vhost: optimize interrupt enable/disable
As we now only update used ring after enabling
the backend, we can write flags with __put_user:
as that's done on data path, it matters.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index c16d225..c14c42b 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -998,7 +998,7 @@
static int vhost_update_used_flags(struct vhost_virtqueue *vq)
{
void __user *used;
- if (put_user(vq->used_flags, &vq->used->flags) < 0)
+ if (__put_user(vq->used_flags, &vq->used->flags) < 0)
return -EFAULT;
if (unlikely(vq->log_used)) {
/* Make sure the flag is seen before log. */
@@ -1016,7 +1016,7 @@
static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event)
{
- if (put_user(vq->avail_idx, vhost_avail_event(vq)))
+ if (__put_user(vq->avail_idx, vhost_avail_event(vq)))
return -EFAULT;
if (unlikely(vq->log_used)) {
void __user *used;