4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Gerd Hoffmann <kraxel@xxxxxxxxxx> commit d02d270014f70dcab0117776b81a37b6fca745ae upstream. 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. Cc: stable@xxxxxxxxxxxxxxx Reported-by: Alain Magloire <amagloire@xxxxxxxxxxxxxx> Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx> Reviewed-by: Dave Airlie <airlied@xxxxxxxxxx> Link: http://patchwork.freedesktop.org/patch/msgid/20180403095904.11152-1-kraxel@xxxxxxxxxx Signed-off-by: Sean Paul <seanpaul@xxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/virtio/virtgpu_vq.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/gpu/drm/virtio/virtgpu_vq.c +++ b/drivers/gpu/drm/virtio/virtgpu_vq.c @@ -324,7 +324,7 @@ retry: 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 { @@ -399,7 +399,7 @@ retry: 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 {
