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1/*
2 * Functions related to generic helpers functions
3 */
4#include <linux/kernel.h>
5#include <linux/module.h>
6#include <linux/bio.h>
7#include <linux/blkdev.h>
8#include <linux/scatterlist.h>
9
10#include "blk.h"
11
12struct bio_batch {
13 atomic_t done;
14 unsigned long flags;
15 struct completion *wait;
16};
17
18static void bio_batch_end_io(struct bio *bio, int err)
19{
20 struct bio_batch *bb = bio->bi_private;
21
22 if (err && (err != -EOPNOTSUPP))
23 clear_bit(BIO_UPTODATE, &bb->flags);
24 if (atomic_dec_and_test(&bb->done))
25 complete(bb->wait);
26 bio_put(bio);
27}
28
29/**
30 * blkdev_issue_discard - queue a discard
31 * @bdev: blockdev to issue discard for
32 * @sector: start sector
33 * @nr_sects: number of sectors to discard
34 * @gfp_mask: memory allocation flags (for bio_alloc)
35 * @flags: BLKDEV_IFL_* flags to control behaviour
36 *
37 * Description:
38 * Issue a discard request for the sectors in question.
39 */
40int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
41 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
42{
43 DECLARE_COMPLETION_ONSTACK(wait);
44 struct request_queue *q = bdev_get_queue(bdev);
45 int type = REQ_WRITE | REQ_DISCARD;
46 unsigned int max_discard_sectors, granularity;
47 int alignment;
48 struct bio_batch bb;
49 struct bio *bio;
50 int ret = 0;
51 struct blk_plug plug;
52
53 if (!q)
54 return -ENXIO;
55
56 if (!blk_queue_discard(q))
57 return -EOPNOTSUPP;
58
59 /* Zero-sector (unknown) and one-sector granularities are the same. */
60 granularity = max(q->limits.discard_granularity >> 9, 1U);
61 alignment = (bdev_discard_alignment(bdev) >> 9) % granularity;
62
63 /*
64 * Ensure that max_discard_sectors is of the proper
65 * granularity, so that requests stay aligned after a split.
66 */
67 max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9);
68 max_discard_sectors -= max_discard_sectors % granularity;
69 if (unlikely(!max_discard_sectors)) {
70 /* Avoid infinite loop below. Being cautious never hurts. */
71 return -EOPNOTSUPP;
72 }
73
74 if (flags & BLKDEV_DISCARD_SECURE) {
75 if (!blk_queue_secdiscard(q))
76 return -EOPNOTSUPP;
77 type |= REQ_SECURE;
78 }
79
80 atomic_set(&bb.done, 1);
81 bb.flags = 1 << BIO_UPTODATE;
82 bb.wait = &wait;
83
84 blk_start_plug(&plug);
85 while (nr_sects) {
86 unsigned int req_sects;
87 sector_t end_sect, tmp;
88
89 bio = bio_alloc(gfp_mask, 1);
90 if (!bio) {
91 ret = -ENOMEM;
92 break;
93 }
94
95 req_sects = min_t(sector_t, nr_sects, max_discard_sectors);
96
97 /*
98 * If splitting a request, and the next starting sector would be
99 * misaligned, stop the discard at the previous aligned sector.
100 */
101 end_sect = sector + req_sects;
102 tmp = end_sect;
103 if (req_sects < nr_sects &&
104 sector_div(tmp, granularity) != alignment) {
105 end_sect = end_sect - alignment;
106 sector_div(end_sect, granularity);
107 end_sect = end_sect * granularity + alignment;
108 req_sects = end_sect - sector;
109 }
110
111 bio->bi_iter.bi_sector = sector;
112 bio->bi_end_io = bio_batch_end_io;
113 bio->bi_bdev = bdev;
114 bio->bi_private = &bb;
115
116 bio->bi_iter.bi_size = req_sects << 9;
117 nr_sects -= req_sects;
118 sector = end_sect;
119
120 atomic_inc(&bb.done);
121 submit_bio(type, bio);
122
123 /*
124 * We can loop for a long time in here, if someone does
125 * full device discards (like mkfs). Be nice and allow
126 * us to schedule out to avoid softlocking if preempt
127 * is disabled.
