xref: /freebsd/sys/cam/scsi/scsi_targ_bh.c (revision 8aac90f18aef7c9eea906c3ff9a001ca7b94f375)
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/param.h>
32 #include <sys/queue.h>
33 #include <sys/systm.h>
34 #include <sys/kernel.h>
35 #include <sys/types.h>
36 #include <sys/bio.h>
37 #include <sys/conf.h>
38 #include <sys/devicestat.h>
39 #include <sys/malloc.h>
40 #include <sys/uio.h>
41 
42 #include <cam/cam.h>
43 #include <cam/cam_ccb.h>
44 #include <cam/cam_periph.h>
45 #include <cam/cam_queue.h>
46 #include <cam/cam_xpt_periph.h>
47 #include <cam/cam_debug.h>
48 #include <cam/cam_sim.h>
49 
50 #include <cam/scsi/scsi_all.h>
51 #include <cam/scsi/scsi_message.h>
52 
53 static MALLOC_DEFINE(M_SCSIBH, "SCSI bh", "SCSI blackhole buffers");
54 
55 typedef enum {
56 	TARGBH_STATE_NORMAL,
57 	TARGBH_STATE_EXCEPTION,
58 	TARGBH_STATE_TEARDOWN
59 } targbh_state;
60 
61 typedef enum {
62 	TARGBH_FLAG_NONE	 = 0x00,
63 	TARGBH_FLAG_LUN_ENABLED	 = 0x01
64 } targbh_flags;
65 
66 typedef enum {
67 	TARGBH_CCB_WORKQ
68 } targbh_ccb_types;
69 
70 #define MAX_ACCEPT	8
71 #define MAX_IMMEDIATE	16
72 #define MAX_BUF_SIZE	256	/* Max inquiry/sense/mode page transfer */
73 
74 /* Offsets into our private CCB area for storing accept information */
75 #define ccb_type	ppriv_field0
76 #define ccb_descr	ppriv_ptr1
77 
78 /* We stick a pointer to the originating accept TIO in each continue I/O CCB */
79 #define ccb_atio	ppriv_ptr1
80 
81 TAILQ_HEAD(ccb_queue, ccb_hdr);
82 
83 struct targbh_softc {
84 	struct		ccb_queue pending_queue;
85 	struct		ccb_queue work_queue;
86 	struct		ccb_queue unknown_atio_queue;
87 	struct		devstat device_stats;
88 	targbh_state	state;
89 	targbh_flags	flags;
90 	u_int		init_level;
91 	u_int		inq_data_len;
92 	struct		ccb_accept_tio *accept_tio_list;
93 	struct		ccb_hdr_slist immed_notify_slist;
94 };
95 
96 struct targbh_cmd_desc {
97 	struct	  ccb_accept_tio* atio_link;
98 	u_int	  data_resid;	/* How much left to transfer */
99 	u_int	  data_increment;/* Amount to send before next disconnect */
100 	void*	  data;		/* The data. Can be from backing_store or not */
101 	void*	  backing_store;/* Backing store allocated for this descriptor*/
102 	u_int	  max_size;	/* Size of backing_store */
103 	uint32_t timeout;
104 	uint8_t  status;	/* Status to return to initiator */
105 };
106 
107 static struct scsi_inquiry_data no_lun_inq_data =
108 {
109 	T_NODEVICE | (SID_QUAL_BAD_LU << 5), 0,
110 	/* version */2, /* format version */2
111 };
112 
113 static struct scsi_sense_data_fixed no_lun_sense_data =
114 {
115 	SSD_CURRENT_ERROR|SSD_ERRCODE_VALID,
116 	0,
117 	SSD_KEY_NOT_READY,
118 	{ 0, 0, 0, 0 },
119 	/*extra_len*/offsetof(struct scsi_sense_data_fixed, fru)
120                    - offsetof(struct scsi_sense_data_fixed, extra_len),
121 	{ 0, 0, 0, 0 },
122 	/* Logical Unit Not Supported */
123 	/*ASC*/0x25, /*ASCQ*/0
124 };
125 
126 static const int request_sense_size = offsetof(struct scsi_sense_data_fixed, fru);
127 
128 static periph_init_t	targbhinit;
129 static void		targbhasync(void *callback_arg, uint32_t code,
130 				    struct cam_path *path, void *arg);
131 static cam_status	targbhenlun(struct cam_periph *periph);
132 static cam_status	targbhdislun(struct cam_periph *periph);
133 static periph_ctor_t	targbhctor;
134 static periph_dtor_t	targbhdtor;
135 static periph_start_t	targbhstart;
136 static void		targbhdone(struct cam_periph *periph,
137 				   union ccb *done_ccb);
138 #ifdef NOTYET
139 static  int		targbherror(union ccb *ccb, uint32_t cam_flags,
140 				    uint32_t sense_flags);
141 #endif
142 static struct targbh_cmd_desc*	targbhallocdescr(void);
143 static void		targbhfreedescr(struct targbh_cmd_desc *buf);
144 
145 static struct periph_driver targbhdriver =
146 {
147 	targbhinit, "targbh",
148 	TAILQ_HEAD_INITIALIZER(targbhdriver.units), /* generation */ 0
149 };
150 
151 PERIPHDRIVER_DECLARE(targbh, targbhdriver);
152 
153 static void
154 targbhinit(void)
155 {
156 	cam_status status;
157 
158 	/*
159 	 * Install a global async callback.  This callback will
160 	 * receive async callbacks like "new path registered".
