xref: /freebsd/sys/cam/scsi/scsi_targ_bh.c (revision 031beb4e239bfce798af17f5fe8dba8bcaf13d99)
1 /*-
2  * Implementation of the Target Mode 'Black Hole device' for CAM.
3  *
4  * SPDX-License-Identifier: BSD-2-Clause
5  *
6  * Copyright (c) 1999 Justin T. Gibbs.
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions, and the following disclaimer,
14  *    without modification, immediately at the beginning of the file.
15  * 2. The name of the author may not be used to endorse or promote products
16  *    derived from this software without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
22  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  */
30 
31 #include <sys/cdefs.h>
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 #include <cam/cam_sim.h>
50 
51 #include <cam/scsi/scsi_all.h>
52 #include <cam/scsi/scsi_message.h>
53 
54 static MALLOC_DEFINE(M_SCSIBH, "SCSI bh", "SCSI blackhole buffers");
55 
56 typedef enum {
57 	TARGBH_STATE_NORMAL,
58 	TARGBH_STATE_EXCEPTION,
59 	TARGBH_STATE_TEARDOWN
60 } targbh_state;
61 
62 typedef enum {
63 	TARGBH_FLAG_NONE	 = 0x00,
64 	TARGBH_FLAG_LUN_ENABLED	 = 0x01
65 } targbh_flags;
66 
67 typedef enum {
68 	TARGBH_CCB_WORKQ
69 } targbh_ccb_types;
70 
71 #define MAX_ACCEPT	8
72 #define MAX_IMMEDIATE	16
73 #define MAX_BUF_SIZE	256	/* Max inquiry/sense/mode page transfer */
74 
75 /* Offsets into our private CCB area for storing accept information */
76 #define ccb_type	ppriv_field0
77 #define ccb_descr	ppriv_ptr1
78 
79 /* We stick a pointer to the originating accept TIO in each continue I/O CCB */
80 #define ccb_atio	ppriv_ptr1
81 
82 TAILQ_HEAD(ccb_queue, ccb_hdr);
83 
84 struct targbh_softc {
85 	struct		ccb_queue pending_queue;
86 	struct		ccb_queue work_queue;
87 	struct		ccb_queue unknown_atio_queue;
88 	struct		devstat device_stats;
89 	targbh_state	state;
90 	targbh_flags	flags;
91 	u_int		init_level;
92 	u_int		inq_data_len;
93 	struct		ccb_accept_tio *accept_tio_list;
94 	struct		ccb_hdr_slist immed_notify_slist;
95 };
96 
97 struct targbh_cmd_desc {
98 	struct	  ccb_accept_tio* atio_link;
99 	u_int	  data_resid;	/* How much left to transfer */
100 	u_int	  data_increment;/* Amount to send before next disconnect */
101 	void*	  data;		/* The data. Can be from backing_store or not */
102 	void*	  backing_store;/* Backing store allocated for this descriptor*/
103 	u_int	  max_size;	/* Size of backing_store */
104 	uint32_t timeout;
105 	uint8_t  status;	/* Status to return to initiator */
106 };
107 
108 static struct scsi_inquiry_data no_lun_inq_data =
109 {
110 	T_NODEVICE | (SID_QUAL_BAD_LU << 5), 0,
111 	/* version */2, /* format version */2
112 };
113 
114 static struct scsi_sense_data_fixed no_lun_sense_data =
115 {
116 	SSD_CURRENT_ERROR|SSD_ERRCODE_VALID,
117 	0,
118 	SSD_KEY_NOT_READY,
119 	{ 0, 0, 0, 0 },
120 	/*extra_len*/offsetof(struct scsi_sense_data_fixed, fru)
121                    - offsetof(struct scsi_sense_data_fixed, extra_len),
122 	{ 0, 0, 0, 0 },
123 	/* Logical Unit Not Supported */
124 	/*ASC*/0x25, /*ASCQ*/0
125 };
126 
127 static const int request_sense_size = offsetof(struct scsi_sense_data_fixed, fru);
128 
129 static periph_init_t	targbhinit;
130 static void		targbhasync(void *callback_arg, uint32_t code,
131 				    struct cam_path *path, void *arg);
132 static cam_status	targbhenlun(struct cam_periph *periph);
133 static cam_status	targbhdislun(struct cam_periph *periph);
134 static periph_ctor_t	targbhctor;
135 static periph_dtor_t	targbhdtor;
136 static periph_start_t	targbhstart;
137 static void		targbhdone(struct cam_periph *periph,
138 				   union ccb *done_ccb);
139 #ifdef NOTYET
140 static  int		targbherror(union ccb *ccb, uint32_t cam_flags,
141 				    uint32_t sense_flags);
142 #endif
143 static struct targbh_cmd_desc*	targbhallocdescr(void);
144 static void		targbhfreedescr(struct targbh_cmd_desc *buf);
145 
146 static struct periph_driver targbhdriver =
147 {
148 	targbhinit, "targbh",
149 	TAILQ_HEAD_INITIALIZER(targbhdriver.units), /* generation */ 0
150 };
151 
152 PERIPHDRIVER_DECLARE(targbh, targbhdriver);
153 
154 static void
155 targbhinit(void)
156 {
157 	cam_status status;
158 
159 	/*
160 	 * Install a global async callback.  This callback will
161 	 * receive async callbacks like "new path registered".
