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 <mpatocka@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mikulas Patocka 2011-10-31 17:08:57 -07:00 committed by Linus Torvalds
parent 20c8c62891
commit 09f363c736
2 changed files with 2 additions and 1 deletions

View File

@ -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);

View File

@ -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.