xref: /freebsd/sys/cam/scsi/scsi_targ_bh.c (revision c98323078dede7579020518ec84cdcb478e5c142)
1 /*
2  * Implementation of the Target Mode 'Black Hole device' for CAM.
3  *
4  * Copyright (c) 1999 Justin T. Gibbs.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions, and the following disclaimer,
12  *    without modification, immediately at the beginning of the file.
13  * 2. The name of the author may not be used to endorse or promote products
14  *    derived from this software without specific prior written permission.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
20  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/param.h>
33 #include <sys/queue.h>
34 #include <sys/systm.h>
35 #include <sys/kernel.h>
36 #include <sys/types.h>
37 #include <sys/bio.h>
38 #include <sys/conf.h>
39 #include <sys/devicestat.h>
40 #include <sys/malloc.h>
41 #include <sys/uio.h>
42 
43 #include <cam/cam.h>
44 #include <cam/cam_ccb.h>
45 #include <cam/cam_periph.h>
46 #include <cam/cam_queue.h>
47 #include <cam/cam_xpt_periph.h>
48 #include <cam/cam_debug.h>
49 
50 #include <cam/scsi/scsi_all.h>
51 #include <cam/scsi/scsi_message.h>
52 
53 typedef enum {
54 	TARGBH_STATE_NORMAL,
55 	TARGBH_STATE_EXCEPTION,
56 	TARGBH_STATE_TEARDOWN
57 } targbh_state;
58 
59 typedef enum {
60 	TARGBH_FLAG_NONE	 = 0x00,
61 	TARGBH_FLAG_LUN_ENABLED	 = 0x01
62 } targbh_flags;
63 
64 typedef enum {
65 	TARGBH_CCB_WORKQ,
66 	TARGBH_CCB_WAITING
67 } targbh_ccb_types;
68 
69 #define MAX_ACCEPT	8
70 #define MAX_IMMEDIATE	16
71 #define MAX_BUF_SIZE	256	/* Max inquiry/sense/mode page transfer */
72 
73 /* Offsets into our private CCB area for storing accept information */
74 #define ccb_type	ppriv_field0
75 #define ccb_descr	ppriv_ptr1
76 
77 /* We stick a pointer to the originating accept TIO in each continue I/O CCB */
78 #define ccb_atio	ppriv_ptr1
79 
80 TAILQ_HEAD(ccb_queue, ccb_hdr);
81 
82 struct targbh_softc {
83 	struct		ccb_queue pending_queue;
84 	struct		ccb_queue work_queue;
85 	struct		ccb_queue unknown_atio_queue;
86 	struct		devstat device_stats;
87 	targbh_state	state;
88 	targbh_flags	flags;
89 	u_int		init_level;
90 	u_int		inq_data_len;
91 	struct		ccb_accept_tio *accept_tio_list;
92 	struct		ccb_hdr_slist immed_notify_slist;
93 };
94 
95 struct targbh_cmd_desc {
96 	struct	  ccb_accept_tio* atio_link;
97 	u_int	  data_resid;	/* How much left to transfer */
98 	u_int	  data_increment;/* Amount to send before next disconnect */
99 	void*	  data;		/* The data. Can be from backing_store or not */
100 	void*	  backing_store;/* Backing store allocated for this descriptor*/
101 	u_int	  max_size;	/* Size of backing_store */
102 	u_int32_t timeout;
103 	u_int8_t  status;	/* Status to return to initiator */
104 };
105 
106 static struct scsi_inquiry_data no_lun_inq_data =
107 {
108 	T_NODEVICE | (SID_QUAL_BAD_LU << 5), 0,
109 	/* version */2, /* format version */2
