xref: /dragonfly/sys/bus/cam/scsi/scsi_targ_bh.c (revision 2ee85085)
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 1.4.2.6 2003/11/14 11:31:25 simokawa Exp $
29  * $DragonFly: src/sys/bus/cam/scsi/scsi_targ_bh.c,v 1.9 2005/06/02 20:40:31 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 | 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 = malloc(sizeof(*atio), M_DEVBUF, M_INTWAIT);
280 
281 		atio->ccb_h.ccb_descr = targbhallocdescr();
282 
283 		xpt_setup_ccb(&atio->ccb_h, periph->path, /*priority*/1);
284 		atio->ccb_h.func_code = XPT_ACCEPT_TARGET_IO;
285 		atio->ccb_h.cbfcnp = targbhdone;
286 		xpt_action((union ccb *)atio);
287 		status = atio->ccb_h.status;
288 		if (status != CAM_REQ_INPROG) {
289 			targbhfreedescr(atio->ccb_h.ccb_descr);
290 			free(atio, M_DEVBUF);
291 			break;
292 		}
293 		((struct targbh_cmd_desc*)atio->ccb_h.ccb_descr)->atio_link =
294 		    softc->accept_tio_list;
295 		softc->accept_tio_list = atio;
296 	}
297 
298 	if (i == 0) {
299 		xpt_print_path(periph->path);
300 		printf("targbhenlun - Could not allocate accept tio CCBs: "
301 		       "status = 0x%x\n", status);
302 		targbhdislun(periph);
303 		return (CAM_REQ_CMP_ERR);
304 	}
305 
306 	/*
307 	 * Build up a buffer of immediate notify CCBs
308 	 * so the SIM can tell us of asynchronous target mode events.
309 	 */
310 	for (i = 0; i < MAX_ACCEPT; i++) {
311 		struct ccb_immed_notify *inot;
312 
313 		inot = malloc(sizeof(*inot), M_DEVBUF, M_INTWAIT);
314 
315 		xpt_setup_ccb(&inot->ccb_h, periph->path, /*priority*/1);
316 		inot->ccb_h.func_code = XPT_IMMED_NOTIFY;
317 		inot->ccb_h.cbfcnp = targbhdone;
318 		xpt_action((union ccb *)inot);
319 		status = inot->ccb_h.status;
320 		if (status != CAM_REQ_INPROG) {
321 			free(inot, M_DEVBUF);
322 			break;
323 		}
324 		SLIST_INSERT_HEAD(&softc->immed_notify_slist, &inot->ccb_h,
325 				  periph_links.sle);
326 	}
327 
328 	if (i == 0) {
329 		xpt_print_path(periph->path);
330 		printf("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 	/* XXX Block for Continue I/O completion */
352 
353 	/* Kill off all ACCECPT and IMMEDIATE CCBs */
354 	while ((atio = softc->accept_tio_list) != NULL) {
355 
356 		softc->accept_tio_list =
357 		    ((struct targbh_cmd_desc*)atio->ccb_h.ccb_descr)->atio_link;
358 		xpt_setup_ccb(&ccb.cab.ccb_h, periph->path, /*priority*/1);
359 		ccb.cab.ccb_h.func_code = XPT_ABORT;
360 		ccb.cab.abort_ccb = (union ccb *)atio;
361 		xpt_action(&ccb);
362 	}
363 
364 	while ((ccb_h = SLIST_FIRST(&softc->immed_notify_slist)) != NULL) {
365 		SLIST_REMOVE_HEAD(&softc->immed_notify_slist, periph_links.sle);
366 		xpt_setup_ccb(&ccb.cab.ccb_h, periph->path, /*priority*/1);
367 		ccb.cab.ccb_h.func_code = XPT_ABORT;
368 		ccb.cab.abort_ccb = (union ccb *)ccb_h;
369 		xpt_action(&ccb);
370 	}
371 
372 	/*
373 	 * Dissable this lun.
