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| author | Paolo Bonzini <pbonzini@redhat.com> | 2012-08-02 09:48:49 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2012-08-02 09:48:49 +0200 |
| commit | f6ff53d3611b564661896be23369b54d84941a0e (patch) | |
| tree | 9a6128ce4f3f86e327d088c42e4ddd7002bb410b /block | |
| parent | 1a9b4993b70fb1884716902774dc9025b457760d (diff) | |
| download | lwn-f6ff53d3611b564661896be23369b54d84941a0e.tar.gz lwn-f6ff53d3611b564661896be23369b54d84941a0e.zip | |
block: reorganize rounding of max_discard_sectors
Mostly a preparation for the next patch.
In principle this fixes an infinite loop if max_discard_sectors < granularity,
but that really shouldn't happen.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Tested-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-lib.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/block/blk-lib.c b/block/blk-lib.c index 2b461b496a78..16b06f62e68c 100644 --- a/block/blk-lib.c +++ b/block/blk-lib.c @@ -44,6 +44,7 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector, struct request_queue *q = bdev_get_queue(bdev); int type = REQ_WRITE | REQ_DISCARD; unsigned int max_discard_sectors; + unsigned int granularity; struct bio_batch bb; struct bio *bio; int ret = 0; @@ -54,18 +55,18 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector, if (!blk_queue_discard(q)) return -EOPNOTSUPP; + /* Zero-sector (unknown) and one-sector granularities are the same. */ + granularity = max(q->limits.discard_granularity >> 9, 1U); + /* * Ensure that max_discard_sectors is of the proper * granularity */ max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9); + max_discard_sectors = round_down(max_discard_sectors, granularity); if (unlikely(!max_discard_sectors)) { /* Avoid infinite loop below. Being cautious never hurts. */ return -EOPNOTSUPP; - } else if (q->limits.discard_granularity) { - unsigned int disc_sects = q->limits.discard_granularity >> 9; - - max_discard_sectors &= ~(disc_sects - 1); } if (flags & BLKDEV_DISCARD_SECURE) { |