virtio_ring: pull in spinlock header

we use a spinlock now pull in the correct header to
make virtio_ring.c self sufficient.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index c2aaa0eff6df1869b9786fd6aeb12e5620fe7a83..dd95dfd85e9808575aeb65a04b86a49332d5db14 100644 (file)
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -11,6 +11,7 @@
 #include <linux/module.h>
 #include <linux/hrtimer.h>
 #include <linux/dma-mapping.h>
+#include <linux/spinlock.h>
 #include <xen/xen.h>
 
 #ifdef DEBUG