162 	 */
163 	status = xpt_register_async(AC_PATH_REGISTERED | AC_PATH_DEREGISTERED,
164 				    targbhasync, NULL, NULL);
165 
166 	if (status != CAM_REQ_CMP) {
167 		printf("targbh: Failed to attach master async callback "
168 		       "due to status 0x%x!\n", status);
169 	}
170 }
171 
172 static void
173 targbhasync(void *callback_arg, uint32_t code,
174 	    struct cam_path *path, void *arg)
175 {
176 	struct cam_path *new_path;
177 	struct ccb_pathinq *cpi;
178 	path_id_t bus_path_id;
179 	cam_status status;
180 
181 	cpi = (struct ccb_pathinq *)arg;
182 	if (code == AC_PATH_REGISTERED)
183 		bus_path_id = cpi->ccb_h.path_id;
184 	else
185 		bus_path_id = xpt_path_path_id(path);
186 	/*
187 	 * Allocate a peripheral instance for
188 	 * this target instance.
189 	 */
190 	status = xpt_create_path(&new_path, NULL,
191 				 bus_path_id,
192 				 CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD);
193 	if (status != CAM_REQ_CMP) {
194 		printf("targbhasync: Unable to create path "
195 			"due to status 0x%x\n", status);
196 		return;
197 	}
198 
199 	switch (code) {
200 	case AC_PATH_REGISTERED:
201 	{
202 		/* Only attach to controllers that support target mode */
203 		if ((cpi->target_sprt & PIT_PROCESSOR) == 0)
204 			break;
205 
206 		status = cam_periph_alloc(targbhctor, NULL, targbhdtor,
207 					  targbhstart,
208 					  "targbh", CAM_PERIPH_BIO,
209 					  new_path, targbhasync,
210 					  AC_PATH_REGISTERED,
211 					  cpi);
212 		break;
213 	}
214 	case AC_PATH_DEREGISTERED:
215 	{
216 		struct cam_periph *periph;
217 
218 		if ((periph = cam_periph_find(new_path, "targbh")) != NULL)
219 			cam_periph_invalidate(periph);
220 		break;
221 	}
222 	default:
223 		break;
224 	}
225 	xpt_free_path(new_path);
226 }
227 
228 /* Attempt to enable our lun */
229 static cam_status
230 targbhenlun(struct cam_periph *periph)
231 {
232 	union ccb immed_ccb;
233 	struct targbh_softc *softc;
234 	cam_status status;
235 	int i;
236 
237 	softc = (struct targbh_softc *)periph->softc;
238 
239 	if ((softc->flags & TARGBH_FLAG_LUN_ENABLED) != 0)
240 		return (CAM_REQ_CMP);
241 
242 	memset(&immed_ccb, 0, sizeof(immed_ccb));
243 	xpt_setup_ccb(&immed_ccb.ccb_h, periph->path, CAM_PRIORITY_NORMAL);
244 	immed_ccb.ccb_h.func_code = XPT_EN_LUN;
245 
246 	/* Don't need support for any vendor specific commands */
247 	immed_ccb.cel.grp6_len = 0;
248 	immed_ccb.cel.grp7_len = 0;
249 	immed_ccb.cel.enable = 1;
250 	xpt_action(&immed_ccb);
251 	status = immed_ccb.ccb_h.status;
252 	if (status != CAM_REQ_CMP) {
253 		xpt_print(periph->path,
254 		    "targbhenlun - Enable Lun Rejected with status 0x%x\n",
255 		    status);
256 		return (status);
257 	}
258 
259 	softc->flags |= TARGBH_FLAG_LUN_ENABLED;
260 
261 	/*
262 	 * Build up a buffer of accept target I/O
263 	 * operations for incoming selections.
