xref: /freebsd/sys/cam/ctl/ctl_backend_ramdisk.c (revision f5f7c05209ca2c3748fd8b27c5e80ffad49120eb)
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/time.h>
54 #include <sys/queue.h>
55 #include <sys/conf.h>
56 #include <sys/ioccom.h>
57 #include <sys/module.h>
58 
59 #include <cam/scsi/scsi_all.h>
60 #include <cam/ctl/ctl_io.h>
61 #include <cam/ctl/ctl.h>
62 #include <cam/ctl/ctl_util.h>
63 #include <cam/ctl/ctl_backend.h>
64 #include <cam/ctl/ctl_frontend_internal.h>
65 #include <cam/ctl/ctl_debug.h>
66 #include <cam/ctl/ctl_ioctl.h>
67 #include <cam/ctl/ctl_error.h>
68 
69 typedef enum {
70 	CTL_BE_RAMDISK_LUN_UNCONFIGURED	= 0x01,
71 	CTL_BE_RAMDISK_LUN_CONFIG_ERR	= 0x02,
72 	CTL_BE_RAMDISK_LUN_WAITING	= 0x04
73 } ctl_be_ramdisk_lun_flags;
74 
75 struct ctl_be_ramdisk_lun {
76 	uint64_t size_bytes;
77 	uint64_t size_blocks;
78 	struct ctl_be_ramdisk_softc *softc;
79 	ctl_be_ramdisk_lun_flags flags;
80 	STAILQ_ENTRY(ctl_be_ramdisk_lun) links;
81 	struct ctl_be_lun ctl_be_lun;
82 };
83 
84 struct ctl_be_ramdisk_softc {
85 	struct mtx lock;
86 	int rd_size;
87 #ifdef CTL_RAMDISK_PAGES
88 	uint8_t **ramdisk_pages;
89 	int num_pages;
90 #else
91 	uint8_t *ramdisk_buffer;
92 #endif
93 	int num_luns;
94 	STAILQ_HEAD(, ctl_be_ramdisk_lun) lun_list;
95 };
96 
97 static struct ctl_be_ramdisk_softc rd_softc;
98 
99 int ctl_backend_ramdisk_init(void);
100 void ctl_backend_ramdisk_shutdown(void);
101 static int ctl_backend_ramdisk_move_done(union ctl_io *io);
102 static int ctl_backend_ramdisk_submit(union ctl_io *io);
103 static int ctl_backend_ramdisk_ioctl(struct cdev *dev, u_long cmd,
104 				     caddr_t addr, int flag, struct thread *td);
105 static int ctl_backend_ramdisk_rm(struct ctl_be_ramdisk_softc *softc,
106 				  struct ctl_lun_req *req);
107 static int ctl_backend_ramdisk_create(struct ctl_be_ramdisk_softc *softc,
108 				      struct ctl_lun_req *req, int do_wait);
109 static int ctl_backend_ramdisk_modify(struct ctl_be_ramdisk_softc *softc,
110 				  struct ctl_lun_req *req);
111 static void ctl_backend_ramdisk_lun_shutdown(void *be_lun);
112 static void ctl_backend_ramdisk_lun_config_status(void *be_lun,
113 						  ctl_lun_config_status status);
114 static int ctl_backend_ramdisk_config_write(union ctl_io *io);
115 static int ctl_backend_ramdisk_config_read(union ctl_io *io);
116 
117 static struct ctl_backend_driver ctl_be_ramdisk_driver =
118 {
119 	.name = "ramdisk",
120 	.flags = CTL_BE_FLAG_HAS_CONFIG,
121 	.init = ctl_backend_ramdisk_init,
122 	.data_submit = ctl_backend_ramdisk_submit,
123 	.data_move_done = ctl_backend_ramdisk_move_done,
124 	.config_read = ctl_backend_ramdisk_config_read,
125 	.config_write = ctl_backend_ramdisk_config_write,
126 	.ioctl = ctl_backend_ramdisk_ioctl
127 };
128 
129 MALLOC_DEFINE(M_RAMDISK, "ramdisk", "Memory used for CTL RAMdisk");
130 CTL_BACKEND_DECLARE(cbr, ctl_be_ramdisk_driver);
131 
132 int
133 ctl_backend_ramdisk_init(void)
134 {
135 	struct ctl_be_ramdisk_softc *softc;
136 #ifdef CTL_RAMDISK_PAGES
137 	int i;
