1 // SPDX-License-Identifier: GPL-2.0
3 * Functions related to generic helpers functions
5 #include <linux/kernel.h>
6 #include <linux/module.h>
8 #include <linux/blkdev.h>
9 #include <linux/scatterlist.h>
13 static sector_t bio_discard_limit(struct block_device *bdev, sector_t sector)
15 unsigned int discard_granularity = bdev_discard_granularity(bdev);
16 sector_t granularity_aligned_sector;
18 if (bdev_is_partition(bdev))
19 sector += bdev->bd_start_sect;
21 granularity_aligned_sector =
22 round_up(sector, discard_granularity >> SECTOR_SHIFT);
25 * Make sure subsequent bios start aligned to the discard granularity if
26 * it needs to be split.
28 if (granularity_aligned_sector != sector)
29 return granularity_aligned_sector - sector;
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.
35 return round_down(UINT_MAX, discard_granularity) >> SECTOR_SHIFT;
38 int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
39 sector_t nr_sects, gfp_t gfp_mask, int flags,
42 struct request_queue *q = bdev_get_queue(bdev);
43 struct bio *bio = *biop;
47 if (bdev_read_only(bdev))
50 if (flags & BLKDEV_DISCARD_SECURE) {
51 if (!blk_queue_secure_erase(q))
53 op = REQ_OP_SECURE_ERASE;
55 if (!bdev_max_discard_sectors(bdev))
60 /* In case the discard granularity isn't set by buggy device driver */
61 if (WARN_ON_ONCE(!bdev_discard_granularity(bdev))) {
62 char dev_name[BDEVNAME_SIZE];
64 bdevname(bdev, dev_name);
65 pr_err_ratelimited("%s: Error: discard_granularity is 0.\n", dev_name);
69 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
70 if ((sector | nr_sects) & bs_mask)
78 min(nr_sects, bio_discard_limit(bdev, sector));
80 bio = blk_next_bio(bio, bdev, 0, op, gfp_mask);
81 bio->bi_iter.bi_sector = sector;
82 bio->bi_iter.bi_size = req_sects << 9;
84 nr_sects -= req_sects;
87 * We can loop for a long time in here, if someone does
88 * full device discards (like mkfs). Be nice and allow
89 * us to schedule out to avoid softlocking if preempt
98 EXPORT_SYMBOL(__blkdev_issue_discard);
101 * blkdev_issue_discard - queue a discard
102 * @bdev: blockdev to issue discard for
103 * @sector: start sector
104 * @nr_sects: number of sectors to discard
105 * @gfp_mask: memory allocation flags (for bio_alloc)
106 * @flags: BLKDEV_DISCARD_* flags to control behaviour
109 * Issue a discard request for the sectors in question.
111 int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
112 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
114 struct bio *bio = NULL;
115 struct blk_plug plug;
118 blk_start_plug(&plug);
119 ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, flags,
122 ret = submit_bio_wait(bio);
123 if (ret == -EOPNOTSUPP)
127 blk_finish_plug(&plug);
131 EXPORT_SYMBOL(blkdev_issue_discard);
133 static int __blkdev_issue_write_zeroes(struct block_device *bdev,
134 sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
135 struct bio **biop, unsigned flags)
137 struct bio *bio = *biop;
138 unsigned int max_write_zeroes_sectors;
140 if (bdev_read_only(bdev))
143 /* Ensure that max_write_zeroes_sectors doesn't overflow bi_size */
144 max_write_zeroes_sectors = bdev_write_zeroes_sectors(bdev);
146 if (max_write_zeroes_sectors == 0)
150 bio = blk_next_bio(bio, bdev, 0, REQ_OP_WRITE_ZEROES, gfp_mask);
151 bio->bi_iter.bi_sector = sector;
152 if (flags & BLKDEV_ZERO_NOUNMAP)
153 bio->bi_opf |= REQ_NOUNMAP;
155 if (nr_sects > max_write_zeroes_sectors) {
156 bio->bi_iter.bi_size = max_write_zeroes_sectors << 9;
157 nr_sects -= max_write_zeroes_sectors;
158 sector += max_write_zeroes_sectors;
160 bio->bi_iter.bi_size = nr_sects << 9;
171 * Convert a number of 512B sectors to a number of pages.
