[PATCH RFC v5 net-next 2/6] virtio_ring: try to disable event index callbacks in virtqueue_disable_cb()

From: Jason Wang
Date: Mon Feb 09 2015 - 03:40:04 EST

Currently, we do nothing to prevent the callbacks in
virtqueue_disable_cb() when event index is used. This may cause
spurious interrupts which may damage the performance. This patch tries
to publish avail event as the used even to prevent the callbacks.

Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
drivers/virtio/virtio_ring.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 545fed5..e9ffbfb 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -539,6 +539,8 @@ void virtqueue_disable_cb(struct virtqueue *_vq)
struct vring_virtqueue *vq = to_vvq(_vq);

vq->vring.avail->flags |= cpu_to_virtio16(_vq->vdev, VRING_AVAIL_F_NO_INTERRUPT);
+ vring_used_event(&vq->vring) = cpu_to_virtio16(_vq->vdev,
+ vq->vring.avail->idx);


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