xref: /dragonfly/sys/bus/cam/scsi/scsi_targ_bh.c (revision 3641b7ca)
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 1.19 2008/05/18 20:30:20 pavalos 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/thread2.h>
41 #include <sys/uio.h>
42 
43 #include "../cam.h"
44 #include "../cam_ccb.h"
45 #include "../cam_extend.h"
46 #include "../cam_periph.h"
47 #include "../cam_queue.h"
48 #include "../cam_xpt_periph.h"
49 #include "../cam_debug.h"
50 #include "../cam_sim.h"
51 
52 #include "scsi_all.h"
53 #include "scsi_message.h"
54 
55 MALLOC_DEFINE(M_SCSIBH, "SCSI bh", "SCSI blackhole buffers");
56 
57 typedef enum {
58 	TARGBH_STATE_NORMAL,
59 	TARGBH_STATE_EXCEPTION,
60 	TARGBH_STATE_TEARDOWN
61 } targbh_state;
62 
63 typedef enum {
64 	TARGBH_FLAG_NONE	 = 0x00,
65 	TARGBH_FLAG_LUN_ENABLED	 = 0x01
66 } targbh_flags;
67 
68 typedef enum {
69 	TARGBH_CCB_WORKQ,
70 	TARGBH_CCB_WAITING
71 } targbh_ccb_types;
72 
73 #define MAX_ACCEPT	8
74 #define MAX_IMMEDIATE	16
75 #define MAX_BUF_SIZE	256	/* Max inquiry/sense/mode page transfer */
76 
77 /* Offsets into our private CCB area for storing accept information */
78 #define ccb_type	ppriv_field0
79 #define ccb_descr	ppriv_ptr1
80 
81 /* We stick a pointer to the originating accept TIO in each continue I/O CCB */
82 #define ccb_atio	ppriv_ptr1
83 
84 TAILQ_HEAD(ccb_queue, ccb_hdr);
85 
86 struct targbh_softc {
87 	struct		ccb_queue pending_queue;
88 	struct		ccb_queue work_queue;
89 	struct		ccb_queue unknown_atio_queue;
90 	struct		devstat device_stats;
91 	targbh_state	state;
92 	targbh_flags	flags;
93 	u_int		init_level;
94 	u_int		inq_data_len;
95 	struct		ccb_accept_tio *accept_tio_list;
96 	struct		ccb_hdr_slist immed_notify_slist;
97 };
98 
99 struct targbh_cmd_desc {
100 	struct	  ccb_accept_tio* atio_link;
101 	u_int	  data_resid;	/* How much left to transfer */
102 	u_int	  data_increment;/* Amount to send before next disconnect */
103 	void*	  data;		/* The data. Can be from backing_store or not */
104 	void*	  backing_store;/* Backing store allocated for this descriptor*/
105 	u_int	  max_size;	/* Size of backing_store */
106 	u_int32_t timeout;
107 	u_int8_t  status;	/* Status to return to initiator */
108 };
109 
110 static struct scsi_inquiry_data no_lun_inq_data =
111 {
112 	T_NODEVICE | (SID_QUAL_BAD_LU << 5), 0,
113 	/* version */2, /* format version */2
114 };
115 
116 static struct scsi_sense_data no_lun_sense_data =
117 {
118 	SSD_CURRENT_ERROR|SSD_ERRCODE_VALID,
119 	0,
120 	SSD_KEY_NOT_READY,
121 	{ 0, 0, 0, 0 },
122 	/*extra_len*/offsetof(struct scsi_sense_data, fru)
123                    - offsetof(struct scsi_sense_data, extra_len),
124 	{ 0, 0, 0, 0 },
125 	/* Logical Unit Not Supported */
126 	/*ASC*/0x25, /*ASCQ*/0
127 };
128 
129 static const int request_sense_size = offsetof(struct scsi_sense_data, fru);
130 
131 static periph_init_t	targbhinit;
132 static void		targbhasync(void *callback_arg, u_int32_t code,
133 				    struct cam_path *path, void *arg);
134 static cam_status	targbhenlun(struct cam_periph *periph);
135 static cam_status	targbhdislun(struct cam_periph *periph);
136 static periph_ctor_t	targbhctor;
137 static periph_dtor_t	targbhdtor;
138 static periph_start_t	targbhstart;
139 static void		targbhdone(struct cam_periph *periph,
140 				   union ccb *done_ccb);
141 #ifdef NOTYET
142 static  int		targbherror(union ccb *ccb, u_int32_t cam_flags,
143 				    u_int32_t sense_flags);
144 #endif
145 static struct targbh_cmd_desc*	targbhallocdescr(void);
146 static void		targbhfreedescr(struct targbh_cmd_desc *buf);
147 
148 static struct periph_driver targbhdriver =
149 {
150 	targbhinit, "targbh",
151 	TAILQ_HEAD_INITIALIZER(targbhdriver.units), /* generation */ 0
152 };
153 
154 PERIPHDRIVER_DECLARE(targbh, targbhdriver);
155 
156 static void
157 targbhinit(void)
158 {
159 	cam_status status;
160 
161 	/*
162 	 * Install a global async callback.  This callback will
163 	 * receive async callbacks like "new path registered".