172 * The result is limited to a number of pages that can fit into a BIO.
173 * Also make sure that the result is always at least 1 (page) for the cases
174 * where nr_sects is lower than the number of sectors in a page.
176 static unsigned int __blkdev_sectors_to_bio_pages(sector_t nr_sects)
178 sector_t pages = DIV_ROUND_UP_SECTOR_T(nr_sects, PAGE_SIZE / 512);
180 return min(pages, (sector_t)BIO_MAX_VECS);
183 static int __blkdev_issue_zero_pages(struct block_device *bdev,
184 sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
187 struct bio *bio = *biop;
191 if (bdev_read_only(bdev))
194 while (nr_sects != 0) {
195 bio = blk_next_bio(bio, bdev, __blkdev_sectors_to_bio_pages(nr_sects),
196 REQ_OP_WRITE, gfp_mask);
197 bio->bi_iter.bi_sector = sector;
199 while (nr_sects != 0) {
200 sz = min((sector_t) PAGE_SIZE, nr_sects << 9);
201 bi_size = bio_add_page(bio, ZERO_PAGE(0), sz, 0);
202 nr_sects -= bi_size >> 9;
203 sector += bi_size >> 9;
215 * __blkdev_issue_zeroout - generate number of zero filed write bios
216 * @bdev: blockdev to issue
217 * @sector: start sector
218 * @nr_sects: number of sectors to write
219 * @gfp_mask: memory allocation flags (for bio_alloc)
220 * @biop: pointer to anchor bio
221 * @flags: controls detailed behavior
224 * Zero-fill a block range, either using hardware offload or by explicitly
225 * writing zeroes to the device.
227 * If a device is using logical block provisioning, the underlying space will
228 * not be released if %flags contains BLKDEV_ZERO_NOUNMAP.
230 * If %flags contains BLKDEV_ZERO_NOFALLBACK, the function will return
231 * -EOPNOTSUPP if no explicit hardware offload for zeroing is provided.
233 int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
234 sector_t nr_sects, gfp_t gfp_mask, struct bio **biop,
240 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
241 if ((sector | nr_sects) & bs_mask)
244 ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects, gfp_mask,
246 if (ret != -EOPNOTSUPP || (flags & BLKDEV_ZERO_NOFALLBACK))
249 return __blkdev_issue_zero_pages(bdev, sector, nr_sects, gfp_mask,
252 EXPORT_SYMBOL(__blkdev_issue_zeroout);
255 * blkdev_issue_zeroout - zero-fill a block range
256 * @bdev: blockdev to write
257 * @sector: start sector
258 * @nr_sects: number of sectors to write
259 * @gfp_mask: memory allocation flags (for bio_alloc)
260 * @flags: controls detailed behavior
263 * Zero-fill a block range, either using hardware offload or by explicitly
264 * writing zeroes to the device. See __blkdev_issue_zeroout() for the
265 * valid values for %flags.
267 int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
268 sector_t nr_sects, gfp_t gfp_mask, unsigned flags)
273 struct blk_plug plug;
274 bool try_write_zeroes = !!bdev_write_zeroes_sectors(bdev);
276 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
277 if ((sector | nr_sects) & bs_mask)
282 blk_start_plug(&plug);
283 if (try_write_zeroes) {
284 ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects,
285 gfp_mask, &bio, flags);
286 } else if (!(flags & BLKDEV_ZERO_NOFALLBACK)) {
287 ret = __blkdev_issue_zero_pages(bdev, sector, nr_sects,
290 /* No zeroing offload support */
293 if (ret == 0 && bio) {
294 ret = submit_bio_wait(bio);
297 blk_finish_plug(&plug);
298 if (ret && try_write_zeroes) {
299 if (!(flags & BLKDEV_ZERO_NOFALLBACK)) {
300 try_write_zeroes = false;
303 if (!bdev_write_zeroes_sectors(bdev)) {
305 * Zeroing offload support was indicated, but the
306 * device reported ILLEGAL REQUEST (for some devices
307 * there is no non-destructive way to verify whether
308 * WRITE ZEROES is actually supported).
316 EXPORT_SYMBOL(blkdev_issue_zeroout);