Loading...
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 int error;
15 struct completion *wait;
16};
17
18static void bio_batch_end_io(struct bio *bio)
19{
20 struct bio_batch *bb = bio->bi_private;
21
22 if (bio->bi_error && bio->bi_error != -EOPNOTSUPP)
23 bb->error = bio->bi_error;
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 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 if (flags & BLKDEV_DISCARD_SECURE) {
64 if (!blk_queue_secdiscard(q))
65 return -EOPNOTSUPP;
66 type |= REQ_SECURE;
67 }
68
69 atomic_set(&bb.done, 1);
70 bb.error = 0;
71 bb.wait = &wait;
72
73 blk_start_plug(&plug);
74 while (nr_sects) {
75 unsigned int req_sects;
76 sector_t end_sect, tmp;
77
78 bio = bio_alloc(gfp_mask, 1);
79 if (!bio) {
80 ret = -ENOMEM;
81 break;
82 }
83
84 /* Make sure bi_size doesn't overflow */
85 req_sects = min_t(sector_t, nr_sects, UINT_MAX >> 9);
86
87 /*
88 * If splitting a request, and the next starting sector would be
89 * misaligned, stop the discard at the previous aligned sector.
90 */
91 end_sect = sector + req_sects;
92 tmp = end_sect;
93 if (req_sects < nr_sects &&
94 sector_div(tmp, granularity) != alignment) {
95 end_sect = end_sect - alignment;
96 sector_div(end_sect, granularity);
97 end_sect = end_sect * granularity + alignment;
98 req_sects = end_sect - sector;
99 }
100
101 bio->bi_iter.bi_sector = sector;
102 bio->bi_end_io = bio_batch_end_io;
103 bio->bi_bdev = bdev;
104 bio->bi_private = &bb;
105
106 bio->bi_iter.bi_size = req_sects << 9;
107 nr_sects -= req_sects;
108 sector = end_sect;
109
110 atomic_inc(&bb.done);
111 submit_bio(type, bio);
112
113 /*
114 * We can loop for a long time in here, if someone does
115 * full device discards (like mkfs). Be nice and allow
116 * us to schedule out to avoid softlocking if preempt
117 * is disabled.
118 */
119 cond_resched();
120 }
121 blk_finish_plug(&plug);
122
123 /* Wait for bios in-flight */
124 if (!atomic_dec_and_test(&bb.done))
125 wait_for_completion_io(&wait);
126
127 if (bb.error)
128 return bb.error;
129 return ret;
130}
131EXPORT_SYMBOL(blkdev_issue_discard);
132
133/**
134 * blkdev_issue_write_same - queue a write same operation
135 * @bdev: target blockdev
136 * @sector: start sector
137 * @nr_sects: number of sectors to write
138 * @gfp_mask: memory allocation flags (for bio_alloc)
139 * @page: page containing data to write
140 *
141 * Description:
142 * Issue a write same request for the sectors in question.