164 	 */
165 	status = xpt_register_async(AC_PATH_REGISTERED | AC_PATH_DEREGISTERED,
166 				    targbhasync, NULL, NULL);
167 
168 	if (status != CAM_REQ_CMP) {
169 		kprintf("targbh: Failed to attach master async callback "
170 		       "due to status 0x%x!\n", status);
171 	}
172 }
173 
174 static void
175 targbhasync(void *callback_arg, u_int32_t code,
176 	    struct cam_path *path, void *arg)
177 {
178 	struct cam_path *new_path;
179 	struct ccb_pathinq *cpi;
180 	path_id_t bus_path_id;
181 	cam_status status;
182 
183 	cpi = (struct ccb_pathinq *)arg;
184 	if (code == AC_PATH_REGISTERED)
185 		bus_path_id = cpi->ccb_h.path_id;
186 	else
187 		bus_path_id = xpt_path_path_id(path);
188 	/*
189 	 * Allocate a peripheral instance for
190 	 * this target instance.
191 	 */
192 	status = xpt_create_path(&new_path, NULL,
193 				 bus_path_id,
194 				 CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD);
195 	if (status != CAM_REQ_CMP) {
196 		kprintf("targbhasync: Unable to create path "
197 			"due to status 0x%x\n", status);
198 		return;
199 	}
200 
201 	switch (code) {
202 	case AC_PATH_REGISTERED:
203 	{
204 		/* Only attach to controllers that support target mode */
205 		if ((cpi->target_sprt & PIT_PROCESSOR) == 0)
206 			break;
207 
208 		status = cam_periph_alloc(targbhctor, NULL, targbhdtor,
209 					  targbhstart,
210 					  "targbh", CAM_PERIPH_BIO,
211 					  new_path, targbhasync,
212 					  AC_PATH_REGISTERED,
213 					  cpi);
214 		break;
215 	}
216 	case AC_PATH_DEREGISTERED:
217 	{
218 		struct cam_periph *periph;
219 
220 		if ((periph = cam_periph_find(new_path, "targbh")) != NULL)
221 			cam_periph_invalidate(periph);
222 		break;
223 	}
224 	default:
225 		break;
226 	}
227 	xpt_free_path(new_path);
228 }
229 
230 /* Attempt to enable our lun */
231 static cam_status
232 targbhenlun(struct cam_periph *periph)
233 {
234 	union ccb immed_ccb;
235 	struct targbh_softc *softc;
236 	cam_status status;
237 	int i;
238 
239 	softc = (struct targbh_softc *)periph->softc;
240 
241 	if ((softc->flags & TARGBH_FLAG_LUN_ENABLED) != 0)
242 		return (CAM_REQ_CMP);
243 
244 	xpt_setup_ccb(&immed_ccb.ccb_h, periph->path, /*priority*/1);
245 	immed_ccb.ccb_h.func_code = XPT_EN_LUN;
246 
247 	/* Don't need support for any vendor specific commands */
248 	immed_ccb.cel.grp6_len = 0;
249 	immed_ccb.cel.grp7_len = 0;
250 	immed_ccb.cel.enable = 1;
251 	xpt_action(&immed_ccb);
252 	status = immed_ccb.ccb_h.status;
253 	if (status != CAM_REQ_CMP) {
254 		xpt_print(periph->path,
255 		    "targbhenlun - Enable Lun Rejected with status 0x%x\n",
256 		    status);
257 		return (status);
258 	}
259 
260 	softc->flags |= TARGBH_FLAG_LUN_ENABLED;
261 
262 	/*
263 	 * Build up a buffer of accept target I/O
264 	 * operations for incoming selections.
