xref: /freebsd/sys/cam/scsi/scsi_target.c (revision 1669d8afc64812c8d2d1d147ae1fd42ff441e1b1)
1 /*-
2  * Generic SCSI Target Kernel Mode Driver
3  *
4  * Copyright (c) 2002 Nate Lawson.
5  * Copyright (c) 1998, 1999, 2001, 2002 Justin T. Gibbs.
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions, and the following disclaimer,
13  *    without modification, immediately at the beginning of the file.
14  * 2. The name of the author may not be used to endorse or promote products
15  *    derived from this software without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
21  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
32 
33 
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/kernel.h>
37 #include <sys/conf.h>
38 #include <sys/malloc.h>
39 #include <sys/poll.h>
40 #include <sys/vnode.h>
41 #include <sys/lock.h>
42 #include <sys/mutex.h>
43 #include <sys/devicestat.h>
44 #include <sys/proc.h>
45 
46 #include <cam/cam.h>
47 #include <cam/cam_ccb.h>
48 #include <cam/cam_periph.h>
49 #include <cam/cam_xpt_periph.h>
50 #include <cam/cam_sim.h>
51 #include <cam/scsi/scsi_targetio.h>
52 
53 /* Transaction information attached to each CCB sent by the user */
54 struct targ_cmd_descr {
55 	struct cam_periph_map_info  mapinfo;
56 	TAILQ_ENTRY(targ_cmd_descr) tqe;
57 	union ccb *user_ccb;
58 	int	   priority;
59 	int	   func_code;
60 };
61 
62 /* Offset into the private CCB area for storing our descriptor */
63 #define targ_descr	periph_priv.entries[1].ptr
64 
65 TAILQ_HEAD(descr_queue, targ_cmd_descr);
66 
67 typedef enum {
68 	TARG_STATE_RESV		= 0x00, /* Invalid state */
69 	TARG_STATE_OPENED	= 0x01, /* Device opened, softc initialized */
70 	TARG_STATE_LUN_ENABLED	= 0x02  /* Device enabled for a path */
71 } targ_state;
72 
73 /* Per-instance device software context */
74 struct targ_softc {
75 	/* CCBs (CTIOs, ATIOs, INOTs) pending on the controller */
76 	struct ccb_queue	 pending_ccb_queue;
77 
78 	/* Command descriptors awaiting CTIO resources from the XPT */
79 	struct descr_queue	 work_queue;
80 
81 	/* Command descriptors that have been aborted back to the user. */
82 	struct descr_queue	 abort_queue;
83 
84 	/*
85 	 * Queue of CCBs that have been copied out to userland, but our
86 	 * userland daemon has not yet seen.
87 	 */
88 	struct ccb_queue	 user_ccb_queue;
89 
90 	struct cam_periph	*periph;
91 	struct cam_path		*path;
92 	targ_state		 state;
93 	struct selinfo		 read_select;
94 	struct devstat		 device_stats;
95 };
96 
97 static d_open_t		targopen;
98 static d_close_t	targclose;
99 static d_read_t		targread;
100 static d_write_t	targwrite;
101 static d_ioctl_t	targioctl;
102 static d_poll_t		targpoll;
103 static d_kqfilter_t	targkqfilter;
104 static void		targreadfiltdetach(struct knote *kn);
105 static int		targreadfilt(struct knote *kn, long hint);
106 static struct filterops targread_filtops =
107 	{ 1, NULL, targreadfiltdetach, targreadfilt };
108 
109 static struct cdevsw targ_cdevsw = {
110 	.d_version =	D_VERSION,
111 	.d_flags =	D_NEEDGIANT,
112 	.d_open =	targopen,
113 	.d_close =	targclose,
114 	.d_read =	targread,
115 	.d_write =	targwrite,
116 	.d_ioctl =	targioctl,
117 	.d_poll =	targpoll,
118 	.d_name =	"targ",
119 	.d_kqfilter =	targkqfilter
120 };
121 
122 static cam_status	targendislun(struct cam_path *path, int enable,
123 				     int grp6_len, int grp7_len);
124 static cam_status	targenable(struct targ_softc *softc,
125 				   struct cam_path *path,
126 				   int grp6_len, int grp7_len);
127 static cam_status	targdisable(struct targ_softc *softc);
128 static periph_ctor_t    targctor;
129 static periph_dtor_t    targdtor;
130 static periph_start_t   targstart;
131 static int		targusermerge(struct targ_softc *softc,
132 				      struct targ_cmd_descr *descr,
133 				      union ccb *ccb);
134 static int		targsendccb(struct targ_softc *softc, union ccb *ccb,
135 				    struct targ_cmd_descr *descr);
136 static void		targdone(struct cam_periph *periph,
137 				 union  ccb *done_ccb);
138 static int		targreturnccb(struct targ_softc *softc,
139 				      union  ccb *ccb);
140 static union ccb *	targgetccb(struct targ_softc *softc, xpt_opcode type,
141 				   int priority);
142 static void		targfreeccb(struct targ_softc *softc, union ccb *ccb);
143 static struct targ_cmd_descr *
144 			targgetdescr(struct targ_softc *softc);
145 static periph_init_t	targinit;
146 static void		targclone(void *arg, struct ucred *cred, char *name,
147 				  int namelen, struct cdev **dev);
148 static void		targasync(void *callback_arg, u_int32_t code,
149 				  struct cam_path *path, void *arg);
150 static void		abort_all_pending(struct targ_softc *softc);
151 static void		notify_user(struct targ_softc *softc);
152 static int		targcamstatus(cam_status status);
153 static size_t		targccblen(xpt_opcode func_code);
154 
155 static struct periph_driver targdriver =
156 {
157 	targinit, "targ",
158 	TAILQ_HEAD_INITIALIZER(targdriver.units), /* generation */ 0
159 };
160 PERIPHDRIVER_DECLARE(targ, targdriver);
161 
162 static MALLOC_DEFINE(M_TARG, "TARG", "TARG data");
163 
164 /*
165  * Create softc and initialize it. Only one proc can open each targ device.
