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 type, struct bio **biop)
28 struct request_queue *q = bdev_get_queue(bdev);
29 struct bio *bio = *biop;
30 unsigned int granularity;
35 if (!blk_queue_discard(q))
37 if ((type & REQ_SECURE) && !blk_queue_secdiscard(q))
40 /* Zero-sector (unknown) and one-sector granularities are the same. */
41 granularity = max(q->limits.discard_granularity >> 9, 1U);
42 alignment = (bdev_discard_alignment(bdev) >> 9) % granularity;
45 unsigned int req_sects;
46 sector_t end_sect, tmp;
48 /* Make sure bi_size doesn't overflow */
49 req_sects = min_t(sector_t, nr_sects, UINT_MAX >> 9);
52 * If splitting a request, and the next starting sector would be
53 * misaligned, stop the discard at the previous aligned sector.
55 end_sect = sector + req_sects;
57 if (req_sects < nr_sects &&
58 sector_div(tmp, granularity) != alignment) {
59 end_sect = end_sect - alignment;
60 sector_div(end_sect, granularity);
61 end_sect = end_sect * granularity + alignment;
62 req_sects = end_sect - sector;
65 bio = next_bio(bio, 1, gfp_mask);
66 bio->bi_iter.bi_sector = sector;
70 bio->bi_iter.bi_size = req_sects << 9;
71 nr_sects -= req_sects;
75 * We can loop for a long time in here, if someone does
76 * full device discards (like mkfs). Be nice and allow
77 * us to schedule out to avoid softlocking if preempt
86 EXPORT_SYMBOL(__blkdev_issue_discard);
89 * blkdev_issue_discard - queue a discard
90 * @bdev: blockdev to issue discard for
91 * @sector: start sector
92 * @nr_sects: number of sectors to discard
93 * @gfp_mask: memory allocation flags (for bio_alloc)
94 * @flags: BLKDEV_IFL_* flags to control behaviour
97 * Issue a discard request for the sectors in question.
99 int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
100 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
102 int type = REQ_WRITE | REQ_DISCARD;
103 struct bio *bio = NULL;
104 struct blk_plug plug;
107 if (flags & BLKDEV_DISCARD_SECURE)
110 blk_start_plug(&plug);
111 ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, type,
114 ret = submit_bio_wait(bio);
115 if (ret == -EOPNOTSUPP)
118 blk_finish_plug(&plug);
122 EXPORT_SYMBOL(blkdev_issue_discard);
125 * blkdev_issue_write_same - queue a write same operation
126 * @bdev: target blockdev
127 * @sector: start sector
128 * @nr_sects: number of sectors to write
129 * @gfp_mask: memory allocation flags (for bio_alloc)
130 * @page: page containing data to write
133 * Issue a write same request for the sectors in question.
135 int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
136 sector_t nr_sects, gfp_t gfp_mask,
139 struct request_queue *q = bdev_get_queue(bdev);
140 unsigned int max_write_same_sectors;
141 struct bio *bio = NULL;
147 /* Ensure that max_write_same_sectors doesn't overflow bi_size */
148 max_write_same_sectors = UINT_MAX >> 9;
151 bio = next_bio(bio, 1, gfp_mask);
152 bio->bi_iter.bi_sector = sector;
155 bio->bi_io_vec->bv_page = page;
156 bio->bi_io_vec->bv_offset = 0;
157 bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev);
158 bio->bi_rw = REQ_WRITE | REQ_WRITE_SAME;
160 if (nr_sects > max_write_same_sectors) {
161 bio->bi_iter.bi_size = max_write_same_sectors << 9;
162 nr_sects -= max_write_same_sectors;
163 sector += max_write_same_sectors;
165 bio->bi_iter.bi_size = nr_sects << 9;
171 ret = submit_bio_wait(bio);
172 return ret != -EOPNOTSUPP ? ret : 0;
174 EXPORT_SYMBOL(blkdev_issue_write_same);
177 * blkdev_issue_zeroout - generate number of zero filed write bios
178 * @bdev: blockdev to issue
179 * @sector: start sector
180 * @nr_sects: number of sectors to write
181 * @gfp_mask: memory allocation flags (for bio_alloc)
184 * Generate and issue number of bios with zerofiled pages.
187 static int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
188 sector_t nr_sects, gfp_t gfp_mask)
191 struct bio *bio = NULL;
194 while (nr_sects != 0) {
195 bio = next_bio(bio, min(nr_sects, (sector_t)BIO_MAX_PAGES),
197 bio->bi_iter.bi_sector = sector;
199 bio->bi_rw = REQ_WRITE;
201 while (nr_sects != 0) {
202 sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects);
203 ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0);
204 nr_sects -= ret >> 9;
212 return submit_bio_wait(bio);
217 * blkdev_issue_zeroout - zero-fill a block range
218 * @bdev: blockdev to write
219 * @sector: start sector
220 * @nr_sects: number of sectors to write
221 * @gfp_mask: memory allocation flags (for bio_alloc)
222 * @discard: whether to discard the block range
225 * Zero-fill a block range. If the discard flag is set and the block
226 * device guarantees that subsequent READ operations to the block range
227 * in question will return zeroes, the blocks will be discarded. Should
228 * the discard request fail, if the discard flag is not set, or if
229 * discard_zeroes_data is not supported, this function will resort to
230 * zeroing the blocks manually, thus provisioning (allocating,
231 * anchoring) them. If the block device supports the WRITE SAME command
232 * blkdev_issue_zeroout() will use it to optimize the process of
233 * clearing the block range. Otherwise the zeroing will be performed
234 * using regular WRITE calls.
237 int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
238 sector_t nr_sects, gfp_t gfp_mask, bool discard)
240 struct request_queue *q = bdev_get_queue(bdev);
242 if (discard && blk_queue_discard(q) && q->limits.discard_zeroes_data &&
243 blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, 0) == 0)
246 if (bdev_write_same(bdev) &&
247 blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask,
251 return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask);
253 EXPORT_SYMBOL(blkdev_issue_zeroout);