1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (C) 2012-2013 Intel Corporation
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/param.h>
30 #include <sys/bio.h>
31 #include <sys/bus.h>
32 #include <sys/conf.h>
33 #include <sys/disk.h>
34 #include <sys/fcntl.h>
35 #include <sys/ioccom.h>
36 #include <sys/malloc.h>
37 #include <sys/module.h>
38 #include <sys/proc.h>
39 #include <sys/systm.h>
40
41 #include <dev/pci/pcivar.h>
42
43 #include <geom/geom.h>
44
45 #include "nvme_private.h"
46 #include "nvme_linux.h"
47
48 static void nvme_bio_child_inbed(struct bio *parent, int bio_error);
49 static void nvme_bio_child_done(void *arg,
50 const struct nvme_completion *cpl);
51 static uint32_t nvme_get_num_segments(uint64_t addr, uint64_t size,
52 uint32_t alignment);
53 static void nvme_free_child_bios(int num_bios,
54 struct bio **child_bios);
55 static struct bio ** nvme_allocate_child_bios(int num_bios);
56 static struct bio ** nvme_construct_child_bios(struct bio *bp,
57 uint32_t alignment,
58 int *num_bios);
59 static int nvme_ns_split_bio(struct nvme_namespace *ns,
60 struct bio *bp,
61 uint32_t alignment);
62
63 static int
nvme_ns_ioctl(struct cdev * cdev,u_long cmd,caddr_t arg,int flag,struct thread * td)64 nvme_ns_ioctl(struct cdev *cdev, u_long cmd, caddr_t arg, int flag,
65 struct thread *td)
66 {
67 struct nvme_namespace *ns;
68 struct nvme_controller *ctrlr;
69 struct nvme_pt_command *pt;
70
71 ns = cdev->si_drv1;
72 ctrlr = ns->ctrlr;
73
74 switch (cmd) {
75 case NVME_IO_TEST:
76 case NVME_BIO_TEST:
77 nvme_ns_test(ns, cmd, arg);
78 break;
79 case NVME_PASSTHROUGH_CMD:
80 pt = (struct nvme_pt_command *)arg;
81 return (nvme_ctrlr_passthrough_cmd(ctrlr, pt, ns->id,
82 1 /* is_user_buffer */, 0 /* is_admin_cmd */));
83 case NVME_GET_NSID:
84 {
85 struct nvme_get_nsid *gnsid = (struct nvme_get_nsid *)arg;
86 strlcpy(gnsid->cdev, device_get_nameunit(ctrlr->dev),
87 sizeof(gnsid->cdev));
88 gnsid->nsid = ns->id;
89 break;
90 }
91 case DIOCGMEDIASIZE:
92 *(off_t *)arg = (off_t)nvme_ns_get_size(ns);
93 break;
94 case DIOCGSECTORSIZE:
95 *(u_int *)arg = nvme_ns_get_sector_size(ns);
96 break;
97 /* Linux Compatible (see nvme_linux.h) */
98 case NVME_IOCTL_ID:
99 td->td_retval[0] = ns->id;
100 return (0);
101
102 case NVME_IOCTL_ADMIN_CMD:
103 case NVME_IOCTL_IO_CMD: {
104 struct nvme_passthru_cmd *npc = (struct nvme_passthru_cmd *)arg;
105
106 return (nvme_ctrlr_linux_passthru_cmd(ctrlr, npc, ns->id, true,
107 cmd == NVME_IOCTL_ADMIN_CMD));
108 }
109 default:
110 return (ENOTTY);
111 }
112
113 return (0);
114 }
115
116 static int
nvme_ns_open(struct cdev * dev __unused,int flags,int fmt __unused,struct thread * td)117 nvme_ns_open(struct cdev *dev __unused, int flags, int fmt __unused,
118 struct thread *td)
119 {
120 int error = 0;
121
122 if (flags & FWRITE)
123 error = securelevel_gt(td->td_ucred, 0);
124
125 return (error);
126 }
127
128 static int
nvme_ns_close(struct cdev * dev __unused,int flags,int fmt __unused,struct thread * td)129 nvme_ns_close(struct cdev *dev __unused, int flags, int fmt __unused,
130 struct thread *td)
131 {
132
133 return (0);
134 }
135
136 static void
nvme_ns_strategy_done(void * arg,const struct nvme_completion * cpl)137 nvme_ns_strategy_done(void *arg, const struct nvme_completion *cpl)
138 {
139 struct bio *bp = arg;
140
141 /*
142 * TODO: add more extensive translation of NVMe status codes
143 * to different bio error codes (i.e. EIO, EINVAL, etc.)