264 	 */
265 	for (i = 0; i < MAX_ACCEPT; i++) {
266 		struct ccb_accept_tio *atio;
267 
268 		atio = (struct ccb_accept_tio*)malloc(sizeof(*atio), M_SCSIBH,
269 						      M_ZERO | M_NOWAIT);
270 		if (atio == NULL) {
271 			status = CAM_RESRC_UNAVAIL;
272 			break;
273 		}
274 
275 		atio->ccb_h.ccb_descr = targbhallocdescr();
276 
277 		if (atio->ccb_h.ccb_descr == NULL) {
278 			free(atio, M_SCSIBH);
279 			status = CAM_RESRC_UNAVAIL;
280 			break;
281 		}
282 
283 		xpt_setup_ccb(&atio->ccb_h, periph->path, CAM_PRIORITY_NORMAL);
284 		atio->ccb_h.func_code = XPT_ACCEPT_TARGET_IO;
285 		atio->ccb_h.cbfcnp = targbhdone;
286 		((struct targbh_cmd_desc*)atio->ccb_h.ccb_descr)->atio_link =
287 		    softc->accept_tio_list;
288 		softc->accept_tio_list = atio;
289 		xpt_action((union ccb *)atio);
290 		status = atio->ccb_h.status;
291 		if (status != CAM_REQ_INPROG)
292 			break;
293 	}
294 
295 	if (i == 0) {
296 		xpt_print(periph->path,
297 		    "targbhenlun - Could not allocate accept tio CCBs: status "
298 		    "= 0x%x\n", status);
299 		targbhdislun(periph);
300 		return (CAM_REQ_CMP_ERR);
301 	}
302 
303 	/*
304 	 * Build up a buffer of immediate notify CCBs
305 	 * so the SIM can tell us of asynchronous target mode events.
306 	 */
307 	for (i = 0; i < MAX_ACCEPT; i++) {
308 		struct ccb_immediate_notify *inot;
309 
310 		inot = (struct ccb_immediate_notify*)malloc(sizeof(*inot),
311 			    M_SCSIBH, M_ZERO | M_NOWAIT);
312 
313 		if (inot == NULL) {
314 			status = CAM_RESRC_UNAVAIL;
315 			break;
316 		}
317 
318 		xpt_setup_ccb(&inot->ccb_h, periph->path, CAM_PRIORITY_NORMAL);
319 		inot->ccb_h.func_code = XPT_IMMEDIATE_NOTIFY;
320 		inot->ccb_h.cbfcnp = targbhdone;
321 		SLIST_INSERT_HEAD(&softc->immed_notify_slist, &inot->ccb_h,
322 				  periph_links.sle);
323 		xpt_action((union ccb *)inot);
324 		status = inot->ccb_h.status;
325 		if (status != CAM_REQ_INPROG)
326 			break;
327 	}
328 
329 	if (i == 0) {
330 		xpt_print(periph->path,
331 		    "targbhenlun - Could not allocate immediate notify "
332 		    "CCBs: status = 0x%x\n", status);
333 		targbhdislun(periph);
334 		return (CAM_REQ_CMP_ERR);
335 	}
336 
337 	return (CAM_REQ_CMP);
338 }
339 
340 static cam_status
341 targbhdislun(struct cam_periph *periph)
342 {
343 	union ccb ccb;
344 	struct targbh_softc *softc;
345 	struct ccb_accept_tio* atio;
346 	struct ccb_hdr *ccb_h;
347 
348 	softc = (struct targbh_softc *)periph->softc;
349 	if ((softc->flags & TARGBH_FLAG_LUN_ENABLED) == 0)
350 		return CAM_REQ_CMP;
351 
352 	memset(&ccb, 0, sizeof(ccb));
353 
354 	/* XXX Block for Continue I/O completion */
355 
356 	/* Kill off all ACCECPT and IMMEDIATE CCBs */
357 	while ((atio = softc->accept_tio_list) != NULL) {
358 
359 		softc->accept_tio_list =
360 		    ((struct targbh_cmd_desc*)atio->ccb_h.ccb_descr)->atio_link;
361 		xpt_setup_ccb(&ccb.cab.ccb_h, periph->path, CAM_PRIORITY_NORMAL);
362 		ccb.cab.ccb_h.func_code = XPT_ABORT;
363 		ccb.cab.abort_ccb = (union ccb *)atio;
364 		xpt_action(&ccb);
365 	}
366 
367 	while ((ccb_h = SLIST_FIRST(&softc->immed_notify_slist)) != NULL) {
