xref: /dragonfly/sys/bus/cam/scsi/scsi_targ_bh.c (revision 1d1731fa)
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  * $FreeBSD: src/sys/cam/scsi/scsi_targ_bh.c,v 1.4.2.5 2001/07/30 00:15:22 mjacob Exp $
29  * $DragonFly: src/sys/bus/cam/scsi/scsi_targ_bh.c,v 1.4 2003/08/07 21:16:45 dillon Exp $
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/buf.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.h"
43 #include "../cam_ccb.h"
44 #include "../cam_extend.h"
45 #include "../cam_periph.h"
46 #include "../cam_queue.h"
47 #include "../cam_xpt_periph.h"
48 #include "../cam_debug.h"
49 
50 #include "scsi_all.h"
51 #include "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 DATA_SET(periphdriver_set, 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;
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_periph *periph;
189 
190 	periph = (struct cam_periph *)callback_arg;
191 	switch (code) {
192 	case AC_PATH_REGISTERED:
193 	{
194 		struct ccb_pathinq *cpi;
195 		struct cam_path *new_path;
196 		cam_status status;
197 
198 		cpi = (struct ccb_pathinq *)arg;
199 
200 		/* Only attach to controllers that support target mode */
201 		if ((cpi->target_sprt & PIT_PROCESSOR) == 0)
202 			break;
203 
204 		/*
205 		 * Allocate a peripheral instance for
206 		 * this target instance.
207 		 */
208 		status = xpt_create_path(&new_path, NULL,
209 					 xpt_path_path_id(path),
210 					 CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD);
211 		if (status != CAM_REQ_CMP) {
212 			printf("targbhasync: Unable to create path "
213 				"due to status 0x%x\n", status);
214 			break;
215 		}
216 		status = cam_periph_alloc(targbhctor, NULL, targbhdtor,
217 					  targbhstart,
218 					  "targbh", CAM_PERIPH_BIO,
219 					  new_path, targbhasync,
220 					  AC_PATH_REGISTERED,
221 					  cpi);
222 		xpt_free_path(new_path);
223 		if (status != CAM_REQ_CMP
224 		 && status != CAM_REQ_INPROG)
225 			printf("targbhasync: Unable to allocate new periph "
226 			       "due to status 0x%x\n", status);
227 		break;
228 	}
229 	case AC_PATH_DEREGISTERED:
230 	{
231 		targbhdislun(periph);
232 		break;
233 	}
234 	default:
235 		break;
236 	}
237 }
238 
239 /* Attempt to enable our lun */
240 static cam_status
241 targbhenlun(struct cam_periph *periph)
242 {
243 	union ccb immed_ccb;
244 	struct targbh_softc *softc;
245 	cam_status status;
246 	int i;
247 
248 	softc = (struct targbh_softc *)periph->softc;
249 
250 	if ((softc->flags & TARGBH_FLAG_LUN_ENABLED) != 0)
251 		return (CAM_REQ_CMP);
252 
253 	xpt_setup_ccb(&immed_ccb.ccb_h, periph->path, /*priority*/1);
254 	immed_ccb.ccb_h.func_code = XPT_EN_LUN;
255 
256 	/* Don't need support for any vendor specific commands */
257 	immed_ccb.cel.grp6_len = 0;
258 	immed_ccb.cel.grp7_len = 0;
259 	immed_ccb.cel.enable = 1;
260 	xpt_action(&immed_ccb);
261 	status = immed_ccb.ccb_h.status;
262 	if (status != CAM_REQ_CMP) {
263 		xpt_print_path(periph->path);
264 		printf("targbhenlun - Enable Lun Rejected with status 0x%x\n",
265 		       status);
266 		return (status);
267 	}
268 
269 	softc->flags |= TARGBH_FLAG_LUN_ENABLED;
270 
271 	/*
272 	 * Build up a buffer of accept target I/O
273 	 * operations for incoming selections.
