xref: /freebsd/sys/cam/ctl/ctl_backend_ramdisk.c (revision 5bd73b51076b5cb5a2c9810f76c1d7ed20c4460e)
1 /*-
2  * Copyright (c) 2003, 2008 Silicon Graphics International Corp.
3  * Copyright (c) 2012 The FreeBSD Foundation
4  * All rights reserved.
5  *
6  * Portions of this software were developed by Edward Tomasz Napierala
7  * under sponsorship from the FreeBSD Foundation.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions, and the following disclaimer,
14  *    without modification.
15  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
16  *    substantially similar to the "NO WARRANTY" disclaimer below
17  *    ("Disclaimer") and any redistribution must be conditioned upon
18  *    including a substantially similar Disclaimer requirement for further
19  *    binary redistribution.
20  *
21  * NO WARRANTY
22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
24  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
25  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
26  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
30  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
31  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
32  * POSSIBILITY OF SUCH DAMAGES.
33  *
34  * $Id: //depot/users/kenm/FreeBSD-test2/sys/cam/ctl/ctl_backend_ramdisk.c#3 $
35  */
36 /*
37  * CAM Target Layer backend for a "fake" ramdisk.
38  *
39  * Author: Ken Merry <ken@FreeBSD.org>
40  */
41 
42 #include <sys/cdefs.h>
43 __FBSDID("$FreeBSD$");
44 
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/kernel.h>
48 #include <sys/condvar.h>
49 #include <sys/types.h>
50 #include <sys/lock.h>
51 #include <sys/mutex.h>
52 #include <sys/malloc.h>
53 #include <sys/taskqueue.h>
54 #include <sys/time.h>
55 #include <sys/queue.h>
56 #include <sys/conf.h>
57 #include <sys/ioccom.h>
58 #include <sys/module.h>
59 
60 #include <cam/scsi/scsi_all.h>
61 #include <cam/ctl/ctl_io.h>
62 #include <cam/ctl/ctl.h>
63 #include <cam/ctl/ctl_util.h>
64 #include <cam/ctl/ctl_backend.h>
65 #include <cam/ctl/ctl_frontend_internal.h>
66 #include <cam/ctl/ctl_debug.h>
67 #include <cam/ctl/ctl_ioctl.h>
68 #include <cam/ctl/ctl_error.h>
69 
70 typedef enum {
71 	CTL_BE_RAMDISK_LUN_UNCONFIGURED	= 0x01,
72 	CTL_BE_RAMDISK_LUN_CONFIG_ERR	= 0x02,
73 	CTL_BE_RAMDISK_LUN_WAITING	= 0x04
74 } ctl_be_ramdisk_lun_flags;
75 
76 struct ctl_be_ramdisk_lun {
77 	char lunname[32];
78 	uint64_t size_bytes;
79 	uint64_t size_blocks;
80 	struct ctl_be_ramdisk_softc *softc;
81 	ctl_be_ramdisk_lun_flags flags;
82 	STAILQ_ENTRY(ctl_be_ramdisk_lun) links;
83 	struct ctl_be_lun ctl_be_lun;
84 	struct taskqueue *io_taskqueue;
85 	struct task io_task;
86 	STAILQ_HEAD(, ctl_io_hdr) cont_queue;
87 	struct mtx_padalign queue_lock;
88 };
89 
90 struct ctl_be_ramdisk_softc {
91 	struct mtx lock;
92 	int rd_size;
93 #ifdef CTL_RAMDISK_PAGES
94 	uint8_t **ramdisk_pages;
95 	int num_pages;
96 #else
97 	uint8_t *ramdisk_buffer;
98 #endif
99 	int num_luns;
100 	STAILQ_HEAD(, ctl_be_ramdisk_lun) lun_list;
101 };
102 
103 static struct ctl_be_ramdisk_softc rd_softc;
104 
105 int ctl_backend_ramdisk_init(void);
106 void ctl_backend_ramdisk_shutdown(void);
107 static int ctl_backend_ramdisk_move_done(union ctl_io *io);
108 static int ctl_backend_ramdisk_submit(union ctl_io *io);
109 static void ctl_backend_ramdisk_continue(union ctl_io *io);
110 static int ctl_backend_ramdisk_ioctl(struct cdev *dev, u_long cmd,
111 				     caddr_t addr, int flag, struct thread *td);
112 static int ctl_backend_ramdisk_rm(struct ctl_be_ramdisk_softc *softc,
113 				  struct ctl_lun_req *req);
114 static int ctl_backend_ramdisk_create(struct ctl_be_ramdisk_softc *softc,
115 				      struct ctl_lun_req *req, int do_wait);
116 static int ctl_backend_ramdisk_modify(struct ctl_be_ramdisk_softc *softc,
117 				  struct ctl_lun_req *req);
118 static void ctl_backend_ramdisk_worker(void *context, int pending);
119 static void ctl_backend_ramdisk_lun_shutdown(void *be_lun);
120 static void ctl_backend_ramdisk_lun_config_status(void *be_lun,