110 };
111 
112 static struct scsi_sense_data no_lun_sense_data =
113 {
114 	SSD_CURRENT_ERROR|SSD_ERRCODE_VALID,
115 	0,
116 	SSD_KEY_NOT_READY,
117 	{ 0, 0, 0, 0 },
118 	/*extra_len*/offsetof(struct scsi_sense_data, fru)
119                    - offsetof(struct scsi_sense_data, extra_len),
120 	{ 0, 0, 0, 0 },
121 	/* Logical Unit Not Supported */
122 	/*ASC*/0x25, /*ASCQ*/0
123 };
124 
125 static const int request_sense_size = offsetof(struct scsi_sense_data, fru);
126 
127 static periph_init_t	targbhinit;
128 static void		targbhasync(void *callback_arg, u_int32_t code,
129 				    struct cam_path *path, void *arg);
130 static cam_status	targbhenlun(struct cam_periph *periph);
131 static cam_status	targbhdislun(struct cam_periph *periph);
132 static periph_ctor_t	targbhctor;
133 static periph_dtor_t	targbhdtor;
134 static periph_start_t	targbhstart;
135 static void		targbhdone(struct cam_periph *periph,
136 				   union ccb *done_ccb);
137 #ifdef NOTYET
138 static  int		targbherror(union ccb *ccb, u_int32_t cam_flags,
139 				    u_int32_t sense_flags);
140 #endif
141 static struct targbh_cmd_desc*	targbhallocdescr(void);
142 static void		targbhfreedescr(struct targbh_cmd_desc *buf);
143 
144 static struct periph_driver targbhdriver =
145 {
146 	targbhinit, "targbh",
147 	TAILQ_HEAD_INITIALIZER(targbhdriver.units), /* generation */ 0
148 };
149 
150 PERIPHDRIVER_DECLARE(targbh, targbhdriver);
151 
152 static void
153 targbhinit(void)
154 {
155 	cam_status status;
156 	struct cam_path *path;
157 
158 	/*
159 	 * Install a global async callback.  This callback will
160 	 * receive async callbacks like "new path registered".
161 	 */
162 	status = xpt_create_path(&path, /*periph*/NULL, CAM_XPT_PATH_ID,
163 				 CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD);
164 
165 	if (status == CAM_REQ_CMP) {
166 		struct ccb_setasync csa;
167 
168 		xpt_setup_ccb(&csa.ccb_h, path, /*priority*/5);
169 		csa.ccb_h.func_code = XPT_SASYNC_CB;
170 		csa.event_enable = AC_PATH_REGISTERED | AC_PATH_DEREGISTERED;
171 		csa.callback = targbhasync;
172 		csa.callback_arg = NULL;
173 		xpt_action((union ccb *)&csa);
174 		status = csa.ccb_h.status;
175 		xpt_free_path(path);
176         }
177 
178 	if (status != CAM_REQ_CMP) {
179 		printf("targbh: Failed to attach master async callback "
180 		       "due to status 0x%x!\n", status);
181 	}
182 }
183 
184 static void
185 targbhasync(void *callback_arg, u_int32_t code,
186 	    struct cam_path *path, void *arg)
187 {
188 	struct cam_path *new_path;
189 	struct ccb_pathinq *cpi;
190 	path_id_t bus_path_id;
191 	cam_status status;
192 
193 	cpi = (struct ccb_pathinq *)arg;
194 	if (code == AC_PATH_REGISTERED)
195 		bus_path_id = cpi->ccb_h.path_id;
196 	else
197 		bus_path_id = xpt_path_path_id(path);
198 	/*
199 	 * Allocate a peripheral instance for
200 	 * this target instance.