368 		SLIST_REMOVE_HEAD(&softc->immed_notify_slist, periph_links.sle);
369 		xpt_setup_ccb(&ccb.cab.ccb_h, periph->path, CAM_PRIORITY_NORMAL);
370 		ccb.cab.ccb_h.func_code = XPT_ABORT;
371 		ccb.cab.abort_ccb = (union ccb *)ccb_h;
372 		xpt_action(&ccb);
373 	}
374 
375 	/*
376 	 * Dissable this lun.
377 	 */
378 	xpt_setup_ccb(&ccb.cel.ccb_h, periph->path, CAM_PRIORITY_NORMAL);
379 	ccb.cel.ccb_h.func_code = XPT_EN_LUN;
380 	ccb.cel.enable = 0;
381 	xpt_action(&ccb);
382 
383 	if (ccb.cel.ccb_h.status != CAM_REQ_CMP)
384 		printf("targbhdislun - Disabling lun on controller failed "
385 		       "with status 0x%x\n", ccb.cel.ccb_h.status);
386 	else
387 		softc->flags &= ~TARGBH_FLAG_LUN_ENABLED;
388 	return (ccb.cel.ccb_h.status);
389 }
390 
391 static cam_status
392 targbhctor(struct cam_periph *periph, void *arg)
393 {
394 	struct targbh_softc *softc;
395 
396 	/* Allocate our per-instance private storage */
397 	softc = (struct targbh_softc *)malloc(sizeof(*softc),
398 					      M_SCSIBH, M_NOWAIT);
399 	if (softc == NULL) {
400 		printf("targctor: unable to malloc softc\n");
401 		return (CAM_REQ_CMP_ERR);
402 	}
403 
404 	bzero(softc, sizeof(*softc));
405 	TAILQ_INIT(&softc->pending_queue);
406 	TAILQ_INIT(&softc->work_queue);
407 	softc->accept_tio_list = NULL;
408 	SLIST_INIT(&softc->immed_notify_slist);
409 	softc->state = TARGBH_STATE_NORMAL;
410 	periph->softc = softc;
411 	softc->init_level++;
412 
413 	if (targbhenlun(periph) != CAM_REQ_CMP)
414 		cam_periph_invalidate(periph);
415 	return (CAM_REQ_CMP);
416 }
417 
418 static void
419 targbhdtor(struct cam_periph *periph)
420 {
421 	struct targbh_softc *softc;
422 
423 	softc = (struct targbh_softc *)periph->softc;
424 
425 	softc->state = TARGBH_STATE_TEARDOWN;
426 
427 	targbhdislun(periph);
428 
429 	switch (softc->init_level) {
430 	case 0:
431 		panic("targdtor - impossible init level");
432 	case 1:
433 		/* FALLTHROUGH */
434 	default:
435 		/* XXX Wait for callback of targbhdislun() */
436 		cam_periph_sleep(periph, softc, PRIBIO, "targbh", hz/2);
437 		free(softc, M_SCSIBH);
438 		break;
439 	}
440 }
441 
442 static void
443 targbhstart(struct cam_periph *periph, union ccb *start_ccb)
444 {
445 	struct targbh_softc *softc;
446 	struct ccb_hdr *ccbh;
447 	struct ccb_accept_tio *atio;
448 	struct targbh_cmd_desc *desc;
449 	struct ccb_scsiio *csio;
450 	ccb_flags flags;
451 
452 	softc = (struct targbh_softc *)periph->softc;
453 
454 	ccbh = TAILQ_FIRST(&softc->work_queue);
455 	if (ccbh == NULL) {
456 		xpt_release_ccb(start_ccb);
457 	} else {
458 		TAILQ_REMOVE(&softc->work_queue, ccbh, periph_links.tqe);
459 		TAILQ_INSERT_HEAD(&softc->pending_queue, ccbh,
460 				  periph_links.tqe);
461 		atio = (struct ccb_accept_tio*)ccbh;
462 		desc = (struct targbh_cmd_desc *)atio->ccb_h.ccb_descr;
463 
464 		/* Is this a tagged request? */
465 		flags = atio->ccb_h.flags &
466 		    (CAM_DIS_DISCONNECT|CAM_TAG_ACTION_VALID|CAM_DIR_MASK);
467 
468 		csio = &start_ccb->csio;
469 		/*
470 		 * If we are done with the transaction, tell the
471 		 * controller to send status and perform a CMD_CMPLT.