121 						  ctl_lun_config_status status);
122 static int ctl_backend_ramdisk_config_write(union ctl_io *io);
123 static int ctl_backend_ramdisk_config_read(union ctl_io *io);
124 
125 static struct ctl_backend_driver ctl_be_ramdisk_driver =
126 {
127 	.name = "ramdisk",
128 	.flags = CTL_BE_FLAG_HAS_CONFIG,
129 	.init = ctl_backend_ramdisk_init,
130 	.data_submit = ctl_backend_ramdisk_submit,
131 	.data_move_done = ctl_backend_ramdisk_move_done,
132 	.config_read = ctl_backend_ramdisk_config_read,
133 	.config_write = ctl_backend_ramdisk_config_write,
134 	.ioctl = ctl_backend_ramdisk_ioctl
135 };
136 
137 MALLOC_DEFINE(M_RAMDISK, "ramdisk", "Memory used for CTL RAMdisk");
138 CTL_BACKEND_DECLARE(cbr, ctl_be_ramdisk_driver);
139 
140 int
141 ctl_backend_ramdisk_init(void)
142 {
143 	struct ctl_be_ramdisk_softc *softc;
144 #ifdef CTL_RAMDISK_PAGES
145 	int i;
146 #endif
147 
148 
149 	softc = &rd_softc;
150 
151 	memset(softc, 0, sizeof(*softc));
152 
153 	mtx_init(&softc->lock, "ctlramdisk", NULL, MTX_DEF);
154 
155 	STAILQ_INIT(&softc->lun_list);
156 	softc->rd_size = 1024 * 1024;
157 #ifdef CTL_RAMDISK_PAGES
158 	softc->num_pages = softc->rd_size / PAGE_SIZE;
159 	softc->ramdisk_pages = (uint8_t **)malloc(sizeof(uint8_t *) *
160 						  softc->num_pages, M_RAMDISK,
161 						  M_WAITOK);
162 	for (i = 0; i < softc->num_pages; i++)
163 		softc->ramdisk_pages[i] = malloc(PAGE_SIZE, M_RAMDISK,M_WAITOK);
164 #else
165 	softc->ramdisk_buffer = (uint8_t *)malloc(softc->rd_size, M_RAMDISK,
166 						  M_WAITOK);
167 #endif
168 
169 	return (0);
170 }
171 
172 void
173 ctl_backend_ramdisk_shutdown(void)
174 {
175 	struct ctl_be_ramdisk_softc *softc;
176 	struct ctl_be_ramdisk_lun *lun, *next_lun;
177 #ifdef CTL_RAMDISK_PAGES
178 	int i;
179 #endif
180 
181 	softc = &rd_softc;
182 
183 	mtx_lock(&softc->lock);
184 	for (lun = STAILQ_FIRST(&softc->lun_list); lun != NULL; lun = next_lun){
185 		/*
186 		 * Grab the next LUN.  The current LUN may get removed by
187 		 * ctl_invalidate_lun(), which will call our LUN shutdown
188 		 * routine, if there is no outstanding I/O for this LUN.
189 		 */
190 		next_lun = STAILQ_NEXT(lun, links);
191 
192 		/*
193 		 * Drop our lock here.  Since ctl_invalidate_lun() can call
194 		 * back into us, this could potentially lead to a recursive
195 		 * lock of the same mutex, which would cause a hang.
196 		 */
197 		mtx_unlock(&softc->lock);
198 		ctl_disable_lun(&lun->ctl_be_lun);
199 		ctl_invalidate_lun(&lun->ctl_be_lun);
200 		mtx_lock(&softc->lock);
201 	}
202 	mtx_unlock(&softc->lock);
203 
204 #ifdef CTL_RAMDISK_PAGES
205 	for (i = 0; i < softc->num_pages; i++)
206 		free(softc->ramdisk_pages[i], M_RAMDISK);
207 
208 	free(softc->ramdisk_pages, M_RAMDISK);
209 #else
210 	free(softc->ramdisk_buffer, M_RAMDISK);
211 #endif
212 
213 	if (ctl_backend_deregister(&ctl_be_ramdisk_driver) != 0) {
214 		printf("ctl_backend_ramdisk_shutdown: "
215 		       "ctl_backend_deregister() failed!\n");
216 	}
217 }
218 
219 static int
220 ctl_backend_ramdisk_move_done(union ctl_io *io)
221 {
222 	struct ctl_be_lun *ctl_be_lun;
223 	struct ctl_be_ramdisk_lun *be_lun;
224 #ifdef CTL_TIME_IO
225 	struct bintime cur_bt;
226 #endif
227 
228 	CTL_DEBUG_PRINT(("ctl_backend_ramdisk_move_done\n"));
229 	ctl_be_lun = (struct ctl_be_lun *)io->io_hdr.ctl_private[
230 		CTL_PRIV_BACKEND_LUN].ptr;
231 	be_lun = (struct ctl_be_ramdisk_lun *)ctl_be_lun->be_lun;
232 #ifdef CTL_TIME_IO
233 	getbintime(&cur_bt);
234 	bintime_sub(&cur_bt, &io->io_hdr.dma_start_bt);
235 	bintime_add(&io->io_hdr.dma_bt, &cur_bt);
236 	io->io_hdr.num_dmas++;
237 #endif
238 	if (io->scsiio.kern_sg_entries > 0)
239 		free(io->scsiio.kern_data_ptr, M_RAMDISK);
240 	io->scsiio.kern_rel_offset += io->scsiio.kern_data_len;
241 	if ((io->io_hdr.port_status == 0)
242 	 && ((io->io_hdr.flags & CTL_FLAG_ABORT) == 0)
243 	 && ((io->io_hdr.status & CTL_STATUS_MASK) == CTL_STATUS_NONE)) {
244 		if (io->io_hdr.ctl_private[CTL_PRIV_BACKEND].integer > 0) {
245 			mtx_lock(&be_lun->queue_lock);
246 			STAILQ_INSERT_TAIL(&be_lun->cont_queue,
