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