472 		 * If we have associated sense data, see if we can
473 		 * send that too.
474 		 */
475 		if (desc->data_resid == desc->data_increment) {
476 			flags |= CAM_SEND_STATUS;
477 			if (atio->sense_len) {
478 				csio->sense_len = atio->sense_len;
479 				csio->sense_data = atio->sense_data;
480 				flags |= CAM_SEND_SENSE;
481 			}
482 		}
483 
484 		cam_fill_ctio(csio,
485 			      /*retries*/2,
486 			      targbhdone,
487 			      flags,
488 			      (flags & CAM_TAG_ACTION_VALID)?
489 				MSG_SIMPLE_Q_TAG : 0,
490 			      atio->tag_id,
491 			      atio->init_id,
492 			      desc->status,
493 			      /*data_ptr*/desc->data_increment == 0
494 					  ? NULL : desc->data,
495 			      /*dxfer_len*/desc->data_increment,
496 			      /*timeout*/desc->timeout);
497 
498 		/* Override our wildcard attachment */
499 		start_ccb->ccb_h.target_id = atio->ccb_h.target_id;
500 		start_ccb->ccb_h.target_lun = atio->ccb_h.target_lun;
501 
502 		start_ccb->ccb_h.ccb_type = TARGBH_CCB_WORKQ;
503 		start_ccb->ccb_h.ccb_atio = atio;
504 		CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
505 			  ("Sending a CTIO\n"));
506 		xpt_action(start_ccb);
507 		/*
508 		 * If the queue was frozen waiting for the response
509 		 * to this ATIO (for instance disconnection was disallowed),
510 		 * then release it now that our response has been queued.
511 		 */
512 		if ((atio->ccb_h.status & CAM_DEV_QFRZN) != 0) {
513 			cam_release_devq(periph->path,
514 					 /*relsim_flags*/0,
515 					 /*reduction*/0,
516 					 /*timeout*/0,
517 					 /*getcount_only*/0);
518 			atio->ccb_h.status &= ~CAM_DEV_QFRZN;
519 		}
520 		ccbh = TAILQ_FIRST(&softc->work_queue);
521 	}
522 	if (ccbh != NULL)
523 		xpt_schedule(periph, CAM_PRIORITY_NORMAL);
524 }
525 
526 static void
527 targbhdone(struct cam_periph *periph, union ccb *done_ccb)
528 {
529 	struct targbh_softc *softc;
530 
531 	softc = (struct targbh_softc *)periph->softc;
532 
533 	switch (done_ccb->ccb_h.func_code) {
534 	case XPT_ACCEPT_TARGET_IO:
535 	{
536 		struct ccb_accept_tio *atio;
537 		struct targbh_cmd_desc *descr;
538 		uint8_t *cdb;
539 		int priority;
540 
541 		atio = &done_ccb->atio;
542 		descr = (struct targbh_cmd_desc*)atio->ccb_h.ccb_descr;
543 		cdb = atio->cdb_io.cdb_bytes;
544 		if (softc->state == TARGBH_STATE_TEARDOWN
545 		 || atio->ccb_h.status == CAM_REQ_ABORTED) {
546 			targbhfreedescr(descr);
547 			xpt_free_ccb(done_ccb);
548 			return;
549 		}
550 
551 		/*
552 		 * Determine the type of incoming command and
553 		 * setup our buffer for a response.
