z3fold: fix spinlock unlocking in page reclaim

Commmit 5a27aa822029 ("z3fold: add kref refcounting") introduced a bug
in z3fold_reclaim_page() with function exit that may leave pool->lock
spinlock held.  Here comes the trivial fix.

Fixes: 5a27aa822029 ("z3fold: add kref refcounting")
Link: http://lkml.kernel.org/r/20170311222239.7b83d8e7ef1914e05497649f@gmail.com
Reported-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Vitaly Wool <vitalywool@gmail.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/mm/z3fold.c b/mm/z3fold.c
index 8970a2fd3b1a..f9492bccfd79 100644
--- a/mm/z3fold.c
+++ b/mm/z3fold.c
@@ -667,6 +667,7 @@ next:
                         z3fold_page_unlock(zhdr);
                         spin_lock(&pool->lock);
                         if (kref_put(&zhdr->refcount, release_z3fold_page)) {
+                                spin_unlock(&pool->lock);
                                 atomic64_dec(&pool->pages_nr);
                                 return 0;
                         }