374 	 */
375 	xpt_setup_ccb(&ccb.cel.ccb_h, periph->path, /*priority*/1);
376 	ccb.cel.ccb_h.func_code = XPT_EN_LUN;
377 	ccb.cel.enable = 0;
378 	xpt_action(&ccb);
379 
380 	if (ccb.cel.ccb_h.status != CAM_REQ_CMP)
381 		printf("targbhdislun - Disabling lun on controller failed "
382 		       "with status 0x%x\n", ccb.cel.ccb_h.status);
383 	else
384 		softc->flags &= ~TARGBH_FLAG_LUN_ENABLED;
385 	return (ccb.cel.ccb_h.status);
386 }
387 
388 static cam_status
389 targbhctor(struct cam_periph *periph, void *arg)
390 {
391 	struct ccb_pathinq *cpi;
392 	struct targbh_softc *softc;
393 
394 	cpi = (struct ccb_pathinq *)arg;
395 
396 	/* Allocate our per-instance private storage */
397 	softc = malloc(sizeof(*softc), M_DEVBUF, M_INTWAIT | M_ZERO);
398 	TAILQ_INIT(&softc->pending_queue);
399 	TAILQ_INIT(&softc->work_queue);
400 	softc->accept_tio_list = NULL;
401 	SLIST_INIT(&softc->immed_notify_slist);
402 	softc->state = TARGBH_STATE_NORMAL;
403 	periph->softc = softc;
404 	softc->init_level++;
405 
406 	return (targbhenlun(periph));
407 }
408 
409 static void
410 targbhdtor(struct cam_periph *periph)
411 {
412 	struct targbh_softc *softc;
413 
414 	softc = (struct targbh_softc *)periph->softc;
415 
416 	softc->state = TARGBH_STATE_TEARDOWN;
417 
418 	targbhdislun(periph);
419 
420 	switch (softc->init_level) {
421 	case 0:
422 		panic("targdtor - impossible init level");;
423 	case 1:
424 		/* FALLTHROUGH */
425 	default:
426 		/* XXX Wait for callback of targbhdislun() */
427 		tsleep(softc, 0, "targbh", hz/2);
428 		free(softc, M_DEVBUF);
429 		break;
430 	}
431 }
432 
433 static void
434 targbhstart(struct cam_periph *periph, union ccb *start_ccb)
435 {
436 	struct targbh_softc *softc;
437 	struct ccb_hdr *ccbh;
438 	struct ccb_accept_tio *atio;
439 	struct targbh_cmd_desc *desc;
440 	struct ccb_scsiio *csio;
441 	ccb_flags flags;
442 
443 	softc = (struct targbh_softc *)periph->softc;
444 
445 	crit_enter();
446 	ccbh = TAILQ_FIRST(&softc->work_queue);
447 	if (periph->immediate_priority <= periph->pinfo.priority) {
448 		start_ccb->ccb_h.ccb_type = TARGBH_CCB_WAITING;
449 		SLIST_INSERT_HEAD(&periph->ccb_list, &start_ccb->ccb_h,
450 				  periph_links.sle);
451 		periph->immediate_priority = CAM_PRIORITY_NONE;
452 		crit_exit();
453 		wakeup(&periph->ccb_list);
454 	} else if (ccbh == NULL) {
455 		crit_exit();
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 		crit_exit();
462 		atio = (struct ccb_accept_tio*)ccbh;
463 		desc = (struct targbh_cmd_desc *)atio->ccb_h.ccb_descr;
464 
465 		/* Is this a tagged request? */
466 		flags = atio->ccb_h.flags & (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 
485 		cam_fill_ctio(csio,
486 			      /*retries*/2,
487 			      targbhdone,
488 			      flags,
489 			      (flags & CAM_TAG_ACTION_VALID)?
