The shrinkers must return -1 to indicate that it is busy. Instead, treat
any negative value as busy.
This fixes a potential bug if scan_objects returns a negative other than -1.
Cc: Glauber Costa <glom...@openvz.org>
Cc: Dave Chinner <dchin...@redhat.com>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Hugh Dickins <hu...@google.com>
Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Signed-off-by: Oskar Andero <oskar.and...@sonymobile.com>
---
include/linux/shrinker.h | 7 ++++---
mm/vmscan.c | 2 +-
2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h
index 3b08869..ced0e91 100644
--- a/include/linux/shrinker.h
+++ b/include/linux/shrinker.h
@@ -38,9 +38,10 @@ struct shrink_control {
* @scan_objects will only be called if @count_objects returned a positive
* value for the number of freeable objects. The callout should scan the cache
* and attempt to free items from the cache. It should then return the number
of
- * objects freed during the scan, or -1 if progress cannot be made due to
- * potential deadlocks. If -1 is returned, then no further attempts to call the
- * @scan_objects will be made from the current reclaim context.
+ * objects freed during the scan, or a negative value if progress cannot be
made
+ * due to potential deadlocks. If a negative value is returned, then no further
+ * attempts to call the @scan_objects will be made from the current reclaim
+ * context.
*/
struct shrinker {
long (*count_objects)(struct shrinker *, struct shrink_control *sc);
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 6bac41e..acb4aef 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -291,7 +291,7 @@ shrink_slab_one(struct shrinker *shrinker, struct
shrink_control *shrinkctl,
shrinkctl->nr_to_scan = nr_to_scan;
ret = shrinker->scan_objects(shrinker, shrinkctl);
- if (ret == -1)
+ if (ret < 0)
break;
freed += ret;
--
1.8.1.5
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