161 	 */
162 	status = xpt_register_async(AC_PATH_REGISTERED | AC_PATH_DEREGISTERED,
163 				    targbhasync, NULL, NULL);
164 
165 	if (status != CAM_REQ_CMP) {
166 		printf("targbh: Failed to attach master async callback "
167 		       "due to status 0x%x!\n", status);
168 	}
169 }
170 
171 static void
172 targbhasync(void *callback_arg, uint32_t code,
173 	    struct cam_path *path, void *arg)
174 {
175 	struct cam_path *new_path;
176 	struct ccb_pathinq *cpi;
177 	path_id_t bus_path_id;
178 	cam_status status;
179 
180 	cpi = (struct ccb_pathinq *)arg;
181 	if (code == AC_PATH_REGISTERED)
182 		bus_path_id = cpi->ccb_h.path_id;
183 	else
184 		bus_path_id = xpt_path_path_id(path);
185 	/*
186 	 * Allocate a peripheral instance for
187 	 * this target instance.
188 	 */
189 	status = xpt_create_path(&new_path, NULL,
190 				 bus_path_id,
191 				 CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD);
192 	if (status != CAM_REQ_CMP) {
193 		printf("targbhasync: Unable to create path "
194 			"due to status 0x%x\n", status);
195 		return;
196 	}
197 
198 	switch (code) {
199 	case AC_PATH_REGISTERED:
200 	{
201 		/* Only attach to controllers that support target mode */
202 		if ((cpi->target_sprt & PIT_PROCESSOR) == 0)
203 			break;
204 
205 		status = cam_periph_alloc(targbhctor, NULL, targbhdtor,
206 					  targbhstart,
207 					  "targbh", CAM_PERIPH_BIO,
208 					  new_path, targbhasync,
209 					  AC_PATH_REGISTERED,
210 					  cpi);
211 		break;
212 	}
213 	case AC_PATH_DEREGISTERED:
214 	{
215 		struct cam_periph *periph;
216 
217 		if ((periph = cam_periph_find(new_path, "targbh")) != NULL)
218 			cam_periph_invalidate(periph);
219 		break;
220 	}
221 	default:
222 		break;
223 	}
224 	xpt_free_path(new_path);
225 }
226 
227 /* Attempt to enable our lun */
228 static cam_status
229 targbhenlun(struct cam_periph *periph)
230 {
231 	union ccb immed_ccb;
232 	struct targbh_softc *softc;
233 	cam_status status;
234 	int i;
235 
236 	softc = (struct targbh_softc *)periph->softc;
237 
238 	if ((softc->flags & TARGBH_FLAG_LUN_ENABLED) != 0)
239 		return (CAM_REQ_CMP);
240 
241 	memset(&immed_ccb, 0, sizeof(immed_ccb));
242 	xpt_setup_ccb(&immed_ccb.ccb_h, periph->path, CAM_PRIORITY_NORMAL);
243 	immed_ccb.ccb_h.func_code = XPT_EN_LUN;
244 
245 	/* Don't need support for any vendor specific commands */
246 	immed_ccb.cel.grp6_len = 0;
247 	immed_ccb.cel.grp7_len = 0;
248 	immed_ccb.cel.enable = 1;
249 	xpt_action(&immed_ccb);
250 	status = immed_ccb.ccb_h.status;
251 	if (status != CAM_REQ_CMP) {
252 		xpt_print(periph->path,
253 		    "targbhenlun - Enable Lun Rejected with status 0x%x\n",
254 		    status);
255 		return (status);
256 	}
257 
258 	softc->flags |= TARGBH_FLAG_LUN_ENABLED;
259 
260 	/*
261 	 * Build up a buffer of accept target I/O
262 	 * operations for incoming selections.