201 	 */
202 	status = xpt_create_path(&new_path, NULL,
203 				 bus_path_id,
204 				 CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD);
205 	if (status != CAM_REQ_CMP) {
206 		printf("targbhasync: Unable to create path "
207 			"due to status 0x%x\n", status);
208 		return;
209 	}
210 
211 	switch (code) {
212 	case AC_PATH_REGISTERED:
213 	{
214 		/* Only attach to controllers that support target mode */
215 		if ((cpi->target_sprt & PIT_PROCESSOR) == 0)
216 			break;
217 
218 		status = cam_periph_alloc(targbhctor, NULL, targbhdtor,
219 					  targbhstart,
220 					  "targbh", CAM_PERIPH_BIO,
221 					  new_path, targbhasync,
222 					  AC_PATH_REGISTERED,
223 					  cpi);
224 		break;
225 	}
226 	case AC_PATH_DEREGISTERED:
227 	{
228 		struct cam_periph *periph;
229 
230 		if ((periph = cam_periph_find(new_path, "targbh")) != NULL)
231 			cam_periph_invalidate(periph);
232 		break;
233 	}
234 	default:
235 		break;
236 	}
237 	xpt_free_path(new_path);
238 }
239 
240 /* Attempt to enable our lun */
241 static cam_status
242 targbhenlun(struct cam_periph *periph)
243 {
244 	union ccb immed_ccb;
245 	struct targbh_softc *softc;
246 	cam_status status;
247 	int i;
248 
249 	softc = (struct targbh_softc *)periph->softc;
250 
251 	if ((softc->flags & TARGBH_FLAG_LUN_ENABLED) != 0)
252 		return (CAM_REQ_CMP);
253 
254 	xpt_setup_ccb(&immed_ccb.ccb_h, periph->path, /*priority*/1);
255 	immed_ccb.ccb_h.func_code = XPT_EN_LUN;
256 
257 	/* Don't need support for any vendor specific commands */
258 	immed_ccb.cel.grp6_len = 0;
259 	immed_ccb.cel.grp7_len = 0;
260 	immed_ccb.cel.enable = 1;
261 	xpt_action(&immed_ccb);
262 	status = immed_ccb.ccb_h.status;
263 	if (status != CAM_REQ_CMP) {
264 		xpt_print_path(periph->path);
265 		printf("targbhenlun - Enable Lun Rejected with status 0x%x\n",
266 		       status);
267 		return (status);
268 	}
269 
270 	softc->flags |= TARGBH_FLAG_LUN_ENABLED;
271 
272 	/*
273 	 * Build up a buffer of accept target I/O
274 	 * operations for incoming selections.
275 	 */
276 	for (i = 0; i < MAX_ACCEPT; i++) {
277 		struct ccb_accept_tio *atio;
278 
279 		atio = (struct ccb_accept_tio*)malloc(sizeof(*atio), M_DEVBUF,
280 						      M_NOWAIT);
281 		if (atio == NULL) {
282 			status = CAM_RESRC_UNAVAIL;
283 			break;
284 		}
285 
286 		atio->ccb_h.ccb_descr = targbhallocdescr();
287 
288 		if (atio->ccb_h.ccb_descr == NULL) {
289 			free(atio, M_DEVBUF);
290 			status = CAM_RESRC_UNAVAIL;
291 			break;
292 		}
293 
294 		xpt_setup_ccb(&atio->ccb_h, periph->path, /*priority*/1);
295 		atio->ccb_h.func_code = XPT_ACCEPT_TARGET_IO;
296 		atio->ccb_h.cbfcnp = targbhdone;
297 		xpt_action((union ccb *)atio);
298 		status = atio->ccb_h.status;
299 		if (status != CAM_REQ_INPROG) {
300 			targbhfreedescr(atio->ccb_h.ccb_descr);
301 			free(atio, M_DEVBUF);
302 			break;
303 		}
304 		((struct targbh_cmd_desc*)atio->ccb_h.ccb_descr)->atio_link =
305 		    softc->accept_tio_list;
306 		softc->accept_tio_list = atio;
307 	}
308 
309 	if (i == 0) {
310 		xpt_print_path(periph->path);
311 		printf("targbhenlun - Could not allocate accept tio CCBs: "
312 		       "status = 0x%x\n", status);
313 		targbhdislun(periph);
314 		return (CAM_REQ_CMP_ERR);
315 	}
316 
317 	/*
318 	 * Build up a buffer of immediate notify CCBs
319 	 * so the SIM can tell us of asynchronous target mode events.