128 */
129 cond_resched();
130 }
131 blk_finish_plug(&plug);
132
133 /* Wait for bios in-flight */
134 if (!atomic_dec_and_test(&bb.done))
135 wait_for_completion_io(&wait);
136
137 if (!test_bit(BIO_UPTODATE, &bb.flags))
138 ret = -EIO;
139
140 return ret;
141}
142EXPORT_SYMBOL(blkdev_issue_discard);
143
144/**
145 * blkdev_issue_write_same - queue a write same operation
146 * @bdev: target blockdev
147 * @sector: start sector
148 * @nr_sects: number of sectors to write
149 * @gfp_mask: memory allocation flags (for bio_alloc)
150 * @page: page containing data to write
151 *
152 * Description:
153 * Issue a write same request for the sectors in question.
154 */
155int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
156 sector_t nr_sects, gfp_t gfp_mask,
157 struct page *page)
158{
159 DECLARE_COMPLETION_ONSTACK(wait);
160 struct request_queue *q = bdev_get_queue(bdev);
161 unsigned int max_write_same_sectors;
162 struct bio_batch bb;
163 struct bio *bio;
164 int ret = 0;
165
166 if (!q)
167 return -ENXIO;
168
169 max_write_same_sectors = q->limits.max_write_same_sectors;
170
171 if (max_write_same_sectors == 0)
172 return -EOPNOTSUPP;
173
174 atomic_set(&bb.done, 1);
175 bb.flags = 1 << BIO_UPTODATE;
176 bb.wait = &wait;
177
178 while (nr_sects) {
179 bio = bio_alloc(gfp_mask, 1);
180 if (!bio) {
181 ret = -ENOMEM;
182 break;
183 }
184
185 bio->bi_iter.bi_sector = sector;
186 bio->bi_end_io = bio_batch_end_io;
187 bio->bi_bdev = bdev;
188 bio->bi_private = &bb;
189 bio->bi_vcnt = 1;
190 bio->bi_io_vec->bv_page = page;
191 bio->bi_io_vec->bv_offset = 0;
192 bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev);
193
194 if (nr_sects > max_write_same_sectors) {
195 bio->bi_iter.bi_size = max_write_same_sectors << 9;
196 nr_sects -= max_write_same_sectors;
197 sector += max_write_same_sectors;
198 } else {
199 bio->bi_iter.bi_size = nr_sects << 9;
200 nr_sects = 0;
201 }
202
203 atomic_inc(&bb.done);
204 submit_bio(REQ_WRITE | REQ_WRITE_SAME, bio);
205 }
206
207 /* Wait for bios in-flight */
208 if (!atomic_dec_and_test(&bb.done))
209 wait_for_completion_io(&wait);
210
211 if (!test_bit(BIO_UPTODATE, &bb.flags))
212 ret = -ENOTSUPP;
213
214 return ret;
215}
216EXPORT_SYMBOL(blkdev_issue_write_same);
217
218/**
219 * blkdev_issue_zeroout - generate number of zero filed write bios
220 * @bdev: blockdev to issue
221 * @sector: start sector
222 * @nr_sects: number of sectors to write
223 * @gfp_mask: memory allocation flags (for bio_alloc)
224 *
225 * Description:
226 * Generate and issue number of bios with zerofiled pages.