265 	 */
266 	for (i = 0; i < MAX_ACCEPT; i++) {
267 		struct ccb_accept_tio *atio;
268 
269 		atio = kmalloc(sizeof(*atio), M_SCSIBH, M_INTWAIT);
270 
271 		atio->ccb_h.ccb_descr = targbhallocdescr();
272 
273 		xpt_setup_ccb(&atio->ccb_h, periph->path, /*priority*/1);
274 		atio->ccb_h.func_code = XPT_ACCEPT_TARGET_IO;
275 		atio->ccb_h.cbfcnp = targbhdone;
276 		xpt_action((union ccb *)atio);
277 		status = atio->ccb_h.status;
278 		if (status != CAM_REQ_INPROG) {
279 			targbhfreedescr(atio->ccb_h.ccb_descr);
280 			kfree(atio, M_SCSIBH);
281 			break;
282 		}
283 		((struct targbh_cmd_desc*)atio->ccb_h.ccb_descr)->atio_link =
284 		    softc->accept_tio_list;
285 		softc->accept_tio_list = atio;
286 	}
287 
288 	if (i == 0) {
289 		xpt_print(periph->path,
290 		    "targbhenlun - Could not allocate accept tio CCBs: status "
291 		    "= 0x%x\n", status);
292 		targbhdislun(periph);
293 		return (CAM_REQ_CMP_ERR);
294 	}
295 
296 	/*
297 	 * Build up a buffer of immediate notify CCBs
298 	 * so the SIM can tell us of asynchronous target mode events.
299 	 */
300 	for (i = 0; i < MAX_ACCEPT; i++) {
301 		struct ccb_immed_notify *inot;
302 
303 		inot = kmalloc(sizeof(*inot), M_SCSIBH, M_INTWAIT);
304 
305 		xpt_setup_ccb(&inot->ccb_h, periph->path, /*priority*/1);
306 		inot->ccb_h.func_code = XPT_IMMED_NOTIFY;
307 		inot->ccb_h.cbfcnp = targbhdone;
308 		xpt_action((union ccb *)inot);
309 		status = inot->ccb_h.status;
310 		if (status != CAM_REQ_INPROG) {
311 			kfree(inot, M_SCSIBH);
312 			break;
313 		}
314 		SLIST_INSERT_HEAD(&softc->immed_notify_slist, &inot->ccb_h,
315 				  periph_links.sle);
316 	}
317 
318 	if (i == 0) {
319 		xpt_print(periph->path,
320 		    "targbhenlun - Could not allocate immediate notify "
321 		    "CCBs: status = 0x%x\n", status);
322 		targbhdislun(periph);
323 		return (CAM_REQ_CMP_ERR);
324 	}
325 
326 	return (CAM_REQ_CMP);
327 }
328 
329 static cam_status
330 targbhdislun(struct cam_periph *periph)
331 {
332 	union ccb ccb;
333 	struct targbh_softc *softc;
334 	struct ccb_accept_tio* atio;
335 	struct ccb_hdr *ccb_h;
336 
337 	softc = (struct targbh_softc *)periph->softc;
338 	if ((softc->flags & TARGBH_FLAG_LUN_ENABLED) == 0)
339 		return CAM_REQ_CMP;
340 
341 	/* XXX Block for Continue I/O completion */
342 
343 	/* Kill off all ACCECPT and IMMEDIATE CCBs */
344 	while ((atio = softc->accept_tio_list) != NULL) {
345 
346 		softc->accept_tio_list =
347 		    ((struct targbh_cmd_desc*)atio->ccb_h.ccb_descr)->atio_link;
348 		xpt_setup_ccb(&ccb.cab.ccb_h, periph->path, /*priority*/1);
349 		ccb.cab.ccb_h.func_code = XPT_ABORT;
350 		ccb.cab.abort_ccb = (union ccb *)atio;
351 		xpt_action(&ccb);
352 	}
353 
354 	while ((ccb_h = SLIST_FIRST(&softc->immed_notify_slist)) != NULL) {
355 		SLIST_REMOVE_HEAD(&softc->immed_notify_slist, periph_links.sle);
356 		xpt_setup_ccb(&ccb.cab.ccb_h, periph->path, /*priority*/1);
357 		ccb.cab.ccb_h.func_code = XPT_ABORT;
358 		ccb.cab.abort_ccb = (union ccb *)ccb_h;
359 		xpt_action(&ccb);
360 	}
361 
362 	/*
363 	 * Dissable this lun.
