virtio: correct the memory barrier in virtqueue_kick_prepare()
authorJason Wang <jasowang@redhat.com>
Fri, 20 Jan 2012 08:17:08 +0000 (16:17 +0800)
committerRusty Russell <rusty@rustcorp.com.au>
Fri, 27 Jan 2012 21:40:23 +0000 (07:40 +1030)
commita72caae21803b74e04e2afda5e035f149d4ea118
tree680a59aa70e790a3735ae054be5888c0892ecb41
parent4dbc5d9f4f791df8a5879f4a655f517adc7f56d1
virtio: correct the memory barrier in virtqueue_kick_prepare()

Use virtio_mb() to make sure the available index to be exposed before
checking the the avail event. Otherwise we may get stale value of
avail event in guest and never kick the host after.

Note: this fixes a bug introduced by ee7cd8981e15bcb365fc762afe3fc47b8242f630.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org
drivers/virtio/virtio_ring.c