227 */
228
229int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
230 sector_t nr_sects, gfp_t gfp_mask)
231{
232 int ret;
233 struct bio *bio;
234 struct bio_batch bb;
235 unsigned int sz;
236 DECLARE_COMPLETION_ONSTACK(wait);
237
238 atomic_set(&bb.done, 1);
239 bb.flags = 1 << BIO_UPTODATE;
240 bb.wait = &wait;
241
242 ret = 0;
243 while (nr_sects != 0) {
244 bio = bio_alloc(gfp_mask,
245 min(nr_sects, (sector_t)BIO_MAX_PAGES));
246 if (!bio) {
247 ret = -ENOMEM;
248 break;
249 }
250
251 bio->bi_iter.bi_sector = sector;
252 bio->bi_bdev = bdev;
253 bio->bi_end_io = bio_batch_end_io;
254 bio->bi_private = &bb;
255
256 while (nr_sects != 0) {
257 sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects);
258 ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0);
259 nr_sects -= ret >> 9;
260 sector += ret >> 9;
261 if (ret < (sz << 9))
262 break;
263 }
264 ret = 0;
265 atomic_inc(&bb.done);
266 submit_bio(WRITE, bio);
267 }
268
269 /* Wait for bios in-flight */
270 if (!atomic_dec_and_test(&bb.done))
271 wait_for_completion_io(&wait);
272
273 if (!test_bit(BIO_UPTODATE, &bb.flags))
274 /* One of bios in the batch was completed with error.*/
275 ret = -EIO;
276
277 return ret;
278}
279
280/**
281 * blkdev_issue_zeroout - zero-fill a block range
282 * @bdev: blockdev to write
283 * @sector: start sector
284 * @nr_sects: number of sectors to write
285 * @gfp_mask: memory allocation flags (for bio_alloc)
286 *
287 * Description:
288 * Generate and issue number of bios with zerofiled pages.
289 */
290
291int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
292 sector_t nr_sects, gfp_t gfp_mask)
293{
294 if (bdev_write_same(bdev)) {
295 unsigned char bdn[BDEVNAME_SIZE];
296
297 if (!blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask,
298 ZERO_PAGE(0)))
299 return 0;
300
301 bdevname(bdev, bdn);
302 pr_err("%s: WRITE SAME failed. Manually zeroing.\n", bdn);
303 }
304
305 return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask);
306}
307EXPORT_SYMBOL(blkdev_issue_zeroout);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Functions related to generic helpers functions
4 */
5#include <linux/kernel.h>
6#include <linux/module.h>
7#include <linux/bio.h>
8#include <linux/blkdev.h>
9#include <linux/scatterlist.h>
10
11#include "blk.h"
12
13static struct bio *next_bio(struct bio *bio, unsigned int nr_pages,
14 gfp_t gfp)
15{
16 struct bio *new = bio_alloc(gfp, nr_pages);
17
18 if (bio) {
19 bio_chain(bio, new);
20 submit_bio(bio);
21 }
22
23 return new;
24}
25
26int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
27 sector_t nr_sects, gfp_t gfp_mask, int flags,
28 struct bio **biop)
29{
30 struct request_queue *q = bdev_get_queue(bdev);
31 struct bio *bio = *biop;
32 unsigned int granularity;
33 unsigned int op;
34 int alignment;
35 sector_t bs_mask;
36
37 if (!q)
38 return -ENXIO;
39
40 if (bdev_read_only(bdev))
41 return -EPERM;
42
43 if (flags & BLKDEV_DISCARD_SECURE) {
44 if (!blk_queue_secure_erase(q))
45 return -EOPNOTSUPP;
46 op = REQ_OP_SECURE_ERASE;
47 } else {
48 if (!blk_queue_discard(q))
49 return -EOPNOTSUPP;
50 op = REQ_OP_DISCARD;
51 }
52
53 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
54 if ((sector | nr_sects) & bs_mask)
55 return -EINVAL;
56
57 /* Zero-sector (unknown) and one-sector granularities are the same. */
58 granularity = max(q->limits.discard_granularity >> 9, 1U);
59 alignment = (bdev_discard_alignment(bdev) >> 9) % granularity;
60
61 while (nr_sects) {
62 unsigned int req_sects;
63 sector_t end_sect, tmp;
64
65 /* Make sure bi_size doesn't overflow */
66 req_sects = min_t(sector_t, nr_sects, UINT_MAX >> 9);
67
68 /**
69 * If splitting a request, and the next starting sector would be
70 * misaligned, stop the discard at the previous aligned sector.