143 */
144int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
145 sector_t nr_sects, gfp_t gfp_mask,
146 struct page *page)
147{
148 DECLARE_COMPLETION_ONSTACK(wait);
149 struct request_queue *q = bdev_get_queue(bdev);
150 unsigned int max_write_same_sectors;
151 struct bio_batch bb;
152 struct bio *bio;
153 int ret = 0;
154
155 if (!q)
156 return -ENXIO;
157
158 /* Ensure that max_write_same_sectors doesn't overflow bi_size */
159 max_write_same_sectors = UINT_MAX >> 9;
160
161 atomic_set(&bb.done, 1);
162 bb.error = 0;
163 bb.wait = &wait;
164
165 while (nr_sects) {
166 bio = bio_alloc(gfp_mask, 1);
167 if (!bio) {
168 ret = -ENOMEM;
169 break;
170 }
171
172 bio->bi_iter.bi_sector = sector;
173 bio->bi_end_io = bio_batch_end_io;
174 bio->bi_bdev = bdev;
175 bio->bi_private = &bb;
176 bio->bi_vcnt = 1;
177 bio->bi_io_vec->bv_page = page;
178 bio->bi_io_vec->bv_offset = 0;
179 bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev);
180
181 if (nr_sects > max_write_same_sectors) {
182 bio->bi_iter.bi_size = max_write_same_sectors << 9;
183 nr_sects -= max_write_same_sectors;
184 sector += max_write_same_sectors;
185 } else {
186 bio->bi_iter.bi_size = nr_sects << 9;
187 nr_sects = 0;
188 }
189
190 atomic_inc(&bb.done);
191 submit_bio(REQ_WRITE | REQ_WRITE_SAME, bio);
192 }
193
194 /* Wait for bios in-flight */
195 if (!atomic_dec_and_test(&bb.done))
196 wait_for_completion_io(&wait);
197
198 if (bb.error)
199 return bb.error;
200 return ret;
201}
202EXPORT_SYMBOL(blkdev_issue_write_same);
203
204/**
205 * blkdev_issue_zeroout - generate number of zero filed write bios
206 * @bdev: blockdev to issue
207 * @sector: start sector
208 * @nr_sects: number of sectors to write
209 * @gfp_mask: memory allocation flags (for bio_alloc)
210 *
211 * Description:
212 * Generate and issue number of bios with zerofiled pages.
213 */
214
215static int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
216 sector_t nr_sects, gfp_t gfp_mask)
217{
218 int ret;
219 struct bio *bio;
220 struct bio_batch bb;
221 unsigned int sz;
222 DECLARE_COMPLETION_ONSTACK(wait);
223
224 atomic_set(&bb.done, 1);
225 bb.error = 0;
226 bb.wait = &wait;
227
228 ret = 0;
229 while (nr_sects != 0) {
230 bio = bio_alloc(gfp_mask,
231 min(nr_sects, (sector_t)BIO_MAX_PAGES));
232 if (!bio) {
233 ret = -ENOMEM;
234 break;
235 }
236
237 bio->bi_iter.bi_sector = sector;
238 bio->bi_bdev = bdev;
239 bio->bi_end_io = bio_batch_end_io;
240 bio->bi_private = &bb;
241
242 while (nr_sects != 0) {
243 sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects);
244 ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0);
245 nr_sects -= ret >> 9;
246 sector += ret >> 9;
247 if (ret < (sz << 9))
248 break;
249 }
250 ret = 0;
251 atomic_inc(&bb.done);
252 submit_bio(WRITE, bio);
253 }
254
255 /* Wait for bios in-flight */
256 if (!atomic_dec_and_test(&bb.done))
257 wait_for_completion_io(&wait);
258
259 if (bb.error)
260 return bb.error;
261 return ret;
262}
263
264/**
265 * blkdev_issue_zeroout - zero-fill a block range
266 * @bdev: blockdev to write
267 * @sector: start sector
268 * @nr_sects: number of sectors to write
269 * @gfp_mask: memory allocation flags (for bio_alloc)
270 * @discard: whether to discard the block range
271 *
272 * Description:
273 * Zero-fill a block range. If the discard flag is set and the block
274 * device guarantees that subsequent READ operations to the block range
275 * in question will return zeroes, the blocks will be discarded. Should
276 * the discard request fail, if the discard flag is not set, or if
277 * discard_zeroes_data is not supported, this function will resort to
278 * zeroing the blocks manually, thus provisioning (allocating,
279 * anchoring) them. If the block device supports the WRITE SAME command
280 * blkdev_issue_zeroout() will use it to optimize the process of
281 * clearing the block range. Otherwise the zeroing will be performed
282 * using regular WRITE calls.