247 			    &io->io_hdr, links);
248 			mtx_unlock(&be_lun->queue_lock);
249 			taskqueue_enqueue(be_lun->io_taskqueue,
250 			    &be_lun->io_task);
251 			return (0);
252 		}
253 		io->io_hdr.status = CTL_SUCCESS;
254 	} else if ((io->io_hdr.port_status != 0)
255 	      && ((io->io_hdr.flags & CTL_FLAG_ABORT) == 0)
256 	      && ((io->io_hdr.status & CTL_STATUS_MASK) == CTL_STATUS_NONE)){
257 		/*
258 		 * For hardware error sense keys, the sense key
259 		 * specific value is defined to be a retry count,
260 		 * but we use it to pass back an internal FETD
261 		 * error code.  XXX KDM  Hopefully the FETD is only
262 		 * using 16 bits for an error code, since that's
263 		 * all the space we have in the sks field.
264 		 */
265 		ctl_set_internal_failure(&io->scsiio,
266 					 /*sks_valid*/ 1,
267 					 /*retry_count*/
268 					 io->io_hdr.port_status);
269 	}
270 	ctl_data_submit_done(io);
271 	return(0);
272 }
273 
274 static int
275 ctl_backend_ramdisk_submit(union ctl_io *io)
276 {
277 	struct ctl_be_lun *ctl_be_lun;
278 	struct ctl_lba_len_flags *lbalen;
279 
280 	ctl_be_lun = (struct ctl_be_lun *)io->io_hdr.ctl_private[
281 		CTL_PRIV_BACKEND_LUN].ptr;
282 	lbalen = (struct ctl_lba_len_flags *)&io->io_hdr.ctl_private[CTL_PRIV_LBA_LEN];
283 	if (lbalen->flags & CTL_LLF_VERIFY) {
284 		ctl_set_success(&io->scsiio);
285 		ctl_data_submit_done(io);
286 		return (CTL_RETVAL_COMPLETE);
287 	}
288 	io->io_hdr.ctl_private[CTL_PRIV_BACKEND].integer =
289 	    lbalen->len * ctl_be_lun->blocksize;
290 	ctl_backend_ramdisk_continue(io);
291 	return (CTL_RETVAL_COMPLETE);
292 }
293 
294 static void
295 ctl_backend_ramdisk_continue(union ctl_io *io)
296 {
297 	struct ctl_be_ramdisk_softc *softc;
298 	int len, len_filled, sg_filled;
299 #ifdef CTL_RAMDISK_PAGES
300 	struct ctl_sg_entry *sg_entries;
301 	int i;
302 #endif
303 
304 	softc = &rd_softc;
305 	len = io->io_hdr.ctl_private[CTL_PRIV_BACKEND].integer;
306 #ifdef CTL_RAMDISK_PAGES
307 	sg_filled = min(btoc(len), softc->num_pages);
308 	if (sg_filled > 1) {
309 		io->scsiio.kern_data_ptr = malloc(sizeof(struct ctl_sg_entry) *
310 						  sg_filled, M_RAMDISK,
311 						  M_WAITOK);
312 		sg_entries = (struct ctl_sg_entry *)io->scsiio.kern_data_ptr;
313 		for (i = 0, len_filled = 0; i < sg_filled; i++) {
314 			sg_entries[i].addr = softc->ramdisk_pages[i];
315 			sg_entries[i].len = ctl_min(PAGE_SIZE,
316 						    len - len_filled);
317 			len_filled += sg_entries[i].len;
318 		}
319 		io->io_hdr.flags |= CTL_FLAG_KDPTR_SGLIST;
320 	} else {
321 		sg_filled = 0;
322 		len_filled = len;
323 		io->scsiio.kern_data_ptr = softc->ramdisk_pages[0];
324 	}
325 #else
326 	sg_filled = 0;
327 	len_filled = min(len, softc->rd_size);
328 	io->scsiio.kern_data_ptr = softc->ramdisk_buffer;
329 #endif /* CTL_RAMDISK_PAGES */
330 
331 	io->scsiio.be_move_done = ctl_backend_ramdisk_move_done;
332 	io->scsiio.kern_data_resid = 0;
333 	io->scsiio.kern_data_len = len_filled;
334 	io->scsiio.kern_sg_entries = sg_filled;
335 	io->io_hdr.flags |= CTL_FLAG_ALLOCATED;
336 	io->io_hdr.ctl_private[CTL_PRIV_BACKEND].integer -= len_filled;
337 #ifdef CTL_TIME_IO
338 	getbintime(&io->io_hdr.dma_start_bt);
339 #endif
340 	ctl_datamove(io);
341 }
342 
343 static void
344 ctl_backend_ramdisk_worker(void *context, int pending)
345 {
346 	struct ctl_be_ramdisk_softc *softc;
347 	struct ctl_be_ramdisk_lun *be_lun;
348 	union ctl_io *io;
349 
350 	be_lun = (struct ctl_be_ramdisk_lun *)context;
351 	softc = be_lun->softc;
352 
353 	mtx_lock(&be_lun->queue_lock);
354 	for (;;) {
355 		io = (union ctl_io *)STAILQ_FIRST(&be_lun->cont_queue);
356 		if (io != NULL) {
357 			STAILQ_REMOVE(&be_lun->cont_queue, &io->io_hdr,
358 				      ctl_io_hdr, links);
359 
360 			mtx_unlock(&be_lun->queue_lock);
361 
362 			ctl_backend_ramdisk_continue(io);
363 
364 			mtx_lock(&be_lun->queue_lock);
365 			continue;
366 		}
367 
368 		/*
369 		 * If we get here, there is no work left in the queues, so
370 		 * just break out and let the task queue go to sleep.
