summaryrefslogtreecommitdiff
path: root/include/linux/virtio_ring.h
diff options
context:
space:
mode:
authorMichael S. Tsirkin <mst@redhat.com>2015-12-20 14:52:10 +0300
committerMichael S. Tsirkin <mst@redhat.com>2016-01-12 21:47:00 +0300
commitd307fb16f788823b29aab9aa7e4821ac8a124b19 (patch)
tree62a988d99febab95f276b807f365d1b4abbd90e9 /include/linux/virtio_ring.h
parent6a65d26385bf487926a0616650927303058551e3 (diff)
downloadlinux-d307fb16f788823b29aab9aa7e4821ac8a124b19.tar.xz
Revert "virtio_ring: Update weak barriers to use dma_wmb/rmb"
This reverts commit 9e1a27ea42691429e31f158cce6fc61bc79bb2e9. While that commit optimizes !CONFIG_SMP, it mixes up DMA and SMP concepts, making the code hard to figure out. A better way to optimize this is with the new __smp_XXX barriers. As a first step, go back to full rmb/wmb barriers for !SMP. We switch to __smp_XXX barriers in the next patch. Cc: Peter Zijlstra <peterz@infradead.org> Cc: Alexander Duyck <alexander.duyck@gmail.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Diffstat (limited to 'include/linux/virtio_ring.h')
-rw-r--r--include/linux/virtio_ring.h23
1 files changed, 19 insertions, 4 deletions
diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h
index 8e50888a6d59..67e06fe18c03 100644
--- a/include/linux/virtio_ring.h
+++ b/include/linux/virtio_ring.h
@@ -21,20 +21,19 @@
* actually quite cheap.
*/
+#ifdef CONFIG_SMP
static inline void virtio_mb(bool weak_barriers)
{
-#ifdef CONFIG_SMP
if (weak_barriers)
smp_mb();
else
-#endif
mb();
}
static inline void virtio_rmb(bool weak_barriers)
{
if (weak_barriers)
- dma_rmb();
+ smp_rmb();
else
rmb();
}
@@ -42,10 +41,26 @@ static inline void virtio_rmb(bool weak_barriers)
static inline void virtio_wmb(bool weak_barriers)
{
if (weak_barriers)
- dma_wmb();
+ smp_wmb();
else
wmb();
}
+#else
+static inline void virtio_mb(bool weak_barriers)
+{
+ mb();
+}
+
+static inline void virtio_rmb(bool weak_barriers)
+{
+ rmb();
+}
+
+static inline void virtio_wmb(bool weak_barriers)
+{
+ wmb();
+}
+#endif
struct virtio_device;
struct virtqueue;