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| author | Chris Mason <chris.mason@oracle.com> | 2011-02-07 19:21:48 -0500 |
|---|---|---|
| committer | NeilBrown <neilb@suse.de> | 2011-02-08 09:53:28 +1100 |
| commit | e91ece5590b3c728624ab57043fc7a05069c604a (patch) | |
| tree | 4c5fd4ad374caf5bd9c5f575b0a228b5cdf2f191 /drivers/md/md.c | |
| parent | c6751b2bde477f56ceef67aa1d298ce44e8e2e23 (diff) | |
| download | lwn-e91ece5590b3c728624ab57043fc7a05069c604a.tar.gz lwn-e91ece5590b3c728624ab57043fc7a05069c604a.zip | |
md_make_request: don't touch the bio after calling make_request
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.
Cc: <stable@kernel.org>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Diffstat (limited to 'drivers/md/md.c')
| -rw-r--r-- | drivers/md/md.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c index 1138d1053e9a..0cc30ecda4c1 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -287,6 +287,7 @@ static int md_make_request(struct request_queue *q, struct bio *bio) 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 request_queue *q, struct bio *bio) 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) |