320 	 */
321 	for (i = 0; i < MAX_ACCEPT; i++) {
322 		struct ccb_immed_notify *inot;
323 
324 		inot = (struct ccb_immed_notify*)malloc(sizeof(*inot), M_DEVBUF,
325 						        M_NOWAIT);
326 
327 		if (inot == NULL) {
328 			status = CAM_RESRC_UNAVAIL;
329 			break;
330 		}
331 
332 		xpt_setup_ccb(&inot->ccb_h, periph->path, /*priority*/1);
333 		inot->ccb_h.func_code = XPT_IMMED_NOTIFY;
334 		inot->ccb_h.cbfcnp = targbhdone;
335 		xpt_action((union ccb *)inot);
336 		status = inot->ccb_h.status;
337 		if (status != CAM_REQ_INPROG) {
338 			free(inot, M_DEVBUF);
339 			break;
340 		}
341 		SLIST_INSERT_HEAD(&softc->immed_notify_slist, &inot->ccb_h,
342 				  periph_links.sle);
343 	}
344 
345 	if (i == 0) {
346 		xpt_print_path(periph->path);
347 		printf("targbhenlun - Could not allocate immediate notify "
348 		       "CCBs: status = 0x%x\n", status);
349 		targbhdislun(periph);
350 		return (CAM_REQ_CMP_ERR);
351 	}
352 
353 	return (CAM_REQ_CMP);
354 }
355 
356 static cam_status
357 targbhdislun(struct cam_periph *periph)
358 {
359 	union ccb ccb;
360 	struct targbh_softc *softc;
361 	struct ccb_accept_tio* atio;
362 	struct ccb_hdr *ccb_h;
363 
364 	softc = (struct targbh_softc *)periph->softc;
365 	if ((softc->flags & TARGBH_FLAG_LUN_ENABLED) == 0)
366 		return CAM_REQ_CMP;
367 
368 	/* XXX Block for Continue I/O completion */
369 
370 	/* Kill off all ACCECPT and IMMEDIATE CCBs */
371 	while ((atio = softc->accept_tio_list) != NULL) {
372 
373 		softc->accept_tio_list =
374 		    ((struct targbh_cmd_desc*)atio->ccb_h.ccb_descr)->atio_link;
375 		xpt_setup_ccb(&ccb.cab.ccb_h, periph->path, /*priority*/1);
376 		ccb.cab.ccb_h.func_code = XPT_ABORT;
377 		ccb.cab.abort_ccb = (union ccb *)atio;
378 		xpt_action(&ccb);
379 	}
380 
381 	while ((ccb_h = SLIST_FIRST(&softc->immed_notify_slist)) != NULL) {
382 		SLIST_REMOVE_HEAD(&softc->immed_notify_slist, periph_links.sle);
383 		xpt_setup_ccb(&ccb.cab.ccb_h, periph->path, /*priority*/1);
384 		ccb.cab.ccb_h.func_code = XPT_ABORT;
385 		ccb.cab.abort_ccb = (union ccb *)ccb_h;
386 		xpt_action(&ccb);
387 	}
388 
389 	/*
390 	 * Dissable this lun.