138 #endif
139 
140 
141 	softc = &rd_softc;
142 
143 	memset(softc, 0, sizeof(*softc));
144 
145 	mtx_init(&softc->lock, "ramdisk", NULL, MTX_DEF);
146 
147 	STAILQ_INIT(&softc->lun_list);
148 	softc->rd_size = 4 * 1024 * 1024;
149 #ifdef CTL_RAMDISK_PAGES
150 	softc->num_pages = softc->rd_size / PAGE_SIZE;
151 	softc->ramdisk_pages = (uint8_t **)malloc(sizeof(uint8_t *) *
152 						  softc->num_pages, M_RAMDISK,
153 						  M_WAITOK);
154 	for (i = 0; i < softc->num_pages; i++)
155 		softc->ramdisk_pages[i] = malloc(PAGE_SIZE, M_RAMDISK,M_WAITOK);
156 #else
157 	softc->ramdisk_buffer = (uint8_t *)malloc(softc->rd_size, M_RAMDISK,
158 						  M_WAITOK);
159 #endif
160 
161 	return (0);
162 }
163 
164 void
165 ctl_backend_ramdisk_shutdown(void)
166 {
167 	struct ctl_be_ramdisk_softc *softc;
168 	struct ctl_be_ramdisk_lun *lun, *next_lun;
169 #ifdef CTL_RAMDISK_PAGES
170 	int i;
171 #endif
172 
173 	softc = &rd_softc;
174 
175 	mtx_lock(&softc->lock);
176 	for (lun = STAILQ_FIRST(&softc->lun_list); lun != NULL; lun = next_lun){
177 		/*
178 		 * Grab the next LUN.  The current LUN may get removed by
179 		 * ctl_invalidate_lun(), which will call our LUN shutdown
180 		 * routine, if there is no outstanding I/O for this LUN.
181 		 */
182 		next_lun = STAILQ_NEXT(lun, links);
183 
184 		/*
185 		 * Drop our lock here.  Since ctl_invalidate_lun() can call
186 		 * back into us, this could potentially lead to a recursive
187 		 * lock of the same mutex, which would cause a hang.
188 		 */
189 		mtx_unlock(&softc->lock);
190 		ctl_disable_lun(&lun->ctl_be_lun);
191 		ctl_invalidate_lun(&lun->ctl_be_lun);
192 		mtx_lock(&softc->lock);
193 	}
194 	mtx_unlock(&softc->lock);
195 
196 #ifdef CTL_RAMDISK_PAGES
197 	for (i = 0; i < softc->num_pages; i++)
198 		free(softc->ramdisk_pages[i], M_RAMDISK);
199 
200 	free(softc->ramdisk_pages, M_RAMDISK);
201 #else
202 	free(softc->ramdisk_buffer, M_RAMDISK);
203 #endif
204 
205 	if (ctl_backend_deregister(&ctl_be_ramdisk_driver) != 0) {
206 		printf("ctl_backend_ramdisk_shutdown: "
207 		       "ctl_backend_deregister() failed!\n");
208 	}
209 }
210 
211 static int
212 ctl_backend_ramdisk_move_done(union ctl_io *io)
213 {
214 #ifdef CTL_TIME_IO
215 	struct bintime cur_bt;
216 #endif
217 
218 	CTL_DEBUG_PRINT(("ctl_backend_ramdisk_move_done\n"));
219 	if ((io->io_hdr.port_status == 0)
220 	 && ((io->io_hdr.flags & CTL_FLAG_ABORT) == 0)
221 	 && ((io->io_hdr.status & CTL_STATUS_MASK) == CTL_STATUS_NONE))
222 		io->io_hdr.status = CTL_SUCCESS;
223 	else if ((io->io_hdr.port_status != 0)
224 	      && ((io->io_hdr.flags & CTL_FLAG_ABORT) == 0)
225 	      && ((io->io_hdr.status & CTL_STATUS_MASK) == CTL_STATUS_NONE)){
226 		/*
227 		 * For hardware error sense keys, the sense key
228 		 * specific value is defined to be a retry count,
229 		 * but we use it to pass back an internal FETD
230 		 * error code.  XXX KDM  Hopefully the FETD is only
231 		 * using 16 bits for an error code, since that's
232 		 * all the space we have in the sks field.