71 */
72 end_sect = sector + req_sects;
73 tmp = end_sect;
74 if (req_sects < nr_sects &&
75 sector_div(tmp, granularity) != alignment) {
76 end_sect = end_sect - alignment;
77 sector_div(end_sect, granularity);
78 end_sect = end_sect * granularity + alignment;
79 req_sects = end_sect - sector;
80 }
81
82 bio = next_bio(bio, 0, gfp_mask);
83 bio->bi_iter.bi_sector = sector;
84 bio_set_dev(bio, bdev);
85 bio_set_op_attrs(bio, op, 0);
86
87 bio->bi_iter.bi_size = req_sects << 9;
88 nr_sects -= req_sects;
89 sector = end_sect;
90
91 /*
92 * We can loop for a long time in here, if someone does
93 * full device discards (like mkfs). Be nice and allow
94 * us to schedule out to avoid softlocking if preempt
95 * is disabled.
96 */
97 cond_resched();
98 }
99
100 *biop = bio;
101 return 0;
102}
103EXPORT_SYMBOL(__blkdev_issue_discard);
104
105/**
106 * blkdev_issue_discard - queue a discard
107 * @bdev: blockdev to issue discard for
108 * @sector: start sector
109 * @nr_sects: number of sectors to discard
110 * @gfp_mask: memory allocation flags (for bio_alloc)
111 * @flags: BLKDEV_DISCARD_* flags to control behaviour
112 *
113 * Description:
114 * Issue a discard request for the sectors in question.
115 */
116int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
117 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
118{
119 struct bio *bio = NULL;
120 struct blk_plug plug;
121 int ret;
122
123 blk_start_plug(&plug);
124 ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, flags,
125 &bio);
126 if (!ret && bio) {
127 ret = submit_bio_wait(bio);
128 if (ret == -EOPNOTSUPP)
129 ret = 0;
130 bio_put(bio);
131 }
132 blk_finish_plug(&plug);
133
134 return ret;
135}
136EXPORT_SYMBOL(blkdev_issue_discard);
137
138/**
139 * __blkdev_issue_write_same - generate number of bios with same page
140 * @bdev: target blockdev
141 * @sector: start sector
142 * @nr_sects: number of sectors to write
143 * @gfp_mask: memory allocation flags (for bio_alloc)
144 * @page: page containing data to write
145 * @biop: pointer to anchor bio
146 *
147 * Description:
148 * Generate and issue number of bios(REQ_OP_WRITE_SAME) with same page.
149 */
150static int __blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
151 sector_t nr_sects, gfp_t gfp_mask, struct page *page,
152 struct bio **biop)
153{
154 struct request_queue *q = bdev_get_queue(bdev);
155 unsigned int max_write_same_sectors;
156 struct bio *bio = *biop;
157 sector_t bs_mask;
158
159 if (!q)
160 return -ENXIO;
161
162 if (bdev_read_only(bdev))
163 return -EPERM;
164
165 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
166 if ((sector | nr_sects) & bs_mask)
167 return -EINVAL;
168
169 if (!bdev_write_same(bdev))
170 return -EOPNOTSUPP;
171
172 /* Ensure that max_write_same_sectors doesn't overflow bi_size */
173 max_write_same_sectors = UINT_MAX >> 9;
174
175 while (nr_sects) {
176 bio = next_bio(bio, 1, gfp_mask);
177 bio->bi_iter.bi_sector = sector;
178 bio_set_dev(bio, bdev);
179 bio->bi_vcnt = 1;
180 bio->bi_io_vec->bv_page = page;
181 bio->bi_io_vec->bv_offset = 0;
182 bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev);
183 bio_set_op_attrs(bio, REQ_OP_WRITE_SAME, 0);
184
185 if (nr_sects > max_write_same_sectors) {
186 bio->bi_iter.bi_size = max_write_same_sectors << 9;
187 nr_sects -= max_write_same_sectors;
188 sector += max_write_same_sectors;
189 } else {
190 bio->bi_iter.bi_size = nr_sects << 9;
191 nr_sects = 0;
192 }
193 cond_resched();
194 }
195
196 *biop = bio;
197 return 0;
198}
199
200/**
201 * blkdev_issue_write_same - queue a write same operation
202 * @bdev: target blockdev
203 * @sector: start sector
204 * @nr_sects: number of sectors to write
205 * @gfp_mask: memory allocation flags (for bio_alloc)
206 * @page: page containing data
207 *
208 * Description:
209 * Issue a write same request for the sectors in question.