274 	 */
275 	for (i = 0; i < MAX_ACCEPT; i++) {
276 		struct ccb_accept_tio *atio;
277 
278 		atio = (struct ccb_accept_tio*)malloc(sizeof(*atio), M_DEVBUF,
279 						      M_NOWAIT);
280 		if (atio == NULL) {
281 			status = CAM_RESRC_UNAVAIL;
282 			break;
283 		}
284 
285 		atio->ccb_h.ccb_descr = targbhallocdescr();
286 
287 		if (atio->ccb_h.ccb_descr == NULL) {
288 			free(atio, M_DEVBUF);
289 			status = CAM_RESRC_UNAVAIL;
290 			break;
291 		}
292 
293 		xpt_setup_ccb(&atio->ccb_h, periph->path, /*priority*/1);
294 		atio->ccb_h.func_code = XPT_ACCEPT_TARGET_IO;
295 		atio->ccb_h.cbfcnp = targbhdone;
296 		xpt_action((union ccb *)atio);
297 		status = atio->ccb_h.status;
298 		if (status != CAM_REQ_INPROG) {
299 			targbhfreedescr(atio->ccb_h.ccb_descr);
300 			free(atio, M_DEVBUF);
301 			break;
302 		}
303 		((struct targbh_cmd_desc*)atio->ccb_h.ccb_descr)->atio_link =
304 		    softc->accept_tio_list;
305 		softc->accept_tio_list = atio;
306 	}
307 
308 	if (i == 0) {
309 		xpt_print_path(periph->path);
310 		printf("targbhenlun - Could not allocate accept tio CCBs: "
311 		       "status = 0x%x\n", status);
312 		targbhdislun(periph);
313 		return (CAM_REQ_CMP_ERR);
314 	}
315 
316 	/*
317 	 * Build up a buffer of immediate notify CCBs
318 	 * so the SIM can tell us of asynchronous target mode events.
319 	 */
320 	for (i = 0; i < MAX_ACCEPT; i++) {
321 		struct ccb_immed_notify *inot;
322 
323 		inot = (struct ccb_immed_notify*)malloc(sizeof(*inot), M_DEVBUF,
324 						        M_NOWAIT);
325 
326 		if (inot == NULL) {
327 			status = CAM_RESRC_UNAVAIL;
328 			break;
329 		}
330 
331 		xpt_setup_ccb(&inot->ccb_h, periph->path, /*priority*/1);
332 		inot->ccb_h.func_code = XPT_IMMED_NOTIFY;
333 		inot->ccb_h.cbfcnp = targbhdone;
334 		xpt_action((union ccb *)inot);
335 		status = inot->ccb_h.status;
336 		if (status != CAM_REQ_INPROG) {
337 			free(inot, M_DEVBUF);
338 			break;
339 		}
340 		SLIST_INSERT_HEAD(&softc->immed_notify_slist, &inot->ccb_h,
341 				  periph_links.sle);
342 	}
343 
344 	if (i == 0) {
345 		xpt_print_path(periph->path);
346 		printf("targbhenlun - Could not allocate immediate notify "
347 		       "CCBs: status = 0x%x\n", status);
348 		targbhdislun(periph);
349 		return (CAM_REQ_CMP_ERR);
350 	}
351 
352 	return (CAM_REQ_CMP);
353 }
354 
355 static cam_status
356 targbhdislun(struct cam_periph *periph)
357 {
358 	union ccb ccb;
359 	struct targbh_softc *softc;
360 	struct ccb_accept_tio* atio;
361 	struct ccb_hdr *ccb_h;
362 
363 	softc = (struct targbh_softc *)periph->softc;
364 	if ((softc->flags & TARGBH_FLAG_LUN_ENABLED) == 0)
365 		return CAM_REQ_CMP;
366 
367 	/* XXX Block for Continue I/O completion */
368 
369 	/* Kill off all ACCECPT and IMMEDIATE CCBs */
370 	while ((atio = softc->accept_tio_list) != NULL) {
371 
372 		softc->accept_tio_list =
373 		    ((struct targbh_cmd_desc*)atio->ccb_h.ccb_descr)->atio_link;
374 		xpt_setup_ccb(&ccb.cab.ccb_h, periph->path, /*priority*/1);
375 		ccb.cab.ccb_h.func_code = XPT_ABORT;
376 		ccb.cab.abort_ccb = (union ccb *)atio;
377 		xpt_action(&ccb);
378 	}
379 
380 	while ((ccb_h = SLIST_FIRST(&softc->immed_notify_slist)) != NULL) {
381 		SLIST_REMOVE_HEAD(&softc->immed_notify_slist, periph_links.sle);
382 		xpt_setup_ccb(&ccb.cab.ccb_h, periph->path, /*priority*/1);
383 		ccb.cab.ccb_h.func_code = XPT_ABORT;
384 		ccb.cab.abort_ccb = (union ccb *)ccb_h;
385 		xpt_action(&ccb);
386 	}
387 
388 	/*
389 	 * Dissable this lun.