233 		 */
234 		ctl_set_internal_failure(&io->scsiio,
235 					 /*sks_valid*/ 1,
236 					 /*retry_count*/
237 					 io->io_hdr.port_status);
238 	}
239 #ifdef CTL_TIME_IO
240 	getbintime(&cur_bt);
241 	bintime_sub(&cur_bt, &io->io_hdr.dma_start_bt);
242 	bintime_add(&io->io_hdr.dma_bt, &cur_bt);
243 	io->io_hdr.num_dmas++;
244 #endif
245 
246 	if (io->scsiio.kern_sg_entries > 0)
247 		free(io->scsiio.kern_data_ptr, M_RAMDISK);
248 	ctl_done(io);
249 	return(0);
250 }
251 
252 static int
253 ctl_backend_ramdisk_submit(union ctl_io *io)
254 {
255 	struct ctl_lba_len lbalen;
256 #ifdef CTL_RAMDISK_PAGES
257 	struct ctl_sg_entry *sg_entries;
258 	int len_filled;
259 	int i;
260 #endif
261 	int num_sg_entries, len;
262 	struct ctl_be_ramdisk_softc *softc;
263 	struct ctl_be_lun *ctl_be_lun;
264 	struct ctl_be_ramdisk_lun *be_lun;
265 
266 	softc = &rd_softc;
267 
268 	ctl_be_lun = (struct ctl_be_lun *)io->io_hdr.ctl_private[
269 		CTL_PRIV_BACKEND_LUN].ptr;
270 	be_lun = (struct ctl_be_ramdisk_lun *)ctl_be_lun->be_lun;
271 
272 	memcpy(&lbalen, io->io_hdr.ctl_private[CTL_PRIV_LBA_LEN].bytes,
273 	       sizeof(lbalen));
274 
275 	len = lbalen.len * ctl_be_lun->blocksize;
276 
277 	/*
278 	 * Kick out the request if it's bigger than we can handle.
279 	 */
280 	if (len > softc->rd_size) {
281 		ctl_set_internal_failure(&io->scsiio,
282 					 /*sks_valid*/ 0,
283 					 /*retry_count*/ 0);
284 		ctl_done(io);
285 		return (CTL_RETVAL_COMPLETE);
286 	}
287 
288 	/*
289 	 * Kick out the request if it's larger than the device size that
290 	 * the user requested.
291 	 */
292 	if (((lbalen.lba * ctl_be_lun->blocksize) + len) > be_lun->size_bytes) {
293 		ctl_set_lba_out_of_range(&io->scsiio);
294 		ctl_done(io);
295 		return (CTL_RETVAL_COMPLETE);
296 	}
297 
298 #ifdef CTL_RAMDISK_PAGES
299 	num_sg_entries = len >> PAGE_SHIFT;
300 	if ((len & (PAGE_SIZE - 1)) != 0)
301 		num_sg_entries++;
302 
303 	if (num_sg_entries > 1) {
304 		io->scsiio.kern_data_ptr = malloc(sizeof(struct ctl_sg_entry) *
305 						  num_sg_entries, M_RAMDISK,
306 						  M_WAITOK);
307 		sg_entries = (struct ctl_sg_entry *)io->scsiio.kern_data_ptr;
308 		for (i = 0, len_filled = 0; i < num_sg_entries;
309 		     i++, len_filled += PAGE_SIZE) {
310 			sg_entries[i].addr = softc->ramdisk_pages[i];
311 			sg_entries[i].len = ctl_min(PAGE_SIZE,
312 						    len - len_filled);
313 		}
314 	} else {
315 #endif /* CTL_RAMDISK_PAGES */
316 		/*
317 		 * If this is less than 1 page, don't bother allocating a
318 		 * scatter/gather list for it.  This saves time/overhead.