364 	 */
365 	xpt_setup_ccb(&ccb.cel.ccb_h, periph->path, /*priority*/1);
366 	ccb.cel.ccb_h.func_code = XPT_EN_LUN;
367 	ccb.cel.enable = 0;
368 	xpt_action(&ccb);
369 
370 	if (ccb.cel.ccb_h.status != CAM_REQ_CMP)
371 		kprintf("targbhdislun - Disabling lun on controller failed "
372 		       "with status 0x%x\n", ccb.cel.ccb_h.status);
373 	else
374 		softc->flags &= ~TARGBH_FLAG_LUN_ENABLED;
375 	return (ccb.cel.ccb_h.status);
376 }
377 
378 static cam_status
379 targbhctor(struct cam_periph *periph, void *arg)
380 {
381 	struct targbh_softc *softc;
382 
383 	/* Allocate our per-instance private storage */
384 	softc = kmalloc(sizeof(*softc), M_SCSIBH, M_INTWAIT | M_ZERO);
385 	TAILQ_INIT(&softc->pending_queue);
386 	TAILQ_INIT(&softc->work_queue);
387 	softc->accept_tio_list = NULL;
388 	SLIST_INIT(&softc->immed_notify_slist);
389 	softc->state = TARGBH_STATE_NORMAL;
390 	periph->softc = softc;
391 	softc->init_level++;
392 
393 	return (targbhenlun(periph));
394 }
395 
396 static void
397 targbhdtor(struct cam_periph *periph)
398 {
399 	struct targbh_softc *softc;
400 
401 	softc = (struct targbh_softc *)periph->softc;
402 
403 	softc->state = TARGBH_STATE_TEARDOWN;
404 
405 	targbhdislun(periph);
406 
407 	switch (softc->init_level) {
408 	case 0:
409 		panic("targdtor - impossible init level");
410 	case 1:
411 		/* FALLTHROUGH */
412 	default:
413 		/* XXX Wait for callback of targbhdislun() */
414 		sim_lock_sleep(softc, 0, "targbh", hz/2, periph->sim->lock);
415 		kfree(softc, M_SCSIBH);
416 		break;
417 	}
418 }
419 
420 static void
421 targbhstart(struct cam_periph *periph, union ccb *start_ccb)
422 {
423 	struct targbh_softc *softc;
424 	struct ccb_hdr *ccbh;
425 	struct ccb_accept_tio *atio;
426 	struct targbh_cmd_desc *desc;
427 	struct ccb_scsiio *csio;
428 	ccb_flags flags;
429 
430 	softc = (struct targbh_softc *)periph->softc;
431 
432 	ccbh = TAILQ_FIRST(&softc->work_queue);
433 	if (periph->immediate_priority <= periph->pinfo.priority) {
434 		start_ccb->ccb_h.ccb_type = TARGBH_CCB_WAITING;
435 		SLIST_INSERT_HEAD(&periph->ccb_list, &start_ccb->ccb_h,
436 				  periph_links.sle);
437 		periph->immediate_priority = CAM_PRIORITY_NONE;
438 		wakeup(&periph->ccb_list);
439 	} else if (ccbh == NULL) {
440 		xpt_release_ccb(start_ccb);
441 	} else {
442 		TAILQ_REMOVE(&softc->work_queue, ccbh, periph_links.tqe);
443 		TAILQ_INSERT_HEAD(&softc->pending_queue, ccbh,
444 				  periph_links.tqe);
445 		atio = (struct ccb_accept_tio*)ccbh;
446 		desc = (struct targbh_cmd_desc *)atio->ccb_h.ccb_descr;
447 
448 		/* Is this a tagged request? */
449 		flags = atio->ccb_h.flags &
450 		    (CAM_DIS_DISCONNECT|CAM_TAG_ACTION_VALID|CAM_DIR_MASK);
451 
452 		csio = &start_ccb->csio;
453 		/*
454 		 * If we are done with the transaction, tell the
455 		 * controller to send status and perform a CMD_CMPLT.
