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 DIOCGIDENT: {
92 uint8_t *sn = arg;
93 nvme_ctrlr_get_ident(ctrlr, sn);
94 break;
95 }
96 case DIOCGMEDIASIZE:
97 *(off_t *)arg = (off_t)nvme_ns_get_size(ns);
98 break;
99 case DIOCGSECTORSIZE:
100 *(u_int *)arg = nvme_ns_get_sector_size(ns);
101 break;
102 /* Linux Compatible (see nvme_linux.h) */
103 case NVME_IOCTL_ID:
104 td->td_retval[0] = ns->id;
105 return (0);
106
107 case NVME_IOCTL_ADMIN_CMD:
108 case NVME_IOCTL_IO_CMD: {
109 struct nvme_passthru_cmd *npc = (struct nvme_passthru_cmd *)arg;
110
111 return (nvme_ctrlr_linux_passthru_cmd(ctrlr, npc, ns->id, true,
112 cmd == NVME_IOCTL_ADMIN_CMD));
113 }
114 default:
115 return (ENOTTY);
116 }
117
118 return (0);
119 }
120
121 static int
nvme_ns_open(struct cdev * dev __unused,int flags,int fmt __unused,struct thread * td)122 nvme_ns_open(struct cdev *dev __unused, int flags, int fmt __unused,
123 struct thread *td)
124 {
125 int error = 0;
126
127 if (flags & FWRITE)
128 error = securelevel_gt(td->td_ucred, 0);
129
130 return (error);
131 }
132
133 static int
nvme_ns_close(struct cdev * dev __unused,int flags,int fmt __unused,struct thread * td)134 nvme_ns_close(struct cdev *dev __unused, int flags, int fmt __unused,
135 struct thread *td)
136 {
137 return (0);
138 }
139
140 static void
nvme_ns_strategy_done(void * arg,const struct nvme_completion * cpl)141 nvme_ns_strategy_done(void *arg, const struct nvme_completion *cpl)
142 {
143 struct bio *bp = arg;
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 return (&ns->data);
235 }
236
237 uint32_t
nvme_ns_get_stripesize(struct nvme_namespace * ns)238 nvme_ns_get_stripesize(struct nvme_namespace *ns)
239 {
240 uint32_t ss;
241
242 if (NVMEV(NVME_NS_DATA_NSFEAT_NPVALID, ns->data.nsfeat) != 0) {
243 ss = nvme_ns_get_sector_size(ns);
244 if (ns->data.npwa != 0)
245 return ((ns->data.npwa + 1) * ss);
246 else if (ns->data.npwg != 0)
247 return ((ns->data.npwg + 1) * ss);
248 }
249 return (ns->boundary);
250 }
251
252 static void
nvme_ns_bio_done(void * arg,const struct nvme_completion * status)253 nvme_ns_bio_done(void *arg, const struct nvme_completion *status)
254 {
255 struct bio *bp = arg;
256 nvme_cb_fn_t bp_cb_fn;
257
258 bp_cb_fn = bp->bio_driver1;
259
260 if (bp->bio_driver2)
261 free(bp->bio_driver2, M_NVME);
262
263 if (nvme_completion_is_error(status)) {
264 bp->bio_flags |= BIO_ERROR;
265 if (bp->bio_error == 0)
266 bp->bio_error = EIO;
267 }
268
269 if ((bp->bio_flags & BIO_ERROR) == 0)
270 bp->bio_resid = 0;
271 else
272 bp->bio_resid = bp->bio_bcount;
273
274 bp_cb_fn(bp, status);
275 }
276
277 static void
nvme_bio_child_inbed(struct bio * parent,int bio_error)278 nvme_bio_child_inbed(struct bio *parent, int bio_error)
279 {
280 struct nvme_completion parent_cpl;
281 int children, inbed;
282
283 if (bio_error != 0) {
284 parent->bio_flags |= BIO_ERROR;
285 parent->bio_error = bio_error;
286 }
287
288 /*
289 * atomic_fetchadd will return value before adding 1, so we still
290 * must add 1 to get the updated inbed number. Save bio_children
291 * before incrementing to guard against race conditions when
292 * two children bios complete on different queues.
