virtio_ring: let virtqueue_{kick()/notify()} return a bool

virtqueue_{kick()/notify()} should exploit the new host notification API.
If the notify call returned with a negative value the host kick failed
(e.g. a kick triggered after a device was hot-unplugged). In this case
the virtqueue is set to 'broken' and false is returned, otherwise true.

Signed-off-by: Heinz Graalfs <graalfs@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 97dd51619b554f1902bd4018bf1fbaf68ba6b917..b47142723119440945af4149e551a2bc0c282cba 100644 (file)
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -430,13 +430,22 @@ EXPORT_SYMBOL_GPL(virtqueue_kick_prepare);
  * @vq: the struct virtqueue
  *
  * This does not need to be serialized.
+ *
+ * Returns false if host notify failed or queue is broken, otherwise true.
  */
-void virtqueue_notify(struct virtqueue *_vq)
+bool virtqueue_notify(struct virtqueue *_vq)
 {
        struct vring_virtqueue *vq = to_vvq(_vq);
 
+       if (unlikely(vq->broken))
+               return false;
+
        /* Prod other side to tell it about changes. */
-       vq->notify(_vq);
+       if (vq->notify(_vq) < 0) {
+               vq->broken = true;
+               return false;
+       }
+       return true;
 }
 EXPORT_SYMBOL_GPL(virtqueue_notify);
 
@@ -449,11 +458,14 @@ EXPORT_SYMBOL_GPL(virtqueue_notify);
  *
  * Caller must ensure we don't call this with other virtqueue
  * operations at the same time (except where noted).
+ *
+ * Returns false if kick failed, otherwise true.
  */
-void virtqueue_kick(struct virtqueue *vq)
+bool virtqueue_kick(struct virtqueue *vq)
 {
        if (virtqueue_kick_prepare(vq))
-               virtqueue_notify(vq);
+               return virtqueue_notify(vq);
+       return true;
 }
 EXPORT_SYMBOL_GPL(virtqueue_kick);
 

diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 36d36cc893295387bb0bb841218eb0021c0ab59d..9b4de15fcb2ff5099723c70368bcc49705881da2 100644 (file)
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -51,11 +51,11 @@ int virtqueue_add_sgs(struct virtqueue *vq,
                      void *data,
                      gfp_t gfp);
 
-void virtqueue_kick(struct virtqueue *vq);
+bool virtqueue_kick(struct virtqueue *vq);
 
 bool virtqueue_kick_prepare(struct virtqueue *vq);
 
-void virtqueue_notify(struct virtqueue *vq);
+bool virtqueue_notify(struct virtqueue *vq);
 
 void *virtqueue_get_buf(struct virtqueue *vq, unsigned int *len);