144 */
145 if (nvme_completion_is_error(cpl)) {
146 bp->bio_error = EIO;
147 bp->bio_flags |= BIO_ERROR;
148 bp->bio_resid = bp->bio_bcount;
149 } else
150 bp->bio_resid = 0;
151
152 biodone(bp);
153 }
154
155 static void
nvme_ns_strategy(struct bio * bp)156 nvme_ns_strategy(struct bio *bp)
157 {
158 struct nvme_namespace *ns;
159 int err;
160
161 ns = bp->bio_dev->si_drv1;
162 err = nvme_ns_bio_process(ns, bp, nvme_ns_strategy_done);
163
164 if (err) {
165 bp->bio_error = err;
166 bp->bio_flags |= BIO_ERROR;
167 bp->bio_resid = bp->bio_bcount;
168 biodone(bp);
169 }
170
171 }
172
173 static struct cdevsw nvme_ns_cdevsw = {
174 .d_version = D_VERSION,
175 .d_flags = D_DISK,
176 .d_read = physread,
177 .d_write = physwrite,
178 .d_open = nvme_ns_open,
179 .d_close = nvme_ns_close,
180 .d_strategy = nvme_ns_strategy,
181 .d_ioctl = nvme_ns_ioctl
182 };
183
184 uint32_t
nvme_ns_get_max_io_xfer_size(struct nvme_namespace * ns)185 nvme_ns_get_max_io_xfer_size(struct nvme_namespace *ns)
186 {
187 return ns->ctrlr->max_xfer_size;
188 }
189
190 uint32_t
nvme_ns_get_sector_size(struct nvme_namespace * ns)191 nvme_ns_get_sector_size(struct nvme_namespace *ns)
192 {
193 uint8_t flbas_fmt, lbads;
194
195 flbas_fmt = NVMEV(NVME_NS_DATA_FLBAS_FORMAT, ns->data.flbas);
196 lbads = NVMEV(NVME_NS_DATA_LBAF_LBADS, ns->data.lbaf[flbas_fmt]);
197
198 return (1 << lbads);
199 }
200
201 uint64_t
nvme_ns_get_num_sectors(struct nvme_namespace * ns)202 nvme_ns_get_num_sectors(struct nvme_namespace *ns)
203 {
204 return (ns->data.nsze);
205 }
206
207 uint64_t
nvme_ns_get_size(struct nvme_namespace * ns)208 nvme_ns_get_size(struct nvme_namespace *ns)
209 {
210 return (nvme_ns_get_num_sectors(ns) * nvme_ns_get_sector_size(ns));
211 }
212
213 uint32_t
nvme_ns_get_flags(struct nvme_namespace * ns)214 nvme_ns_get_flags(struct nvme_namespace *ns)
215 {
216 return (ns->flags);
217 }
218
219 const char *
nvme_ns_get_serial_number(struct nvme_namespace * ns)220 nvme_ns_get_serial_number(struct nvme_namespace *ns)
221 {
222 return ((const char *)ns->ctrlr->cdata.sn);
223 }
224
225 const char *
nvme_ns_get_model_number(struct nvme_namespace * ns)226 nvme_ns_get_model_number(struct nvme_namespace *ns)
227 {
228 return ((const char *)ns->ctrlr->cdata.mn);
229 }
230
231 const struct nvme_namespace_data *
nvme_ns_get_data(struct nvme_namespace * ns)232 nvme_ns_get_data(struct nvme_namespace *ns)
233 {
234
235 return (&ns->data);
236 }
237
238 uint32_t
nvme_ns_get_stripesize(struct nvme_namespace * ns)239 nvme_ns_get_stripesize(struct nvme_namespace *ns)
240 {
241 uint32_t ss;
242
243 if (NVMEV(NVME_NS_DATA_NSFEAT_NPVALID, ns->data.nsfeat) != 0) {
244 ss = nvme_ns_get_sector_size(ns);
245 if (ns->data.npwa != 0)
246 return ((ns->data.npwa + 1) * ss);
