On Tue, Apr 03, 2018 at 11:59:04AM +0200, Gerd Hoffmann wrote:
> Wait until we have enough space in the virt queue to actually queue up
> our request. Avoids the guest spinning in case we have a non-zero
> amount of free entries but not enough for the request.
Ping airlied, can you please either pick it up or review so I can commit
myself?
thanks,
Gerd
> Cc: stable@xxxxxxxxxxxxxxx
> Reported-by: Alain Magloire <amagloire@xxxxxxxxxxxxxx>
> Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
> ---
> drivers/gpu/drm/virtio/virtgpu_vq.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
> index 48e4f1df6e..020070d483 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_vq.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
> @@ -293,7 +293,7 @@ static int virtio_gpu_queue_ctrl_buffer_locked(struct virtio_gpu_device *vgdev,
> ret = virtqueue_add_sgs(vq, sgs, outcnt, incnt, vbuf, GFP_ATOMIC);
> if (ret == -ENOSPC) {
> spin_unlock(&vgdev->ctrlq.qlock);
> - wait_event(vgdev->ctrlq.ack_queue, vq->num_free);
> + wait_event(vgdev->ctrlq.ack_queue, vq->num_free >= outcnt + incnt);
> spin_lock(&vgdev->ctrlq.qlock);
> goto retry;
> } else {
> @@ -368,7 +368,7 @@ static int virtio_gpu_queue_cursor(struct virtio_gpu_device *vgdev,
> ret = virtqueue_add_sgs(vq, sgs, outcnt, 0, vbuf, GFP_ATOMIC);
> if (ret == -ENOSPC) {
> spin_unlock(&vgdev->cursorq.qlock);
> - wait_event(vgdev->cursorq.ack_queue, vq->num_free);
> + wait_event(vgdev->cursorq.ack_queue, vq->num_free >= outcnt);
> spin_lock(&vgdev->cursorq.qlock);
> goto retry;
> } else {
> --
> 2.9.3
>