Commit 09f363c7 authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Linus Torvalds

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: default avatarMikulas Patocka <>
Cc: Dave Chinner <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent 20c8c628
......@@ -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);
......@@ -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.
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