247 else if (ns->data.npwg != 0)
248 return ((ns->data.npwg + 1) * ss);
249 }
250 return (ns->boundary);
251 }
252
253 static void
nvme_ns_bio_done(void * arg,const struct nvme_completion * status)254 nvme_ns_bio_done(void *arg, const struct nvme_completion *status)
255 {
256 struct bio *bp = arg;
257 nvme_cb_fn_t bp_cb_fn;
258
259 bp_cb_fn = bp->bio_driver1;
260
261 if (bp->bio_driver2)
262 free(bp->bio_driver2, M_NVME);
263
264 if (nvme_completion_is_error(status)) {
265 bp->bio_flags |= BIO_ERROR;
266 if (bp->bio_error == 0)
267 bp->bio_error = EIO;
268 }
269
270 if ((bp->bio_flags & BIO_ERROR) == 0)
271 bp->bio_resid = 0;
272 else
273 bp->bio_resid = bp->bio_bcount;
274
275 bp_cb_fn(bp, status);
276 }
277
278 static void
nvme_bio_child_inbed(struct bio * parent,int bio_error)279 nvme_bio_child_inbed(struct bio *parent, int bio_error)
280 {
281 struct nvme_completion parent_cpl;
282 int children, inbed;
283
284 if (bio_error != 0) {
285 parent->bio_flags |= BIO_ERROR;
286 parent->bio_error = bio_error;
287 }
288
289 /*
290 * atomic_fetchadd will return value before adding 1, so we still
291 * must add 1 to get the updated inbed number. Save bio_children
292 * before incrementing to guard against race conditions when
293 * two children bios complete on different queues.
294 */
295 children = atomic_load_acq_int(&parent->bio_children);
296 inbed = atomic_fetchadd_int(&parent->bio_inbed, 1) + 1;
297 if (inbed == children) {
298 bzero(&parent_cpl, sizeof(parent_cpl));
299 if (parent->bio_flags & BIO_ERROR) {
300 parent_cpl.status &= ~NVMEM(NVME_STATUS_SC);
301 parent_cpl.status |= NVMEF(NVME_STATUS_SC,
302 NVME_SC_DATA_TRANSFER_ERROR);
303 }
304 nvme_ns_bio_done(parent, &parent_cpl);
305 }
306 }
307
308 static void
nvme_bio_child_done(void * arg,const struct nvme_completion * cpl)309 nvme_bio_child_done(void *arg, const struct nvme_completion *cpl)
310 {
311 struct bio *child = arg;
312 struct bio *parent;
313 int bio_error;
314
315 parent = child->bio_parent;
316 g_destroy_bio(child);
317 bio_error = nvme_completion_is_error(cpl) ? EIO : 0;
318 nvme_bio_child_inbed(parent, bio_error);
319 }
320
321 static uint32_t
nvme_get_num_segments(uint64_t addr,uint64_t size,uint32_t align)322 nvme_get_num_segments(uint64_t addr, uint64_t size, uint32_t align)
323 {
324 uint32_t num_segs, offset, remainder;
325
326 if (align == 0)
327 return (1);
328
329 KASSERT((align & (align - 1)) == 0, ("alignment not power of 2\n"));
330
331 num_segs = size / align;
332 remainder = size & (align - 1);
333 offset = addr & (align - 1);
334 if (remainder > 0 || offset > 0)
335 num_segs += 1 + (remainder + offset - 1) / align;
336 return (num_segs);
337 }
338
339 static void
nvme_free_child_bios(int num_bios,struct bio ** child_bios)340 nvme_free_child_bios(int num_bios, struct bio **child_bios)