283 */
284
285int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
286 sector_t nr_sects, gfp_t gfp_mask, bool discard)
287{
288 struct request_queue *q = bdev_get_queue(bdev);
289
290 if (discard && blk_queue_discard(q) && q->limits.discard_zeroes_data &&
291 blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, 0) == 0)
292 return 0;
293
294 if (bdev_write_same(bdev) &&
295 blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask,
296 ZERO_PAGE(0)) == 0)
297 return 0;
298
299 return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask);
300}
301EXPORT_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 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
38struct bio *blk_alloc_discard_bio(struct block_device *bdev,
39 sector_t *sector, sector_t *nr_sects, gfp_t gfp_mask)
40{
41 sector_t bio_sects = min(*nr_sects, bio_discard_limit(bdev, *sector));
42 struct bio *bio;
43
44 if (!bio_sects)
45 return NULL;
46
47 bio = bio_alloc(bdev, 0, REQ_OP_DISCARD, gfp_mask);
48 if (!bio)
49 return NULL;
50 bio->bi_iter.bi_sector = *sector;
51 bio->bi_iter.bi_size = bio_sects << SECTOR_SHIFT;
52 *sector += bio_sects;
53 *nr_sects -= bio_sects;
54 /*
55 * We can loop for a long time in here if someone does full device
56 * discards (like mkfs). Be nice and allow us to schedule out to avoid
57 * softlocking if preempt is disabled.
58 */
59 cond_resched();
60 return bio;
61}
62
63int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
64 sector_t nr_sects, gfp_t gfp_mask, struct bio **biop)
65{
66 struct bio *bio;
67
68 while ((bio = blk_alloc_discard_bio(bdev, §or, &nr_sects,
69 gfp_mask)))
70 *biop = bio_chain_and_submit(*biop, bio);
71 return 0;
72}
73EXPORT_SYMBOL(__blkdev_issue_discard);
74
75/**
76 * blkdev_issue_discard - queue a discard
77 * @bdev: blockdev to issue discard for
78 * @sector: start sector
79 * @nr_sects: number of sectors to discard
80 * @gfp_mask: memory allocation flags (for bio_alloc)
81 *
82 * Description:
83 * Issue a discard request for the sectors in question.
84 */
85int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
86 sector_t nr_sects, gfp_t gfp_mask)
87{
88 struct bio *bio = NULL;
89 struct blk_plug plug;
90 int ret;
91
92 blk_start_plug(&plug);
93 ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, &bio);
94 if (!ret && bio) {
95 ret = submit_bio_wait(bio);
96 if (ret == -EOPNOTSUPP)
97 ret = 0;
98 bio_put(bio);
99 }
100 blk_finish_plug(&plug);
101
102 return ret;
103}
104EXPORT_SYMBOL(blkdev_issue_discard);
105
106static sector_t bio_write_zeroes_limit(struct block_device *bdev)
107{
108 sector_t bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
109
110 return min(bdev_write_zeroes_sectors(bdev),
111 (UINT_MAX >> SECTOR_SHIFT) & ~bs_mask);
112}
113
114/*
115 * There is no reliable way for the SCSI subsystem to determine whether a
116 * device supports a WRITE SAME operation without actually performing a write
117 * to media. As a result, write_zeroes is enabled by default and will be
118 * disabled if a zeroing operation subsequently fails. This means that this
119 * queue limit is likely to change at runtime.
120 */
121static void __blkdev_issue_write_zeroes(struct block_device *bdev,
122 sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
123 struct bio **biop, unsigned flags, sector_t limit)
124{
125
126 while (nr_sects) {
127 unsigned int len = min(nr_sects, limit);
128 struct bio *bio;
129
130 if ((flags & BLKDEV_ZERO_KILLABLE) &&
131 fatal_signal_pending(current))
132 break;
133
134 bio = bio_alloc(bdev, 0, REQ_OP_WRITE_ZEROES, gfp_mask);
135 bio->bi_iter.bi_sector = sector;
136 if (flags & BLKDEV_ZERO_NOUNMAP)
137 bio->bi_opf |= REQ_NOUNMAP;
138
139 bio->bi_iter.bi_size = len << SECTOR_SHIFT;
140 *biop = bio_chain_and_submit(*biop, bio);
141
142 nr_sects -= len;
143 sector += len;
144 cond_resched();
145 }
146}
147
148static int blkdev_issue_write_zeroes(struct block_device *bdev, sector_t sector,
149 sector_t nr_sects, gfp_t gfp, unsigned flags)
150{
151 sector_t limit = bio_write_zeroes_limit(bdev);
152 struct bio *bio = NULL;
153 struct blk_plug plug;
154 int ret = 0;
155
156 blk_start_plug(&plug);
157 __blkdev_issue_write_zeroes(bdev, sector, nr_sects, gfp, &bio,
158 flags, limit);
159 if (bio) {
160 if ((flags & BLKDEV_ZERO_KILLABLE) &&
161 fatal_signal_pending(current)) {
162 bio_await_chain(bio);
163 blk_finish_plug(&plug);
164 return -EINTR;
165 }
166 ret = submit_bio_wait(bio);
167 bio_put(bio);
168 }
169 blk_finish_plug(&plug);
170
171 /*
172 * For some devices there is no non-destructive way to verify whether
173 * WRITE ZEROES is actually supported. These will clear the capability
174 * on an I/O error, in which case we'll turn any error into
175 * "not supported" here.
