net: ehea: avoid null pointer dereference

[pandora-kernel.git] / fs / aio.c

diff --git a/fs/aio.c b/fs/aio.c
index 3b65ee7..9acfd07 100644 (file)
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1102,6 +1102,13 @@ static int aio_read_evt(struct kioctx *ioctx, struct io_event *ent)
        head = ring->head % info->nr;
        if (head != ring->tail) {
                struct io_event *evp = aio_ring_event(info, head, KM_USER1);
+
+               /*
+                * Ensure that once we've read the current tail pointer, that
+                * we also see the events that were stored up to the tail.
+                */
+               smp_rmb();
+
                *ent = *evp;
                head = (head + 1) % info->nr;
                smp_mb(); /* finish reading the event before updatng the head */
@@ -1112,9 +1119,9 @@ static int aio_read_evt(struct kioctx *ioctx, struct io_event *ent)
        spin_unlock(&info->ring_lock);
 
 out:
-       kunmap_atomic(ring, KM_USER0);
        dprintk("leaving aio_read_evt: %d  h%lu t%lu\n", ret,
                 (unsigned long)ring->head, (unsigned long)ring->tail);
+       kunmap_atomic(ring, KM_USER0);
        return ret;
 }