210 */
211int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
212 sector_t nr_sects, gfp_t gfp_mask,
213 struct page *page)
214{
215 struct bio *bio = NULL;
216 struct blk_plug plug;
217 int ret;
218
219 blk_start_plug(&plug);
220 ret = __blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask, page,
221 &bio);
222 if (ret == 0 && bio) {
223 ret = submit_bio_wait(bio);
224 bio_put(bio);
225 }
226 blk_finish_plug(&plug);
227 return ret;
228}
229EXPORT_SYMBOL(blkdev_issue_write_same);
230
231static int __blkdev_issue_write_zeroes(struct block_device *bdev,
232 sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
233 struct bio **biop, unsigned flags)
234{
235 struct bio *bio = *biop;
236 unsigned int max_write_zeroes_sectors;
237 struct request_queue *q = bdev_get_queue(bdev);
238
239 if (!q)
240 return -ENXIO;
241
242 if (bdev_read_only(bdev))
243 return -EPERM;
244
245 /* Ensure that max_write_zeroes_sectors doesn't overflow bi_size */
246 max_write_zeroes_sectors = bdev_write_zeroes_sectors(bdev);
247
248 if (max_write_zeroes_sectors == 0)
249 return -EOPNOTSUPP;
250
251 while (nr_sects) {
252 bio = next_bio(bio, 0, gfp_mask);
253 bio->bi_iter.bi_sector = sector;
254 bio_set_dev(bio, bdev);
255 bio->bi_opf = REQ_OP_WRITE_ZEROES;
256 if (flags & BLKDEV_ZERO_NOUNMAP)
257 bio->bi_opf |= REQ_NOUNMAP;
258
259 if (nr_sects > max_write_zeroes_sectors) {
260 bio->bi_iter.bi_size = max_write_zeroes_sectors << 9;
261 nr_sects -= max_write_zeroes_sectors;
262 sector += max_write_zeroes_sectors;
263 } else {
264 bio->bi_iter.bi_size = nr_sects << 9;
265 nr_sects = 0;
266 }
267 cond_resched();
268 }
269
270 *biop = bio;
271 return 0;
272}
273
274/*
275 * Convert a number of 512B sectors to a number of pages.
276 * The result is limited to a number of pages that can fit into a BIO.
277 * Also make sure that the result is always at least 1 (page) for the cases
278 * where nr_sects is lower than the number of sectors in a page.
279 */
280static unsigned int __blkdev_sectors_to_bio_pages(sector_t nr_sects)
281{
282 sector_t pages = DIV_ROUND_UP_SECTOR_T(nr_sects, PAGE_SIZE / 512);
283
284 return min(pages, (sector_t)BIO_MAX_PAGES);
285}
286
287static int __blkdev_issue_zero_pages(struct block_device *bdev,
288 sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
289 struct bio **biop)
290{
291 struct request_queue *q = bdev_get_queue(bdev);
292 struct bio *bio = *biop;
293 int bi_size = 0;
294 unsigned int sz;
295
296 if (!q)
297 return -ENXIO;
298
299 if (bdev_read_only(bdev))
300 return -EPERM;
301
302 while (nr_sects != 0) {
303 bio = next_bio(bio, __blkdev_sectors_to_bio_pages(nr_sects),
304 gfp_mask);
305 bio->bi_iter.bi_sector = sector;
306 bio_set_dev(bio, bdev);
307 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
308
309 while (nr_sects != 0) {
310 sz = min((sector_t) PAGE_SIZE, nr_sects << 9);
311 bi_size = bio_add_page(bio, ZERO_PAGE(0), sz, 0);
312 nr_sects -= bi_size >> 9;
313 sector += bi_size >> 9;
314 if (bi_size < sz)
315 break;
316 }
317 cond_resched();
318 }
319
320 *biop = bio;
321 return 0;
322}
323
324/**
325 * __blkdev_issue_zeroout - generate number of zero filed write bios
326 * @bdev: blockdev to issue
327 * @sector: start sector
328 * @nr_sects: number of sectors to write
329 * @gfp_mask: memory allocation flags (for bio_alloc)
330 * @biop: pointer to anchor bio
331 * @flags: controls detailed behavior
332 *
333 * Description:
334 * Zero-fill a block range, either using hardware offload or by explicitly
335 * writing zeroes to the device.