371 		 */
372 		break;
373 	}
374 	mtx_unlock(&be_lun->queue_lock);
375 }
376 
377 static int
378 ctl_backend_ramdisk_ioctl(struct cdev *dev, u_long cmd, caddr_t addr,
379 			  int flag, struct thread *td)
380 {
381 	struct ctl_be_ramdisk_softc *softc;
382 	int retval;
383 
384 	retval = 0;
385 	softc = &rd_softc;
386 
387 	switch (cmd) {
388 	case CTL_LUN_REQ: {
389 		struct ctl_lun_req *lun_req;
390 
391 		lun_req = (struct ctl_lun_req *)addr;
392 
393 		switch (lun_req->reqtype) {
394 		case CTL_LUNREQ_CREATE:
395 			retval = ctl_backend_ramdisk_create(softc, lun_req,
396 							    /*do_wait*/ 1);
397 			break;
398 		case CTL_LUNREQ_RM:
399 			retval = ctl_backend_ramdisk_rm(softc, lun_req);
400 			break;
401 		case CTL_LUNREQ_MODIFY:
402 			retval = ctl_backend_ramdisk_modify(softc, lun_req);
403 			break;
404 		default:
405 			lun_req->status = CTL_LUN_ERROR;
406 			snprintf(lun_req->error_str, sizeof(lun_req->error_str),
407 				 "%s: invalid LUN request type %d", __func__,
408 				 lun_req->reqtype);
409 			break;
410 		}
411 		break;
412 	}
413 	default:
414 		retval = ENOTTY;
415 		break;
416 	}
417 
418 	return (retval);
419 }
420 
421 static int
422 ctl_backend_ramdisk_rm(struct ctl_be_ramdisk_softc *softc,
423 		       struct ctl_lun_req *req)
424 {
425 	struct ctl_be_ramdisk_lun *be_lun;
426 	struct ctl_lun_rm_params *params;
427 	int retval;
428 
429 
430 	retval = 0;
431 	params = &req->reqdata.rm;
432 
433 	be_lun = NULL;
434 
435 	mtx_lock(&softc->lock);
436 
437 	STAILQ_FOREACH(be_lun, &softc->lun_list, links) {
438 		if (be_lun->ctl_be_lun.lun_id == params->lun_id)
439 			break;
440 	}
441 	mtx_unlock(&softc->lock);
442 
443 	if (be_lun == NULL) {
444 		snprintf(req->error_str, sizeof(req->error_str),
445 			 "%s: LUN %u is not managed by the ramdisk backend",
446 			 __func__, params->lun_id);
447 		goto bailout_error;
448 	}
449 
450 	retval = ctl_disable_lun(&be_lun->ctl_be_lun);
451 
452 	if (retval != 0) {
453 		snprintf(req->error_str, sizeof(req->error_str),
454 			 "%s: error %d returned from ctl_disable_lun() for "
455 			 "LUN %d", __func__, retval, params->lun_id);
456 		goto bailout_error;
457 	}
458 
459 	/*
460 	 * Set the waiting flag before we invalidate the LUN.  Our shutdown
461 	 * routine can be called any time after we invalidate the LUN,
462 	 * and can be called from our context.
463 	 *
464 	 * This tells the shutdown routine that we're waiting, or we're
465 	 * going to wait for the shutdown to happen.