390 	 */
391 	xpt_setup_ccb(&ccb.cel.ccb_h, periph->path, /*priority*/1);
392 	ccb.cel.ccb_h.func_code = XPT_EN_LUN;
393 	ccb.cel.enable = 0;
394 	xpt_action(&ccb);
395 
396 	if (ccb.cel.ccb_h.status != CAM_REQ_CMP)
397 		printf("targbhdislun - Disabling lun on controller failed "
398 		       "with status 0x%x\n", ccb.cel.ccb_h.status);
399 	else
400 		softc->flags &= ~TARGBH_FLAG_LUN_ENABLED;
401 	return (ccb.cel.ccb_h.status);
402 }
403 
404 static cam_status
405 targbhctor(struct cam_periph *periph, void *arg)
406 {
407 	struct ccb_pathinq *cpi;
408 	struct targbh_softc *softc;
409 
410 	cpi = (struct ccb_pathinq *)arg;
411 
412 	/* Allocate our per-instance private storage */
413 	softc = (struct targbh_softc *)malloc(sizeof(*softc),
414 					      M_DEVBUF, M_NOWAIT);
415 	if (softc == NULL) {
416 		printf("targctor: unable to malloc softc\n");
417 		return (CAM_REQ_CMP_ERR);
418 	}
419 
420 	bzero(softc, sizeof(*softc));
421 	TAILQ_INIT(&softc->pending_queue);
422 	TAILQ_INIT(&softc->work_queue);
423 	softc->accept_tio_list = NULL;
424 	SLIST_INIT(&softc->immed_notify_slist);
425 	softc->state = TARGBH_STATE_NORMAL;
426 	periph->softc = softc;
427 	softc->init_level++;
428 
429 	return (targbhenlun(periph));
430 }
431 
432 static void
433 targbhdtor(struct cam_periph *periph)
434 {
435 	struct targbh_softc *softc;
436 
437 	softc = (struct targbh_softc *)periph->softc;
438 
439 	softc->state = TARGBH_STATE_TEARDOWN;
440 
441 	targbhdislun(periph);
442 
443 	switch (softc->init_level) {
444 	default:
445 		/* FALLTHROUGH */
446 	case 1:
447 		free(softc, M_DEVBUF);
448 		break;
449 	case 0:
450 		panic("targdtor - impossible init level");;
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 & (CAM_TAG_ACTION_VALID|CAM_DIR_MASK);
489 
490 		csio = &start_ccb->csio;
491 		/*
492 		 * If we are done with the transaction, tell the
493 		 * controller to send status and perform a CMD_CMPLT.
494 		 * If we have associated sense data, see if we can
495 		 * send that too.
496 		 */
497 		if (desc->data_resid == desc->data_increment) {
498 			flags |= CAM_SEND_STATUS;
499 			if (atio->sense_len) {
500 				csio->sense_len = atio->sense_len;
501 				csio->sense_data = atio->sense_data;
502 				flags |= CAM_SEND_SENSE;
503 			}
504 
505 		}
506 
507 		cam_fill_ctio(csio,
508 			      /*retries*/2,
509 			      targbhdone,
510 			      flags,
511 			      (flags & CAM_TAG_ACTION_VALID)?