336 *
337 * If a device is using logical block provisioning, the underlying space will
338 * not be released if %flags contains BLKDEV_ZERO_NOUNMAP.
339 *
340 * If %flags contains BLKDEV_ZERO_NOFALLBACK, the function will return
341 * -EOPNOTSUPP if no explicit hardware offload for zeroing is provided.
342 */
343int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
344 sector_t nr_sects, gfp_t gfp_mask, struct bio **biop,
345 unsigned flags)
346{
347 int ret;
348 sector_t bs_mask;
349
350 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
351 if ((sector | nr_sects) & bs_mask)
352 return -EINVAL;
353
354 ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects, gfp_mask,
355 biop, flags);
356 if (ret != -EOPNOTSUPP || (flags & BLKDEV_ZERO_NOFALLBACK))
357 return ret;
358
359 return __blkdev_issue_zero_pages(bdev, sector, nr_sects, gfp_mask,
360 biop);
361}
362EXPORT_SYMBOL(__blkdev_issue_zeroout);
363
364/**
365 * blkdev_issue_zeroout - zero-fill a block range
366 * @bdev: blockdev to write
367 * @sector: start sector
368 * @nr_sects: number of sectors to write
369 * @gfp_mask: memory allocation flags (for bio_alloc)
370 * @flags: controls detailed behavior
371 *
372 * Description:
373 * Zero-fill a block range, either using hardware offload or by explicitly
374 * writing zeroes to the device. See __blkdev_issue_zeroout() for the
375 * valid values for %flags.
376 */
377int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
378 sector_t nr_sects, gfp_t gfp_mask, unsigned flags)
379{
380 int ret = 0;
381 sector_t bs_mask;
382 struct bio *bio;
383 struct blk_plug plug;
384 bool try_write_zeroes = !!bdev_write_zeroes_sectors(bdev);
385
386 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
387 if ((sector | nr_sects) & bs_mask)
388 return -EINVAL;
389
390retry:
391 bio = NULL;
392 blk_start_plug(&plug);
393 if (try_write_zeroes) {
394 ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects,
395 gfp_mask, &bio, flags);
396 } else if (!(flags & BLKDEV_ZERO_NOFALLBACK)) {
397 ret = __blkdev_issue_zero_pages(bdev, sector, nr_sects,
398 gfp_mask, &bio);
399 } else {
400 /* No zeroing offload support */
401 ret = -EOPNOTSUPP;
402 }
403 if (ret == 0 && bio) {
404 ret = submit_bio_wait(bio);
405 bio_put(bio);
406 }
407 blk_finish_plug(&plug);
408 if (ret && try_write_zeroes) {
409 if (!(flags & BLKDEV_ZERO_NOFALLBACK)) {
410 try_write_zeroes = false;
411 goto retry;
412 }
413 if (!bdev_write_zeroes_sectors(bdev)) {
414 /*
415 * Zeroing offload support was indicated, but the
416 * device reported ILLEGAL REQUEST (for some devices
417 * there is no non-destructive way to verify whether
418 * WRITE ZEROES is actually supported).
419 */
420 ret = -EOPNOTSUPP;
421 }
422 }
423
424 return ret;
425}
426EXPORT_SYMBOL(blkdev_issue_zeroout);