293 */
294 children = atomic_load_acq_int(&parent->bio_children);
295 inbed = atomic_fetchadd_int(&parent->bio_inbed, 1) + 1;
296 if (inbed == children) {
297 bzero(&parent_cpl, sizeof(parent_cpl));
298 if (parent->bio_flags & BIO_ERROR) {
299 parent_cpl.status &= ~NVMEM(NVME_STATUS_SC);
300 parent_cpl.status |= NVMEF(NVME_STATUS_SC,
301 NVME_SC_DATA_TRANSFER_ERROR);
302 }
303 nvme_ns_bio_done(parent, &parent_cpl);
304 }
305 }
306
307 static void
nvme_bio_child_done(void * arg,const struct nvme_completion * cpl)308 nvme_bio_child_done(void *arg, const struct nvme_completion *cpl)
309 {
310 struct bio *child = arg;
311 struct bio *parent;
312 int bio_error;
313
314 parent = child->bio_parent;
315 g_destroy_bio(child);
316 bio_error = nvme_completion_is_error(cpl) ? EIO : 0;
317 nvme_bio_child_inbed(parent, bio_error);
318 }
319
320 static uint32_t
nvme_get_num_segments(uint64_t addr,uint64_t size,uint32_t align)321 nvme_get_num_segments(uint64_t addr, uint64_t size, uint32_t align)
322 {
323 uint32_t num_segs, offset, remainder;
324
325 if (align == 0)
326 return (1);
327
328 KASSERT((align & (align - 1)) == 0, ("alignment not power of 2\n"));
329
330 num_segs = size / align;
331 remainder = size & (align - 1);
332 offset = addr & (align - 1);
333 if (remainder > 0 || offset > 0)
334 num_segs += 1 + (remainder + offset - 1) / align;
335 return (num_segs);
336 }
337
338 static void
nvme_free_child_bios(int num_bios,struct bio ** child_bios)339 nvme_free_child_bios(int num_bios, struct bio **child_bios)
340 {
341 int i;
342
343 for (i = 0; i < num_bios; i++) {
344 if (child_bios[i] != NULL)
345 g_destroy_bio(child_bios[i]);
346 }
347
348 free(child_bios, M_NVME);
349 }
350
351 static struct bio **
nvme_allocate_child_bios(int num_bios)352 nvme_allocate_child_bios(int num_bios)
353 {
354 struct bio **child_bios;
355 int err = 0, i;
356
357 child_bios = malloc(num_bios * sizeof(struct bio *), M_NVME, M_NOWAIT);
358 if (child_bios == NULL)
359 return (NULL);
360
361 for (i = 0; i < num_bios; i++) {
362 child_bios[i] = g_new_bio();
363 if (child_bios[i] == NULL)
364 err = ENOMEM;
365 }
366
367 if (err == ENOMEM) {
368 nvme_free_child_bios(num_bios, child_bios);
369 return (NULL);
370 }
371
372 return (child_bios);
373 }
374
375 static struct bio **
nvme_construct_child_bios(struct bio * bp,uint32_t alignment,int * num_bios)376 nvme_construct_child_bios(struct bio *bp, uint32_t alignment, int *num_bios)
377 {
378 struct bio **child_bios;
379 struct bio *child;
380 uint64_t cur_offset;
381 caddr_t data;
382 uint32_t rem_bcount;
383 int i;
384 struct vm_page **ma;
385 uint32_t ma_offset;
386
387 *num_bios = nvme_get_num_segments(bp->bio_offset, bp->bio_bcount,
388 alignment);
389 child_bios = nvme_allocate_child_bios(*num_bios);
390 if (child_bios == NULL)
391 return (NULL);
392
393 bp->bio_children = *num_bios;
394 bp->bio_inbed = 0;
395 cur_offset = bp->bio_offset;
396 rem_bcount = bp->bio_bcount;
397 data = bp->bio_data;
398 ma_offset = bp->bio_ma_offset;
399 ma = bp->bio_ma;
400
401 for (i = 0; i < *num_bios; i++) {
402 child = child_bios[i];
403 child->bio_parent = bp;
404 child->bio_cmd = bp->bio_cmd;
405 child->bio_offset = cur_offset;
406 child->bio_bcount = min(rem_bcount,
407 alignment - (cur_offset & (alignment - 1)));
408 child->bio_flags = bp->bio_flags;
409 if (bp->bio_flags & BIO_UNMAPPED) {
410 child->bio_ma_offset = ma_offset;
411 child->bio_ma = ma;
