Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit e91ece55 authored by Chris Mason's avatar Chris Mason Committed by NeilBrown
Browse files

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: default avatarChris Mason <chris.mason@oracle.com>
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent c6751b2b

drivers/md/md.c

+7 −2
Original line number Original line Diff line number Diff line
@@ -287,6 +287,7 @@ static int md_make_request(struct request_queue *q, struct bio *bio) 
	mddev_t *mddev = q->queuedata;

	mddev_t *mddev = q->queuedata;

	int rv;

	int rv;

	int cpu;

	int cpu;

	unsigned int sectors;





	if (mddev == NULL || mddev->pers == NULL

	if (mddev == NULL || mddev->pers == NULL

	    || !mddev->ready) {

	    || !mddev->ready) {
@@ -311,12 +312,16 @@ static int md_make_request(struct request_queue *q, struct bio *bio) 
	atomic_inc(&mddev->active_io);

	atomic_inc(&mddev->active_io);

	rcu_read_unlock();

	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);

	rv = mddev->pers->make_request(mddev, bio);





	cpu = part_stat_lock();

	cpu = part_stat_lock();

	part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);

	part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);

	part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw],

	part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw], sectors);

		      bio_sectors(bio));

	part_stat_unlock();

	part_stat_unlock();





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

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