Use RCU_READ_LOCK_GUARD instead of manual rcu_read_(un)lock
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20191025103403.120616-2-dgilbert@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>