319 		 */
320 		num_sg_entries = 0;
321 #ifdef CTL_RAMDISK_PAGES
322 		io->scsiio.kern_data_ptr = softc->ramdisk_pages[0];
323 #else
324 		io->scsiio.kern_data_ptr = softc->ramdisk_buffer;
325 #endif
326 #ifdef CTL_RAMDISK_PAGES
327 	}
328 #endif
329 
330 	io->scsiio.be_move_done = ctl_backend_ramdisk_move_done;
331 	io->scsiio.kern_data_len = len;
332 	io->scsiio.kern_total_len = len;
333 	io->scsiio.kern_rel_offset = 0;
334 	io->scsiio.kern_data_resid = 0;
335 	io->scsiio.kern_sg_entries = num_sg_entries;
336 	io->io_hdr.flags |= CTL_FLAG_ALLOCATED | CTL_FLAG_KDPTR_SGLIST;
337 #ifdef CTL_TIME_IO
338 	getbintime(&io->io_hdr.dma_start_bt);
339 #endif
340 	ctl_datamove(io);
341 
342 	return (CTL_RETVAL_COMPLETE);
343 }
344 
345 static int
346 ctl_backend_ramdisk_ioctl(struct cdev *dev, u_long cmd, caddr_t addr,
347 			  int flag, struct thread *td)
348 {
349 	struct ctl_be_ramdisk_softc *softc;
350 	int retval;
351 
352 	retval = 0;
353 	softc = &rd_softc;
354 
355 	switch (cmd) {
356 	case CTL_LUN_REQ: {
357 		struct ctl_lun_req *lun_req;
358 
359 		lun_req = (struct ctl_lun_req *)addr;
360 
361 		switch (lun_req->reqtype) {
362 		case CTL_LUNREQ_CREATE:
363 			retval = ctl_backend_ramdisk_create(softc, lun_req,
364 							    /*do_wait*/ 1);
365 			break;
366 		case CTL_LUNREQ_RM:
367 			retval = ctl_backend_ramdisk_rm(softc, lun_req);
368 			break;
369 		case CTL_LUNREQ_MODIFY:
370 			retval = ctl_backend_ramdisk_modify(softc, lun_req);
371 			break;
372 		default:
373 			lun_req->status = CTL_LUN_ERROR;
374 			snprintf(lun_req->error_str, sizeof(lun_req->error_str),
375 				 "%s: invalid LUN request type %d", __func__,
376 				 lun_req->reqtype);
377 			break;
378 		}
379 		break;
380 	}
381 	default:
382 		retval = ENOTTY;
383 		break;
384 	}
385 
386 	return (retval);
387 }
388 
389 static int
390 ctl_backend_ramdisk_rm(struct ctl_be_ramdisk_softc *softc,
391 		       struct ctl_lun_req *req)
392 {
393 	struct ctl_be_ramdisk_lun *be_lun;
394 	struct ctl_lun_rm_params *params;
395 	int retval;
396 
397 
398 	retval = 0;
399 	params = &req->reqdata.rm;
400 
401 	be_lun = NULL;
402 
403 	mtx_lock(&softc->lock);
404 
405 	STAILQ_FOREACH(be_lun, &softc->lun_list, links) {
406 		if (be_lun->ctl_be_lun.lun_id == params->lun_id)
407 			break;
408 	}
409 	mtx_unlock(&softc->lock);
410 
411 	if (be_lun == NULL) {
412 		snprintf(req->error_str, sizeof(req->error_str),
413 			 "%s: LUN %u is not managed by the ramdisk backend",
414 			 __func__, params->lun_id);
415 		goto bailout_error;
416 	}
417 
418 	retval = ctl_disable_lun(&be_lun->ctl_be_lun);
419 
420 	if (retval != 0) {
421 		snprintf(req->error_str, sizeof(req->error_str),
422 			 "%s: error %d returned from ctl_disable_lun() for "
423 			 "LUN %d", __func__, retval, params->lun_id);
424 		goto bailout_error;
425 	}
426 
427 	/*
428 	 * Set the waiting flag before we invalidate the LUN.  Our shutdown
429 	 * routine can be called any time after we invalidate the LUN,
430 	 * and can be called from our context.
431 	 *
432 	 * This tells the shutdown routine that we're waiting, or we're
433 	 * going to wait for the shutdown to happen.
434 	 */
435 	mtx_lock(&softc->lock);
436 	be_lun->flags |= CTL_BE_RAMDISK_LUN_WAITING;
437 	mtx_unlock(&softc->lock);
438 
439 	retval = ctl_invalidate_lun(&be_lun->ctl_be_lun);
440 	if (retval != 0) {
441 		snprintf(req->error_str, sizeof(req->error_str),
442 			 "%s: error %d returned from ctl_invalidate_lun() for "
443 			 "LUN %d", __func__, retval, params->lun_id);
444 		goto bailout_error;
445 	}
446 
447 	mtx_lock(&softc->lock);
448 
449 	while ((be_lun->flags & CTL_BE_RAMDISK_LUN_UNCONFIGURED) == 0) {
450 		retval = msleep(be_lun, &softc->lock, PCATCH, "ctlram", 0);
451  		if (retval == EINTR)
452 			break;
453 	}
454 	be_lun->flags &= ~CTL_BE_RAMDISK_LUN_WAITING;
455 
456 	/*
457 	 * We only remove this LUN from the list and free it (below) if
458 	 * retval == 0.  If the user interrupted the wait, we just bail out
459 	 * without actually freeing the LUN.  We let the shutdown routine
460 	 * free the LUN if that happens.