176 */
177 if (ret && !bdev_write_zeroes_sectors(bdev))
178 return -EOPNOTSUPP;
179 return ret;
180}
181
182/*
183 * Convert a number of 512B sectors to a number of pages.
184 * The result is limited to a number of pages that can fit into a BIO.
185 * Also make sure that the result is always at least 1 (page) for the cases
186 * where nr_sects is lower than the number of sectors in a page.
187 */
188static unsigned int __blkdev_sectors_to_bio_pages(sector_t nr_sects)
189{
190 sector_t pages = DIV_ROUND_UP_SECTOR_T(nr_sects, PAGE_SIZE / 512);
191
192 return min(pages, (sector_t)BIO_MAX_VECS);
193}
194
195static void __blkdev_issue_zero_pages(struct block_device *bdev,
196 sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
197 struct bio **biop, unsigned int flags)
198{
199 while (nr_sects) {
200 unsigned int nr_vecs = __blkdev_sectors_to_bio_pages(nr_sects);
201 struct bio *bio;
202
203 bio = bio_alloc(bdev, nr_vecs, REQ_OP_WRITE, gfp_mask);
204 bio->bi_iter.bi_sector = sector;
205
206 if ((flags & BLKDEV_ZERO_KILLABLE) &&
207 fatal_signal_pending(current))
208 break;
209
210 do {
211 unsigned int len, added;
212
213 len = min_t(sector_t,
214 PAGE_SIZE, nr_sects << SECTOR_SHIFT);
215 added = bio_add_page(bio, ZERO_PAGE(0), len, 0);
216 if (added < len)
217 break;
218 nr_sects -= added >> SECTOR_SHIFT;
219 sector += added >> SECTOR_SHIFT;
220 } while (nr_sects);
221
222 *biop = bio_chain_and_submit(*biop, bio);
223 cond_resched();
224 }
225}
226
227static int blkdev_issue_zero_pages(struct block_device *bdev, sector_t sector,
228 sector_t nr_sects, gfp_t gfp, unsigned flags)
229{
230 struct bio *bio = NULL;
231 struct blk_plug plug;
232 int ret = 0;
233
234 if (flags & BLKDEV_ZERO_NOFALLBACK)
235 return -EOPNOTSUPP;
236
237 blk_start_plug(&plug);
238 __blkdev_issue_zero_pages(bdev, sector, nr_sects, gfp, &bio, flags);
239 if (bio) {
240 if ((flags & BLKDEV_ZERO_KILLABLE) &&
241 fatal_signal_pending(current)) {
242 bio_await_chain(bio);
243 blk_finish_plug(&plug);
244 return -EINTR;
245 }
246 ret = submit_bio_wait(bio);
247 bio_put(bio);
248 }
249 blk_finish_plug(&plug);
250
251 return ret;
252}
253
254/**
255 * __blkdev_issue_zeroout - generate number of zero filed write bios
256 * @bdev: blockdev to issue
257 * @sector: start sector
258 * @nr_sects: number of sectors to write
259 * @gfp_mask: memory allocation flags (for bio_alloc)
260 * @biop: pointer to anchor bio
261 * @flags: controls detailed behavior
262 *
263 * Description:
264 * Zero-fill a block range, either using hardware offload or by explicitly
265 * writing zeroes to the device.