263 	 */
264 	for (i = 0; i < MAX_ACCEPT; i++) {
265 		struct ccb_accept_tio *atio;
266 
267 		atio = (struct ccb_accept_tio*)malloc(sizeof(*atio), M_SCSIBH,
268 						      M_ZERO | M_NOWAIT);
269 		if (atio == NULL) {
270 			status = CAM_RESRC_UNAVAIL;
271 			break;
272 		}
273 
274 		atio->ccb_h.ccb_descr = targbhallocdescr();
275 
276 		if (atio->ccb_h.ccb_descr == NULL) {
277 			free(atio, M_SCSIBH);
278 			status = CAM_RESRC_UNAVAIL;
279 			break;
280 		}
281 
282 		xpt_setup_ccb(&atio->ccb_h, periph->path, CAM_PRIORITY_NORMAL);
283 		atio->ccb_h.func_code = XPT_ACCEPT_TARGET_IO;
284 		atio->ccb_h.cbfcnp = targbhdone;
285 		((struct targbh_cmd_desc*)atio->ccb_h.ccb_descr)->atio_link =
286 		    softc->accept_tio_list;
287 		softc->accept_tio_list = atio;
288 		xpt_action((union ccb *)atio);
289 		status = atio->ccb_h.status;
290 		if (status != CAM_REQ_INPROG)
291 			break;
292 	}
293 
294 	if (i == 0) {
295 		xpt_print(periph->path,
296 		    "targbhenlun - Could not allocate accept tio CCBs: status "
297 		    "= 0x%x\n", status);
298 		targbhdislun(periph);
299 		return (CAM_REQ_CMP_ERR);
300 	}
301 
302 	/*
303 	 * Build up a buffer of immediate notify CCBs
304 	 * so the SIM can tell us of asynchronous target mode events.
305 	 */
306 	for (i = 0; i < MAX_ACCEPT; i++) {
307 		struct ccb_immediate_notify *inot;
308 
309 		inot = (struct ccb_immediate_notify*)malloc(sizeof(*inot),
310 			    M_SCSIBH, M_ZERO | M_NOWAIT);
311 
312 		if (inot == NULL) {
313 			status = CAM_RESRC_UNAVAIL;
314 			break;
315 		}
316 
317 		xpt_setup_ccb(&inot->ccb_h, periph->path, CAM_PRIORITY_NORMAL);
318 		inot->ccb_h.func_code = XPT_IMMEDIATE_NOTIFY;
319 		inot->ccb_h.cbfcnp = targbhdone;
320 		SLIST_INSERT_HEAD(&softc->immed_notify_slist, &inot->ccb_h,
321 				  periph_links.sle);
322 		xpt_action((union ccb *)inot);
323 		status = inot->ccb_h.status;
324 		if (status != CAM_REQ_INPROG)
325 			break;
326 	}
327 
328 	if (i == 0) {
329 		xpt_print(periph->path,
330 		    "targbhenlun - Could not allocate immediate notify "
331 		    "CCBs: status = 0x%x\n", status);
332 		targbhdislun(periph);
333 		return (CAM_REQ_CMP_ERR);
334 	}
335 
336 	return (CAM_REQ_CMP);
337 }
338 
339 static cam_status
340 targbhdislun(struct cam_periph *periph)
341 {
342 	union ccb ccb;
343 	struct targbh_softc *softc;
344 	struct ccb_accept_tio* atio;
345 	struct ccb_hdr *ccb_h;
346 
347 	softc = (struct targbh_softc *)periph->softc;
348 	if ((softc->flags & TARGBH_FLAG_LUN_ENABLED) == 0)
349 		return CAM_REQ_CMP;
350 
351 	memset(&ccb, 0, sizeof(ccb));
352 
353 	/* XXX Block for Continue I/O completion */
354 
355 	/* Kill off all ACCECPT and IMMEDIATE CCBs */
356 	while ((atio = softc->accept_tio_list) != NULL) {
357 
358 		softc->accept_tio_list =
359 		    ((struct targbh_cmd_desc*)atio->ccb_h.ccb_descr)->atio_link;
360 		xpt_setup_ccb(&ccb.cab.ccb_h, periph->path, CAM_PRIORITY_NORMAL);
361 		ccb.cab.ccb_h.func_code = XPT_ABORT;
362 		ccb.cab.abort_ccb = (union ccb *)atio;
363 		xpt_action(&ccb);
364 	}
365 
366 	while ((ccb_h = SLIST_FIRST(&softc->immed_notify_slist)) != NULL) {
