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>
15 struct completion *wait;
18 static void bio_batch_end_io(struct bio *bio)
20 struct bio_batch *bb = bio->bi_private;
22 if (bio->bi_error && bio->bi_error != -EOPNOTSUPP)
23 bb->error = bio->bi_error;
24 if (atomic_dec_and_test(&bb->done))
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
38 * Issue a discard request for the sectors in question.
40 int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
41 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
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;
56 if (!blk_queue_discard(q))
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;
63 if (flags & BLKDEV_DISCARD_SECURE) {
64 if (!blk_queue_secdiscard(q))
69 atomic_set(&bb.done, 1);
73 blk_start_plug(&plug);
75 unsigned int req_sects;
76 sector_t end_sect, tmp;
78 bio = bio_alloc(gfp_mask, 1);
84 /* Make sure bi_size doesn't overflow */
85 req_sects = min_t(sector_t, nr_sects, UINT_MAX >> 9);
88 * If splitting a request, and the next starting sector would be
89 * misaligned, stop the discard at the previous aligned sector.
91 end_sect = sector + req_sects;
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;
101 bio->bi_iter.bi_sector = sector;
102 bio->bi_end_io = bio_batch_end_io;
104 bio->bi_private = &bb;
106 bio->bi_iter.bi_size = req_sects << 9;
107 nr_sects -= req_sects;
110 atomic_inc(&bb.done);
111 submit_bio(type, bio);
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
121 blk_finish_plug(&plug);
123 /* Wait for bios in-flight */
124 if (!atomic_dec_and_test(&bb.done))
125 wait_for_completion_io(&wait);
131 EXPORT_SYMBOL(blkdev_issue_discard);
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
142 * Issue a write same request for the sectors in question.
144 int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
145 sector_t nr_sects, gfp_t gfp_mask,
148 DECLARE_COMPLETION_ONSTACK(wait);
149 struct request_queue *q = bdev_get_queue(bdev);
150 unsigned int max_write_same_sectors;
158 /* Ensure that max_write_same_sectors doesn't overflow bi_size */
159 max_write_same_sectors = UINT_MAX >> 9;
161 atomic_set(&bb.done, 1);
166 bio = bio_alloc(gfp_mask, 1);
172 bio->bi_iter.bi_sector = sector;
173 bio->bi_end_io = bio_batch_end_io;
175 bio->bi_private = &bb;
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);
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;
186 bio->bi_iter.bi_size = nr_sects << 9;
190 atomic_inc(&bb.done);
191 submit_bio(REQ_WRITE | REQ_WRITE_SAME, bio);
194 /* Wait for bios in-flight */
195 if (!atomic_dec_and_test(&bb.done))
196 wait_for_completion_io(&wait);
202 EXPORT_SYMBOL(blkdev_issue_write_same);
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)
212 * Generate and issue number of bios with zerofiled pages.
215 static int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
216 sector_t nr_sects, gfp_t gfp_mask)
222 DECLARE_COMPLETION_ONSTACK(wait);
224 atomic_set(&bb.done, 1);
229 while (nr_sects != 0) {
230 bio = bio_alloc(gfp_mask,
231 min(nr_sects, (sector_t)BIO_MAX_PAGES));
237 bio->bi_iter.bi_sector = sector;
239 bio->bi_end_io = bio_batch_end_io;
240 bio->bi_private = &bb;
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;
251 atomic_inc(&bb.done);
252 submit_bio(WRITE, bio);
255 /* Wait for bios in-flight */
256 if (!atomic_dec_and_test(&bb.done))
257 wait_for_completion_io(&wait);
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
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.
285 int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
286 sector_t nr_sects, gfp_t gfp_mask, bool discard)
288 struct request_queue *q = bdev_get_queue(bdev);
290 if (discard && blk_queue_discard(q) && q->limits.discard_zeroes_data &&
291 blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, 0) == 0)
294 if (bdev_write_same(bdev) &&
295 blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask,
299 return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask);
301 EXPORT_SYMBOL(blkdev_issue_zeroout);