166  * There is no locking here because a periph doesn't get created until an
167  * ioctl is issued to do so, and that can't happen until this method returns.
168  */
169 static int
170 targopen(struct cdev *dev, int flags, int fmt, struct thread *td)
171 {
172 	struct targ_softc *softc;
173 
174 	if (dev->si_drv1 != 0) {
175 		return (EBUSY);
176 	}
177 
178 	/* Mark device busy before any potentially blocking operations */
179 	dev->si_drv1 = (void *)~0;
180 
181 	/* Create the targ device, allocate its softc, initialize it */
182 	if ((dev->si_flags & SI_NAMED) == 0) {
183 		make_dev(&targ_cdevsw, minor(dev), UID_ROOT, GID_WHEEL, 0600,
184 			 "targ%d", dev2unit(dev));
185 	}
186 	MALLOC(softc, struct targ_softc *, sizeof(*softc), M_TARG,
187 	       M_WAITOK | M_ZERO);
188 	dev->si_drv1 = softc;
189 	softc->state = TARG_STATE_OPENED;
190 	softc->periph = NULL;
191 	softc->path = NULL;
192 
193 	TAILQ_INIT(&softc->pending_ccb_queue);
194 	TAILQ_INIT(&softc->work_queue);
195 	TAILQ_INIT(&softc->abort_queue);
196 	TAILQ_INIT(&softc->user_ccb_queue);
197 	knlist_init(&softc->read_select.si_note, NULL, NULL, NULL, NULL);
198 
199 	return (0);
200 }
201 
202 /* Disable LUN if enabled and teardown softc */
203 static int
204 targclose(struct cdev *dev, int flag, int fmt, struct thread *td)
205 {
206 	struct targ_softc     *softc;
207 	struct cam_periph     *periph;
208 	int    error;
209 
210 	softc = (struct targ_softc *)dev->si_drv1;
211 	if ((softc->periph == NULL) ||
212 	    (softc->state & TARG_STATE_LUN_ENABLED) == 0) {
213 		destroy_dev(dev);
214 		FREE(softc, M_TARG);
215 		return (0);
216 	}
217 
218 	/*
219 	 * Acquire a hold on the periph so that it doesn't go away before
220 	 * we are ready at the end of the function.
221 	 */
222 	periph = softc->periph;
223 	cam_periph_acquire(periph);
224 	cam_periph_lock(periph);
225 	error = targdisable(softc);
226 	if (error == CAM_REQ_CMP) {
227 		dev->si_drv1 = 0;
228 		if (softc->periph != NULL) {
229 			cam_periph_invalidate(softc->periph);
230 			softc->periph = NULL;
231 		}
232 		destroy_dev(dev);
233 		FREE(softc, M_TARG);
234 	}
235 	cam_periph_unlock(periph);
236 	cam_periph_release(periph);
237 
238 	return (error);
239 }
240 
241 /* Enable/disable LUNs, set debugging level */
242 static int
243 targioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flag, struct thread *td)
244 {
245 	struct targ_softc *softc;
246 	cam_status	   status;
247 
248 	softc = (struct targ_softc *)dev->si_drv1;
249 
250 	switch (cmd) {
251 	case TARGIOCENABLE:
252 	{
253 		struct ioc_enable_lun	*new_lun;
254 		struct cam_path		*path;
255 		struct cam_sim		*sim;
256 
257 		new_lun = (struct ioc_enable_lun *)addr;
258 		status = xpt_create_path_unlocked(&path, /*periph*/NULL,
259 						  new_lun->path_id,
260 						  new_lun->target_id,
261 						  new_lun->lun_id);
262 		if (status != CAM_REQ_CMP) {
263 			printf("Couldn't create path, status %#x\n", status);
264 			break;
265 		}
266 		sim = xpt_path_sim(path);
267 		mtx_lock(sim->mtx);
268 		status = targenable(softc, path, new_lun->grp6_len,
269 				    new_lun->grp7_len);
270 		xpt_free_path(path);
271 		mtx_unlock(sim->mtx);
272 		break;
273 	}
274 	case TARGIOCDISABLE:
275 		if (softc->periph == NULL) {
276 			status = CAM_DEV_NOT_THERE;
277 			break;
278 		}
279 		cam_periph_lock(softc->periph);
280 		status = targdisable(softc);
281 		cam_periph_unlock(softc->periph);
282 		break;
283 	case TARGIOCDEBUG:
284 	{
285 #ifdef	CAMDEBUG
286 		struct ccb_debug cdbg;
287 
288 		/* If no periph available, disallow debugging changes */
289 		if ((softc->state & TARG_STATE_LUN_ENABLED) == 0) {
290 			status = CAM_DEV_NOT_THERE;
291 			break;
292 		}
293 		bzero(&cdbg, sizeof cdbg);
294 		if (*((int *)addr) != 0)
295 			cdbg.flags = CAM_DEBUG_PERIPH;
296 		else
297 			cdbg.flags = CAM_DEBUG_NONE;
298 		cam_periph_lock(softc->periph);
299 		xpt_setup_ccb(&cdbg.ccb_h, softc->path, /*priority*/0);
300 		cdbg.ccb_h.func_code = XPT_DEBUG;
301 		cdbg.ccb_h.cbfcnp = targdone;
302 
303 		xpt_action((union ccb *)&cdbg);
304 		cam_periph_unlock(softc->periph);
305 		status = cdbg.ccb_h.status & CAM_STATUS_MASK;
306 #else
307 		status = CAM_FUNC_NOTAVAIL;
308 #endif
309 		break;
310 	}
311 	default:
312 		status = CAM_PROVIDE_FAIL;
313 		break;
314 	}
315 
316 	return (targcamstatus(status));
317 }
318 
319 /* Writes are always ready, reads wait for user_ccb_queue or abort_queue */
320 static int
321 targpoll(struct cdev *dev, int poll_events, struct thread *td)
322 {
323 	struct targ_softc *softc;
324 	int	revents;
325 
326 	softc = (struct targ_softc *)dev->si_drv1;
327 
328 	/* Poll for write() is always ok. */
329 	revents = poll_events & (POLLOUT | POLLWRNORM);
330 	if ((poll_events & (POLLIN | POLLRDNORM)) != 0) {