391 	 */
392 	xpt_setup_ccb(&ccb.cel.ccb_h, periph->path, /*priority*/1);
393 	ccb.cel.ccb_h.func_code = XPT_EN_LUN;
394 	ccb.cel.enable = 0;
395 	xpt_action(&ccb);
396 
397 	if (ccb.cel.ccb_h.status != CAM_REQ_CMP)
398 		printf("targbhdislun - Disabling lun on controller failed "
399 		       "with status 0x%x\n", ccb.cel.ccb_h.status);
400 	else
401 		softc->flags &= ~TARGBH_FLAG_LUN_ENABLED;
402 	return (ccb.cel.ccb_h.status);
403 }
404 
405 static cam_status
406 targbhctor(struct cam_periph *periph, void *arg)
407 {
408 	struct targbh_softc *softc;
409 
410 	/* Allocate our per-instance private storage */
411 	softc = (struct targbh_softc *)malloc(sizeof(*softc),
412 					      M_DEVBUF, M_NOWAIT);
413 	if (softc == NULL) {
414 		printf("targctor: unable to malloc softc\n");
415 		return (CAM_REQ_CMP_ERR);
416 	}
417 
418 	bzero(softc, sizeof(*softc));
419 	TAILQ_INIT(&softc->pending_queue);
420 	TAILQ_INIT(&softc->work_queue);
421 	softc->accept_tio_list = NULL;
422 	SLIST_INIT(&softc->immed_notify_slist);
423 	softc->state = TARGBH_STATE_NORMAL;
424 	periph->softc = softc;
425 	softc->init_level++;
426 
427 	return (targbhenlun(periph));
428 }
429 
430 static void
431 targbhdtor(struct cam_periph *periph)
432 {
433 	struct targbh_softc *softc;
434 
435 	softc = (struct targbh_softc *)periph->softc;
436 
437 	softc->state = TARGBH_STATE_TEARDOWN;
438 
439 	targbhdislun(periph);
440 
441 	switch (softc->init_level) {
442 	case 0:
443 		panic("targdtor - impossible init level");;
444 	case 1:
445 		/* FALLTHROUGH */
446 	default:
447 		/* XXX Wait for callback of targbhdislun() */
448 		tsleep(softc, PRIBIO, "targbh", hz/2);
449 		free(softc, M_DEVBUF);
450 		break;
451 	}
452 }
453 
454 static void
455 targbhstart(struct cam_periph *periph, union ccb *start_ccb)
456 {
457 	struct targbh_softc *softc;
458 	struct ccb_hdr *ccbh;
459 	struct ccb_accept_tio *atio;
460 	struct targbh_cmd_desc *desc;
461 	struct ccb_scsiio *csio;
462 	ccb_flags flags;
463 	int    s;
464 
465 	softc = (struct targbh_softc *)periph->softc;
466 
467 	s = splbio();
468 	ccbh = TAILQ_FIRST(&softc->work_queue);
469 	if (periph->immediate_priority <= periph->pinfo.priority) {
470 		start_ccb->ccb_h.ccb_type = TARGBH_CCB_WAITING;
471 		SLIST_INSERT_HEAD(&periph->ccb_list, &start_ccb->ccb_h,
472 				  periph_links.sle);
473 		periph->immediate_priority = CAM_PRIORITY_NONE;
474 		splx(s);
475 		wakeup(&periph->ccb_list);
476 	} else if (ccbh == NULL) {
477 		splx(s);
478 		xpt_release_ccb(start_ccb);
479 	} else {
480 		TAILQ_REMOVE(&softc->work_queue, ccbh, periph_links.tqe);
481 		TAILQ_INSERT_HEAD(&softc->pending_queue, ccbh,
482 				  periph_links.tqe);
483 		splx(s);
484 		atio = (struct ccb_accept_tio*)ccbh;
485 		desc = (struct targbh_cmd_desc *)atio->ccb_h.ccb_descr;
486 
487 		/* Is this a tagged request? */
488 		flags = atio->ccb_h.flags &
489 		    (CAM_DIS_DISCONNECT|CAM_TAG_ACTION_VALID|CAM_DIR_MASK);
490 
491 		csio = &start_ccb->csio;
492 		/*
493 		 * If we are done with the transaction, tell the
494 		 * controller to send status and perform a CMD_CMPLT.
495 		 * If we have associated sense data, see if we can
496 		 * send that too.