412 child->bio_ma_n =
413 nvme_get_num_segments(child->bio_ma_offset,
414 child->bio_bcount, PAGE_SIZE);
415 ma_offset = (ma_offset + child->bio_bcount) &
416 PAGE_MASK;
417 ma += child->bio_ma_n;
418 if (ma_offset != 0)
419 ma -= 1;
420 } else {
421 child->bio_data = data;
422 data += child->bio_bcount;
423 }
424 cur_offset += child->bio_bcount;
425 rem_bcount -= child->bio_bcount;
426 }
427
428 return (child_bios);
429 }
430
431 static int
nvme_ns_split_bio(struct nvme_namespace * ns,struct bio * bp,uint32_t alignment)432 nvme_ns_split_bio(struct nvme_namespace *ns, struct bio *bp,
433 uint32_t alignment)
434 {
435 struct bio *child;
436 struct bio **child_bios;
437 int err, i, num_bios;
438
439 child_bios = nvme_construct_child_bios(bp, alignment, &num_bios);
440 if (child_bios == NULL)
441 return (ENOMEM);
442
443 counter_u64_add(ns->ctrlr->alignment_splits, 1);
444 for (i = 0; i < num_bios; i++) {
445 child = child_bios[i];
446 err = nvme_ns_bio_process(ns, child, nvme_bio_child_done);
447 if (err != 0) {
448 nvme_bio_child_inbed(bp, err);
449 g_destroy_bio(child);
450 }
451 }
452
453 free(child_bios, M_NVME);
454 return (0);
455 }
456
457 int
nvme_ns_bio_process(struct nvme_namespace * ns,struct bio * bp,nvme_cb_fn_t cb_fn)458 nvme_ns_bio_process(struct nvme_namespace *ns, struct bio *bp,
459 nvme_cb_fn_t cb_fn)
460 {
461 struct nvme_dsm_range *dsm_range;
462 uint32_t num_bios;
463 int err;
464
465 bp->bio_driver1 = cb_fn;
466
467 if (ns->boundary > 0 &&
468 (bp->bio_cmd == BIO_READ || bp->bio_cmd == BIO_WRITE)) {
469 num_bios = nvme_get_num_segments(bp->bio_offset,
470 bp->bio_bcount, ns->boundary);
471 if (num_bios > 1)
472 return (nvme_ns_split_bio(ns, bp, ns->boundary));
473 }
474
475 switch (bp->bio_cmd) {
476 case BIO_READ:
477 err = nvme_ns_cmd_read_bio(ns, bp, nvme_ns_bio_done, bp);
478 break;
479 case BIO_WRITE:
480 err = nvme_ns_cmd_write_bio(ns, bp, nvme_ns_bio_done, bp);
481 break;
482 case BIO_FLUSH:
483 err = nvme_ns_cmd_flush(ns, nvme_ns_bio_done, bp);
484 break;
485 case BIO_DELETE:
486 dsm_range =
487 malloc(sizeof(struct nvme_dsm_range), M_NVME,
488 M_ZERO | M_NOWAIT);
489 if (!dsm_range) {
490 err = ENOMEM;
491 break;
492 }
493 dsm_range->length =
494 htole32(bp->bio_bcount/nvme_ns_get_sector_size(ns));
495 dsm_range->starting_lba =
496 htole64(bp->bio_offset/nvme_ns_get_sector_size(ns));
497 bp->bio_driver2 = dsm_range;
498 err = nvme_ns_cmd_deallocate(ns, dsm_range, 1,
499 nvme_ns_bio_done, bp);
500 if (err != 0)
501 free(dsm_range, M_NVME);
502 break;
503 default:
504 err = EOPNOTSUPP;
505 break;
506 }
507
508 return (err);
509 }
510
511 int
nvme_ns_ioctl_process(struct nvme_namespace * ns,u_long cmd,caddr_t arg,int flag,struct thread * td)512 nvme_ns_ioctl_process(struct nvme_namespace *ns, u_long cmd, caddr_t arg,
513 int flag, struct thread *td)
514 {
515 return (nvme_ns_ioctl(ns->cdev, cmd, arg, flag, td));
516 }
517
518 int
nvme_ns_construct(struct nvme_namespace * ns,uint32_t id,struct nvme_controller * ctrlr)519 nvme_ns_construct(struct nvme_namespace *ns, uint32_t id,
520 struct nvme_controller *ctrlr)
521 {
522 struct make_dev_args md_args;
523 struct nvme_completion_poll_status status;
524 int res;
525 int unit;
526 uint8_t flbas_fmt;
527 uint8_t vwc_present;
528
529 ns->ctrlr = ctrlr;
530 ns->id = id;
531
532 /*
533 * Namespaces are reconstructed after a controller reset, so check
534 * to make sure we only call mtx_init once on each mtx.