331 		/* Poll for read() depends on user and abort queues. */
332 		cam_periph_lock(softc->periph);
333 		if (!TAILQ_EMPTY(&softc->user_ccb_queue) ||
334 		    !TAILQ_EMPTY(&softc->abort_queue)) {
335 			revents |= poll_events & (POLLIN | POLLRDNORM);
336 		}
337 		cam_periph_unlock(softc->periph);
338 		/* Only sleep if the user didn't poll for write. */
339 		if (revents == 0)
340 			selrecord(td, &softc->read_select);
341 	}
342 
343 	return (revents);
344 }
345 
346 static int
347 targkqfilter(struct cdev *dev, struct knote *kn)
348 {
349 	struct  targ_softc *softc;
350 
351 	softc = (struct targ_softc *)dev->si_drv1;
352 	kn->kn_hook = (caddr_t)softc;
353 	kn->kn_fop = &targread_filtops;
354 	knlist_add(&softc->read_select.si_note, kn, 0);
355 	return (0);
356 }
357 
358 static void
359 targreadfiltdetach(struct knote *kn)
360 {
361 	struct  targ_softc *softc;
362 
363 	softc = (struct targ_softc *)kn->kn_hook;
364 	knlist_remove(&softc->read_select.si_note, kn, 0);
365 }
366 
367 /* Notify the user's kqueue when the user queue or abort queue gets a CCB */
368 static int
369 targreadfilt(struct knote *kn, long hint)
370 {
371 	struct targ_softc *softc;
372 	int	retval;
373 
374 	softc = (struct targ_softc *)kn->kn_hook;
375 	cam_periph_lock(softc->periph);
376 	retval = !TAILQ_EMPTY(&softc->user_ccb_queue) ||
377 		 !TAILQ_EMPTY(&softc->abort_queue);
378 	cam_periph_unlock(softc->periph);
379 	return (retval);
380 }
381 
382 /* Send the HBA the enable/disable message */
383 static cam_status
384 targendislun(struct cam_path *path, int enable, int grp6_len, int grp7_len)
385 {
386 	struct ccb_en_lun en_ccb;
387 	cam_status	  status;
388 
389 	/* Tell the lun to begin answering selects */
390 	xpt_setup_ccb(&en_ccb.ccb_h, path, /*priority*/1);
391 	en_ccb.ccb_h.func_code = XPT_EN_LUN;
392 	/* Don't need support for any vendor specific commands */
393 	en_ccb.grp6_len = grp6_len;
394 	en_ccb.grp7_len = grp7_len;
395 	en_ccb.enable = enable ? 1 : 0;
396 	xpt_action((union ccb *)&en_ccb);
397 	status = en_ccb.ccb_h.status & CAM_STATUS_MASK;
398 	if (status != CAM_REQ_CMP) {
399 		xpt_print(path, "%sable lun CCB rejected, status %#x\n",
400 		    enable ? "en" : "dis", status);
401 	}
402 	return (status);
403 }
404 
405 /* Enable target mode on a LUN, given its path */
406 static cam_status
407 targenable(struct targ_softc *softc, struct cam_path *path, int grp6_len,
408 	   int grp7_len)
409 {
410 	struct cam_periph *periph;
411 	struct ccb_pathinq cpi;
412 	cam_status	   status;
413 
414 	if ((softc->state & TARG_STATE_LUN_ENABLED) != 0)
415 		return (CAM_LUN_ALRDY_ENA);
416 
417 	/* Make sure SIM supports target mode */
418 	xpt_setup_ccb(&cpi.ccb_h, path, /*priority*/1);
419 	cpi.ccb_h.func_code = XPT_PATH_INQ;
420 	xpt_action((union ccb *)&cpi);
421 	status = cpi.ccb_h.status & CAM_STATUS_MASK;
422 	if (status != CAM_REQ_CMP) {
423 		printf("pathinq failed, status %#x\n", status);
424 		goto enable_fail;
425 	}
426 	if ((cpi.target_sprt & PIT_PROCESSOR) == 0) {
427 		printf("controller does not support target mode\n");
428 		status = CAM_FUNC_NOTAVAIL;
429 		goto enable_fail;
430 	}
431 
432 	/* Destroy any periph on our path if it is disabled */
433 	periph = cam_periph_find(path, "targ");
434 	if (periph != NULL) {
435 		struct targ_softc *del_softc;
436 
437 		del_softc = (struct targ_softc *)periph->softc;
438 		if ((del_softc->state & TARG_STATE_LUN_ENABLED) == 0) {
439 			cam_periph_invalidate(del_softc->periph);
440 			del_softc->periph = NULL;
441 		} else {
442 			printf("Requested path still in use by targ%d\n",
443 			       periph->unit_number);
444 			status = CAM_LUN_ALRDY_ENA;
445 			goto enable_fail;
446 		}
447 	}
448 
449 	/* Create a periph instance attached to this path */
450 	status = cam_periph_alloc(targctor, NULL, targdtor, targstart,
451 			"targ", CAM_PERIPH_BIO, path, targasync, 0, softc);
452 	if (status != CAM_REQ_CMP) {
453 		printf("cam_periph_alloc failed, status %#x\n", status);
454 		goto enable_fail;
455 	}
456 
457 	/* Ensure that the periph now exists. */
458 	if (cam_periph_find(path, "targ") == NULL) {
459 		panic("targenable: succeeded but no periph?");
460 		/* NOTREACHED */
461 	}
462 
463 	/* Send the enable lun message */
464 	status = targendislun(path, /*enable*/1, grp6_len, grp7_len);
465 	if (status != CAM_REQ_CMP) {
466 		printf("enable lun failed, status %#x\n", status);
467 		goto enable_fail;
468 	}
469 	softc->state |= TARG_STATE_LUN_ENABLED;
470 
471 enable_fail:
472 	return (status);
473 }
474 
475 /* Disable this softc's target instance if enabled */
476 static cam_status
477 targdisable(struct targ_softc *softc)
478 {
479 	cam_status status;
480 
481 	if ((softc->state & TARG_STATE_LUN_ENABLED) == 0)