497 		 */
498 		if (desc->data_resid == desc->data_increment) {
499 			flags |= CAM_SEND_STATUS;
500 			if (atio->sense_len) {
501 				csio->sense_len = atio->sense_len;
502 				csio->sense_data = atio->sense_data;
503 				flags |= CAM_SEND_SENSE;
504 			}
505 
506 		}
507 
508 		cam_fill_ctio(csio,
509 			      /*retries*/2,
510 			      targbhdone,
511 			      flags,
512 			      (flags & CAM_TAG_ACTION_VALID)?
513 				MSG_SIMPLE_Q_TAG : 0,
514 			      atio->tag_id,
515 			      atio->init_id,
516 			      desc->status,
517 			      /*data_ptr*/desc->data_increment == 0
518 					  ? NULL : desc->data,
519 			      /*dxfer_len*/desc->data_increment,
520 			      /*timeout*/desc->timeout);
521 
522 		/* Override our wildcard attachment */
523 		start_ccb->ccb_h.target_id = atio->ccb_h.target_id;
524 		start_ccb->ccb_h.target_lun = atio->ccb_h.target_lun;
525 
526 		start_ccb->ccb_h.ccb_type = TARGBH_CCB_WORKQ;
527 		start_ccb->ccb_h.ccb_atio = atio;
528 		CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
529 			  ("Sending a CTIO\n"));
530 		xpt_action(start_ccb);
531 		/*
532 		 * If the queue was frozen waiting for the response
533 		 * to this ATIO (for instance disconnection was disallowed),
534 		 * then release it now that our response has been queued.
535 		 */
536 		if ((atio->ccb_h.status & CAM_DEV_QFRZN) != 0) {
537 			cam_release_devq(periph->path,
538 					 /*relsim_flags*/0,
539 					 /*reduction*/0,
540 					 /*timeout*/0,
541 					 /*getcount_only*/0);
542 			atio->ccb_h.status &= ~CAM_DEV_QFRZN;
543 		}
544 		s = splbio();
545 		ccbh = TAILQ_FIRST(&softc->work_queue);
546 		splx(s);
547 	}
548 	if (ccbh != NULL)
549 		xpt_schedule(periph, /*priority*/1);
550 }
551 
552 static void
553 targbhdone(struct cam_periph *periph, union ccb *done_ccb)
554 {
555 	struct targbh_softc *softc;
556 
557 	softc = (struct targbh_softc *)periph->softc;
558 
559 	if (done_ccb->ccb_h.ccb_type == TARGBH_CCB_WAITING) {
560 		/* Caller will release the CCB */
561 		wakeup(&done_ccb->ccb_h.cbfcnp);
562 		return;
563 	}
564 
565 	switch (done_ccb->ccb_h.func_code) {
566 	case XPT_ACCEPT_TARGET_IO:
567 	{
568 		struct ccb_accept_tio *atio;
569 		struct targbh_cmd_desc *descr;
570 		u_int8_t *cdb;
571 		int priority;
572 
573 		atio = &done_ccb->atio;
574 		descr = (struct targbh_cmd_desc*)atio->ccb_h.ccb_descr;
575 		cdb = atio->cdb_io.cdb_bytes;
576 		if (softc->state == TARGBH_STATE_TEARDOWN
577 		 || atio->ccb_h.status == CAM_REQ_ABORTED) {
578 			targbhfreedescr(descr);
579 			free(done_ccb, M_DEVBUF);
580 			return;
581 		}
582 
583 		/*
584 		 * Determine the type of incoming command and
585 		 * setup our buffer for a response.
586 		 */
587 		switch (cdb[0]) {
588 		case INQUIRY:
589 		{
590 			struct scsi_inquiry *inq;
591 
592 			inq = (struct scsi_inquiry *)cdb;
593 			CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
594 				  ("Saw an inquiry!\n"));
595 			/*
596 			 * Validate the command.  We don't
597 			 * support any VPD pages, so complain
598 			 * if EVPD is set.
