From: Mikulas Patocka Date: Wed, 28 Sep 2011 00:50:23 +0000 (+1000) Subject: vmscan: fix shrinker callback bug in fs/super.c X-Git-Tag: next-20110929~2^2~137 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=1fbe161400fb0aed7c8eaff4a04081bb0073821b;p=karo-tx-linux.git vmscan: fix shrinker callback bug in fs/super.c The callback must not return -1 when nr_to_scan is zero. Fix the bug in fs/super.c and add this requirement to the callback specification. Signed-off-by: Mikulas Patocka Cc: Dave Chinner Signed-off-by: Andrew Morton <> --- diff --git a/fs/super.c b/fs/super.c index 631e0ca155b4..360045ece782 100644 --- a/fs/super.c +++ b/fs/super.c @@ -61,7 +61,7 @@ static int prune_super(struct shrinker *shrink, struct shrink_control *sc) return -1; if (!grab_super_passive(sb)) - return -1; + return !sc->nr_to_scan ? 0 : -1; if (sb->s_op && sb->s_op->nr_cached_objects) fs_objects = sb->s_op->nr_cached_objects(sb); diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h index ac6b8ee07825..07ceb97d53fa 100644 --- a/include/linux/shrinker.h +++ b/include/linux/shrinker.h @@ -20,6 +20,7 @@ struct shrink_control { * 'nr_to_scan' entries and attempt to free them up. It should return * the number of objects which remain in the cache. If it returns -1, it means * it cannot do any scanning at this time (eg. there is a risk of deadlock). + * The callback must not return -1 if nr_to_scan is zero. * * The 'gfpmask' refers to the allocation we are currently trying to * fulfil.