461 	 */
462 	if (retval == 0) {
463 		STAILQ_REMOVE(&softc->lun_list, be_lun, ctl_be_ramdisk_lun,
464 			      links);
465 		softc->num_luns--;
466 	}
467 
468 	mtx_unlock(&softc->lock);
469 
470 	if (retval == 0)
471 		free(be_lun, M_RAMDISK);
472 
473 	req->status = CTL_LUN_OK;
474 
475 	return (retval);
476 
477 bailout_error:
478 
479 	/*
480 	 * Don't leave the waiting flag set.
481 	 */
482 	mtx_lock(&softc->lock);
483 	be_lun->flags &= ~CTL_BE_RAMDISK_LUN_WAITING;
484 	mtx_unlock(&softc->lock);
485 
486 	req->status = CTL_LUN_ERROR;
487 
488 	return (0);
489 }
490 
491 static int
492 ctl_backend_ramdisk_create(struct ctl_be_ramdisk_softc *softc,
493 			   struct ctl_lun_req *req, int do_wait)
494 {
495 	struct ctl_be_ramdisk_lun *be_lun;
496 	struct ctl_lun_create_params *params;
497 	uint32_t blocksize;
498 	char tmpstr[32];
499 	int retval;
500 
501 	retval = 0;
502 	params = &req->reqdata.create;
503 	if (params->blocksize_bytes != 0)
504 		blocksize = params->blocksize_bytes;
505 	else
506 		blocksize = 512;
507 
508 	be_lun = malloc(sizeof(*be_lun), M_RAMDISK, M_ZERO | (do_wait ?
509 			M_WAITOK : M_NOWAIT));
510 
511 	if (be_lun == NULL) {
512 		snprintf(req->error_str, sizeof(req->error_str),
513 			 "%s: error allocating %zd bytes", __func__,
514 			 sizeof(*be_lun));
515 		goto bailout_error;
516 	}
517 
518 	if (params->flags & CTL_LUN_FLAG_DEV_TYPE)
519 		be_lun->ctl_be_lun.lun_type = params->device_type;
520 	else
521 		be_lun->ctl_be_lun.lun_type = T_DIRECT;
522 
523 	if (be_lun->ctl_be_lun.lun_type == T_DIRECT) {
524 
525 		if (params->lun_size_bytes < blocksize) {
526 			snprintf(req->error_str, sizeof(req->error_str),
527 				 "%s: LUN size %ju < blocksize %u", __func__,
528 				 params->lun_size_bytes, blocksize);
529 			goto bailout_error;
530 		}
531 
532 		be_lun->size_blocks = params->lun_size_bytes / blocksize;
533 		be_lun->size_bytes = be_lun->size_blocks * blocksize;
534 
535 		be_lun->ctl_be_lun.maxlba = be_lun->size_blocks - 1;
536 	} else {
537 		be_lun->ctl_be_lun.maxlba = 0;
538 		blocksize = 0;
539 		be_lun->size_bytes = 0;
540 		be_lun->size_blocks = 0;
541 	}
542 
543 	be_lun->ctl_be_lun.blocksize = blocksize;
544 
545 	/* Tell the user the blocksize we ended up using */
546 	params->blocksize_bytes = blocksize;
547 
548 	/* Tell the user the exact size we ended up using */
549 	params->lun_size_bytes = be_lun->size_bytes;
550 
551 	be_lun->softc = softc;
552 
553 	be_lun->flags = CTL_BE_RAMDISK_LUN_UNCONFIGURED;
554 	be_lun->ctl_be_lun.flags = CTL_LUN_FLAG_PRIMARY;
555 	be_lun->ctl_be_lun.be_lun = be_lun;
556 
557 	if (params->flags & CTL_LUN_FLAG_ID_REQ) {
558 		be_lun->ctl_be_lun.req_lun_id = params->req_lun_id;
559 		be_lun->ctl_be_lun.flags |= CTL_LUN_FLAG_ID_REQ;
560 	} else
561 		be_lun->ctl_be_lun.req_lun_id = 0;
562 
563 	be_lun->ctl_be_lun.lun_shutdown = ctl_backend_ramdisk_lun_shutdown;
564 	be_lun->ctl_be_lun.lun_config_status =
565 		ctl_backend_ramdisk_lun_config_status;
566 	be_lun->ctl_be_lun.be = &ctl_be_ramdisk_driver;
567 	if ((params->flags & CTL_LUN_FLAG_SERIAL_NUM) == 0) {