482 		return (CAM_REQ_CMP);
483 
484 	CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH, ("targdisable\n"));
485 
486 	/* Abort any ccbs pending on the controller */
487 	abort_all_pending(softc);
488 
489 	/* Disable this lun */
490 	status = targendislun(softc->path, /*enable*/0,
491 			      /*grp6_len*/0, /*grp7_len*/0);
492 	if (status == CAM_REQ_CMP)
493 		softc->state &= ~TARG_STATE_LUN_ENABLED;
494 	else
495 		printf("Disable lun failed, status %#x\n", status);
496 
497 	return (status);
498 }
499 
500 /* Initialize a periph (called from cam_periph_alloc) */
501 static cam_status
502 targctor(struct cam_periph *periph, void *arg)
503 {
504 	struct targ_softc *softc;
505 
506 	/* Store pointer to softc for periph-driven routines */
507 	softc = (struct targ_softc *)arg;
508 	periph->softc = softc;
509 	softc->periph = periph;
510 	softc->path = periph->path;
511 	return (CAM_REQ_CMP);
512 }
513 
514 static void
515 targdtor(struct cam_periph *periph)
516 {
517 	struct targ_softc     *softc;
518 	struct ccb_hdr	      *ccb_h;
519 	struct targ_cmd_descr *descr;
520 
521 	softc = (struct targ_softc *)periph->softc;
522 
523 	/*
524 	 * targdisable() aborts CCBs back to the user and leaves them
525 	 * on user_ccb_queue and abort_queue in case the user is still
526 	 * interested in them.  We free them now.
527 	 */
528 	while ((ccb_h = TAILQ_FIRST(&softc->user_ccb_queue)) != NULL) {
529 		TAILQ_REMOVE(&softc->user_ccb_queue, ccb_h, periph_links.tqe);
530 		targfreeccb(softc, (union ccb *)ccb_h);
531 	}
532 	while ((descr = TAILQ_FIRST(&softc->abort_queue)) != NULL) {
533 		TAILQ_REMOVE(&softc->abort_queue, descr, tqe);
534 		FREE(descr, M_TARG);
535 	}
536 
537 	softc->periph = NULL;
538 	softc->path = NULL;
539 	periph->softc = NULL;
540 }
541 
542 /* Receive CCBs from user mode proc and send them to the HBA */
543 static int
544 targwrite(struct cdev *dev, struct uio *uio, int ioflag)
545 {
546 	union ccb *user_ccb;
547 	struct targ_softc *softc;
548 	struct targ_cmd_descr *descr;
549 	int write_len, error;
550 	int func_code, priority;
551 
552 	softc = (struct targ_softc *)dev->si_drv1;
553 	write_len = error = 0;
554 	CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH,
555 		  ("write - uio_resid %d\n", uio->uio_resid));
556 	while (uio->uio_resid >= sizeof(user_ccb) && error == 0) {
557 		union ccb *ccb;
558 
559 		error = uiomove((caddr_t)&user_ccb, sizeof(user_ccb), uio);
560 		if (error != 0) {
561 			CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH,
562 				  ("write - uiomove failed (%d)\n", error));
563 			break;
564 		}
565 		priority = fuword32(&user_ccb->ccb_h.pinfo.priority);
566 		if (priority == -1) {
567 			error = EINVAL;
568 			break;
569 		}
570 		func_code = fuword32(&user_ccb->ccb_h.func_code);
571 		switch (func_code) {
572 		case XPT_ACCEPT_TARGET_IO:
573 		case XPT_IMMED_NOTIFY:
574 			cam_periph_lock(softc->periph);
575 			ccb = targgetccb(softc, func_code, priority);
576 			descr = (struct targ_cmd_descr *)ccb->ccb_h.targ_descr;
577 			descr->user_ccb = user_ccb;
578 			descr->func_code = func_code;
579 			CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH,
580 				  ("Sent ATIO/INOT (%p)\n", user_ccb));
581 			xpt_action(ccb);
582 			TAILQ_INSERT_TAIL(&softc->pending_ccb_queue,
583 					  &ccb->ccb_h,
584 					  periph_links.tqe);
585 			cam_periph_unlock(softc->periph);
586 			break;
587 		default:
588 			cam_periph_lock(softc->periph);
589 			if ((func_code & XPT_FC_QUEUED) != 0) {
590 				CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH,
591 					  ("Sending queued ccb %#x (%p)\n",
592 					  func_code, user_ccb));
593 				descr = targgetdescr(softc);
594 				descr->user_ccb = user_ccb;
595 				descr->priority = priority;
596 				descr->func_code = func_code;
597 				TAILQ_INSERT_TAIL(&softc->work_queue,
598 						  descr, tqe);
599 				xpt_schedule(softc->periph, priority);
600 			} else {
601 				CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH,
602 					  ("Sending inline ccb %#x (%p)\n",
603 					  func_code, user_ccb));
604 				ccb = targgetccb(softc, func_code, priority);
605 				descr = (struct targ_cmd_descr *)
606 					 ccb->ccb_h.targ_descr;
607 				descr->user_ccb = user_ccb;
608 				descr->priority = priority;
609 				descr->func_code = func_code;
610 				if (targusermerge(softc, descr, ccb) != EFAULT)
611 					targsendccb(softc, ccb, descr);
612 				targreturnccb(softc, ccb);
613 			}
614 			cam_periph_unlock(softc->periph);
615 			break;
616 		}
617 		write_len += sizeof(user_ccb);
618 	}
619 
620 	/*
621 	 * If we've successfully taken in some amount of
622 	 * data, return success for that data first.  If
623 	 * an error is persistent, it will be reported
624 	 * on the next write.
