virtio_ring: switch to dma_XX barriers for rpmsg

mstsirkin · mstsirkin · commit 55e49dc43a83 · 2018-06-07T20:54:23.000+03:00
virtio is using barriers to order memory accesses, thus
dma_wmb/rmb is a good match.

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 &lt;ohad@wizery.com&gt;
Cc: Bjorn Andersson &lt;bjorn.andersson@linaro.org&gt;
Cc: linux-remoteproc@vger.kernel.org
Signed-off-by: Michael S. Tsirkin &lt;mst@redhat.com&gt;
diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h
@@ -35,15 +35,15 @@ 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)
 {
 	if (weak_barriers)
 		virt_wmb();
 	else
-		wmb();
+		dma_wmb();
 }
 
 static inline void virtio_store_mb(bool weak_barriers,

Original file line number	Diff line number	Diff line change
`@@ -35,15 +35,15 @@ static inline void virtio_rmb(bool weak_barriers)`
`35`	`35`	`if (weak_barriers)`
`36`	`36`	`virt_rmb();`
`37`	`37`	`else`
`38`		`- rmb();`
	`38`	`+ dma_rmb();`
`39`	`39`	`}`
`40`	`40`
`41`	`41`	`static inline void virtio_wmb(bool weak_barriers)`
`42`	`42`	`{`
`43`	`43`	`if (weak_barriers)`
`44`	`44`	`virt_wmb();`
`45`	`45`	`else`
`46`		`- wmb();`
	`46`	`+ dma_wmb();`
`47`	`47`	`}`
`48`	`48`
`49`	`49`	`static inline void virtio_store_mb(bool weak_barriers,`