490 				MSG_SIMPLE_Q_TAG : 0,
491 			      atio->tag_id,
492 			      atio->init_id,
493 			      desc->status,
494 			      /*data_ptr*/desc->data_increment == 0
495 					  ? NULL : desc->data,
496 			      /*dxfer_len*/desc->data_increment,
497 			      /*timeout*/desc->timeout);
498 
499 		/* Override our wildcard attachment */
500 		start_ccb->ccb_h.target_id = atio->ccb_h.target_id;
501 		start_ccb->ccb_h.target_lun = atio->ccb_h.target_lun;
502 
503 		start_ccb->ccb_h.ccb_type = TARGBH_CCB_WORKQ;
504 		start_ccb->ccb_h.ccb_atio = atio;
505 		CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
506 			  ("Sending a CTIO\n"));
507 		xpt_action(start_ccb);
508 		crit_enter();
509 		ccbh = TAILQ_FIRST(&softc->work_queue);
510 		crit_exit();
511 	}
512 	if (ccbh != NULL)
513 		xpt_schedule(periph, /*priority*/1);
514 }
515 
516 static void
517 targbhdone(struct cam_periph *periph, union ccb *done_ccb)
518 {
519 	struct targbh_softc *softc;
520 
521 	softc = (struct targbh_softc *)periph->softc;
522 
523 	if (done_ccb->ccb_h.ccb_type == TARGBH_CCB_WAITING) {
524 		/* Caller will release the CCB */
525 		wakeup(&done_ccb->ccb_h.cbfcnp);
526 		return;
527 	}
528 
529 	switch (done_ccb->ccb_h.func_code) {
530 	case XPT_ACCEPT_TARGET_IO:
531 	{
532 		struct ccb_accept_tio *atio;
533 		struct targbh_cmd_desc *descr;
534 		u_int8_t *cdb;
535 
536 		atio = &done_ccb->atio;
537 		descr = (struct targbh_cmd_desc*)atio->ccb_h.ccb_descr;
538 		cdb = atio->cdb_io.cdb_bytes;
539 		if (softc->state == TARGBH_STATE_TEARDOWN
540 		 || atio->ccb_h.status == CAM_REQ_ABORTED) {
541 			targbhfreedescr(descr);
542 			free(done_ccb, M_DEVBUF);
543 			return;
544 		}
545 
546 		/*
547 		 * Determine the type of incoming command and
548 		 * setup our buffer for a response.
549 		 */
550 		switch (cdb[0]) {
551 		case INQUIRY:
552 		{
553 			struct scsi_inquiry *inq;
554 
555 			inq = (struct scsi_inquiry *)cdb;
556 			CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
557 				  ("Saw an inquiry!\n"));
558 			/*
559 			 * Validate the command.  We don't
560 			 * support any VPD pages, so complain
561 			 * if EVPD is set.
562 			 */
563 			if ((inq->byte2 & SI_EVPD) != 0
564 			 || inq->page_code != 0) {
565 				atio->ccb_h.flags &= ~CAM_DIR_MASK;
566 				atio->ccb_h.flags |= CAM_DIR_NONE;
567 				/*
568 				 * This needs to have other than a
569 				 * no_lun_sense_data response.
570 				 */
571 				atio->sense_data = no_lun_sense_data;
572 				atio->sense_len = sizeof(no_lun_sense_data);
573 				descr->data_resid = 0;
574 				descr->data_increment = 0;
575 				descr->status = SCSI_STATUS_CHECK_COND;
576 				break;
577 			}
578 			/*
579 			 * Direction is always relative
580 			 * to the initator.
581 			 */
582 			atio->ccb_h.flags &= ~CAM_DIR_MASK;
583 			atio->ccb_h.flags |= CAM_DIR_IN;
584 			descr->data = &no_lun_inq_data;
585 			descr->data_resid = MIN(sizeof(no_lun_inq_data),
586 						SCSI_CDB6_LEN(inq->length));
587 			descr->data_increment = descr->data_resid;
588 			descr->timeout = 5 * 1000;
589 			descr->status = SCSI_STATUS_OK;
590 			break;
591 		}
592 		case REQUEST_SENSE:
593 		{
594 			struct scsi_request_sense *rsense;
595 
596 			rsense = (struct scsi_request_sense *)cdb;
597 			/* Refer to static sense data */
598 			atio->ccb_h.flags &= ~CAM_DIR_MASK;
599 			atio->ccb_h.flags |= CAM_DIR_IN;
600 			descr->data = &no_lun_sense_data;
