mm/memunmap: don't access uninitialized memmap in memunmap_pages()

[linux-2.6-block.git] / fs / fs-writeback.c

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 8aaa7eec7b74a24018795aae91e29781bdbc89ac..8461a63220398024c2aef5d4795d2f2aadd4ebfa 100644 (file)
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -164,8 +164,13 @@ static void finish_writeback_work(struct bdi_writeback *wb,
 
        if (work->auto_free)
                kfree(work);
-       if (done && atomic_dec_and_test(&done->cnt))
-               wake_up_all(done->waitq);
+       if (done) {
+               wait_queue_head_t *waitq = done->waitq;
+
+               /* @done can't be accessed after the following dec */
+               if (atomic_dec_and_test(&done->cnt))
+                       wake_up_all(waitq);
+       }
 }
 
 static void wb_queue_work(struct bdi_writeback *wb,
@@ -900,7 +905,7 @@ restart:
  * cgroup_writeback_by_id - initiate cgroup writeback from bdi and memcg IDs
  * @bdi_id: target bdi id
  * @memcg_id: target memcg css id
- * @nr_pages: number of pages to write, 0 for best-effort dirty flushing
+ * @nr: number of pages to write, 0 for best-effort dirty flushing
  * @reason: reason why some writeback work initiated
  * @done: target wb_completion
  *