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 * Ensure that max discard sectors doesn't overflow bi_size and hopefully
31 * it is of the proper granularity as long as the granularity is a power
34 #define MAX_BIO_SECTORS ((1U << 31) >> 9)
37 * blkdev_issue_discard - queue a discard
38 * @bdev: blockdev to issue discard for
39 * @sector: start sector
40 * @nr_sects: number of sectors to discard
41 * @gfp_mask: memory allocation flags (for bio_alloc)
42 * @flags: BLKDEV_IFL_* flags to control behaviour
45 * Issue a discard request for the sectors in question.
47 int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
48 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
50 DECLARE_COMPLETION_ONSTACK(wait);
51 struct request_queue *q = bdev_get_queue(bdev);
52 int type = REQ_WRITE | REQ_DISCARD;
61 if (!blk_queue_discard(q))
64 if (flags & BLKDEV_DISCARD_SECURE) {
65 if (!blk_queue_secdiscard(q))
70 atomic_set(&bb.done, 1);
74 blk_start_plug(&plug);
76 unsigned int req_sects;
79 bio = bio_alloc(gfp_mask, 1);
85 req_sects = min_t(sector_t, nr_sects, MAX_BIO_SECTORS);
86 end_sect = sector + req_sects;
88 bio->bi_iter.bi_sector = sector;
89 bio->bi_end_io = bio_batch_end_io;
91 bio->bi_private = &bb;
93 bio->bi_iter.bi_size = req_sects << 9;
94 nr_sects -= req_sects;
98 submit_bio(type, bio);
101 * We can loop for a long time in here, if someone does
102 * full device discards (like mkfs). Be nice and allow
103 * us to schedule out to avoid softlocking if preempt
108 blk_finish_plug(&plug);
110 /* Wait for bios in-flight */
111 if (!atomic_dec_and_test(&bb.done))
112 wait_for_completion_io(&wait);
118 EXPORT_SYMBOL(blkdev_issue_discard);
121 * blkdev_issue_write_same - queue a write same operation
122 * @bdev: target blockdev
123 * @sector: start sector
124 * @nr_sects: number of sectors to write
125 * @gfp_mask: memory allocation flags (for bio_alloc)
126 * @page: page containing data to write
129 * Issue a write same request for the sectors in question.
131 int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
132 sector_t nr_sects, gfp_t gfp_mask,
135 DECLARE_COMPLETION_ONSTACK(wait);
136 struct request_queue *q = bdev_get_queue(bdev);
137 unsigned int max_write_same_sectors;
145 /* Ensure that max_write_same_sectors doesn't overflow bi_size */
146 max_write_same_sectors = UINT_MAX >> 9;
148 atomic_set(&bb.done, 1);
153 bio = bio_alloc(gfp_mask, 1);
159 bio->bi_iter.bi_sector = sector;
160 bio->bi_end_io = bio_batch_end_io;
162 bio->bi_private = &bb;
164 bio->bi_io_vec->bv_page = page;
165 bio->bi_io_vec->bv_offset = 0;
166 bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev);
168 if (nr_sects > max_write_same_sectors) {
169 bio->bi_iter.bi_size = max_write_same_sectors << 9;
170 nr_sects -= max_write_same_sectors;
171 sector += max_write_same_sectors;
173 bio->bi_iter.bi_size = nr_sects << 9;
177 atomic_inc(&bb.done);
178 submit_bio(REQ_WRITE | REQ_WRITE_SAME, bio);
181 /* Wait for bios in-flight */
182 if (!atomic_dec_and_test(&bb.done))
183 wait_for_completion_io(&wait);
189 EXPORT_SYMBOL(blkdev_issue_write_same);
192 * blkdev_issue_zeroout - generate number of zero filed write bios
193 * @bdev: blockdev to issue
194 * @sector: start sector
195 * @nr_sects: number of sectors to write
196 * @gfp_mask: memory allocation flags (for bio_alloc)
199 * Generate and issue number of bios with zerofiled pages.
202 static int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
203 sector_t nr_sects, gfp_t gfp_mask)
209 DECLARE_COMPLETION_ONSTACK(wait);
211 atomic_set(&bb.done, 1);
216 while (nr_sects != 0) {
217 bio = bio_alloc(gfp_mask,
218 min(nr_sects, (sector_t)BIO_MAX_PAGES));
224 bio->bi_iter.bi_sector = sector;
226 bio->bi_end_io = bio_batch_end_io;
227 bio->bi_private = &bb;
229 while (nr_sects != 0) {
230 sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects);
231 ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0);
232 nr_sects -= ret >> 9;
238 atomic_inc(&bb.done);
239 submit_bio(WRITE, bio);
242 /* Wait for bios in-flight */
243 if (!atomic_dec_and_test(&bb.done))
244 wait_for_completion_io(&wait);
252 * blkdev_issue_zeroout - zero-fill a block range
253 * @bdev: blockdev to write
254 * @sector: start sector
255 * @nr_sects: number of sectors to write
256 * @gfp_mask: memory allocation flags (for bio_alloc)
257 * @discard: whether to discard the block range
260 * Zero-fill a block range. If the discard flag is set and the block
261 * device guarantees that subsequent READ operations to the block range
262 * in question will return zeroes, the blocks will be discarded. Should
263 * the discard request fail, if the discard flag is not set, or if
264 * discard_zeroes_data is not supported, this function will resort to
265 * zeroing the blocks manually, thus provisioning (allocating,
266 * anchoring) them. If the block device supports the WRITE SAME command
267 * blkdev_issue_zeroout() will use it to optimize the process of
268 * clearing the block range. Otherwise the zeroing will be performed
269 * using regular WRITE calls.
272 int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
273 sector_t nr_sects, gfp_t gfp_mask, bool discard)
275 struct request_queue *q = bdev_get_queue(bdev);
277 if (discard && blk_queue_discard(q) && q->limits.discard_zeroes_data &&
278 blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, 0) == 0)
281 if (bdev_write_same(bdev) &&
282 blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask,
286 return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask);
288 EXPORT_SYMBOL(blkdev_issue_zeroout);