From: Kent Overstreet <kmo@daterainc.com>
Date: Tue, 24 Sep 2013 06:17:34 +0000 (-0700)
Subject: bcache: Fix a shrinker deadlock
X-Git-Tag: v3.10.15~44
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=7866bece346caecd88c53c6603e178ce4ebda87b;p=platform%2Fkernel%2Flinux-3.10.git

bcache: Fix a shrinker deadlock

commit a698e08c82dfb9771e0bac12c7337c706d729b6d upstream.

GFP_NOIO means we could be getting called recursively - mca_alloc() ->
mca_data_alloc() - definitely can't use mutex_lock(bucket_lock) then.
Whoops.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index 833c590..7d3deab 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -633,7 +633,7 @@ static int bch_mca_shrink(struct shrinker *shrink, struct shrink_control *sc)
 		return mca_can_free(c) * c->btree_pages;
 
 	/* Return -1 if we can't do anything right now */
-	if (sc->gfp_mask & __GFP_WAIT)
+	if (sc->gfp_mask & __GFP_IO)
 		mutex_lock(&c->bucket_lock);
 	else if (!mutex_trylock(&c->bucket_lock))
 		return -1;