554 		 */
555 		switch (cdb[0]) {
556 		case INQUIRY:
557 		{
558 			struct scsi_inquiry *inq;
559 
560 			inq = (struct scsi_inquiry *)cdb;
561 			CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
562 				  ("Saw an inquiry!\n"));
563 			/*
564 			 * Validate the command.  We don't
565 			 * support any VPD pages, so complain
566 			 * if EVPD is set.
567 			 */
568 			if ((inq->byte2 & SI_EVPD) != 0
569 			 || inq->page_code != 0) {
570 				atio->ccb_h.flags &= ~CAM_DIR_MASK;
571 				atio->ccb_h.flags |= CAM_DIR_NONE;
572 				/*
573 				 * This needs to have other than a
574 				 * no_lun_sense_data response.
575 				 */
576 				bcopy(&no_lun_sense_data, &atio->sense_data,
577 				      min(sizeof(no_lun_sense_data),
578 					  sizeof(atio->sense_data)));
579 				atio->sense_len = sizeof(no_lun_sense_data);
580 				descr->data_resid = 0;
581 				descr->data_increment = 0;
582 				descr->status = SCSI_STATUS_CHECK_COND;
583 				break;
584 			}
585 			/*
586 			 * Direction is always relative
587 			 * to the initator.
588 			 */
589 			atio->ccb_h.flags &= ~CAM_DIR_MASK;
590 			atio->ccb_h.flags |= CAM_DIR_IN;
591 			descr->data = &no_lun_inq_data;
592 			descr->data_resid = MIN(sizeof(no_lun_inq_data),
593 						scsi_2btoul(inq->length));
594 			descr->data_increment = descr->data_resid;
595 			descr->timeout = 5 * 1000;
596 			descr->status = SCSI_STATUS_OK;
597 			break;
598 		}
599 		case REQUEST_SENSE:
600 		{
601 			struct scsi_request_sense *rsense;
602 
603 			rsense = (struct scsi_request_sense *)cdb;
604 			/* Refer to static sense data */
605 			atio->ccb_h.flags &= ~CAM_DIR_MASK;
606 			atio->ccb_h.flags |= CAM_DIR_IN;
607 			descr->data = &no_lun_sense_data;
608 			descr->data_resid = request_sense_size;
609 			descr->data_resid = MIN(descr->data_resid,
610 						SCSI_CDB6_LEN(rsense->length));
611 			descr->data_increment = descr->data_resid;
612 			descr->timeout = 5 * 1000;
613 			descr->status = SCSI_STATUS_OK;
614 			break;
615 		}
616 		default:
617 			/* Constant CA, tell initiator */
618 			/* Direction is always relative to the initator */
619 			atio->ccb_h.flags &= ~CAM_DIR_MASK;
620 			atio->ccb_h.flags |= CAM_DIR_NONE;
621 			bcopy(&no_lun_sense_data, &atio->sense_data,
622 			      min(sizeof(no_lun_sense_data),
623 				  sizeof(atio->sense_data)));
624 			atio->sense_len = sizeof (no_lun_sense_data);
625 			descr->data_resid = 0;
626 			descr->data_increment = 0;
627 			descr->timeout = 5 * 1000;
628 			descr->status = SCSI_STATUS_CHECK_COND;
629 			break;
630 		}
631 
632 		/* Queue us up to receive a Continue Target I/O ccb. */
633 		if ((atio->ccb_h.flags & CAM_DIS_DISCONNECT) != 0) {
634 			TAILQ_INSERT_HEAD(&softc->work_queue, &atio->ccb_h,
635 					  periph_links.tqe);
636 			priority = 0;
637 		} else {
638 			TAILQ_INSERT_TAIL(&softc->work_queue, &atio->ccb_h,
639 					  periph_links.tqe);
640 			priority = CAM_PRIORITY_NORMAL;
641 		}
642 		xpt_schedule(periph, priority);
643 		break;
644 	}
645 	case XPT_CONT_TARGET_IO:
646 	{
647 		struct ccb_accept_tio *atio;
648 		struct targbh_cmd_desc *desc;
649 
650 		CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
651 			  ("Received completed CTIO\n"));
652 		atio = (struct ccb_accept_tio*)done_ccb->ccb_h.ccb_atio;
653 		desc = (struct targbh_cmd_desc *)atio->ccb_h.ccb_descr;
654 
655 		TAILQ_REMOVE(&softc->pending_queue, &atio->ccb_h,
656 			     periph_links.tqe);
657 
658 		/*
659 		 * We could check for CAM_SENT_SENSE bein set here,
660 		 * but since we're not maintaining any CA/UA state,
661 		 * there's no point.
