Loading...
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);
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);