367 		SLIST_REMOVE_HEAD(&softc->immed_notify_slist, periph_links.sle);
368 		xpt_setup_ccb(&ccb.cab.ccb_h, periph->path, CAM_PRIORITY_NORMAL);
369 		ccb.cab.ccb_h.func_code = XPT_ABORT;
370 		ccb.cab.abort_ccb = (union ccb *)ccb_h;
371 		xpt_action(&ccb);
372 	}
373 
374 	/*
375 	 * Dissable this lun.
376 	 */
377 	xpt_setup_ccb(&ccb.cel.ccb_h, periph->path, CAM_PRIORITY_NORMAL);
378 	ccb.cel.ccb_h.func_code = XPT_EN_LUN;
379 	ccb.cel.enable = 0;
380 	xpt_action(&ccb);
381 
382 	if (ccb.cel.ccb_h.status != CAM_REQ_CMP)
383 		printf("targbhdislun - Disabling lun on controller failed "
384 		       "with status 0x%x\n", ccb.cel.ccb_h.status);
385 	else
386 		softc->flags &= ~TARGBH_FLAG_LUN_ENABLED;
387 	return (ccb.cel.ccb_h.status);
388 }
389 
390 static cam_status
391 targbhctor(struct cam_periph *periph, void *arg)
392 {
393 	struct targbh_softc *softc;
394 
395 	/* Allocate our per-instance private storage */
396 	softc = (struct targbh_softc *)malloc(sizeof(*softc),
397 					      M_SCSIBH, M_NOWAIT);
398 	if (softc == NULL) {
399 		printf("targctor: unable to malloc softc\n");
400 		return (CAM_REQ_CMP_ERR);
401 	}
402 
403 	bzero(softc, sizeof(*softc));
404 	TAILQ_INIT(&softc->pending_queue);
405 	TAILQ_INIT(&softc->work_queue);
406 	softc->accept_tio_list = NULL;
407 	SLIST_INIT(&softc->immed_notify_slist);
408 	softc->state = TARGBH_STATE_NORMAL;
409 	periph->softc = softc;
410 	softc->init_level++;
411 
412 	if (targbhenlun(periph) != CAM_REQ_CMP)
413 		cam_periph_invalidate(periph);
414 	return (CAM_REQ_CMP);
415 }
416 
417 static void
418 targbhdtor(struct cam_periph *periph)
419 {
420 	struct targbh_softc *softc;
421 
422 	softc = (struct targbh_softc *)periph->softc;
423 
424 	softc->state = TARGBH_STATE_TEARDOWN;
425 
426 	targbhdislun(periph);
427 
428 	switch (softc->init_level) {
429 	case 0:
430 		panic("targdtor - impossible init level");
431 	case 1:
432 		/* FALLTHROUGH */
433 	default:
434 		/* XXX Wait for callback of targbhdislun() */
435 		cam_periph_sleep(periph, softc, PRIBIO, "targbh", hz/2);
436 		free(softc, M_SCSIBH);
437 		break;
438 	}
439 }
440 
441 static void
442 targbhstart(struct cam_periph *periph, union ccb *start_ccb)
443 {
444 	struct targbh_softc *softc;
445 	struct ccb_hdr *ccbh;
446 	struct ccb_accept_tio *atio;
447 	struct targbh_cmd_desc *desc;
448 	struct ccb_scsiio *csio;
449 	ccb_flags flags;
450 
451 	softc = (struct targbh_softc *)periph->softc;
452 
453 	ccbh = TAILQ_FIRST(&softc->work_queue);
454 	if (ccbh == NULL) {
455 		xpt_release_ccb(start_ccb);
456 	} else {
457 		TAILQ_REMOVE(&softc->work_queue, ccbh, periph_links.tqe);
458 		TAILQ_INSERT_HEAD(&softc->pending_queue, ccbh,
459 				  periph_links.tqe);
460 		atio = (struct ccb_accept_tio*)ccbh;
461 		desc = (struct targbh_cmd_desc *)atio->ccb_h.ccb_descr;
462 
463 		/* Is this a tagged request? */
464 		flags = atio->ccb_h.flags &
465 		    (CAM_DIS_DISCONNECT|CAM_TAG_ACTION_VALID|CAM_DIR_MASK);
466 
467 		csio = &start_ccb->csio;
468 		/*
469 		 * If we are done with the transaction, tell the
470 		 * controller to send status and perform a CMD_CMPLT.