535 *
536 * TODO: Move this somewhere where it gets called at controller
537 * construction time, which is not invoked as part of each
538 * controller reset.
539 */
540 if (!mtx_initialized(&ns->lock))
541 mtx_init(&ns->lock, "nvme ns lock", NULL, MTX_DEF);
542
543 status.done = 0;
544 nvme_ctrlr_cmd_identify_namespace(ctrlr, id, &ns->data,
545 nvme_completion_poll_cb, &status);
546 nvme_completion_poll(&status);
547 if (nvme_completion_is_error(&status.cpl)) {
548 nvme_printf(ctrlr, "nvme_identify_namespace failed\n");
549 return (ENXIO);
550 }
551
552 /* Convert data to host endian */
553 nvme_namespace_data_swapbytes(&ns->data);
554
555 /*
556 * If the size of is zero, chances are this isn't a valid
557 * namespace (eg one that's not been configured yet). The
558 * standard says the entire id will be zeros, so this is a
559 * cheap way to test for that.
560 */
561 if (ns->data.nsze == 0)
562 return (ENXIO);
563
564 flbas_fmt = NVMEV(NVME_NS_DATA_FLBAS_FORMAT, ns->data.flbas);
565
566 /*
567 * Note: format is a 0-based value, so > is appropriate here,
568 * not >=.
569 */
570 if (flbas_fmt > ns->data.nlbaf) {
571 nvme_printf(ctrlr,
572 "lba format %d exceeds number supported (%d)\n",
573 flbas_fmt, ns->data.nlbaf + 1);
574 return (ENXIO);
575 }
576
577 /*
578 * Older Intel devices (like the PC35xxx and P45xx series) advertise in
579 * vendor specific space an alignment that improves performance. If
580 * present use for the stripe size. NVMe 1.3 standardized this as
581 * NOIOB, and newer Intel drives use that.
582 */
583 if ((ctrlr->quirks & QUIRK_INTEL_ALIGNMENT) != 0) {
584 if (ctrlr->cdata.vs[3] != 0)
585 ns->boundary =
586 1 << (ctrlr->cdata.vs[3] + NVME_MPS_SHIFT +
587 NVME_CAP_HI_MPSMIN(ctrlr->cap_hi));
588 else
589 ns->boundary = 0;
590 } else {
591 ns->boundary = ns->data.noiob * nvme_ns_get_sector_size(ns);
592 }
593
594 if (nvme_ctrlr_has_dataset_mgmt(&ctrlr->cdata))
595 ns->flags |= NVME_NS_DEALLOCATE_SUPPORTED;
596
597 vwc_present = NVMEV(NVME_CTRLR_DATA_VWC_PRESENT, ctrlr->cdata.vwc);
598 if (vwc_present)
599 ns->flags |= NVME_NS_FLUSH_SUPPORTED;
600
601 /*
602 * cdev may have already been created, if we are reconstructing the
603 * namespace after a controller-level reset.
604 */
605 if (ns->cdev != NULL)
606 return (0);
607
608 /*
609 * Namespace IDs start at 1, so we need to subtract 1 to create a
610 * correct unit number.
611 */
612 unit = device_get_unit(ctrlr->dev) * NVME_MAX_NAMESPACES + ns->id - 1;
613
614 make_dev_args_init(&md_args);
615 md_args.mda_devsw = &nvme_ns_cdevsw;
616 md_args.mda_unit = unit;
617 md_args.mda_mode = 0600;
618 md_args.mda_si_drv1 = ns;
619 res = make_dev_s(&md_args, &ns->cdev, "%sn%d",
620 device_get_nameunit(ctrlr->dev), ns->id);
621 if (res != 0)
622 return (ENXIO);
623 ns->cdev->si_drv2 = make_dev_alias(ns->cdev, "%sns%d",
624 device_get_nameunit(ctrlr->dev), ns->id);
625 ns->cdev->si_flags |= SI_UNMAPPED;
626
627 return (0);
628 }
629
630 void
nvme_ns_destruct(struct nvme_namespace * ns)631 nvme_ns_destruct(struct nvme_namespace *ns)
632 {
633 if (ns->cdev != NULL) {
634 if (ns->cdev->si_drv2 != NULL)
635 destroy_dev(ns->cdev->si_drv2);
636 destroy_dev(ns->cdev);
637 }
638 }
639