625 	 */
626 	if (error != 0 && write_len == 0)
627 		return (error);
628 	if (write_len == 0 && uio->uio_resid != 0)
629 		return (ENOSPC);
630 	return (0);
631 }
632 
633 /* Process requests (descrs) via the periph-supplied CCBs */
634 static void
635 targstart(struct cam_periph *periph, union ccb *start_ccb)
636 {
637 	struct targ_softc *softc;
638 	struct targ_cmd_descr *descr, *next_descr;
639 	int error;
640 
641 	softc = (struct targ_softc *)periph->softc;
642 	CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH, ("targstart %p\n", start_ccb));
643 
644 	descr = TAILQ_FIRST(&softc->work_queue);
645 	if (descr == NULL) {
646 		xpt_release_ccb(start_ccb);
647 	} else {
648 		TAILQ_REMOVE(&softc->work_queue, descr, tqe);
649 		next_descr = TAILQ_FIRST(&softc->work_queue);
650 
651 		/* Initiate a transaction using the descr and supplied CCB */
652 		error = targusermerge(softc, descr, start_ccb);
653 		if (error == 0)
654 			error = targsendccb(softc, start_ccb, descr);
655 		if (error != 0) {
656 			xpt_print(periph->path,
657 			    "targsendccb failed, err %d\n", error);
658 			xpt_release_ccb(start_ccb);
659 			suword(&descr->user_ccb->ccb_h.status,
660 			       CAM_REQ_CMP_ERR);
661 			TAILQ_INSERT_TAIL(&softc->abort_queue, descr, tqe);
662 			notify_user(softc);
663 		}
664 
665 		/* If we have more work to do, stay scheduled */
666 		if (next_descr != NULL)
667 			xpt_schedule(periph, next_descr->priority);
668 	}
669 }
670 
671 static int
672 targusermerge(struct targ_softc *softc, struct targ_cmd_descr *descr,
673 	      union ccb *ccb)
674 {
675 	struct ccb_hdr *u_ccbh, *k_ccbh;
676 	size_t ccb_len;
677 	int error;
678 
679 	u_ccbh = &descr->user_ccb->ccb_h;
680 	k_ccbh = &ccb->ccb_h;
681 
682 	/*
683 	 * There are some fields in the CCB header that need to be
684 	 * preserved, the rest we get from the user ccb. (See xpt_merge_ccb)
685 	 */
686 	xpt_setup_ccb(k_ccbh, softc->path, descr->priority);
687 	k_ccbh->retry_count = fuword32(&u_ccbh->retry_count);
688 	k_ccbh->func_code = descr->func_code;
689 	k_ccbh->flags = fuword32(&u_ccbh->flags);
690 	k_ccbh->timeout = fuword32(&u_ccbh->timeout);
691 	ccb_len = targccblen(k_ccbh->func_code) - sizeof(struct ccb_hdr);
692 	error = copyin(u_ccbh + 1, k_ccbh + 1, ccb_len);
693 	if (error != 0) {
694 		k_ccbh->status = CAM_REQ_CMP_ERR;
695 		return (error);
696 	}
697 
698 	/* Translate usermode abort_ccb pointer to its kernel counterpart */
699 	if (k_ccbh->func_code == XPT_ABORT) {
700 		struct ccb_abort *cab;
701 		struct ccb_hdr *ccb_h;
702 
703 		cab = (struct ccb_abort *)ccb;
704 		TAILQ_FOREACH(ccb_h, &softc->pending_ccb_queue,
705 		    periph_links.tqe) {
706 			struct targ_cmd_descr *ab_descr;
707 
708 			ab_descr = (struct targ_cmd_descr *)ccb_h->targ_descr;
709 			if (ab_descr->user_ccb == cab->abort_ccb) {
710 				CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH,
711 					  ("Changing abort for %p to %p\n",
712 					  cab->abort_ccb, ccb_h));
713 				cab->abort_ccb = (union ccb *)ccb_h;
714 				break;
715 			}
716 		}
717 		/* CCB not found, set appropriate status */
718 		if (ccb_h == NULL) {
719 			k_ccbh->status = CAM_PATH_INVALID;
720 			error = ESRCH;
721 		}
722 	}
723 
724 	return (error);
725 }
726 
727 /* Build and send a kernel CCB formed from descr->user_ccb */
728 static int
729 targsendccb(struct targ_softc *softc, union ccb *ccb,
730 	    struct targ_cmd_descr *descr)
731 {
732 	struct cam_periph_map_info *mapinfo;
733 	struct ccb_hdr *ccb_h;
734 	int error;
735 
736 	ccb_h = &ccb->ccb_h;
737 	mapinfo = &descr->mapinfo;
738 	mapinfo->num_bufs_used = 0;
739 
740 	/*
741 	 * There's no way for the user to have a completion
742 	 * function, so we put our own completion function in here.
743 	 * We also stash in a reference to our descriptor so targreturnccb()
744 	 * can find our mapping info.
745 	 */
746 	ccb_h->cbfcnp = targdone;
747 	ccb_h->targ_descr = descr;
748 
749 	/*
750 	 * We only attempt to map the user memory into kernel space
751 	 * if they haven't passed in a physical memory pointer,
752 	 * and if there is actually an I/O operation to perform.
753 	 * Right now cam_periph_mapmem() only supports SCSI and device
754 	 * match CCBs.  For the SCSI CCBs, we only pass the CCB in if
755 	 * there's actually data to map.  cam_periph_mapmem() will do the
756 	 * right thing, even if there isn't data to map, but since CCBs
757 	 * without data are a reasonably common occurance (e.g. test unit
758 	 * ready), it will save a few cycles if we check for it here.
759 	 */
760 	if (((ccb_h->flags & CAM_DATA_PHYS) == 0)
761 	 && (((ccb_h->func_code == XPT_CONT_TARGET_IO)
762 	    && ((ccb_h->flags & CAM_DIR_MASK) != CAM_DIR_NONE))
763 	  || (ccb_h->func_code == XPT_DEV_MATCH))) {
764 
765 		error = cam_periph_mapmem(ccb, mapinfo);
766 
767 		/*
768 		 * cam_periph_mapmem returned an error, we can't continue.