599 			 */
600 			if ((inq->byte2 & SI_EVPD) != 0
601 			 || inq->page_code != 0) {
602 				atio->ccb_h.flags &= ~CAM_DIR_MASK;
603 				atio->ccb_h.flags |= CAM_DIR_NONE;
604 				/*
605 				 * This needs to have other than a
606 				 * no_lun_sense_data response.
607 				 */
608 				atio->sense_data = no_lun_sense_data;
609 				atio->sense_len = sizeof(no_lun_sense_data);
610 				descr->data_resid = 0;
611 				descr->data_increment = 0;
612 				descr->status = SCSI_STATUS_CHECK_COND;
613 				break;
614 			}
615 			/*
616 			 * Direction is always relative
617 			 * to the initator.
618 			 */
619 			atio->ccb_h.flags &= ~CAM_DIR_MASK;
620 			atio->ccb_h.flags |= CAM_DIR_IN;
621 			descr->data = &no_lun_inq_data;
622 			descr->data_resid = MIN(sizeof(no_lun_inq_data),
623 						SCSI_CDB6_LEN(inq->length));
624 			descr->data_increment = descr->data_resid;
625 			descr->timeout = 5 * 1000;
626 			descr->status = SCSI_STATUS_OK;
627 			break;
628 		}
629 		case REQUEST_SENSE:
630 		{
631 			struct scsi_request_sense *rsense;
632 
633 			rsense = (struct scsi_request_sense *)cdb;
634 			/* Refer to static sense data */
635 			atio->ccb_h.flags &= ~CAM_DIR_MASK;
636 			atio->ccb_h.flags |= CAM_DIR_IN;
637 			descr->data = &no_lun_sense_data;
638 			descr->data_resid = request_sense_size;
639 			descr->data_resid = MIN(descr->data_resid,
640 						SCSI_CDB6_LEN(rsense->length));
641 			descr->data_increment = descr->data_resid;
642 			descr->timeout = 5 * 1000;
643 			descr->status = SCSI_STATUS_OK;
644 			break;
645 		}
646 		default:
647 			/* Constant CA, tell initiator */
648 			/* Direction is always relative to the initator */
649 			atio->ccb_h.flags &= ~CAM_DIR_MASK;
650 			atio->ccb_h.flags |= CAM_DIR_NONE;
651 			atio->sense_data = no_lun_sense_data;
652 			atio->sense_len = sizeof (no_lun_sense_data);
653 			descr->data_resid = 0;
654 			descr->data_increment = 0;
655 			descr->timeout = 5 * 1000;
656 			descr->status = SCSI_STATUS_CHECK_COND;
657 			break;
658 		}
659 
660 		/* Queue us up to receive a Continue Target I/O ccb. */
661 		if ((atio->ccb_h.flags & CAM_DIS_DISCONNECT) != 0) {
662 			TAILQ_INSERT_HEAD(&softc->work_queue, &atio->ccb_h,
663 					  periph_links.tqe);
664 			priority = 0;
665 		} else {
666 			TAILQ_INSERT_TAIL(&softc->work_queue, &atio->ccb_h,
667 					  periph_links.tqe);
668 			priority = 1;
669 		}
670 		xpt_schedule(periph, priority);
671 		break;
672 	}
673 	case XPT_CONT_TARGET_IO:
674 	{
675 		struct ccb_accept_tio *atio;
676 		struct targbh_cmd_desc *desc;
677 
678 		CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
679 			  ("Received completed CTIO\n"));
680 		atio = (struct ccb_accept_tio*)done_ccb->ccb_h.ccb_atio;
681 		desc = (struct targbh_cmd_desc *)atio->ccb_h.ccb_descr;
682 
683 		TAILQ_REMOVE(&softc->pending_queue, &atio->ccb_h,
684 			     periph_links.tqe);
685 
686 		/*
687 		 * We could check for CAM_SENT_SENSE bein set here,
688 		 * but since we're not maintaining any CA/UA state,
689 		 * there's no point.
