From: Kent Overstreet <kmo@daterainc.com>
Date: Fri, 30 Aug 2013 21:12:24 +0000 (-0700)
Subject: bcache: Fix a shrinker deadlock
X-Git-Tag: next-20130912~34^2~6^2~51
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=b5a1a5cfffbcf355f52e67a9b57db4914395ca70;p=karo-tx-linux.git

bcache: Fix a shrinker deadlock

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>
Cc: linux-stable <stable@vger.kernel.org> # >= v3.10
---

diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index 60908de2af5f..55e8666f9544 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -617,7 +617,7 @@ 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;