769 		 * Return the error to the user.
770 		 */
771 		if (error) {
772 			ccb_h->status = CAM_REQ_CMP_ERR;
773 			mapinfo->num_bufs_used = 0;
774 			return (error);
775 		}
776 	}
777 
778 	/*
779 	 * Once queued on the pending CCB list, this CCB will be protected
780 	 * by our error recovery handler.
781 	 */
782 	CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH, ("sendccb %p\n", ccb));
783 	if (XPT_FC_IS_QUEUED(ccb)) {
784 		TAILQ_INSERT_TAIL(&softc->pending_ccb_queue, ccb_h,
785 				  periph_links.tqe);
786 	}
787 	xpt_action(ccb);
788 
789 	return (0);
790 }
791 
792 /* Completion routine for CCBs (called at splsoftcam) */
793 static void
794 targdone(struct cam_periph *periph, union ccb *done_ccb)
795 {
796 	struct targ_softc *softc;
797 	cam_status status;
798 
799 	CAM_DEBUG(periph->path, CAM_DEBUG_PERIPH, ("targdone %p\n", done_ccb));
800 	softc = (struct targ_softc *)periph->softc;
801 	TAILQ_REMOVE(&softc->pending_ccb_queue, &done_ccb->ccb_h,
802 		     periph_links.tqe);
803 	status = done_ccb->ccb_h.status & CAM_STATUS_MASK;
804 
805 	/* If we're no longer enabled, throw away CCB */
806 	if ((softc->state & TARG_STATE_LUN_ENABLED) == 0) {
807 		targfreeccb(softc, done_ccb);
808 		return;
809 	}
810 	/* abort_all_pending() waits for pending queue to be empty */
811 	if (TAILQ_EMPTY(&softc->pending_ccb_queue))
812 		wakeup(&softc->pending_ccb_queue);
813 
814 	switch (done_ccb->ccb_h.func_code) {
815 	/* All FC_*_QUEUED CCBs go back to userland */
816 	case XPT_IMMED_NOTIFY:
817 	case XPT_ACCEPT_TARGET_IO:
818 	case XPT_CONT_TARGET_IO:
819 		TAILQ_INSERT_TAIL(&softc->user_ccb_queue, &done_ccb->ccb_h,
820 				  periph_links.tqe);
821 		notify_user(softc);
822 		break;
823 	default:
824 		panic("targdone: impossible xpt opcode %#x",
825 		      done_ccb->ccb_h.func_code);
826 		/* NOTREACHED */
827 	}
828 }
829 
830 /* Return CCBs to the user from the user queue and abort queue */
831 static int
832 targread(struct cdev *dev, struct uio *uio, int ioflag)
833 {
834 	struct descr_queue	*abort_queue;
835 	struct targ_cmd_descr	*user_descr;
836 	struct targ_softc	*softc;
837 	struct ccb_queue  *user_queue;
838 	struct ccb_hdr	  *ccb_h;
839 	union  ccb	  *user_ccb;
840 	int		   read_len, error;
841 
842 	error = 0;
843 	read_len = 0;
844 	softc = (struct targ_softc *)dev->si_drv1;
845 	user_queue = &softc->user_ccb_queue;
846 	abort_queue = &softc->abort_queue;
847 	CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH, ("targread\n"));
848 
849 	/* If no data is available, wait or return immediately */
850 	cam_periph_lock(softc->periph);
851 	ccb_h = TAILQ_FIRST(user_queue);
852 	user_descr = TAILQ_FIRST(abort_queue);
853 	while (ccb_h == NULL && user_descr == NULL) {
854 		if ((ioflag & IO_NDELAY) == 0) {
855 			error = msleep(user_queue, softc->periph->sim->mtx,
856 			    PRIBIO | PCATCH, "targrd", 0);
857 			ccb_h = TAILQ_FIRST(user_queue);
858 			user_descr = TAILQ_FIRST(abort_queue);
859 			if (error != 0) {
860 				if (error == ERESTART) {
861 					continue;
862 				} else {
863 					goto read_fail;
864 				}
865 			}
866 		} else {
867 			cam_periph_unlock(softc->periph);
868 			return (EAGAIN);
869 		}
870 	}
871 
872 	/* Data is available so fill the user's buffer */
873 	while (ccb_h != NULL) {
874 		struct targ_cmd_descr *descr;
875 
876 		if (uio->uio_resid < sizeof(user_ccb))
877 			break;
878 		TAILQ_REMOVE(user_queue, ccb_h, periph_links.tqe);
879 		descr = (struct targ_cmd_descr *)ccb_h->targ_descr;
880 		user_ccb = descr->user_ccb;
881 		CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH,
882 			  ("targread ccb %p (%p)\n", ccb_h, user_ccb));
883 		error = targreturnccb(softc, (union ccb *)ccb_h);
884 		if (error != 0)
885 			goto read_fail;
886 		cam_periph_unlock(softc->periph);
887 		error = uiomove((caddr_t)&user_ccb, sizeof(user_ccb), uio);
888 		cam_periph_lock(softc->periph);
889 		if (error != 0)
890 			goto read_fail;
891 		read_len += sizeof(user_ccb);
892 
893 		ccb_h = TAILQ_FIRST(user_queue);
894 	}
895 
896 	/* Flush out any aborted descriptors */
897 	while (user_descr != NULL) {
898 		if (uio->uio_resid < sizeof(user_ccb))
899 			break;
900 		TAILQ_REMOVE(abort_queue, user_descr, tqe);
901 		user_ccb = user_descr->user_ccb;
902 		CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH,
903 			  ("targread aborted descr %p (%p)\n",
904 			  user_descr, user_ccb));
905 		suword(&user_ccb->ccb_h.status, CAM_REQ_ABORTED);
906 		cam_periph_unlock(softc->periph);
907 		error = uiomove((caddr_t)&user_ccb, sizeof(user_ccb), uio);
908 		cam_periph_lock(softc->periph);
909 		if (error != 0)
910 			goto read_fail;
911 		read_len += sizeof(user_ccb);
912 
913 		user_descr = TAILQ_FIRST(abort_queue);
914 	}
915 
916 	/*
917 	 * If we've successfully read some amount of data, don't report an
918 	 * error.  If the error is persistent, it will be reported on the
919 	 * next read().
