cdev;
418 	struct Scsi_Host *shost = ERR_PTR(-ENXIO), *p;
419 
420 	down_read(&class->subsys.rwsem);
421 	list_for_each_entry(cdev, &class->children, node) {
422 		p = class_to_shost(cdev);
423 		if (p->host_no == hostnum) {
424 			shost = scsi_host_get(p);
425 			break;
426 		}
427 	}
428 	up_read(&class->subsys.rwsem);
429 
430 	return shost;
431 }
432 EXPORT_SYMBOL(scsi_host_lookup);
433 
434 /**
435  * scsi_host_get - inc a Scsi_Host ref count
436  * @shost:	Pointer to Scsi_Host to inc.
437  **/
438 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
439 {
440 	if ((shost->shost_state == SHOST_DEL) ||
441 		!get_device(&shost->shost_gendev))
442 		return NULL;
443 	return shost;
444 }
445 EXPORT_SYMBOL(scsi_host_get);
446 
447 /**
448  * scsi_host_put - dec a Scsi_Host ref count
449  * @shost:	Pointer to Scsi_Host to dec.
450  **/
451 void scsi_host_put(struct Scsi_Host *shost)
452 {
453 	put_device(&shost->shost_gendev);
454 }
455 EXPORT_SYMBOL(scsi_host_put);
456 
457 int scsi_init_hosts(void)
458 {
459 	return class_register(&shost_class);
460 }
461 
462 void scsi_exit_hosts(void)
463 {
464 	class_unregister(&shost_class);
465 }
466 
467 int scsi_is_host_device(const struct device *dev)
468 {
469 	return dev->release == scsi_host_dev_release;
470 }
471 EXPORT_SYMBOL(scsi_is_host_device);
472 
473 /**
474  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
475  * @shost:	Pointer to Scsi_Host.
476  * @work:	Work to queue for execution.
477  *
478  * Return value:
479  * 	0 on success / != 0 for error
480  **/
481 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
482 {
483 	if (unlikely(!shost->work_q)) {
484 		printk(KERN_ERR
485 			"ERROR: Scsi host '%s' attempted to queue scsi-work, "
486 			"when no workqueue created.\n", shost->hostt->name);
487 		dump_stack();
488 
489 		return -EINVAL;
490 	}
491 
492 	return queue_work(shost->work_q, work);
493 }
494 EXPORT_SYMBOL_GPL(scsi_queue_work);
495 
496 /**
497  * scsi_flush_work - Flush a Scsi_Host's workqueue.
498  * @shost:	Pointer to Scsi_Host.
499  **/
500 void scsi_flush_work(struct Scsi_Host *shost)
501 {
502 	if (!shost->work_q) {
503 		printk(KERN_ERR
504 			"ERROR: Scsi host '%s' attempted to flush scsi-work, "
505 			"when no workqueue created.\n", shost->hostt->name);
506 		dump_stack();
507 		return;
508 	}
509 
510 	flush_workqueue(shost->work_q);
511 }
512 EXPORT_SYMBOL_GPL(scsi_flush_work);
513