On Fri, Aug 23, 2019 at 2:55 AM Gerd Hoffmann <kraxel@xxxxxxxxxx> wrote:
>
> Use drm_gem_reservation_object_wait() in virtio_gpu_wait_ioctl().
> This also makes the ioctl run lockless.
>
> v5: handle lookup failure.
> v2: use reservation_object_test_signaled_rcu for VIRTGPU_WAIT_NOWAIT.
>
> Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
> Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
> ---
> drivers/gpu/drm/virtio/virtgpu_ioctl.c | 25 +++++++++++--------------
> 1 file changed, 11 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> index 0a88ef11b9d3..74b6bad01d7f 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> @@ -466,23 +466,20 @@ static int virtio_gpu_wait_ioctl(struct drm_device *dev, void *data,
> struct drm_file *file)
> {
> struct drm_virtgpu_3d_wait *args = data;
> - struct drm_gem_object *gobj = NULL;
> - struct virtio_gpu_object *qobj = NULL;
> + struct drm_gem_object *obj;
> + long timeout = 15 * HZ;
> int ret;
> - bool nowait = false;
>
> - gobj = drm_gem_object_lookup(file, args->handle);
> - if (gobj == NULL)
> - return -ENOENT;
> + if (args->flags & VIRTGPU_WAIT_NOWAIT) {
> + obj = drm_gem_object_lookup(file, args->handle);
> + if (obj == NULL)
> + return -ENOENT;
> + ret = dma_resv_test_signaled_rcu(obj->resv, true);
> + drm_gem_object_put_unlocked(obj);
> + return ret ? 0 : -EBUSY;
> + }
>
> - qobj = gem_to_virtio_gpu_obj(gobj);
> -
> - if (args->flags & VIRTGPU_WAIT_NOWAIT)
> - nowait = true;
> - ret = virtio_gpu_object_wait(qobj, nowait);
> -
> - drm_gem_object_put_unlocked(gobj);
> - return ret;
> + return drm_gem_dma_resv_wait(file, args->handle, true, timeout);
This changes the return value from -EBUSY to -ETIME when the wait
times out. I think we can use dma_resv_wait_timeout_rcu directly
here.
> }
>
> static int virtio_gpu_get_caps_ioctl(struct drm_device *dev,
> --
> 2.18.1
>
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