lkml.org 
[lkml]   [2011]   [Feb]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[220/272] md_make_request: dont touch the bio after calling make_request
    2.6.37-stable review patch.  If anyone has any objections, please let us know.

    ------------------

    From: Chris Mason <chris.mason@oracle.com>

    commit e91ece5590b3c728624ab57043fc7a05069c604a upstream.

    md_make_request was calling bio_sectors() for part_stat_add
    after it was calling the make_request function. This is
    bad because the make_request function can free the bio and
    because the bi_size field can change around.

    The fix here was suggested by Jens Axboe. It saves the
    sector count before the make_request call. I hit this
    with CONFIG_DEBUG_PAGEALLOC turned on while trying to break
    his pretty fusionio card.

    Signed-off-by: Chris Mason <chris.mason@oracle.com>
    Signed-off-by: NeilBrown <neilb@suse.de>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

    ---
    drivers/md/md.c | 9 +++++++--
    1 file changed, 7 insertions(+), 2 deletions(-)

    --- a/drivers/md/md.c
    +++ b/drivers/md/md.c
    @@ -287,6 +287,7 @@ static int md_make_request(struct reques
    mddev_t *mddev = q->queuedata;
    int rv;
    int cpu;
    + unsigned int sectors;

    if (mddev == NULL || mddev->pers == NULL
    || !mddev->ready) {
    @@ -311,12 +312,16 @@ static int md_make_request(struct reques
    atomic_inc(&mddev->active_io);
    rcu_read_unlock();

    + /*
    + * save the sectors now since our bio can
    + * go away inside make_request
    + */
    + sectors = bio_sectors(bio);
    rv = mddev->pers->make_request(mddev, bio);

    cpu = part_stat_lock();
    part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
    - part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw],
    - bio_sectors(bio));
    + part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw], sectors);
    part_stat_unlock();

    if (atomic_dec_and_test(&mddev->active_io) && mddev->suspended)



    \
     
     \ /
      Last update: 2011-02-16 01:39    [W:4.709 / U:0.332 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site