471 		 * If we have associated sense data, see if we can
472 		 * send that too.
473 		 */
474 		if (desc->data_resid == desc->data_increment) {
475 			flags |= CAM_SEND_STATUS;
476 			if (atio->sense_len) {
477 				csio->sense_len = atio->sense_len;
478 				csio->sense_data = atio->sense_data;
479 				flags |= CAM_SEND_SENSE;
480 			}
481 		}
482 
483 		cam_fill_ctio(csio,
484 			      /*retries*/2,
485 			      targbhdone,
486 			      flags,
487 			      (flags & CAM_TAG_ACTION_VALID)?
488 				MSG_SIMPLE_Q_TAG : 0,
489 			      atio->tag_id,
490 			      atio->init_id,
491 			      desc->status,
492 			      /*data_ptr*/desc->data_increment == 0
493 					  ? NULL : desc->data,
494 			      /*dxfer_len*/desc->data_increment,
495 			      /*timeout*/desc->timeout);
496 
497 		/* Override our wildcard attachment */
498 		start_ccb->ccb_h.target_id = atio->ccb_h.target_id;
499 		start_ccb->ccb_h.target_lun = atio->ccb_h.target_lun;
500 
501 		start_ccb->ccb_h.ccb_type = TARGBH_CCB_WORKQ;
502 		start_ccb->ccb_h.ccb_atio = atio;
503 		CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
504 			  ("Sending a CTIO\n"));
505 		xpt_action(start_ccb);
506 		/*
507 		 * If the queue was frozen waiting for the response
508 		 * to this ATIO (for instance disconnection was disallowed),
509 		 * then release it now that our response has been queued.
510 		 */
511 		if ((atio->ccb_h.status & CAM_DEV_QFRZN) != 0) {
512 			cam_release_devq(periph->path,
513 					 /*relsim_flags*/0,
514 					 /*reduction*/0,
515 					 /*timeout*/0,
516 					 /*getcount_only*/0);
517 			atio->ccb_h.status &= ~CAM_DEV_QFRZN;
518 		}
519 		ccbh = TAILQ_FIRST(&softc->work_queue);
520 	}
521 	if (ccbh != NULL)
522 		xpt_schedule(periph, CAM_PRIORITY_NORMAL);
523 }
524 
525 static void
526 targbhdone(struct cam_periph *periph, union ccb *done_ccb)
527 {
528 	struct targbh_softc *softc;
529 
530 	softc = (struct targbh_softc *)periph->softc;
531 
532 	switch (done_ccb->ccb_h.func_code) {
533 	case XPT_ACCEPT_TARGET_IO:
534 	{
535 		struct ccb_accept_tio *atio;
536 		struct targbh_cmd_desc *descr;
537 		uint8_t *cdb;
538 		int priority;
539 
540 		atio = &done_ccb->atio;
541 		descr = (struct targbh_cmd_desc*)atio->ccb_h.ccb_descr;
542 		cdb = atio->cdb_io.cdb_bytes;
543 		if (softc->state == TARGBH_STATE_TEARDOWN
544 		 || atio->ccb_h.status == CAM_REQ_ABORTED) {
545 			targbhfreedescr(descr);
546 			xpt_free_ccb(done_ccb);
547 			return;
548 		}
549 
550 		/*
551 		 * Determine the type of incoming command and
552 		 * setup our buffer for a response.