466 	 */
467 	mtx_lock(&softc->lock);
468 	be_lun->flags |= CTL_BE_RAMDISK_LUN_WAITING;
469 	mtx_unlock(&softc->lock);
470 
471 	retval = ctl_invalidate_lun(&be_lun->ctl_be_lun);
472 	if (retval != 0) {
473 		snprintf(req->error_str, sizeof(req->error_str),
474 			 "%s: error %d returned from ctl_invalidate_lun() for "
475 			 "LUN %d", __func__, retval, params->lun_id);
476 		mtx_lock(&softc->lock);
477 		be_lun->flags &= ~CTL_BE_RAMDISK_LUN_WAITING;
478 		mtx_unlock(&softc->lock);
479 		goto bailout_error;
480 	}
481 
482 	mtx_lock(&softc->lock);
483 
484 	while ((be_lun->flags & CTL_BE_RAMDISK_LUN_UNCONFIGURED) == 0) {
485 		retval = msleep(be_lun, &softc->lock, PCATCH, "ctlram", 0);
486  		if (retval == EINTR)
487 			break;
488 	}
489 	be_lun->flags &= ~CTL_BE_RAMDISK_LUN_WAITING;
490 
491 	/*
492 	 * We only remove this LUN from the list and free it (below) if
493 	 * retval == 0.  If the user interrupted the wait, we just bail out
494 	 * without actually freeing the LUN.  We let the shutdown routine
495 	 * free the LUN if that happens.
496 	 */
497 	if (retval == 0) {
498 		STAILQ_REMOVE(&softc->lun_list, be_lun, ctl_be_ramdisk_lun,
499 			      links);
500 		softc->num_luns--;
501 	}
502 
503 	mtx_unlock(&softc->lock);
504 
505 	if (retval == 0) {
506 		taskqueue_drain(be_lun->io_taskqueue, &be_lun->io_task);
507 		taskqueue_free(be_lun->io_taskqueue);
508 		ctl_free_opts(&be_lun->ctl_be_lun.options);
509 		mtx_destroy(&be_lun->queue_lock);
510 		free(be_lun, M_RAMDISK);
511 	}
512 
513 	req->status = CTL_LUN_OK;
514 
515 	return (retval);
516 
517 bailout_error:
518 	req->status = CTL_LUN_ERROR;
519 
520 	return (0);
521 }
522 
523 static int
524 ctl_backend_ramdisk_create(struct ctl_be_ramdisk_softc *softc,
525 			   struct ctl_lun_req *req, int do_wait)
526 {
527 	struct ctl_be_ramdisk_lun *be_lun;
528 	struct ctl_lun_create_params *params;
529 	uint32_t blocksize;
530 	char *value;
531 	char tmpstr[32];
532 	int retval, unmap;
533 
534 	retval = 0;
535 	params = &req->reqdata.create;
536 	if (params->blocksize_bytes != 0)
537 		blocksize = params->blocksize_bytes;
538 	else
539 		blocksize = 512;
540 
541 	be_lun = malloc(sizeof(*be_lun), M_RAMDISK, M_ZERO | (do_wait ?
542 			M_WAITOK : M_NOWAIT));
543 
544 	if (be_lun == NULL) {
545 		snprintf(req->error_str, sizeof(req->error_str),
546 			 "%s: error allocating %zd bytes", __func__,
547 			 sizeof(*be_lun));
548 		goto bailout_error;
549 	}
550 	sprintf(be_lun->lunname, "cram%d", softc->num_luns);
551 	ctl_init_opts(&be_lun->ctl_be_lun.options,
552 	    req->num_be_args, req->kern_be_args);
553 
554 	if (params->flags & CTL_LUN_FLAG_DEV_TYPE)
555 		be_lun->ctl_be_lun.lun_type = params->device_type;
556 	else
557 		be_lun->ctl_be_lun.lun_type = T_DIRECT;
558 
559 	if (be_lun->ctl_be_lun.lun_type == T_DIRECT) {
560 
561 		if (params->lun_size_bytes < blocksize) {
562 			snprintf(req->error_str, sizeof(req->error_str),
563 				 "%s: LUN size %ju < blocksize %u", __func__,
564 				 params->lun_size_bytes, blocksize);
565 			goto bailout_error;
566 		}
567 
568 		be_lun->size_blocks = params->lun_size_bytes / blocksize;
569 		be_lun->size_bytes = be_lun->size_blocks * blocksize;
570 
571 		be_lun->ctl_be_lun.maxlba = be_lun->size_blocks - 1;
572 	} else {
573 		be_lun->ctl_be_lun.maxlba = 0;
574 		blocksize = 0;
575 		be_lun->size_bytes = 0;
576 		be_lun->size_blocks = 0;
577 	}
578 
579 	be_lun->ctl_be_lun.blocksize = blocksize;
580 
581 	/* Tell the user the blocksize we ended up using */
582 	params->blocksize_bytes = blocksize;
583 
584 	/* Tell the user the exact size we ended up using */
585 	params->lun_size_bytes = be_lun->size_bytes;
586 
587 	be_lun->softc = softc;
588 
589 	unmap = 0;
