The patch titled
vmscan: fix shrinker callback bug in fs/super.c
has been added to the -mm tree. Its filename is
vmscan-fix-shrinker-callback-bug-in-fs-superc.patch
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------------------------------------------------------
Subject: vmscan: fix shrinker callback bug in fs/super.c
From: Mikulas Patocka <mpatocka@xxxxxxxxxx>
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@xxxxxxxxxx>
Cc: Dave Chinner <david@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/super.c | 2 +-
include/linux/shrinker.h | 1 +
2 files changed, 2 insertions(+), 1 deletion(-)
diff -puN fs/super.c~vmscan-fix-shrinker-callback-bug-in-fs-superc fs/super.c
--- a/fs/super.c~vmscan-fix-shrinker-callback-bug-in-fs-superc
+++ a/fs/super.c
@@ -61,7 +61,7 @@ static int prune_super(struct shrinker *
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 -puN include/linux/shrinker.h~vmscan-fix-shrinker-callback-bug-in-fs-superc include/linux/shrinker.h
--- a/include/linux/shrinker.h~vmscan-fix-shrinker-callback-bug-in-fs-superc
+++ a/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.
_
Patches currently in -mm which might be from mpatocka@xxxxxxxxxx are
linux-next.patch
vmscan-fix-shrinker-callback-bug-in-fs-superc.patch
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