553 		 */
554 		switch (cdb[0]) {
555 		case INQUIRY:
556 		{
557 			struct scsi_inquiry *inq;
558 
559 			inq = (struct scsi_inquiry *)cdb;
560 			CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
561 				  ("Saw an inquiry!\n"));
562 			/*
563 			 * Validate the command.  We don't
564 			 * support any VPD pages, so complain
565 			 * if EVPD is set.
566 			 */
567 			if ((inq->byte2 & SI_EVPD) != 0
568 			 || inq->page_code != 0) {
569 				atio->ccb_h.flags &= ~CAM_DIR_MASK;
570 				atio->ccb_h.flags |= CAM_DIR_NONE;
571 				/*
572 				 * This needs to have other than a
573 				 * no_lun_sense_data response.
574 				 */
575 				bcopy(&no_lun_sense_data, &atio->sense_data,
576 				      min(sizeof(no_lun_sense_data),
577 					  sizeof(atio->sense_data)));
578 				atio->sense_len = sizeof(no_lun_sense_data);
579 				descr->data_resid = 0;
580 				descr->data_increment = 0;
581 				descr->status = SCSI_STATUS_CHECK_COND;
582 				break;
583 			}
584 			/*
585 			 * Direction is always relative
586 			 * to the initator.
587 			 */
588 			atio->ccb_h.flags &= ~CAM_DIR_MASK;
589 			atio->ccb_h.flags |= CAM_DIR_IN;
590 			descr->data = &no_lun_inq_data;
591 			descr->data_resid = MIN(sizeof(no_lun_inq_data),
592 						scsi_2btoul(inq->length));
593 			descr->data_increment = descr->data_resid;
594 			descr->timeout = 5 * 1000;
595 			descr->status = SCSI_STATUS_OK;
596 			break;
597 		}
598 		case REQUEST_SENSE:
599 		{
600 			struct scsi_request_sense *rsense;
601 
602 			rsense = (struct scsi_request_sense *)cdb;
603 			/* Refer to static sense data */
604 			atio->ccb_h.flags &= ~CAM_DIR_MASK;
605 			atio->ccb_h.flags |= CAM_DIR_IN;
606 			descr->data = &no_lun_sense_data;
607 			descr->data_resid = request_sense_size;
608 			descr->data_resid = MIN(descr->data_resid,
609 						SCSI_CDB6_LEN(rsense->length));
610 			descr->data_increment = descr->data_resid;
611 			descr->timeout = 5 * 1000;
612 			descr->status = SCSI_STATUS_OK;
613 			break;
614 		}
615 		default:
616 			/* Constant CA, tell initiator */
617 			/* Direction is always relative to the initator */
618 			atio->ccb_h.flags &= ~CAM_DIR_MASK;
619 			atio->ccb_h.flags |= CAM_DIR_NONE;
620 			bcopy(&no_lun_sense_data, &atio->sense_data,
621 			      min(sizeof(no_lun_sense_data),
622 				  sizeof(atio->sense_data)));
623 			atio->sense_len = sizeof (no_lun_sense_data);
624 			descr->data_resid = 0;
625 			descr->data_increment = 0;
626 			descr->timeout = 5 * 1000;
627 			descr->status = SCSI_STATUS_CHECK_COND;
628 			break;
629 		}
630 
631 		/* Queue us up to receive a Continue Target I/O ccb. */
632 		if ((atio->ccb_h.flags & CAM_DIS_DISCONNECT) != 0) {
633 			TAILQ_INSERT_HEAD(&softc->work_queue, &atio->ccb_h,
634 					  periph_links.tqe);
635 			priority = 0;
636 		} else {
637 			TAILQ_INSERT_TAIL(&softc->work_queue, &atio->ccb_h,
638 					  periph_links.tqe);
639 			priority = CAM_PRIORITY_NORMAL;
640 		}
641 		xpt_schedule(periph, priority);
642 		break;
643 	}
644 	case XPT_CONT_TARGET_IO:
645 	{
646 		struct ccb_accept_tio *atio;
647 		struct targbh_cmd_desc *desc;
648 
649 		CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
650 			  ("Received completed CTIO\n"));
651 		atio = (struct ccb_accept_tio*)done_ccb->ccb_h.ccb_atio;
652 		desc = (struct targbh_cmd_desc *)atio->ccb_h.ccb_descr;
653 
654 		TAILQ_REMOVE(&softc->pending_queue, &atio->ccb_h,
655 			     periph_links.tqe);
656 
657 		/*
658 		 * We could check for CAM_SENT_SENSE bein set here,
659 		 * but since we're not maintaining any CA/UA state,
660 		 * there's no point.
