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

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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>
This commit is contained in:
Heinz Graalfs 2013-10-29 09:39:48 +10:30 • committed by Rusty Russell
commit 5b1bf7cb67
2 changed files with 18 additions and 6 deletions
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20
drivers/virtio/virtio_ring.c
View file

@ -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);

4
include/linux/virtio.h
View file

@ -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);