456 		 * If we have associated sense data, see if we can
457 		 * send that too.
458 		 */
459 		if (desc->data_resid == desc->data_increment) {
460 			flags |= CAM_SEND_STATUS;
461 			if (atio->sense_len) {
462 				csio->sense_len = atio->sense_len;
463 				csio->sense_data = atio->sense_data;
464 				flags |= CAM_SEND_SENSE;
465 			}
466 
467 		}
468 
469 		cam_fill_ctio(csio,
470 			      /*retries*/2,
471 			      targbhdone,
472 			      flags,
473 			      (flags & CAM_TAG_ACTION_VALID)?
474 				MSG_SIMPLE_Q_TAG : 0,
475 			      atio->tag_id,
476 			      atio->init_id,
477 			      desc->status,
478 			      /*data_ptr*/desc->data_increment == 0
479 					  ? NULL : desc->data,
480 			      /*dxfer_len*/desc->data_increment,
481 			      /*timeout*/desc->timeout);
482 
483 		/* Override our wildcard attachment */
484 		start_ccb->ccb_h.target_id = atio->ccb_h.target_id;
485 		start_ccb->ccb_h.target_lun = atio->ccb_h.target_lun;
486 
487 		start_ccb->ccb_h.ccb_type = TARGBH_CCB_WORKQ;
488 		start_ccb->ccb_h.ccb_atio = atio;
489 		CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
490 			  ("Sending a CTIO\n"));
491 		xpt_action(start_ccb);
492 		/*
493 		 * If the queue was frozen waiting for the response
494 		 * to this ATIO (for instance disconnection was disallowed),
495 		 * then release it now that our response has been queued.
496 		 */
497 		if ((atio->ccb_h.status & CAM_DEV_QFRZN) != 0) {
498 			cam_release_devq(periph->path,
499 					 /*relsim_flags*/0,
500 					 /*reduction*/0,
501 					 /*timeout*/0,
502 					 /*getcount_only*/0);
503 			atio->ccb_h.status &= ~CAM_DEV_QFRZN;
504 		}
505 		ccbh = TAILQ_FIRST(&softc->work_queue);
506 	}
507 	if (ccbh != NULL)
508 		xpt_schedule(periph, /*priority*/1);
509 }
510 
511 static void
512 targbhdone(struct cam_periph *periph, union ccb *done_ccb)
513 {
514 	struct targbh_softc *softc;
515 
516 	softc = (struct targbh_softc *)periph->softc;
517 
518 	if (done_ccb->ccb_h.ccb_type == TARGBH_CCB_WAITING) {
519 		/* Caller will release the CCB */
520 		wakeup(&done_ccb->ccb_h.cbfcnp);
521 		return;
522 	}
523 
524 	switch (done_ccb->ccb_h.func_code) {
525 	case XPT_ACCEPT_TARGET_IO:
526 	{
527 		struct ccb_accept_tio *atio;
528 		struct targbh_cmd_desc *descr;
529 		u_int8_t *cdb;
530 		int priority;
531 
532 		atio = &done_ccb->atio;
533 		descr = (struct targbh_cmd_desc*)atio->ccb_h.ccb_descr;
534 		cdb = atio->cdb_io.cdb_bytes;
535 		if (softc->state == TARGBH_STATE_TEARDOWN
536 		 || atio->ccb_h.status == CAM_REQ_ABORTED) {
537 			targbhfreedescr(descr);
538 			xpt_free_ccb(done_ccb);
539 			return;
540 		}
541 
542 		/*
543 		 * Determine the type of incoming command and
544 		 * setup our buffer for a response.