690 		 */
691 		atio->sense_len = 0;
692 		done_ccb->ccb_h.flags &= ~CAM_SEND_SENSE;
693 		done_ccb->ccb_h.status &= ~CAM_SENT_SENSE;
694 
695 		/*
696 		 * Any errors will not change the data we return,
697 		 * so make sure the queue is not left frozen.
698 		 * XXX - At some point there may be errors that
699 		 *       leave us in a connected state with the
700 		 *       initiator...
701 		 */
702 		if ((done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0) {
703 			printf("Releasing Queue\n");
704 			cam_release_devq(done_ccb->ccb_h.path,
705 					 /*relsim_flags*/0,
706 					 /*reduction*/0,
707 					 /*timeout*/0,
708 					 /*getcount_only*/0);
709 			done_ccb->ccb_h.status &= ~CAM_DEV_QFRZN;
710 		}
711 		desc->data_resid -= desc->data_increment;
712 		xpt_release_ccb(done_ccb);
713 		if (softc->state != TARGBH_STATE_TEARDOWN) {
714 
715 			/*
716 			 * Send the original accept TIO back to the
717 			 * controller to handle more work.
718 			 */
719 			CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
720 				  ("Returning ATIO to target\n"));
721 			/* Restore wildcards */
722 			atio->ccb_h.target_id = CAM_TARGET_WILDCARD;
723 			atio->ccb_h.target_lun = CAM_LUN_WILDCARD;
724 			xpt_action((union ccb *)atio);
725 			break;
726 		} else {
727 			targbhfreedescr(desc);
728 			free(atio, M_DEVBUF);
729 		}
730 		break;
731 	}
732 	case XPT_IMMED_NOTIFY:
733 	{
734 		int frozen;
735 
736 		frozen = (done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0;
737 		if (softc->state == TARGBH_STATE_TEARDOWN
738 		 || done_ccb->ccb_h.status == CAM_REQ_ABORTED) {
739 			printf("Freed an immediate notify\n");
740 			free(done_ccb, M_DEVBUF);
741 		} else {
742 			/* Requeue for another immediate event */
743 			xpt_action(done_ccb);
744 		}
745 		if (frozen != 0)
746 			cam_release_devq(periph->path,
747 					 /*relsim_flags*/0,
748 					 /*opening reduction*/0,
749 					 /*timeout*/0,
750 					 /*getcount_only*/0);
751 		break;
752 	}
753 	default:
754 		panic("targbhdone: Unexpected ccb opcode");
755 		break;
756 	}
757 }
758 
759 #ifdef NOTYET
760 static int
761 targbherror(union ccb *ccb, u_int32_t cam_flags, u_int32_t sense_flags)
762 {
763 	return 0;
764 }
765 #endif
766 
767 static struct targbh_cmd_desc*
768 targbhallocdescr()
769 {
770 	struct targbh_cmd_desc* descr;
771 
772 	/* Allocate the targbh_descr structure */
773 	descr = (struct targbh_cmd_desc *)malloc(sizeof(*descr),
774 					       M_DEVBUF, M_NOWAIT);
775 	if (descr == NULL)
776 		return (NULL);
777 
778 	bzero(descr, sizeof(*descr));
779 
780 	/* Allocate buffer backing store */
781 	descr->backing_store = malloc(MAX_BUF_SIZE, M_DEVBUF, M_NOWAIT);
782 	if (descr->backing_store == NULL) {
783 		free(descr, M_DEVBUF);
784 		return (NULL);
785 	}
786 	descr->max_size = MAX_BUF_SIZE;
787 	return (descr);
788 }
789 
790 static void
791 targbhfreedescr(struct targbh_cmd_desc *descr)
792 {
793 	free(descr->backing_store, M_DEVBUF);
794 	free(descr, M_DEVBUF);
795 }
796