512 				MSG_SIMPLE_Q_TAG : 0,
513 			      atio->tag_id,
514 			      atio->init_id,
515 			      desc->status,
516 			      /*data_ptr*/desc->data_increment == 0
517 					  ? NULL : desc->data,
518 			      /*dxfer_len*/desc->data_increment,
519 			      /*timeout*/desc->timeout);
520 
521 		/* Override our wildcard attachment */
522 		start_ccb->ccb_h.target_id = atio->ccb_h.target_id;
523 		start_ccb->ccb_h.target_lun = atio->ccb_h.target_lun;
524 
525 		start_ccb->ccb_h.ccb_type = TARGBH_CCB_WORKQ;
526 		start_ccb->ccb_h.ccb_atio = atio;
527 		CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
528 			  ("Sending a CTIO\n"));
529 		xpt_action(start_ccb);
530 		s = splbio();
531 		ccbh = TAILQ_FIRST(&softc->work_queue);
532 		splx(s);
533 	}
534 	if (ccbh != NULL)
535 		xpt_schedule(periph, /*priority*/1);
536 }
537 
538 static void
539 targbhdone(struct cam_periph *periph, union ccb *done_ccb)
540 {
541 	struct targbh_softc *softc;
542 
543 	softc = (struct targbh_softc *)periph->softc;
544 
545 	if (done_ccb->ccb_h.ccb_type == TARGBH_CCB_WAITING) {
546 		/* Caller will release the CCB */
547 		wakeup(&done_ccb->ccb_h.cbfcnp);
548 		return;
549 	}
550 
551 	switch (done_ccb->ccb_h.func_code) {
552 	case XPT_ACCEPT_TARGET_IO:
553 	{
554 		struct ccb_accept_tio *atio;
555 		struct targbh_cmd_desc *descr;
556 		u_int8_t *cdb;
557 
558 		atio = &done_ccb->atio;
559 		descr = (struct targbh_cmd_desc*)atio->ccb_h.ccb_descr;
560 		cdb = atio->cdb_io.cdb_bytes;
561 		if (softc->state == TARGBH_STATE_TEARDOWN
562 		 || atio->ccb_h.status == CAM_REQ_ABORTED) {
563 			targbhfreedescr(descr);
564 			free(done_ccb, M_DEVBUF);
565 			return;
566 		}
567 
568 		/*
569 		 * Determine the type of incoming command and
570 		 * setup our buffer for a response.
571 		 */
572 		switch (cdb[0]) {
573 		case INQUIRY:
574 		{
575 			struct scsi_inquiry *inq;
576 
577 			inq = (struct scsi_inquiry *)cdb;
578 			CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
579 				  ("Saw an inquiry!\n"));
580 			/*
581 			 * Validate the command.  We don't
582 			 * support any VPD pages, so complain
583 			 * if EVPD is set.
584 			 */
585 			if ((inq->byte2 & SI_EVPD) != 0
586 			 || inq->page_code != 0) {
587 				atio->ccb_h.flags &= ~CAM_DIR_MASK;
588 				atio->ccb_h.flags |= CAM_DIR_NONE;
589 				/*
590 				 * This needs to have other than a
591 				 * no_lun_sense_data response.
592 				 */
593 				atio->sense_data = no_lun_sense_data;
594 				atio->sense_len = sizeof(no_lun_sense_data);
595 				descr->data_resid = 0;
596 				descr->data_increment = 0;
597 				descr->status = SCSI_STATUS_CHECK_COND;
598 				break;
599 			}
600 			/*
601 			 * Direction is always relative
602 			 * to the initator.
603 			 */
604 			atio->ccb_h.flags &= ~CAM_DIR_MASK;
605 			atio->ccb_h.flags |= CAM_DIR_IN;
606 			descr->data = &no_lun_inq_data;
607 			descr->data_resid = MIN(sizeof(no_lun_inq_data),
608 						SCSI_CDB6_LEN(inq->length));
609 			descr->data_increment = descr->data_resid;
610 			descr->timeout = 5 * 1000;
611 			descr->status = SCSI_STATUS_OK;
612 			break;
613 		}
614 		case REQUEST_SENSE:
615 		{
616 			struct scsi_request_sense *rsense;
617 
618 			rsense = (struct scsi_request_sense *)cdb;
619 			/* Refer to static sense data */
620 			atio->ccb_h.flags &= ~CAM_DIR_MASK;
621 			atio->ccb_h.flags |= CAM_DIR_IN;
622 			descr->data = &no_lun_sense_data;
623 			descr->data_resid = request_sense_size;
624 			descr->data_resid = MIN(descr->data_resid,
625 						SCSI_CDB6_LEN(rsense->length));