568 		snprintf(tmpstr, sizeof(tmpstr), "MYSERIAL%4d",
569 			 softc->num_luns);
570 		strncpy((char *)be_lun->ctl_be_lun.serial_num, tmpstr,
571 			ctl_min(sizeof(be_lun->ctl_be_lun.serial_num),
572 			sizeof(tmpstr)));
573 
574 		/* Tell the user what we used for a serial number */
575 		strncpy((char *)params->serial_num, tmpstr,
576 			ctl_min(sizeof(params->serial_num), sizeof(tmpstr)));
577 	} else {
578 		strncpy((char *)be_lun->ctl_be_lun.serial_num,
579 			params->serial_num,
580 			ctl_min(sizeof(be_lun->ctl_be_lun.serial_num),
581 			sizeof(params->serial_num)));
582 	}
583 	if ((params->flags & CTL_LUN_FLAG_DEVID) == 0) {
584 		snprintf(tmpstr, sizeof(tmpstr), "MYDEVID%4d", softc->num_luns);
585 		strncpy((char *)be_lun->ctl_be_lun.device_id, tmpstr,
586 			ctl_min(sizeof(be_lun->ctl_be_lun.device_id),
587 			sizeof(tmpstr)));
588 
589 		/* Tell the user what we used for a device ID */
590 		strncpy((char *)params->device_id, tmpstr,
591 			ctl_min(sizeof(params->device_id), sizeof(tmpstr)));
592 	} else {
593 		strncpy((char *)be_lun->ctl_be_lun.device_id,
594 			params->device_id,
595 			ctl_min(sizeof(be_lun->ctl_be_lun.device_id),
596 				sizeof(params->device_id)));
597 	}
598 
599 	mtx_lock(&softc->lock);
600 	softc->num_luns++;
601 	STAILQ_INSERT_TAIL(&softc->lun_list, be_lun, links);
602 
603 	mtx_unlock(&softc->lock);
604 
605 	retval = ctl_add_lun(&be_lun->ctl_be_lun);
606 	if (retval != 0) {
607 		mtx_lock(&softc->lock);
608 		STAILQ_REMOVE(&softc->lun_list, be_lun, ctl_be_ramdisk_lun,
609 			      links);
610 		softc->num_luns--;
611 		mtx_unlock(&softc->lock);
612 		snprintf(req->error_str, sizeof(req->error_str),
613 			 "%s: ctl_add_lun() returned error %d, see dmesg for "
614 			"details", __func__, retval);
615 		retval = 0;
616 		goto bailout_error;
617 	}
618 
619 	if (do_wait == 0)
620 		return (retval);
621 
622 	mtx_lock(&softc->lock);
623 
624 	/*
625 	 * Tell the config_status routine that we're waiting so it won't
626 	 * clean up the LUN in the event of an error.
627 	 */
628 	be_lun->flags |= CTL_BE_RAMDISK_LUN_WAITING;
629 
630 	while (be_lun->flags & CTL_BE_RAMDISK_LUN_UNCONFIGURED) {
631 		retval = msleep(be_lun, &softc->lock, PCATCH, "ctlram", 0);
632 		if (retval == EINTR)
633 			break;
634 	}
635 	be_lun->flags &= ~CTL_BE_RAMDISK_LUN_WAITING;
636 
637 	if (be_lun->flags & CTL_BE_RAMDISK_LUN_CONFIG_ERR) {
638 		snprintf(req->error_str, sizeof(req->error_str),
639 			 "%s: LUN configuration error, see dmesg for details",
640 			 __func__);
641 		STAILQ_REMOVE(&softc->lun_list, be_lun, ctl_be_ramdisk_lun,
642 			      links);
643 		softc->num_luns--;
644 		mtx_unlock(&softc->lock);
645 		goto bailout_error;
646 	} else {
647 		params->req_lun_id = be_lun->ctl_be_lun.lun_id;
648 	}
649 	mtx_unlock(&softc->lock);
650 
651 	req->status = CTL_LUN_OK;
652 
653 	return (retval);
654 
655 bailout_error:
656 	req->status = CTL_LUN_ERROR;
657 	free(be_lun, M_RAMDISK);
658 
659 	return (retval);
660 }
661 
662 static int
663 ctl_backend_ramdisk_modify(struct ctl_be_ramdisk_softc *softc,
664 		       struct ctl_lun_req *req)
