2 * Functions related to generic helpers functions
4 #include <linux/kernel.h>
5 #include <linux/module.h>
7 #include <linux/blkdev.h>
8 #include <linux/scatterlist.h>
12 static struct bio *next_bio(struct bio *bio, unsigned int nr_pages,
15 struct bio *new = bio_alloc(gfp, nr_pages);
25 int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
26 sector_t nr_sects, gfp_t gfp_mask, int flags,
29 struct request_queue *q = bdev_get_queue(bdev);
30 struct bio *bio = *biop;
31 unsigned int granularity;
39 if (flags & BLKDEV_DISCARD_SECURE) {
40 if (flags & BLKDEV_DISCARD_ZERO)
42 if (!blk_queue_secure_erase(q))
44 op = REQ_OP_SECURE_ERASE;
46 if (!blk_queue_discard(q))
48 if ((flags & BLKDEV_DISCARD_ZERO) &&
49 !q->limits.discard_zeroes_data)
54 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
55 if ((sector | nr_sects) & bs_mask)
58 /* Zero-sector (unknown) and one-sector granularities are the same. */
59 granularity = max(q->limits.discard_granularity >> 9, 1U);
60 alignment = (bdev_discard_alignment(bdev) >> 9) % granularity;
63 unsigned int req_sects;
64 sector_t end_sect, tmp;
66 /* Make sure bi_size doesn't overflow */
67 req_sects = min_t(sector_t, nr_sects, UINT_MAX >> 9);
70 * If splitting a request, and the next starting sector would be
71 * misaligned, stop the discard at the previous aligned sector.
73 end_sect = sector + req_sects;
75 if (req_sects < nr_sects &&
76 sector_div(tmp, granularity) != alignment) {
77 end_sect = end_sect - alignment;
78 sector_div(end_sect, granularity);
79 end_sect = end_sect * granularity + alignment;
80 req_sects = end_sect - sector;
83 bio = next_bio(bio, 1, gfp_mask);
84 bio->bi_iter.bi_sector = sector;
86 bio_set_op_attrs(bio, op, 0);
88 bio->bi_iter.bi_size = req_sects << 9;
89 nr_sects -= req_sects;
93 * We can loop for a long time in here, if someone does
94 * full device discards (like mkfs). Be nice and allow
95 * us to schedule out to avoid softlocking if preempt
104 EXPORT_SYMBOL(__blkdev_issue_discard);
107 * blkdev_issue_discard - queue a discard
108 * @bdev: blockdev to issue discard for
109 * @sector: start sector
110 * @nr_sects: number of sectors to discard
111 * @gfp_mask: memory allocation flags (for bio_alloc)
112 * @flags: BLKDEV_IFL_* flags to control behaviour
115 * Issue a discard request for the sectors in question.
117 int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
118 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
120 struct bio *bio = NULL;
121 struct blk_plug plug;
124 blk_start_plug(&plug);
125 ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, flags,
128 ret = submit_bio_wait(bio);
129 if (ret == -EOPNOTSUPP && !(flags & BLKDEV_DISCARD_ZERO))
133 blk_finish_plug(&plug);
137 EXPORT_SYMBOL(blkdev_issue_discard);
140 * blkdev_issue_write_same - queue a write same operation
141 * @bdev: target blockdev
142 * @sector: start sector
143 * @nr_sects: number of sectors to write
144 * @gfp_mask: memory allocation flags (for bio_alloc)
145 * @page: page containing data to write
148 * Issue a write same request for the sectors in question.
150 int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
151 sector_t nr_sects, gfp_t gfp_mask,
154 struct request_queue *q = bdev_get_queue(bdev);
155 unsigned int max_write_same_sectors;
156 struct bio *bio = NULL;
163 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
164 if ((sector | nr_sects) & bs_mask)
167 /* Ensure that max_write_same_sectors doesn't overflow bi_size */
168 max_write_same_sectors = UINT_MAX >> 9;
171 bio = next_bio(bio, 1, gfp_mask);
172 bio->bi_iter.bi_sector = sector;
175 bio->bi_io_vec->bv_page = page;
176 bio->bi_io_vec->bv_offset = 0;
177 bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev);
178 bio_set_op_attrs(bio, REQ_OP_WRITE_SAME, 0);
180 if (nr_sects > max_write_same_sectors) {
181 bio->bi_iter.bi_size = max_write_same_sectors << 9;
182 nr_sects -= max_write_same_sectors;
183 sector += max_write_same_sectors;
185 bio->bi_iter.bi_size = nr_sects << 9;
191 ret = submit_bio_wait(bio);
196 EXPORT_SYMBOL(blkdev_issue_write_same);
199 * blkdev_issue_zeroout - generate number of zero filed write bios
200 * @bdev: blockdev to issue
201 * @sector: start sector
202 * @nr_sects: number of sectors to write
203 * @gfp_mask: memory allocation flags (for bio_alloc)
206 * Generate and issue number of bios with zerofiled pages.
209 static int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
210 sector_t nr_sects, gfp_t gfp_mask)
213 struct bio *bio = NULL;
217 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
218 if ((sector | nr_sects) & bs_mask)
221 while (nr_sects != 0) {
222 bio = next_bio(bio, min(nr_sects, (sector_t)BIO_MAX_PAGES),
224 bio->bi_iter.bi_sector = sector;
226 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
228 while (nr_sects != 0) {
229 sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects);
230 ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0);
231 nr_sects -= ret >> 9;
239 ret = submit_bio_wait(bio);
247 * blkdev_issue_zeroout - zero-fill a block range
248 * @bdev: blockdev to write
249 * @sector: start sector
250 * @nr_sects: number of sectors to write
251 * @gfp_mask: memory allocation flags (for bio_alloc)
252 * @discard: whether to discard the block range
255 * Zero-fill a block range. If the discard flag is set and the block
256 * device guarantees that subsequent READ operations to the block range
257 * in question will return zeroes, the blocks will be discarded. Should
258 * the discard request fail, if the discard flag is not set, or if
259 * discard_zeroes_data is not supported, this function will resort to
260 * zeroing the blocks manually, thus provisioning (allocating,
261 * anchoring) them. If the block device supports the WRITE SAME command
262 * blkdev_issue_zeroout() will use it to optimize the process of
263 * clearing the block range. Otherwise the zeroing will be performed
264 * using regular WRITE calls.
267 int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
268 sector_t nr_sects, gfp_t gfp_mask, bool discard)
271 if (!blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask,
272 BLKDEV_DISCARD_ZERO))
276 if (bdev_write_same(bdev) &&
277 blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask,
281 return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask);
283 EXPORT_SYMBOL(blkdev_issue_zeroout);