590 	value = ctl_get_opt(&be_lun->ctl_be_lun.options, "unmap");
591 	if (value != NULL && strcmp(value, "on") == 0)
592 		unmap = 1;
593 
594 	be_lun->flags = CTL_BE_RAMDISK_LUN_UNCONFIGURED;
595 	be_lun->ctl_be_lun.flags = CTL_LUN_FLAG_PRIMARY;
596 	if (unmap)
597 		be_lun->ctl_be_lun.flags |= CTL_LUN_FLAG_UNMAP;
598 	be_lun->ctl_be_lun.atomicblock = UINT32_MAX;
599 	be_lun->ctl_be_lun.be_lun = be_lun;
600 
601 	if (params->flags & CTL_LUN_FLAG_ID_REQ) {
602 		be_lun->ctl_be_lun.req_lun_id = params->req_lun_id;
603 		be_lun->ctl_be_lun.flags |= CTL_LUN_FLAG_ID_REQ;
604 	} else
605 		be_lun->ctl_be_lun.req_lun_id = 0;
606 
607 	be_lun->ctl_be_lun.lun_shutdown = ctl_backend_ramdisk_lun_shutdown;
608 	be_lun->ctl_be_lun.lun_config_status =
609 		ctl_backend_ramdisk_lun_config_status;
610 	be_lun->ctl_be_lun.be = &ctl_be_ramdisk_driver;
611 	if ((params->flags & CTL_LUN_FLAG_SERIAL_NUM) == 0) {
612 		snprintf(tmpstr, sizeof(tmpstr), "MYSERIAL%4d",
613 			 softc->num_luns);
614 		strncpy((char *)be_lun->ctl_be_lun.serial_num, tmpstr,
615 			ctl_min(sizeof(be_lun->ctl_be_lun.serial_num),
616 			sizeof(tmpstr)));
617 
618 		/* Tell the user what we used for a serial number */
619 		strncpy((char *)params->serial_num, tmpstr,
620 			ctl_min(sizeof(params->serial_num), sizeof(tmpstr)));
621 	} else {
622 		strncpy((char *)be_lun->ctl_be_lun.serial_num,
623 			params->serial_num,
624 			ctl_min(sizeof(be_lun->ctl_be_lun.serial_num),
625 			sizeof(params->serial_num)));
626 	}
627 	if ((params->flags & CTL_LUN_FLAG_DEVID) == 0) {
628 		snprintf(tmpstr, sizeof(tmpstr), "MYDEVID%4d", softc->num_luns);
629 		strncpy((char *)be_lun->ctl_be_lun.device_id, tmpstr,
630 			ctl_min(sizeof(be_lun->ctl_be_lun.device_id),
631 			sizeof(tmpstr)));
632 
633 		/* Tell the user what we used for a device ID */
634 		strncpy((char *)params->device_id, tmpstr,
635 			ctl_min(sizeof(params->device_id), sizeof(tmpstr)));
636 	} else {
637 		strncpy((char *)be_lun->ctl_be_lun.device_id,
638 			params->device_id,
639 			ctl_min(sizeof(be_lun->ctl_be_lun.device_id),
640 				sizeof(params->device_id)));
641 	}
642 
643 	STAILQ_INIT(&be_lun->cont_queue);
644 	mtx_init(&be_lun->queue_lock, "cram queue lock", NULL, MTX_DEF);
645 	TASK_INIT(&be_lun->io_task, /*priority*/0, ctl_backend_ramdisk_worker,
646 	    be_lun);
647 
648 	be_lun->io_taskqueue = taskqueue_create(be_lun->lunname, M_WAITOK,
649 	    taskqueue_thread_enqueue, /*context*/&be_lun->io_taskqueue);
650 	if (be_lun->io_taskqueue == NULL) {
651 		snprintf(req->error_str, sizeof(req->error_str),
652 			 "%s: Unable to create taskqueue", __func__);
653 		goto bailout_error;
654 	}
655 
656 	retval = taskqueue_start_threads(&be_lun->io_taskqueue,
657 					 /*num threads*/1,
658 					 /*priority*/PWAIT,
659 					 /*thread name*/
660 					 "%s taskq", be_lun->lunname);
661 	if (retval != 0)
662 		goto bailout_error;
663 
664 	mtx_lock(&softc->lock);
665 	softc->num_luns++;
666 	STAILQ_INSERT_TAIL(&softc->lun_list, be_lun, links);
667 
668 	mtx_unlock(&softc->lock);
669 
670 	retval = ctl_add_lun(&be_lun->ctl_be_lun);
671 	if (retval != 0) {
672 		mtx_lock(&softc->lock);
673 		STAILQ_REMOVE(&softc->lun_list, be_lun, ctl_be_ramdisk_lun,
674 			      links);
675 		softc->num_luns--;
676 		mtx_unlock(&softc->lock);
677 		snprintf(req->error_str, sizeof(req->error_str),
678 			 "%s: ctl_add_lun() returned error %d, see dmesg for "
679 			"details", __func__, retval);
680 		retval = 0;
681 		goto bailout_error;
682 	}
683 
684 	if (do_wait == 0)
685 		return (retval);
686 
687 	mtx_lock(&softc->lock);
688 
689 	/*
690 	 * Tell the config_status routine that we're waiting so it won't
691 	 * clean up the LUN in the event of an error.