920 	 */
921 	if (read_len == 0 && uio->uio_resid != 0)
922 		error = ENOSPC;
923 
924 read_fail:
925 	cam_periph_unlock(softc->periph);
926 	return (error);
927 }
928 
929 /* Copy completed ccb back to the user */
930 static int
931 targreturnccb(struct targ_softc *softc, union ccb *ccb)
932 {
933 	struct targ_cmd_descr *descr;
934 	struct ccb_hdr *u_ccbh;
935 	size_t ccb_len;
936 	int error;
937 
938 	CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH, ("targreturnccb %p\n", ccb));
939 	descr = (struct targ_cmd_descr *)ccb->ccb_h.targ_descr;
940 	u_ccbh = &descr->user_ccb->ccb_h;
941 
942 	/* Copy out the central portion of the ccb_hdr */
943 	copyout(&ccb->ccb_h.retry_count, &u_ccbh->retry_count,
944 		offsetof(struct ccb_hdr, periph_priv) -
945 		offsetof(struct ccb_hdr, retry_count));
946 
947 	/* Copy out the rest of the ccb (after the ccb_hdr) */
948 	ccb_len = targccblen(ccb->ccb_h.func_code) - sizeof(struct ccb_hdr);
949 	if (descr->mapinfo.num_bufs_used != 0)
950 		cam_periph_unmapmem(ccb, &descr->mapinfo);
951 	error = copyout(&ccb->ccb_h + 1, u_ccbh + 1, ccb_len);
952 	if (error != 0) {
953 		xpt_print(softc->path,
954 		    "targreturnccb - CCB copyout failed (%d)\n", error);
955 	}
956 	/* Free CCB or send back to devq. */
957 	targfreeccb(softc, ccb);
958 
959 	return (error);
960 }
961 
962 static union ccb *
963 targgetccb(struct targ_softc *softc, xpt_opcode type, int priority)
964 {
965 	union ccb *ccb;
966 	int ccb_len;
967 
968 	ccb_len = targccblen(type);
969 	MALLOC(ccb, union ccb *, ccb_len, M_TARG, M_WAITOK);
970 	CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH, ("getccb %p\n", ccb));
971 
972 	xpt_setup_ccb(&ccb->ccb_h, softc->path, priority);
973 	ccb->ccb_h.func_code = type;
974 	ccb->ccb_h.cbfcnp = targdone;
975 	ccb->ccb_h.targ_descr = targgetdescr(softc);
976 	return (ccb);
977 }
978 
979 static void
980 targfreeccb(struct targ_softc *softc, union ccb *ccb)
981 {
982 	CAM_DEBUG_PRINT(CAM_DEBUG_PERIPH, ("targfreeccb descr %p and\n",
983 			ccb->ccb_h.targ_descr));
984 	FREE(ccb->ccb_h.targ_descr, M_TARG);
985 
986 	switch (ccb->ccb_h.func_code) {
987 	case XPT_ACCEPT_TARGET_IO:
988 	case XPT_IMMED_NOTIFY:
989 		CAM_DEBUG_PRINT(CAM_DEBUG_PERIPH, ("freeing ccb %p\n", ccb));
990 		FREE(ccb, M_TARG);
991 		break;
992 	default:
993 		/* Send back CCB if we got it from the periph */
994 		if (XPT_FC_IS_QUEUED(ccb)) {
995 			CAM_DEBUG_PRINT(CAM_DEBUG_PERIPH,
996 					("returning queued ccb %p\n", ccb));
997 			xpt_release_ccb(ccb);
998 		} else {
999 			CAM_DEBUG_PRINT(CAM_DEBUG_PERIPH,
1000 					("freeing ccb %p\n", ccb));
1001 			FREE(ccb, M_TARG);
1002 		}
1003 		break;
1004 	}
1005 }
1006 
1007 static struct targ_cmd_descr *
1008 targgetdescr(struct targ_softc *softc)
1009 {
1010 	struct targ_cmd_descr *descr;
1011 
1012 	MALLOC(descr, struct targ_cmd_descr *, sizeof(*descr), M_TARG,
1013 	       M_WAITOK);
1014 	descr->mapinfo.num_bufs_used = 0;
1015 	return (descr);
1016 }
1017 
1018 static void
1019 targinit(void)
1020 {
1021 	EVENTHANDLER_REGISTER(dev_clone, targclone, 0, 1000);
1022 }
1023 
1024 static void
1025 targclone(void *arg, struct ucred *cred, char *name, int namelen,
1026     struct cdev **dev)
1027 {
1028 	int u;
1029 
1030 	if (*dev != NULL)
1031 		return;
1032 	if (dev_stdclone(name, NULL, "targ", &u) != 1)
1033 		return;
1034 	*dev = make_dev(&targ_cdevsw, unit2minor(u), UID_ROOT, GID_WHEEL,
1035 			0600, "targ%d", u);
1036 	dev_ref(*dev);
1037 	(*dev)->si_flags |= SI_CHEAPCLONE;
1038 }
1039 
1040 static void
1041 targasync(void *callback_arg, u_int32_t code, struct cam_path *path, void *arg)
1042 {
1043 	/* All events are handled in usermode by INOTs */
1044 	panic("targasync() called, should be an INOT instead");
1045 }
1046 
1047 /* Cancel all pending requests and CCBs awaiting work. */
1048 static void
1049 abort_all_pending(struct targ_softc *softc)
1050 {
1051 	struct targ_cmd_descr   *descr;
1052 	struct ccb_abort	 cab;
1053 	struct ccb_hdr		*ccb_h;
1054 	struct cam_sim		*sim;
1055 
1056 	CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH, ("abort_all_pending\n"));
1057 
1058 	/* First abort the descriptors awaiting resources */
1059 	while ((descr = TAILQ_FIRST(&softc->work_queue)) != NULL) {
1060 		CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH,
1061 			  ("Aborting descr from workq %p\n", descr));
1062 		TAILQ_REMOVE(&softc->work_queue, descr, tqe);
1063 		TAILQ_INSERT_TAIL(&softc->abort_queue, descr, tqe);
1064 	}
1065 
1066 	/*
1067 	 * Then abort all pending CCBs.