661 		 */
662 		atio->sense_len = 0;
663 		done_ccb->ccb_h.flags &= ~CAM_SEND_SENSE;
664 		done_ccb->ccb_h.status &= ~CAM_SENT_SENSE;
665 
666 		/*
667 		 * Any errors will not change the data we return,
668 		 * so make sure the queue is not left frozen.
669 		 * XXX - At some point there may be errors that
670 		 *       leave us in a connected state with the
671 		 *       initiator...
672 		 */
673 		if ((done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0) {
674 			printf("Releasing Queue\n");
675 			cam_release_devq(done_ccb->ccb_h.path,
676 					 /*relsim_flags*/0,
677 					 /*reduction*/0,
678 					 /*timeout*/0,
679 					 /*getcount_only*/0);
680 			done_ccb->ccb_h.status &= ~CAM_DEV_QFRZN;
681 		}
682 		desc->data_resid -= desc->data_increment;
683 		xpt_release_ccb(done_ccb);
684 		if (softc->state != TARGBH_STATE_TEARDOWN) {
685 			/*
686 			 * Send the original accept TIO back to the
687 			 * controller to handle more work.
688 			 */
689 			CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
690 				  ("Returning ATIO to target\n"));
691 			/* Restore wildcards */
692 			atio->ccb_h.target_id = CAM_TARGET_WILDCARD;
693 			atio->ccb_h.target_lun = CAM_LUN_WILDCARD;
694 			xpt_action((union ccb *)atio);
695 			break;
696 		} else {
697 			targbhfreedescr(desc);
698 			free(atio, M_SCSIBH);
699 		}
700 		break;
701 	}
702 	case XPT_IMMEDIATE_NOTIFY:
703 	{
704 		int frozen;
705 
706 		frozen = (done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0;
707 		if (softc->state == TARGBH_STATE_TEARDOWN
708 		 || done_ccb->ccb_h.status == CAM_REQ_ABORTED) {
709 			printf("Freed an immediate notify\n");
710 			xpt_free_ccb(done_ccb);
711 		} else {
712 			/* Requeue for another immediate event */
713 			xpt_action(done_ccb);
714 		}
715 		if (frozen != 0)
716 			cam_release_devq(periph->path,
717 					 /*relsim_flags*/0,
718 					 /*opening reduction*/0,
719 					 /*timeout*/0,
720 					 /*getcount_only*/0);
721 		break;
722 	}
723 	default:
724 		panic("targbhdone: Unexpected ccb opcode");
725 		break;
726 	}
727 }
728 
729 #ifdef NOTYET
730 static int
731 targbherror(union ccb *ccb, uint32_t cam_flags, uint32_t sense_flags)
732 {
733 	return 0;
734 }
735 #endif
736 
737 static struct targbh_cmd_desc*
738 targbhallocdescr(void)
739 {
740 	struct targbh_cmd_desc* descr;
741 
742 	/* Allocate the targbh_descr structure */
743 	descr = (struct targbh_cmd_desc *)malloc(sizeof(*descr),
744 					       M_SCSIBH, M_NOWAIT);
745 	if (descr == NULL)
746 		return (NULL);
747 
748 	bzero(descr, sizeof(*descr));
749 
750 	/* Allocate buffer backing store */
751 	descr->backing_store = malloc(MAX_BUF_SIZE, M_SCSIBH, M_NOWAIT);
752 	if (descr->backing_store == NULL) {
753 		free(descr, M_SCSIBH);
754 		return (NULL);
755 	}
756 	descr->max_size = MAX_BUF_SIZE;
757 	return (descr);
758 }
759 
760 static void
761 targbhfreedescr(struct targbh_cmd_desc *descr)
762 {
763 	free(descr->backing_store, M_SCSIBH);
764 	free(descr, M_SCSIBH);
765 }
766