692 	 */
693 	be_lun->flags |= CTL_BE_RAMDISK_LUN_WAITING;
694 
695 	while (be_lun->flags & CTL_BE_RAMDISK_LUN_UNCONFIGURED) {
696 		retval = msleep(be_lun, &softc->lock, PCATCH, "ctlram", 0);
697 		if (retval == EINTR)
698 			break;
699 	}
700 	be_lun->flags &= ~CTL_BE_RAMDISK_LUN_WAITING;
701 
702 	if (be_lun->flags & CTL_BE_RAMDISK_LUN_CONFIG_ERR) {
703 		snprintf(req->error_str, sizeof(req->error_str),
704 			 "%s: LUN configuration error, see dmesg for details",
705 			 __func__);
706 		STAILQ_REMOVE(&softc->lun_list, be_lun, ctl_be_ramdisk_lun,
707 			      links);
708 		softc->num_luns--;
709 		mtx_unlock(&softc->lock);
710 		goto bailout_error;
711 	} else {
712 		params->req_lun_id = be_lun->ctl_be_lun.lun_id;
713 	}
714 	mtx_unlock(&softc->lock);
715 
716 	req->status = CTL_LUN_OK;
717 
718 	return (retval);
719 
720 bailout_error:
721 	req->status = CTL_LUN_ERROR;
722 	if (be_lun != NULL) {
723 		if (be_lun->io_taskqueue != NULL) {
724 			taskqueue_free(be_lun->io_taskqueue);
725 		}
726 		ctl_free_opts(&be_lun->ctl_be_lun.options);
727 		mtx_destroy(&be_lun->queue_lock);
728 		free(be_lun, M_RAMDISK);
729 	}
730 
731 	return (retval);
732 }
733 
734 static int
735 ctl_backend_ramdisk_modify(struct ctl_be_ramdisk_softc *softc,
736 		       struct ctl_lun_req *req)
737 {
738 	struct ctl_be_ramdisk_lun *be_lun;
739 	struct ctl_lun_modify_params *params;
740 	uint32_t blocksize;
741 
742 	params = &req->reqdata.modify;
743 
744 	be_lun = NULL;
745 
746 	mtx_lock(&softc->lock);
747 	STAILQ_FOREACH(be_lun, &softc->lun_list, links) {
748 		if (be_lun->ctl_be_lun.lun_id == params->lun_id)
749 			break;
750 	}
751 	mtx_unlock(&softc->lock);
752 
753 	if (be_lun == NULL) {
754 		snprintf(req->error_str, sizeof(req->error_str),
755 			 "%s: LUN %u is not managed by the ramdisk backend",
756 			 __func__, params->lun_id);
757 		goto bailout_error;
758 	}
759 
760 	if (params->lun_size_bytes == 0) {
761 		snprintf(req->error_str, sizeof(req->error_str),
762 			"%s: LUN size \"auto\" not supported "
763 			"by the ramdisk backend", __func__);
764 		goto bailout_error;
765 	}
766 
767 	blocksize = be_lun->ctl_be_lun.blocksize;
768 
769 	if (params->lun_size_bytes < blocksize) {
770 		snprintf(req->error_str, sizeof(req->error_str),
771 			"%s: LUN size %ju < blocksize %u", __func__,
772 			params->lun_size_bytes, blocksize);
773 		goto bailout_error;
774 	}
775 
776 	be_lun->size_blocks = params->lun_size_bytes / blocksize;
777 	be_lun->size_bytes = be_lun->size_blocks * blocksize;
778 
779 	/*
780 	 * The maximum LBA is the size - 1.
781 	 *
782 	 * XXX: Note that this field is being updated without locking,
783 	 * 	which might cause problems on 32-bit architectures.
784 	 */
785 	be_lun->ctl_be_lun.maxlba = be_lun->size_blocks - 1;
786 	ctl_lun_capacity_changed(&be_lun->ctl_be_lun);
787 
788 	/* Tell the user the exact size we ended up using */
789 	params->lun_size_bytes = be_lun->size_bytes;
790 
791 	req->status = CTL_LUN_OK;
792 
793 	return (0);
794 
795 bailout_error:
796 	req->status = CTL_LUN_ERROR;
797 
798 	return (0);
799 }
800 
801 static void
802 ctl_backend_ramdisk_lun_shutdown(void *be_lun)
803 {
804 	struct ctl_be_ramdisk_lun *lun;
805 	struct ctl_be_ramdisk_softc *softc;
806 	int do_free;
807 
808 	lun = (struct ctl_be_ramdisk_lun *)be_lun;
809 	softc = lun->softc;
810 	do_free = 0;
811 
812 	mtx_lock(&softc->lock);
813 
814 	lun->flags |= CTL_BE_RAMDISK_LUN_UNCONFIGURED;
815 
816 	if (lun->flags & CTL_BE_RAMDISK_LUN_WAITING) {
817 		wakeup(lun);
818 	} else {
819 		STAILQ_REMOVE(&softc->lun_list, lun, ctl_be_ramdisk_lun,
820 			      links);
821 		softc->num_luns--;
822 		do_free = 1;
823 	}
824 
825 	mtx_unlock(&softc->lock);
826 
827 	if (do_free != 0)
828 		free(be_lun, M_RAMDISK);
829 }
830 
831 static void
832 ctl_backend_ramdisk_lun_config_status(void *be_lun,
833 				      ctl_lun_config_status status)
834 {
835 	struct ctl_be_ramdisk_lun *lun;
836 	struct ctl_be_ramdisk_softc *softc;
837 
838 	lun = (struct ctl_be_ramdisk_lun *)be_lun;
839 	softc = lun->softc;
840 
841 	if (status == CTL_LUN_CONFIG_OK) {
842 		mtx_lock(&softc->lock);
843 		lun->flags &= ~CTL_BE_RAMDISK_LUN_UNCONFIGURED;
844 		if (lun->flags & CTL_BE_RAMDISK_LUN_WAITING)
845 			wakeup(lun);
846 		mtx_unlock(&softc->lock);
847 
848 		/*
849 		 * We successfully added the LUN, attempt to enable it.