266 *
267 * If a device is using logical block provisioning, the underlying space will
268 * not be released if %flags contains BLKDEV_ZERO_NOUNMAP.
269 *
270 * If %flags contains BLKDEV_ZERO_NOFALLBACK, the function will return
271 * -EOPNOTSUPP if no explicit hardware offload for zeroing is provided.
272 */
273int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
274 sector_t nr_sects, gfp_t gfp_mask, struct bio **biop,
275 unsigned flags)
276{
277 sector_t limit = bio_write_zeroes_limit(bdev);
278
279 if (bdev_read_only(bdev))
280 return -EPERM;
281
282 if (limit) {
283 __blkdev_issue_write_zeroes(bdev, sector, nr_sects,
284 gfp_mask, biop, flags, limit);
285 } else {
286 if (flags & BLKDEV_ZERO_NOFALLBACK)
287 return -EOPNOTSUPP;
288 __blkdev_issue_zero_pages(bdev, sector, nr_sects, gfp_mask,
289 biop, flags);
290 }
291 return 0;
292}
293EXPORT_SYMBOL(__blkdev_issue_zeroout);
294
295/**
296 * blkdev_issue_zeroout - zero-fill a block range
297 * @bdev: blockdev to write
298 * @sector: start sector
299 * @nr_sects: number of sectors to write
300 * @gfp_mask: memory allocation flags (for bio_alloc)
301 * @flags: controls detailed behavior
302 *
303 * Description:
304 * Zero-fill a block range, either using hardware offload or by explicitly
305 * writing zeroes to the device. See __blkdev_issue_zeroout() for the
306 * valid values for %flags.
307 */
308int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
309 sector_t nr_sects, gfp_t gfp_mask, unsigned flags)
310{
311 int ret;
312
313 if ((sector | nr_sects) & ((bdev_logical_block_size(bdev) >> 9) - 1))
314 return -EINVAL;
315 if (bdev_read_only(bdev))
316 return -EPERM;
317
318 if (bdev_write_zeroes_sectors(bdev)) {
319 ret = blkdev_issue_write_zeroes(bdev, sector, nr_sects,
320 gfp_mask, flags);
321 if (ret != -EOPNOTSUPP)
322 return ret;
323 }
324
325 return blkdev_issue_zero_pages(bdev, sector, nr_sects, gfp_mask, flags);
326}
327EXPORT_SYMBOL(blkdev_issue_zeroout);
328
329int blkdev_issue_secure_erase(struct block_device *bdev, sector_t sector,
330 sector_t nr_sects, gfp_t gfp)
331{
332 sector_t bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
333 unsigned int max_sectors = bdev_max_secure_erase_sectors(bdev);
334 struct bio *bio = NULL;
335 struct blk_plug plug;
336 int ret = 0;
337
338 /* make sure that "len << SECTOR_SHIFT" doesn't overflow */
339 if (max_sectors > UINT_MAX >> SECTOR_SHIFT)
340 max_sectors = UINT_MAX >> SECTOR_SHIFT;
341 max_sectors &= ~bs_mask;
342
343 if (max_sectors == 0)
344 return -EOPNOTSUPP;
345 if ((sector | nr_sects) & bs_mask)
346 return -EINVAL;
347 if (bdev_read_only(bdev))
348 return -EPERM;
349
350 blk_start_plug(&plug);
351 while (nr_sects) {
352 unsigned int len = min_t(sector_t, nr_sects, max_sectors);
353
354 bio = blk_next_bio(bio, bdev, 0, REQ_OP_SECURE_ERASE, gfp);
355 bio->bi_iter.bi_sector = sector;
356 bio->bi_iter.bi_size = len << SECTOR_SHIFT;
357
358 sector += len;
359 nr_sects -= len;
360 cond_resched();
361 }
362 if (bio) {
363 ret = submit_bio_wait(bio);
364 bio_put(bio);
365 }
366 blk_finish_plug(&plug);
367
368 return ret;
369}
370EXPORT_SYMBOL(blkdev_issue_secure_erase);