[PATCH v3 1/3] hw/virtio: Comment virtqueue_flush() must be called with RCU read lock

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

Reported-by: Stefano Garzarella <sgarzare@redhat.com>
Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 include/hw/virtio/virtio.h | 7 +++++++
 hw/virtio/virtio.c         | 1 +
 2 files changed, 8 insertions(+)

diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index 8bab9cfb750..c1c5f6e53c8 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -186,6 +186,13 @@ void virtio_delete_queue(VirtQueue *vq);
 
 void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem,
                     unsigned int len);
+/**
+ * virtqueue_flush:
+ * @vq: The #VirtQueue
+ * @count: Number of elements to flush
+ *
+ * Must be called within RCU critical section.
+ */
 void virtqueue_flush(VirtQueue *vq, unsigned int count);
 void virtqueue_detach_element(VirtQueue *vq, const VirtQueueElement *elem,
                               unsigned int len);
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 3a1f6c520cb..97f60017466 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -896,6 +896,7 @@ static void virtqueue_packed_flush(VirtQueue *vq, unsigned int count)
     }
 }
 
+/* Called within rcu_read_lock().  */
 void virtqueue_flush(VirtQueue *vq, unsigned int count)
 {
     if (virtio_device_disabled(vq->vdev)) {
-- 
2.31.1