Linux Virtualization - Jul 2019 - [PATCH v6 06/18] drm/virtio: remove ttm calls from in virtio_gpu_object_{reserve, unreserve}

Call reservation_object_* directly instead
of using ttm_bo_{reserve,unreserve}.

v4: check for EINTR only.
v3: check for EINTR too.

Signed-off-by: Gerd Hoffmann <kraxel at redhat.com>
Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/virtio/virtgpu_drv.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h
b/drivers/gpu/drm/virtio/virtgpu_drv.h
index 06cc0e961df6..07f6001ea91e 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -402,9 +402,9 @@ static inline int virtio_gpu_object_reserve(struct
virtio_gpu_object *bo)
 {
 	int r;
 
-	r = ttm_bo_reserve(&bo->tbo, true, false, NULL);
+	r = reservation_object_lock_interruptible(bo->gem_base.resv, NULL);
 	if (unlikely(r != 0)) {
-		if (r != -ERESTARTSYS) {
+		if (r != -EINTR) {
 			struct virtio_gpu_device *qdev  				bo->gem_base.dev->dev_private;
 			dev_err(qdev->dev, "%p reserve failed\n", bo);
@@ -416,7 +416,7 @@ static inline int virtio_gpu_object_reserve(struct
virtio_gpu_object *bo)
 
 static inline void virtio_gpu_object_unreserve(struct virtio_gpu_object *bo)
 {
-	ttm_bo_unreserve(&bo->tbo);
+	reservation_object_unlock(bo->gem_base.resv);
 }
 
 /* virgl debufs */
-- 
2.18.1

On Tue, Jul 2, 2019 at 7:19 AM Gerd Hoffmann <kraxel at redhat.com>
wrote:
>
> Call reservation_object_* directly instead
> of using ttm_bo_{reserve,unreserve}.
>
> v4: check for EINTR only.
> v3: check for EINTR too.
>
> Signed-off-by: Gerd Hoffmann <kraxel at redhat.com>
> Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> ---
>  drivers/gpu/drm/virtio/virtgpu_drv.h | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h
b/drivers/gpu/drm/virtio/virtgpu_drv.h
> index 06cc0e961df6..07f6001ea91e 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_drv.h
> +++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
> @@ -402,9 +402,9 @@ static inline int virtio_gpu_object_reserve(struct
virtio_gpu_object *bo)
>  {
>         int r;
>
> -       r = ttm_bo_reserve(&bo->tbo, true, false, NULL);
> +       r = reservation_object_lock_interruptible(bo->gem_base.resv,
NULL);
Can you elaborate a bit about how TTM keeps the BOs alive in, for
example, virtio_gpu_transfer_from_host_ioctl?  In that function, only
three TTM functions are called: ttm_bo_reserve, ttm_bo_validate, and
ttm_bo_unreserve.  I am curious how they keep the BO alive.
>         if (unlikely(r != 0)) {
> -               if (r != -ERESTARTSYS) {
> +               if (r != -EINTR) {
>                         struct virtio_gpu_device *qdev >                
bo->gem_base.dev->dev_private;
>                         dev_err(qdev->dev, "%p reserve
failed\n", bo);
> @@ -416,7 +416,7 @@ static inline int virtio_gpu_object_reserve(struct
virtio_gpu_object *bo)
>
>  static inline void virtio_gpu_object_unreserve(struct virtio_gpu_object
*bo)
>  {
> -       ttm_bo_unreserve(&bo->tbo);
> +       reservation_object_unlock(bo->gem_base.resv);
>  }
>
>  /* virgl debufs */
> --
> 2.18.1
>

Hi,
> > -       r = ttm_bo_reserve(&bo->tbo, true, false, NULL);
> > +       r =
reservation_object_lock_interruptible(bo->gem_base.resv, NULL);
> Can you elaborate a bit about how TTM keeps the BOs alive in, for
> example, virtio_gpu_transfer_from_host_ioctl?  In that function, only
> three TTM functions are called: ttm_bo_reserve, ttm_bo_validate, and
> ttm_bo_unreserve.  I am curious how they keep the BO alive.
It can't go away between reserve and unreserve, and I think it also
can't be evicted then.  Havn't checked how ttm implements that.

cheers,
  Gerd