1068 	 * targdone() will return the aborted CCB via user_ccb_queue
1069 	 */
1070 	xpt_setup_ccb(&cab.ccb_h, softc->path, /*priority*/0);
1071 	cab.ccb_h.func_code = XPT_ABORT;
1072 	cab.ccb_h.status = CAM_REQ_CMP_ERR;
1073 	TAILQ_FOREACH(ccb_h, &softc->pending_ccb_queue, periph_links.tqe) {
1074 		CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH,
1075 			  ("Aborting pending CCB %p\n", ccb_h));
1076 		cab.abort_ccb = (union ccb *)ccb_h;
1077 		xpt_action((union ccb *)&cab);
1078 		if (cab.ccb_h.status != CAM_REQ_CMP) {
1079 			xpt_print(cab.ccb_h.path,
1080 			    "Unable to abort CCB, status %#x\n",
1081 			    cab.ccb_h.status);
1082 		}
1083 	}
1084 
1085 	/* If we aborted at least one pending CCB ok, wait for it. */
1086 	if (cab.ccb_h.status == CAM_REQ_CMP) {
1087 		sim = xpt_path_sim(softc->path);
1088 		msleep(&softc->pending_ccb_queue, sim->mtx,
1089 		       PRIBIO | PCATCH, "tgabrt", 0);
1090 	}
1091 
1092 	/* If we aborted anything from the work queue, wakeup user. */
1093 	if (!TAILQ_EMPTY(&softc->user_ccb_queue)
1094 	 || !TAILQ_EMPTY(&softc->abort_queue))
1095 		notify_user(softc);
1096 }
1097 
1098 /* Notify the user that data is ready */
1099 static void
1100 notify_user(struct targ_softc *softc)
1101 {
1102 	/*
1103 	 * Notify users sleeping via poll(), kqueue(), and
1104 	 * blocking read().
1105 	 */
1106 	selwakeuppri(&softc->read_select, PRIBIO);
1107 	KNOTE_UNLOCKED(&softc->read_select.si_note, 0);
1108 	wakeup(&softc->user_ccb_queue);
1109 }
1110 
1111 /* Convert CAM status to errno values */
1112 static int
1113 targcamstatus(cam_status status)
1114 {
1115 	switch (status & CAM_STATUS_MASK) {
1116 	case CAM_REQ_CMP:	/* CCB request completed without error */
1117 		return (0);
1118 	case CAM_REQ_INPROG:	/* CCB request is in progress */
1119 		return (EINPROGRESS);
1120 	case CAM_REQ_CMP_ERR:	/* CCB request completed with an error */
1121 		return (EIO);
1122 	case CAM_PROVIDE_FAIL:	/* Unable to provide requested capability */
1123 		return (ENOTTY);
1124 	case CAM_FUNC_NOTAVAIL:	/* The requested function is not available */
1125 		return (ENOTSUP);
1126 	case CAM_LUN_ALRDY_ENA:	/* LUN is already enabled for target mode */
1127 		return (EADDRINUSE);
1128 	case CAM_PATH_INVALID:	/* Supplied Path ID is invalid */
1129 	case CAM_DEV_NOT_THERE:	/* SCSI Device Not Installed/there */
1130 		return (ENOENT);
1131 	case CAM_REQ_ABORTED:	/* CCB request aborted by the host */
1132 		return (ECANCELED);
1133 	case CAM_CMD_TIMEOUT:	/* Command timeout */
1134 		return (ETIMEDOUT);
1135 	case CAM_REQUEUE_REQ:	/* Requeue to preserve transaction ordering */
1136 		return (EAGAIN);
1137 	case CAM_REQ_INVALID:	/* CCB request was invalid */
1138 		return (EINVAL);
1139 	case CAM_RESRC_UNAVAIL:	/* Resource Unavailable */
1140 		return (ENOMEM);
1141 	case CAM_BUSY:		/* CAM subsytem is busy */
1142 	case CAM_UA_ABORT:	/* Unable to abort CCB request */
1143 		return (EBUSY);
1144 	default:
1145 		return (ENXIO);
1146 	}
1147 }
1148 
1149 static size_t
1150 targccblen(xpt_opcode func_code)
1151 {
1152 	int len;
1153 
1154 	/* Codes we expect to see as a target */
1155 	switch (func_code) {
1156 	case XPT_CONT_TARGET_IO:
1157 	case XPT_SCSI_IO:
1158 		len = sizeof(struct ccb_scsiio);
1159 		break;
1160 	case XPT_ACCEPT_TARGET_IO:
1161 		len = sizeof(struct ccb_accept_tio);
1162 		break;
1163 	case XPT_IMMED_NOTIFY:
1164 		len = sizeof(struct ccb_immed_notify);
1165 		break;
1166 	case XPT_REL_SIMQ:
1167 		len = sizeof(struct ccb_relsim);
1168 		break;
1169 	case XPT_PATH_INQ:
1170 		len = sizeof(struct ccb_pathinq);
1171 		break;
1172 	case XPT_DEBUG:
1173 		len = sizeof(struct ccb_debug);
1174 		break;
1175 	case XPT_ABORT:
1176 		len = sizeof(struct ccb_abort);
1177 		break;
1178 	case XPT_EN_LUN:
1179 		len = sizeof(struct ccb_en_lun);
1180 		break;
1181 	default:
1182 		len = sizeof(union ccb);
1183 		break;
1184 	}
1185 
1186 	return (len);
1187 }
1188