601 			descr->data_resid = request_sense_size;
602 			descr->data_resid = MIN(descr->data_resid,
603 						SCSI_CDB6_LEN(rsense->length));
604 			descr->data_increment = descr->data_resid;
605 			descr->timeout = 5 * 1000;
606 			descr->status = SCSI_STATUS_OK;
607 			break;
608 		}
609 		default:
610 			/* Constant CA, tell initiator */
611 			/* Direction is always relative to the initator */
612 			atio->ccb_h.flags &= ~CAM_DIR_MASK;
613 			atio->ccb_h.flags |= CAM_DIR_NONE;
614 			atio->sense_data = no_lun_sense_data;
615 			atio->sense_len = sizeof (no_lun_sense_data);
616 			descr->data_resid = 0;
617 			descr->data_increment = 0;
618 			descr->timeout = 5 * 1000;
619 			descr->status = SCSI_STATUS_CHECK_COND;
620 			break;
621 		}
622 
623 		/* Queue us up to receive a Continue Target I/O ccb. */
624 		TAILQ_INSERT_TAIL(&softc->work_queue, &atio->ccb_h,
625 				  periph_links.tqe);
626 		xpt_schedule(periph, /*priority*/1);
627 		break;
628 	}
629 	case XPT_CONT_TARGET_IO:
630 	{
631 		struct ccb_accept_tio *atio;
632 		struct targbh_cmd_desc *desc;
633 
634 		CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
635 			  ("Received completed CTIO\n"));
636 		atio = (struct ccb_accept_tio*)done_ccb->ccb_h.ccb_atio;
637 		desc = (struct targbh_cmd_desc *)atio->ccb_h.ccb_descr;
638 
639 		TAILQ_REMOVE(&softc->pending_queue, &atio->ccb_h,
640 			     periph_links.tqe);
641 
642 		/*
643 		 * We could check for CAM_SENT_SENSE bein set here,
644 		 * but since we're not maintaining any CA/UA state,
645 		 * there's no point.
646 		 */
647 		atio->sense_len = 0;
648 		done_ccb->ccb_h.flags &= ~CAM_SEND_SENSE;
649 		done_ccb->ccb_h.status &= ~CAM_SENT_SENSE;
650 
651 		/* XXX Check for errors */
652 		desc->data_resid -= desc->data_increment;
653 		xpt_release_ccb(done_ccb);
654 		if (softc->state != TARGBH_STATE_TEARDOWN) {
655 
656 			/*
657 			 * Send the original accept TIO back to the
658 			 * controller to handle more work.
659 			 */
660 			CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
661 				  ("Returning ATIO to target\n"));
662 			/* Restore wildcards */
663 			atio->ccb_h.target_id = CAM_TARGET_WILDCARD;
664 			atio->ccb_h.target_lun = CAM_LUN_WILDCARD;
665 			xpt_action((union ccb *)atio);
666 			break;
667 		} else {
668 			targbhfreedescr(desc);
669 			free(atio, M_DEVBUF);
670 		}
671 		break;
672 	}
673 	case XPT_IMMED_NOTIFY:
674 	{
675 		if (softc->state == TARGBH_STATE_TEARDOWN
676 		 || done_ccb->ccb_h.status == CAM_REQ_ABORTED) {
677 			printf("Freed an immediate notify\n");
678 			free(done_ccb, M_DEVBUF);
679 		}
680 		break;
681 	}
682 	default:
683 		panic("targbhdone: Unexpected ccb opcode");
684 		break;
685 	}
686 }
687 
688 #ifdef NOTYET
689 static int
690 targbherror(union ccb *ccb, u_int32_t cam_flags, u_int32_t sense_flags)
691 {
692 	return 0;
693 }
694 #endif
695 
696 static struct targbh_cmd_desc*
697 targbhallocdescr()
698 {
699 	struct targbh_cmd_desc* descr;
700 
701 	/* Allocate the targbh_descr structure */
702 	descr = malloc(sizeof(*descr), M_DEVBUF, M_INTWAIT | M_ZERO);
703 
704 	/* Allocate buffer backing store */
705 	descr->backing_store = malloc(MAX_BUF_SIZE, M_DEVBUF, M_INTWAIT);
706 	descr->max_size = MAX_BUF_SIZE;
707 	return (descr);
708 }
709 
710 static void
711 targbhfreedescr(struct targbh_cmd_desc *descr)
712 {
713 	free(descr->backing_store, M_DEVBUF);
714 	free(descr, M_DEVBUF);
715 }
716