lkml.org 
[lkml]   [2012]   [Mar]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 1/2] block: tweak rounding of max_discard_sectors
    Date
    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



    \
     
     \ /
      Last update: 2012-03-14 18:15    [W:2.338 / U:0.096 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site