On 2018年04月20日 01:35, Michael S. Tsirkin wrote:
virtio is using barriers to order memory accesses, thus
dma_wmb/rmb is a good match.
Build-tested on x86: Before
[mst@tuck linux]$ size drivers/virtio/virtio_ring.o
text data bss dec hex filename
11392 820 0 12212 2fb4 drivers/virtio/virtio_ring.o
After
mst@tuck linux]$ size drivers/virtio/virtio_ring.o
text data bss dec hex filename
11284 820 0 12104 2f48 drivers/virtio/virtio_ring.o
Cc: Ohad Ben-Cohen <ohad@xxxxxxxxxx>
Cc: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
Cc: linux-remoteproc@xxxxxxxxxxxxxxx
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
---
It's good in theory, but could one of RPMSG maintainers please review
and ack this patch? Or even better test it?
All these barriers are useless on Intel anyway ...
include/linux/virtio_ring.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h
index bbf3252..fab0213 100644
--- a/include/linux/virtio_ring.h
+++ b/include/linux/virtio_ring.h
@@ -35,7 +35,7 @@ static inline void virtio_rmb(bool weak_barriers)
if (weak_barriers)
virt_rmb();
else
- rmb();
+ dma_rmb();
}
static inline void virtio_wmb(bool weak_barriers)
@@ -43,7 +43,7 @@ static inline void virtio_wmb(bool weak_barriers)
if (weak_barriers)
virt_wmb();
else
- wmb();
+ dma_wmb();
}
static inline void virtio_store_mb(bool weak_barriers,
Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
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