545 		 */
546 		switch (cdb[0]) {
547 		case INQUIRY:
548 		{
549 			struct scsi_inquiry *inq;
550 
551 			inq = (struct scsi_inquiry *)cdb;
552 			CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
553 				  ("Saw an inquiry!\n"));
554 			/*
555 			 * Validate the command.  We don't
556 			 * support any VPD pages, so complain
557 			 * if EVPD is set.
558 			 */
559 			if ((inq->byte2 & SI_EVPD) != 0
560 			 || inq->page_code != 0) {
561 				atio->ccb_h.flags &= ~CAM_DIR_MASK;
562 				atio->ccb_h.flags |= CAM_DIR_NONE;
563 				/*
564 				 * This needs to have other than a
565 				 * no_lun_sense_data response.
566 				 */
567 				atio->sense_data = no_lun_sense_data;
568 				atio->sense_len = sizeof(no_lun_sense_data);
569 				descr->data_resid = 0;
570 				descr->data_increment = 0;
571 				descr->status = SCSI_STATUS_CHECK_COND;
572 				break;
573 			}
574 			/*
575 			 * Direction is always relative
576 			 * to the initator.
577 			 */
578 			atio->ccb_h.flags &= ~CAM_DIR_MASK;
579 			atio->ccb_h.flags |= CAM_DIR_IN;
580 			descr->data = &no_lun_inq_data;
581 			descr->data_resid = MIN(sizeof(no_lun_inq_data),
582 						SCSI_CDB6_LEN(inq->length));
583 			descr->data_increment = descr->data_resid;
584 			descr->timeout = 5 * 1000;
585 			descr->status = SCSI_STATUS_OK;
586 			break;
587 		}
588 		case REQUEST_SENSE:
589 		{
590 			struct scsi_request_sense *rsense;
591 
592 			rsense = (struct scsi_request_sense *)cdb;
593 			/* Refer to static sense data */
594 			atio->ccb_h.flags &= ~CAM_DIR_MASK;
595 			atio->ccb_h.flags |= CAM_DIR_IN;
596 			descr->data = &no_lun_sense_data;
597 			descr->data_resid = request_sense_size;
598 			descr->data_resid = MIN(descr->data_resid,
599 						SCSI_CDB6_LEN(rsense->length));
600 			descr->data_increment = descr->data_resid;
601 			descr->timeout = 5 * 1000;
602 			descr->status = SCSI_STATUS_OK;
603 			break;
604 		}
605 		default:
606 			/* Constant CA, tell initiator */
607 			/* Direction is always relative to the initator */
608 			atio->ccb_h.flags &= ~CAM_DIR_MASK;
609 			atio->ccb_h.flags |= CAM_DIR_NONE;
610 			atio->sense_data = no_lun_sense_data;
611 			atio->sense_len = sizeof (no_lun_sense_data);
612 			descr->data_resid = 0;
613 			descr->data_increment = 0;
614 			descr->timeout = 5 * 1000;
615 			descr->status = SCSI_STATUS_CHECK_COND;
616 			break;
617 		}
618 
619 		/* Queue us up to receive a Continue Target I/O ccb. */
620 		if ((atio->ccb_h.flags & CAM_DIS_DISCONNECT) != 0) {
621 			TAILQ_INSERT_HEAD(&softc->work_queue, &atio->ccb_h,
622 					  periph_links.tqe);
623 			priority = 0;
624 		} else {
625 			TAILQ_INSERT_TAIL(&softc->work_queue, &atio->ccb_h,
626 					  periph_links.tqe);
627 			priority = 1;
628 		}
629 		xpt_schedule(periph, priority);
630 		break;
631 	}
632 	case XPT_CONT_TARGET_IO:
633 	{
634 		struct ccb_accept_tio *atio;
635 		struct targbh_cmd_desc *desc;
636 
637 		CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
638 			  ("Received completed CTIO\n"));
639 		atio = (struct ccb_accept_tio*)done_ccb->ccb_h.ccb_atio;
640 		desc = (struct targbh_cmd_desc *)atio->ccb_h.ccb_descr;
641 
642 		TAILQ_REMOVE(&softc->pending_queue, &atio->ccb_h,
643 			     periph_links.tqe);
644 
645 		/*
646 		 * We could check for CAM_SENT_SENSE bein set here,
647 		 * but since we're not maintaining any CA/UA state,
648 		 * there's no point.
