Messages in this thread Patch in this message | | | From | Paolo Bonzini <> | Subject | [PATCH 1/2] block: tweak rounding of max_discard_sectors | Date | Wed, 14 Mar 2012 18:12:27 +0100 |
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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.
Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- 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 2b461b4..d4bb160 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; @@ -53,18 +54,18 @@ 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) { -- 1.7.7.6
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