626 			descr->data_increment = descr->data_resid;
627 			descr->timeout = 5 * 1000;
628 			descr->status = SCSI_STATUS_OK;
629 			break;
630 		}
631 		default:
632 			/* Constant CA, tell initiator */
633 			/* Direction is always relative to the initator */
634 			atio->ccb_h.flags &= ~CAM_DIR_MASK;
635 			atio->ccb_h.flags |= CAM_DIR_NONE;
636 			atio->sense_data = no_lun_sense_data;
637 			atio->sense_len = sizeof (no_lun_sense_data);
638 			descr->data_resid = 0;
639 			descr->data_increment = 0;
640 			descr->timeout = 5 * 1000;
641 			descr->status = SCSI_STATUS_CHECK_COND;
642 			break;
643 		}
644 
645 		/* Queue us up to receive a Continue Target I/O ccb. */
646 		TAILQ_INSERT_TAIL(&softc->work_queue, &atio->ccb_h,
647 				  periph_links.tqe);
648 		xpt_schedule(periph, /*priority*/1);
649 		break;
650 	}
651 	case XPT_CONT_TARGET_IO:
652 	{
653 		struct ccb_accept_tio *atio;
654 		struct targbh_cmd_desc *desc;
655 
656 		CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
657 			  ("Received completed CTIO\n"));
658 		atio = (struct ccb_accept_tio*)done_ccb->ccb_h.ccb_atio;
659 		desc = (struct targbh_cmd_desc *)atio->ccb_h.ccb_descr;
660 
661 		TAILQ_REMOVE(&softc->pending_queue, &atio->ccb_h,
662 			     periph_links.tqe);
663 
664 		/*
665 		 * We could check for CAM_SENT_SENSE bein set here,
666 		 * but since we're not maintaining any CA/UA state,
667 		 * there's no point.
668 		 */
669 		atio->sense_len = 0;
670 		done_ccb->ccb_h.flags &= ~CAM_SEND_SENSE;
671 		done_ccb->ccb_h.status &= ~CAM_SENT_SENSE;
672 
673 		/* XXX Check for errors */
674 		desc->data_resid -= desc->data_increment;
675 		xpt_release_ccb(done_ccb);
676 		if (softc->state != TARGBH_STATE_TEARDOWN) {
677 
678 			/*
679 			 * Send the original accept TIO back to the
680 			 * controller to handle more work.
681 			 */
682 			CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
683 				  ("Returning ATIO to target\n"));
684 			/* Restore wildcards */
685 			atio->ccb_h.target_id = CAM_TARGET_WILDCARD;
686 			atio->ccb_h.target_lun = CAM_LUN_WILDCARD;
687 			xpt_action((union ccb *)atio);
688 			break;
689 		} else {
690 			targbhfreedescr(desc);
691 			free(atio, M_DEVBUF);
692 		}
693 		break;
694 	}
695 	case XPT_IMMED_NOTIFY:
696 	{
697 		if (softc->state == TARGBH_STATE_TEARDOWN
698 		 || done_ccb->ccb_h.status == CAM_REQ_ABORTED) {
699 			printf("Freed an immediate notify\n");
700 			free(done_ccb, M_DEVBUF);
701 		}
702 		break;
703 	}
704 	default:
705 		panic("targbhdone: Unexpected ccb opcode");
706 		break;
707 	}
708 }
709 
710 #ifdef NOTYET
711 static int
712 targbherror(union ccb *ccb, u_int32_t cam_flags, u_int32_t sense_flags)
713 {
714 	return 0;
715 }
716 #endif
717 
718 static struct targbh_cmd_desc*
719 targbhallocdescr()
720 {
721 	struct targbh_cmd_desc* descr;
722 
723 	/* Allocate the targbh_descr structure */
724 	descr = (struct targbh_cmd_desc *)malloc(sizeof(*descr),
725 					       M_DEVBUF, M_NOWAIT);
726 	if (descr == NULL)
727 		return (NULL);
728 
729 	bzero(descr, sizeof(*descr));
730 
731 	/* Allocate buffer backing store */
732 	descr->backing_store = malloc(MAX_BUF_SIZE, M_DEVBUF, M_NOWAIT);
733 	if (descr->backing_store == NULL) {
734 		free(descr, M_DEVBUF);
735 		return (NULL);
736 	}
737 	descr->max_size = MAX_BUF_SIZE;
738 	return (descr);
739 }
740 
741 static void
742 targbhfreedescr(struct targbh_cmd_desc *descr)
743 {
744 	free(descr->backing_store, M_DEVBUF);
745 	free(descr, M_DEVBUF);
746 }
747