665 {
666 	struct ctl_be_ramdisk_lun *be_lun;
667 	struct ctl_lun_modify_params *params;
668 	uint32_t blocksize;
669 
670 	params = &req->reqdata.modify;
671 
672 	be_lun = NULL;
673 
674 	mtx_lock(&softc->lock);
675 	STAILQ_FOREACH(be_lun, &softc->lun_list, links) {
676 		if (be_lun->ctl_be_lun.lun_id == params->lun_id)
677 			break;
678 	}
679 	mtx_unlock(&softc->lock);
680 
681 	if (be_lun == NULL) {
682 		snprintf(req->error_str, sizeof(req->error_str),
683 			 "%s: LUN %u is not managed by the ramdisk backend",
684 			 __func__, params->lun_id);
685 		goto bailout_error;
686 	}
687 
688 	if (params->lun_size_bytes == 0) {
689 		snprintf(req->error_str, sizeof(req->error_str),
690 			"%s: LUN size \"auto\" not supported "
691 			"by the ramdisk backend", __func__);
692 		goto bailout_error;
693 	}
694 
695 	blocksize = be_lun->ctl_be_lun.blocksize;
696 
697 	if (params->lun_size_bytes < blocksize) {
698 		snprintf(req->error_str, sizeof(req->error_str),
699 			"%s: LUN size %ju < blocksize %u", __func__,
700 			params->lun_size_bytes, blocksize);
701 		goto bailout_error;
702 	}
703 
704 	be_lun->size_blocks = params->lun_size_bytes / blocksize;
705 	be_lun->size_bytes = be_lun->size_blocks * blocksize;
706 
707 	/*
708 	 * The maximum LBA is the size - 1.
709 	 *
710 	 * XXX: Note that this field is being updated without locking,
711 	 * 	which might cause problems on 32-bit architectures.
712 	 */
713 	be_lun->ctl_be_lun.maxlba = be_lun->size_blocks - 1;
714 	ctl_lun_capacity_changed(&be_lun->ctl_be_lun);
715 
716 	/* Tell the user the exact size we ended up using */
717 	params->lun_size_bytes = be_lun->size_bytes;
718 
719 	req->status = CTL_LUN_OK;
720 
721 	return (0);
722 
723 bailout_error:
724 	req->status = CTL_LUN_ERROR;
725 
726 	return (0);
727 }
728 
729 static void
730 ctl_backend_ramdisk_lun_shutdown(void *be_lun)
731 {
732 	struct ctl_be_ramdisk_lun *lun;
733 	struct ctl_be_ramdisk_softc *softc;
734 	int do_free;
735 
736 	lun = (struct ctl_be_ramdisk_lun *)be_lun;
737 	softc = lun->softc;
738 	do_free = 0;
739 
740 	mtx_lock(&softc->lock);
741 
742 	lun->flags |= CTL_BE_RAMDISK_LUN_UNCONFIGURED;
743 
744 	if (lun->flags & CTL_BE_RAMDISK_LUN_WAITING) {
745 		wakeup(lun);
746 	} else {
747 		STAILQ_REMOVE(&softc->lun_list, be_lun, ctl_be_ramdisk_lun,
748 			      links);
749 		softc->num_luns--;
750 		do_free = 1;
751 	}
752 
753 	mtx_unlock(&softc->lock);
754 
755 	if (do_free != 0)
756 		free(be_lun, M_RAMDISK);
757 }
758 
759 static void
760 ctl_backend_ramdisk_lun_config_status(void *be_lun,
761 				      ctl_lun_config_status status)
762 {
763 	struct ctl_be_ramdisk_lun *lun;
764 	struct ctl_be_ramdisk_softc *softc;
765 
766 	lun = (struct ctl_be_ramdisk_lun *)be_lun;
767 	softc = lun->softc;
768 
769 	if (status == CTL_LUN_CONFIG_OK) {
770 		mtx_lock(&softc->lock);
771 		lun->flags &= ~CTL_BE_RAMDISK_LUN_UNCONFIGURED;
772 		if (lun->flags & CTL_BE_RAMDISK_LUN_WAITING)
773 			wakeup(lun);
774 		mtx_unlock(&softc->lock);
775 
776 		/*
777 		 * We successfully added the LUN, attempt to enable it.
