aio: add missing smp_rmb() in read_events_ring

[platform/adaptation/renesas_rcar/renesas_kernel.git] / fs / aio.c

diff --git a/fs/aio.c b/fs/aio.c
index c6c6845..c4b6b82 100644 (file)
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1134,6 +1134,12 @@ static long aio_read_events_ring(struct kioctx *ctx,
        tail = ring->tail;
        kunmap_atomic(ring);
 
+       /*
+        * 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();
+
        pr_debug("h%u t%u m%u\n", head, tail, ctx->nr_events);
 
        if (head == tail)