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block: add a blk_alloc_discard_bio helper

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Factor out a helper from __blkdev_issue_discard that chews off as much as
possible from a discard range and allocates a bio for it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20240506042027.2289826-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2024-05-06 06:20:25 +02:00 committed by Jens Axboe
parent 81c2168c22
commit e8b4869bc7
2 changed files with 32 additions and 21 deletions
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50
block/blk-lib.c
View File

@ -35,31 +35,39 @@ static sector_t bio_discard_limit(struct block_device *bdev, sector_t sector)
return round_down(UINT_MAX, discard_granularity) >> SECTOR_SHIFT; return round_down(UINT_MAX, discard_granularity) >> SECTOR_SHIFT;
} }
struct bio *blk_alloc_discard_bio(struct block_device *bdev,
sector_t *sector, sector_t *nr_sects, gfp_t gfp_mask)
{
sector_t bio_sects = min(*nr_sects, bio_discard_limit(bdev, *sector));
struct bio *bio;
if (!bio_sects)
return NULL;
bio = bio_alloc(bdev, 0, REQ_OP_DISCARD, gfp_mask);
if (!bio)
return NULL;
bio->bi_iter.bi_sector = *sector;
bio->bi_iter.bi_size = bio_sects << SECTOR_SHIFT;
*sector += bio_sects;
*nr_sects -= bio_sects;
/*
* We can loop for a long time in here if someone does full device
* discards (like mkfs). Be nice and allow us to schedule out to avoid
* softlocking if preempt is disabled.
*/
cond_resched();
return bio;
}
int __blkdev_issue_discard(struct block_device *bdev, sector_t sector, int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask, struct bio **biop) sector_t nr_sects, gfp_t gfp_mask, struct bio **biop)
{ {
struct bio *bio = *biop; struct bio *bio;
while (nr_sects) { while ((bio = blk_alloc_discard_bio(bdev, &sector, &nr_sects,
sector_t req_sects = gfp_mask)))
min(nr_sects, bio_discard_limit(bdev, sector)); *biop = bio_chain_and_submit(*biop, bio);
bio = blk_next_bio(bio, bdev, 0, REQ_OP_DISCARD, gfp_mask);
bio->bi_iter.bi_sector = sector;
bio->bi_iter.bi_size = req_sects << 9;
sector += req_sects;
nr_sects -= req_sects;
/*
* We can loop for a long time in here, if someone does
* full device discards (like mkfs). Be nice and allow
* us to schedule out to avoid softlocking if preempt
* is disabled.
*/
cond_resched();
}
*biop = bio;
return 0; return 0;
} }
EXPORT_SYMBOL(__blkdev_issue_discard); EXPORT_SYMBOL(__blkdev_issue_discard);

3
include/linux/bio.h
View File

@ -833,4 +833,7 @@ struct bio *blk_next_bio(struct bio *bio, struct block_device *bdev,
unsigned int nr_pages, blk_opf_t opf, gfp_t gfp); unsigned int nr_pages, blk_opf_t opf, gfp_t gfp);
struct bio *bio_chain_and_submit(struct bio *prev, struct bio *new); struct bio *bio_chain_and_submit(struct bio *prev, struct bio *new);
struct bio *blk_alloc_discard_bio(struct block_device *bdev,
sector_t *sector, sector_t *nr_sects, gfp_t gfp_mask);
#endif /* __LINUX_BIO_H */ #endif /* __LINUX_BIO_H */