341 {
342 int i;
343
344 for (i = 0; i < num_bios; i++) {
345 if (child_bios[i] != NULL)
346 g_destroy_bio(child_bios[i]);
347 }
348
349 free(child_bios, M_NVME);
350 }
351
352 static struct bio **
nvme_allocate_child_bios(int num_bios)353 nvme_allocate_child_bios(int num_bios)
354 {
355 struct bio **child_bios;
356 int err = 0, i;
357
358 child_bios = malloc(num_bios * sizeof(struct bio *), M_NVME, M_NOWAIT);
359 if (child_bios == NULL)
360 return (NULL);
361
362 for (i = 0; i < num_bios; i++) {
363 child_bios[i] = g_new_bio();
364 if (child_bios[i] == NULL)
365 err = ENOMEM;
366 }
367
368 if (err == ENOMEM) {
369 nvme_free_child_bios(num_bios, child_bios);
370 return (NULL);
371 }
372
373 return (child_bios);
374 }
375
376 static struct bio **
nvme_construct_child_bios(struct bio * bp,uint32_t alignment,int * num_bios)377 nvme_construct_child_bios(struct bio *bp, uint32_t alignment, int *num_bios)
378 {
379 struct bio **child_bios;
380 struct bio *child;
381 uint64_t cur_offset;
382 caddr_t data;
383 uint32_t rem_bcount;
384 int i;
385 struct vm_page **ma;
386 uint32_t ma_offset;
387
388 *num_bios = nvme_get_num_segments(bp->bio_offset, bp->bio_bcount,
389 alignment);
390 child_bios = nvme_allocate_child_bios(*num_bios);
391 if (child_bios == NULL)
392 return (NULL);
393
394 bp->bio_children = *num_bios;
395 bp->bio_inbed = 0;
396 cur_offset = bp->bio_offset;
397 rem_bcount = bp->bio_bcount;
398 data = bp->bio_data;
399 ma_offset = bp->bio_ma_offset;
400 ma = bp->bio_ma;
401
402 for (i = 0; i < *num_bios; i++) {
403 child = child_bios[i];
404 child->bio_parent = bp;
405 child->bio_cmd = bp->bio_cmd;
406 child->bio_offset = cur_offset;
407 child->bio_bcount = min(rem_bcount,
408 alignment - (cur_offset & (alignment - 1)));
409 child->bio_flags = bp->bio_flags;
410 if (bp->bio_flags & BIO_UNMAPPED) {
411 child->bio_ma_offset = ma_offset;
412 child->bio_ma = ma;
413 child->bio_ma_n =
414 nvme_get_num_segments(child->bio_ma_offset,
415 child->bio_bcount, PAGE_SIZE);
416 ma_offset = (ma_offset + child->bio_bcount) &
417 PAGE_MASK;
418 ma += child->bio_ma_n;
419 if (ma_offset != 0)
420 ma -= 1;
421 } else {
422 child->bio_data = data;
423 data += child->bio_bcount;
424 }
425 cur_offset += child->bio_bcount;
426 rem_bcount -= child->bio_bcount;
427 }
428
429 return (child_bios);
430 }
431
432 static int
nvme_ns_split_bio(struct nvme_namespace * ns,struct bio * bp,uint32_t alignment)433 nvme_ns_split_bio(struct nvme_namespace *ns, struct bio *bp,
434 uint32_t alignment)
435 {
436 struct bio *child;
437 struct bio **child_bios;
438 int err, i, num_bios;
439
440 child_bios = nvme_construct_child_bios(bp, alignment, &num_bios);
441 if (child_bios == NULL)
442 return (ENOMEM);
443