649 		 */
650 		atio->sense_len = 0;
651 		done_ccb->ccb_h.flags &= ~CAM_SEND_SENSE;
652 		done_ccb->ccb_h.status &= ~CAM_SENT_SENSE;
653 
654 		/*
655 		 * Any errors will not change the data we return,
656 		 * so make sure the queue is not left frozen.
657 		 * XXX - At some point there may be errors that
658 		 *       leave us in a connected state with the
659 		 *       initiator...
660 		 */
661 		if ((done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0) {
662 			kprintf("Releasing Queue\n");
663 			cam_release_devq(done_ccb->ccb_h.path,
664 					 /*relsim_flags*/0,
665 					 /*reduction*/0,
666 					 /*timeout*/0,
667 					 /*getcount_only*/0);
668 			done_ccb->ccb_h.status &= ~CAM_DEV_QFRZN;
669 		}
670 		desc->data_resid -= desc->data_increment;
671 		xpt_release_ccb(done_ccb);
672 		if (softc->state != TARGBH_STATE_TEARDOWN) {
673 
674 			/*
675 			 * Send the original accept TIO back to the
676 			 * controller to handle more work.
677 			 */
678 			CAM_DEBUG(periph->path, CAM_DEBUG_SUBTRACE,
679 				  ("Returning ATIO to target\n"));
680 			/* Restore wildcards */
681 			atio->ccb_h.target_id = CAM_TARGET_WILDCARD;
682 			atio->ccb_h.target_lun = CAM_LUN_WILDCARD;
683 			xpt_action((union ccb *)atio);
684 			break;
685 		} else {
686 			targbhfreedescr(desc);
687 			kfree(atio, M_SCSIBH);
688 		}
689 		break;
690 	}
691 	case XPT_IMMED_NOTIFY:
692 	{
693 		int frozen;
694 
695 		frozen = (done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0;
696 		if (softc->state == TARGBH_STATE_TEARDOWN
697 		 || done_ccb->ccb_h.status == CAM_REQ_ABORTED) {
698 			kprintf("Freed an immediate notify\n");
699 			xpt_free_ccb(done_ccb);
700 		} else {
701 			/* Requeue for another immediate event */
702 			xpt_action(done_ccb);
703 		}
704 		if (frozen != 0)
705 			cam_release_devq(periph->path,
706 					 /*relsim_flags*/0,
707 					 /*opening reduction*/0,
708 					 /*timeout*/0,
709 					 /*getcount_only*/0);
710 		break;
711 	}
712 	default:
713 		panic("targbhdone: Unexpected ccb opcode");
714 		break;
715 	}
716 }
717 
718 #ifdef NOTYET
719 static int
720 targbherror(union ccb *ccb, u_int32_t cam_flags, u_int32_t sense_flags)
721 {
722 	return 0;
723 }
724 #endif
725 
726 static struct targbh_cmd_desc *
727 targbhallocdescr(void)
728 {
729 	struct targbh_cmd_desc* descr;
730 
731 	/* Allocate the targbh_descr structure */
732 	descr = kmalloc(sizeof(*descr), M_SCSIBH, M_INTWAIT | M_ZERO);
733 
734 	/* Allocate buffer backing store */
735 	descr->backing_store = kmalloc(MAX_BUF_SIZE, M_SCSIBH, M_INTWAIT);
736 	descr->max_size = MAX_BUF_SIZE;
737 	return (descr);
738 }
739 
740 static void
741 targbhfreedescr(struct targbh_cmd_desc *descr)
742 {
743 	kfree(descr->backing_store, M_SCSIBH);
744 	kfree(descr, M_SCSIBH);
745 }
746