850 		 */
851 		if (ctl_enable_lun(&lun->ctl_be_lun) != 0) {
852 			printf("%s: ctl_enable_lun() failed!\n", __func__);
853 			if (ctl_invalidate_lun(&lun->ctl_be_lun) != 0) {
854 				printf("%s: ctl_invalidate_lun() failed!\n",
855 				       __func__);
856 			}
857 		}
858 
859 		return;
860 	}
861 
862 
863 	mtx_lock(&softc->lock);
864 	lun->flags &= ~CTL_BE_RAMDISK_LUN_UNCONFIGURED;
865 
866 	/*
867 	 * If we have a user waiting, let him handle the cleanup.  If not,
868 	 * clean things up here.
869 	 */
870 	if (lun->flags & CTL_BE_RAMDISK_LUN_WAITING) {
871 		lun->flags |= CTL_BE_RAMDISK_LUN_CONFIG_ERR;
872 		wakeup(lun);
873 	} else {
874 		STAILQ_REMOVE(&softc->lun_list, lun, ctl_be_ramdisk_lun,
875 			      links);
876 		softc->num_luns--;
877 		free(lun, M_RAMDISK);
878 	}
879 	mtx_unlock(&softc->lock);
880 }
881 
882 static int
883 ctl_backend_ramdisk_config_write(union ctl_io *io)
884 {
885 	struct ctl_be_ramdisk_softc *softc;
886 	int retval;
887 
888 	retval = 0;
889 	softc = &rd_softc;
890 
891 	switch (io->scsiio.cdb[0]) {
892 	case SYNCHRONIZE_CACHE:
893 	case SYNCHRONIZE_CACHE_16:
894 		/*
895 		 * The upper level CTL code will filter out any CDBs with
896 		 * the immediate bit set and return the proper error.  It
897 		 * will also not allow a sync cache command to go to a LUN
898 		 * that is powered down.
899 		 *
900 		 * We don't really need to worry about what LBA range the
901 		 * user asked to be synced out.  When they issue a sync
902 		 * cache command, we'll sync out the whole thing.
903 		 *
904 		 * This is obviously just a stubbed out implementation.
905 		 * The real implementation will be in the RAIDCore/CTL
906 		 * interface, and can only really happen when RAIDCore
907 		 * implements a per-array cache sync.
908 		 */
909 		ctl_set_success(&io->scsiio);
910 		ctl_config_write_done(io);
911 		break;
912 	case START_STOP_UNIT: {
913 		struct scsi_start_stop_unit *cdb;
914 		struct ctl_be_lun *ctl_be_lun;
915 		struct ctl_be_ramdisk_lun *be_lun;
916 
917 		cdb = (struct scsi_start_stop_unit *)io->scsiio.cdb;
918 
919 		ctl_be_lun = (struct ctl_be_lun *)io->io_hdr.ctl_private[
920 			CTL_PRIV_BACKEND_LUN].ptr;
921 		be_lun = (struct ctl_be_ramdisk_lun *)ctl_be_lun->be_lun;
922 
923 		if (cdb->how & SSS_START)
924 			retval = ctl_start_lun(ctl_be_lun);
925 		else {
926 			retval = ctl_stop_lun(ctl_be_lun);
927 #ifdef NEEDTOPORT
928 			if ((retval == 0)
929 			 && (cdb->byte2 & SSS_ONOFFLINE))
930 				retval = ctl_lun_offline(ctl_be_lun);
931 #endif
932 		}
933 
934 		/*
935 		 * In general, the above routines should not fail.  They
936 		 * just set state for the LUN.  So we've got something
937 		 * pretty wrong here if we can't start or stop the LUN.
938 		 */
939 		if (retval != 0) {
940 			ctl_set_internal_failure(&io->scsiio,
941 						 /*sks_valid*/ 1,
942 						 /*retry_count*/ 0xf051);
943 			retval = CTL_RETVAL_COMPLETE;
944 		} else {
945 			ctl_set_success(&io->scsiio);
946 		}
947 		ctl_config_write_done(io);
948 		break;
949 	}
950 	case WRITE_SAME_10:
951 	case WRITE_SAME_16:
952 	case UNMAP:
953 		ctl_set_success(&io->scsiio);
954 		ctl_config_write_done(io);
955 		break;
956 	default:
957 		ctl_set_invalid_opcode(&io->scsiio);
958 		ctl_config_write_done(io);
959 		retval = CTL_RETVAL_COMPLETE;
960 		break;
961 	}
962 
963 	return (retval);
964 }
965 
966 static int
967 ctl_backend_ramdisk_config_read(union ctl_io *io)
968 {
969 	/*
970 	 * XXX KDM need to implement!!
971 	 */
972 	return (0);
973 }
974