444 counter_u64_add(ns->ctrlr->alignment_splits, 1);
445 for (i = 0; i < num_bios; i++) {
446 child = child_bios[i];
447 err = nvme_ns_bio_process(ns, child, nvme_bio_child_done);
448 if (err != 0) {
449 nvme_bio_child_inbed(bp, err);
450 g_destroy_bio(child);
451 }
452 }
453
454 free(child_bios, M_NVME);
455 return (0);
456 }
457
458 int
nvme_ns_bio_process(struct nvme_namespace * ns,struct bio * bp,nvme_cb_fn_t cb_fn)459 nvme_ns_bio_process(struct nvme_namespace *ns, struct bio *bp,
460 nvme_cb_fn_t cb_fn)
461 {
462 struct nvme_dsm_range *dsm_range;
463 uint32_t num_bios;
464 int err;
465
466 bp->bio_driver1 = cb_fn;
467
468 if (ns->boundary > 0 &&
469 (bp->bio_cmd == BIO_READ || bp->bio_cmd == BIO_WRITE)) {
470 num_bios = nvme_get_num_segments(bp->bio_offset,
471 bp->bio_bcount, ns->boundary);
472 if (num_bios > 1)
473 return (nvme_ns_split_bio(ns, bp, ns->boundary));
474 }
475
476 switch (bp->bio_cmd) {
477 case BIO_READ:
478 err = nvme_ns_cmd_read_bio(ns, bp, nvme_ns_bio_done, bp);
479 break;
480 case BIO_WRITE:
481 err = nvme_ns_cmd_write_bio(ns, bp, nvme_ns_bio_done, bp);
482 break;
483 case BIO_FLUSH:
484 err = nvme_ns_cmd_flush(ns, nvme_ns_bio_done, bp);
485 break;
486 case BIO_DELETE:
487 dsm_range =
488 malloc(sizeof(struct nvme_dsm_range), M_NVME,
489 M_ZERO | M_NOWAIT);
490 if (!dsm_range) {
491 err = ENOMEM;
492 break;
493 }
494 dsm_range->length =
495 htole32(bp->bio_bcount/nvme_ns_get_sector_size(ns));
496 dsm_range->starting_lba =
497 htole64(bp->bio_offset/nvme_ns_get_sector_size(ns));
498 bp->bio_driver2 = dsm_range;
499 err = nvme_ns_cmd_deallocate(ns, dsm_range, 1,
500 nvme_ns_bio_done, bp);
501 if (err != 0)
502 free(dsm_range, M_NVME);
503 break;
504 default:
505 err = EOPNOTSUPP;
506 break;
507 }
508
509 return (err);
510 }
511
512 int
nvme_ns_ioctl_process(struct nvme_namespace * ns,u_long cmd,caddr_t arg,int flag,struct thread * td)513 nvme_ns_ioctl_process(struct nvme_namespace *ns, u_long cmd, caddr_t arg,
514 int flag, struct thread *td)
515 {
516 return (nvme_ns_ioctl(ns->cdev, cmd, arg, flag, td));
517 }
518
519 int
nvme_ns_construct(struct nvme_namespace * ns,uint32_t id,struct nvme_controller * ctrlr)520 nvme_ns_construct(struct nvme_namespace *ns, uint32_t id,
521 struct nvme_controller *ctrlr)
522 {
523 struct make_dev_args md_args;
524 struct nvme_completion_poll_status status;
525 int res;
526 int unit;
527 uint8_t flbas_fmt;
528 uint8_t vwc_present;
529
530 ns->ctrlr = ctrlr;
531 ns->id = id;
532
533 /*
534 * Namespaces are reconstructed after a controller reset, so check
535 * to make sure we only call mtx_init once on each mtx.
536 *
537 * TODO: Move this somewhere where it gets called at controller
538 * construction time, which is not invoked as part of each
539 * controller reset.
