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@xxxxxxxxxx> --- It seems an obvious optimization so I queued this up already. drivers/vhost/vhost.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) 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 @@ int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, 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_used_flags(struct vhost_virtqueue *vq) 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; -- 1.7.5.53.gc233e -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html