662 		 */
663 		atio->sense_len = 0;
664 		done_ccb->ccb_h.flags &= ~CAM_SEND_SENSE;
665 		done_ccb->ccb_h.status &= ~CAM_SENT_SENSE;
666 
667 		/*
668 		 * Any errors will not change the data we return,
669 		 * so make sure the queue is not left frozen.
670 		 * XXX - At some point there may be errors that
671 		 *       leave us in a connected state with the
672 		 *       initiator...
673 		 */
674 		if ((done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0) {
675 			printf("Releasing Queue\n");
676 			cam_release_devq(done_ccb->ccb_h.path,
677 					 /*relsim_flags*/0,
678 					 /*reduction*/0,
679 					 /*timeout*/0,
680 					 /*getcount_only*/0);
681 			done_ccb->ccb_h.status &= ~CAM_DEV_QFRZN;
682 		}
683 		desc->data_resid -= desc->data_increment;
684 		xpt_release_ccb(done_ccb);
685 		if (softc->state != TARGBH_STATE_TEARDOWN) {
686 			/*
687 			 * Send the original accept TIO back to the
688 			 * controller to handle more work.
689 			 */
690 			CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
691 				  ("Returning ATIO to target\n"));
692 			/* Restore wildcards */
693 			atio->ccb_h.target_id = CAM_TARGET_WILDCARD;
694 			atio->ccb_h.target_lun = CAM_LUN_WILDCARD;
695 			xpt_action((union ccb *)atio);
696 			break;
697 		} else {
698 			targbhfreedescr(desc);
699 			free(atio, M_SCSIBH);
700 		}
701 		break;
702 	}
703 	case XPT_IMMEDIATE_NOTIFY:
704 	{
705 		int frozen;
706 
707 		frozen = (done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0;
708 		if (softc->state == TARGBH_STATE_TEARDOWN
709 		 || done_ccb->ccb_h.status == CAM_REQ_ABORTED) {
710 			printf("Freed an immediate notify\n");
711 			xpt_free_ccb(done_ccb);
712 		} else {
713 			/* Requeue for another immediate event */
714 			xpt_action(done_ccb);
715 		}
716 		if (frozen != 0)
717 			cam_release_devq(periph->path,
718 					 /*relsim_flags*/0,
719 					 /*opening reduction*/0,
720 					 /*timeout*/0,
721 					 /*getcount_only*/0);
722 		break;
723 	}
724 	default:
725 		panic("targbhdone: Unexpected ccb opcode");
726 		break;
727 	}
728 }
729 
730 #ifdef NOTYET
731 static int
732 targbherror(union ccb *ccb, uint32_t cam_flags, uint32_t sense_flags)
733 {
734 	return 0;
735 }
736 #endif
737 
738 static struct targbh_cmd_desc*
739 targbhallocdescr(void)
740 {
741 	struct targbh_cmd_desc* descr;
742 
743 	/* Allocate the targbh_descr structure */
744 	descr = (struct targbh_cmd_desc *)malloc(sizeof(*descr),
745 					       M_SCSIBH, M_NOWAIT);
746 	if (descr == NULL)
747 		return (NULL);
748 
749 	bzero(descr, sizeof(*descr));
750 
751 	/* Allocate buffer backing store */
752 	descr->backing_store = malloc(MAX_BUF_SIZE, M_SCSIBH, M_NOWAIT);
753 	if (descr->backing_store == NULL) {
754 		free(descr, M_SCSIBH);
755 		return (NULL);
756 	}
757 	descr->max_size = MAX_BUF_SIZE;
758 	return (descr);
759 }
760 
761 static void
762 targbhfreedescr(struct targbh_cmd_desc *descr)
763 {
764 	free(descr->backing_store, M_SCSIBH);
765 	free(descr, M_SCSIBH);
766 }
767