540 */
541 if (!mtx_initialized(&ns->lock))
542 mtx_init(&ns->lock, "nvme ns lock", NULL, MTX_DEF);
543
544 status.done = 0;
545 nvme_ctrlr_cmd_identify_namespace(ctrlr, id, &ns->data,
546 nvme_completion_poll_cb, &status);
547 nvme_completion_poll(&status);
548 if (nvme_completion_is_error(&status.cpl)) {
549 nvme_printf(ctrlr, "nvme_identify_namespace failed\n");
550 return (ENXIO);
551 }
552
553 /* Convert data to host endian */
554 nvme_namespace_data_swapbytes(&ns->data);
555
556 /*
557 * If the size of is zero, chances are this isn't a valid
558 * namespace (eg one that's not been configured yet). The
559 * standard says the entire id will be zeros, so this is a
560 * cheap way to test for that.
561 */
562 if (ns->data.nsze == 0)
563 return (ENXIO);
564
565 flbas_fmt = NVMEV(NVME_NS_DATA_FLBAS_FORMAT, ns->data.flbas);
566
567 /*
568 * Note: format is a 0-based value, so > is appropriate here,
569 * not >=.
570 */
571 if (flbas_fmt > ns->data.nlbaf) {
572 nvme_printf(ctrlr,
573 "lba format %d exceeds number supported (%d)\n",
574 flbas_fmt, ns->data.nlbaf + 1);
575 return (ENXIO);
576 }
577
578 /*
579 * Older Intel devices (like the PC35xxx and P45xx series) advertise in
580 * vendor specific space an alignment that improves performance. If
581 * present use for the stripe size. NVMe 1.3 standardized this as
582 * NOIOB, and newer Intel drives use that.
583 */
584 if ((ctrlr->quirks & QUIRK_INTEL_ALIGNMENT) != 0) {
585 if (ctrlr->cdata.vs[3] != 0)
586 ns->boundary =
587 1 << (ctrlr->cdata.vs[3] + NVME_MPS_SHIFT +
588 NVME_CAP_HI_MPSMIN(ctrlr->cap_hi));
589 else
590 ns->boundary = 0;
591 } else {
592 ns->boundary = ns->data.noiob * nvme_ns_get_sector_size(ns);
593 }
594
595 if (nvme_ctrlr_has_dataset_mgmt(&ctrlr->cdata))
596 ns->flags |= NVME_NS_DEALLOCATE_SUPPORTED;
597
598 vwc_present = NVMEV(NVME_CTRLR_DATA_VWC_PRESENT, ctrlr->cdata.vwc);
599 if (vwc_present)
600 ns->flags |= NVME_NS_FLUSH_SUPPORTED;
601
602 /*
603 * cdev may have already been created, if we are reconstructing the
604 * namespace after a controller-level reset.
605 */
606 if (ns->cdev != NULL)
607 return (0);
608
609 /*
610 * Namespace IDs start at 1, so we need to subtract 1 to create a
611 * correct unit number.
612 */
613 unit = device_get_unit(ctrlr->dev) * NVME_MAX_NAMESPACES + ns->id - 1;
614
615 make_dev_args_init(&md_args);
616 md_args.mda_devsw = &nvme_ns_cdevsw;
617 md_args.mda_unit = unit;
618 md_args.mda_mode = 0600;
619 md_args.mda_si_drv1 = ns;
620 res = make_dev_s(&md_args, &ns->cdev, "%sn%d",
621 device_get_nameunit(ctrlr->dev), ns->id);
622 if (res != 0)
623 return (ENXIO);
624 ns->cdev->si_drv2 = make_dev_alias(ns->cdev, "%sns%d",
625 device_get_nameunit(ctrlr->dev), ns->id);
626 ns->cdev->si_flags |= SI_UNMAPPED;
627
628 return (0);
629 }
630
631 void
nvme_ns_destruct(struct nvme_namespace * ns)632 nvme_ns_destruct(struct nvme_namespace *ns)
633 {
634
635 if (ns->cdev != NULL) {
636 if (ns->cdev->si_drv2 != NULL)
637 destroy_dev(ns->cdev->si_drv2);
638 destroy_dev(ns->cdev);
639 }
640 }
641