778 		 */
779 		if (ctl_enable_lun(&lun->ctl_be_lun) != 0) {
780 			printf("%s: ctl_enable_lun() failed!\n", __func__);
781 			if (ctl_invalidate_lun(&lun->ctl_be_lun) != 0) {
782 				printf("%s: ctl_invalidate_lun() failed!\n",
783 				       __func__);
784 			}
785 		}
786 
787 		return;
788 	}
789 
790 
791 	mtx_lock(&softc->lock);
792 	lun->flags &= ~CTL_BE_RAMDISK_LUN_UNCONFIGURED;
793 
794 	/*
795 	 * If we have a user waiting, let him handle the cleanup.  If not,
796 	 * clean things up here.
797 	 */
798 	if (lun->flags & CTL_BE_RAMDISK_LUN_WAITING) {
799 		lun->flags |= CTL_BE_RAMDISK_LUN_CONFIG_ERR;
800 		wakeup(lun);
801 	} else {
802 		STAILQ_REMOVE(&softc->lun_list, lun, ctl_be_ramdisk_lun,
803 			      links);
804 		softc->num_luns--;
805 		free(lun, M_RAMDISK);
806 	}
807 	mtx_unlock(&softc->lock);
808 }
809 
810 static int
811 ctl_backend_ramdisk_config_write(union ctl_io *io)
812 {
813 	struct ctl_be_ramdisk_softc *softc;
814 	int retval;
815 
816 	retval = 0;
817 	softc = &rd_softc;
818 
819 	switch (io->scsiio.cdb[0]) {
820 	case SYNCHRONIZE_CACHE:
821 	case SYNCHRONIZE_CACHE_16:
822 		/*
823 		 * The upper level CTL code will filter out any CDBs with
824 		 * the immediate bit set and return the proper error.  It
825 		 * will also not allow a sync cache command to go to a LUN
826 		 * that is powered down.
827 		 *
828 		 * We don't really need to worry about what LBA range the
829 		 * user asked to be synced out.  When they issue a sync
830 		 * cache command, we'll sync out the whole thing.
831 		 *
832 		 * This is obviously just a stubbed out implementation.
833 		 * The real implementation will be in the RAIDCore/CTL
834 		 * interface, and can only really happen when RAIDCore
835 		 * implements a per-array cache sync.
836 		 */
837 		ctl_set_success(&io->scsiio);
838 		ctl_config_write_done(io);
839 		break;
840 	case START_STOP_UNIT: {
841 		struct scsi_start_stop_unit *cdb;
842 		struct ctl_be_lun *ctl_be_lun;
843 		struct ctl_be_ramdisk_lun *be_lun;
844 
845 		cdb = (struct scsi_start_stop_unit *)io->scsiio.cdb;
846 
847 		ctl_be_lun = (struct ctl_be_lun *)io->io_hdr.ctl_private[
848 			CTL_PRIV_BACKEND_LUN].ptr;
849 		be_lun = (struct ctl_be_ramdisk_lun *)ctl_be_lun->be_lun;
850 
851 		if (cdb->how & SSS_START)
852 			retval = ctl_start_lun(ctl_be_lun);
853 		else {
854 			retval = ctl_stop_lun(ctl_be_lun);
855 #ifdef NEEDTOPORT
856 			if ((retval == 0)
857 			 && (cdb->byte2 & SSS_ONOFFLINE))
858 				retval = ctl_lun_offline(ctl_be_lun);
859 #endif
860 		}
861 
862 		/*
863 		 * In general, the above routines should not fail.  They
864 		 * just set state for the LUN.  So we've got something
865 		 * pretty wrong here if we can't start or stop the LUN.
866 		 */
867 		if (retval != 0) {
868 			ctl_set_internal_failure(&io->scsiio,
869 						 /*sks_valid*/ 1,
870 						 /*retry_count*/ 0xf051);
871 			retval = CTL_RETVAL_COMPLETE;
872 		} else {
873 			ctl_set_success(&io->scsiio);
874 		}
875 		ctl_config_write_done(io);
876 		break;
877 	}
878 	default:
879 		ctl_set_invalid_opcode(&io->scsiio);
880 		ctl_config_write_done(io);
881 		retval = CTL_RETVAL_COMPLETE;
882 		break;
883 	}
884 
885 	return (retval);
886 }
887 
888 static int
889 ctl_backend_ramdisk_config_read(union ctl_io *io)
890 {
891 	/*
892 	 * XXX KDM need to implement!!
893 	 */
894 	return (0);
895 }
896