This change makes it so that instead of using smp_wmb/rmb which varies
depending on the kernel configuration we can can use dma_wmb/rmb which for
most architectures should be equal to or slightly more strict than
smp_wmb/rmb.
The advantage to this is that these barriers are available to uniprocessor
builds as well so the performance should improve under such a
configuration.
Signed-off-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxxx>
---
include/linux/virtio_ring.h | 23 ++++-------------------
1 file changed, 4 insertions(+), 19 deletions(-)
diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h
index 67e06fe18c03..8e50888a6d59 100644
--- a/include/linux/virtio_ring.h
+++ b/include/linux/virtio_ring.h
@@ -21,19 +21,20 @@
* 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)
- smp_rmb();
+ dma_rmb();
else
rmb();
}
@@ -41,26 +42,10 @@ static inline void virtio_rmb(bool weak_barriers)
static inline void virtio_wmb(bool weak_barriers)
{
if (weak_barriers)
- smp_wmb();
+ dma_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;
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