Re: [PATCH v4 07/12] drm/virtio: add virtio_gpu_object_array & helpers

From: Chia-I Wu
Date: Wed Jun 26 2019 - 20:49:22 EST


On Wed, Jun 19, 2019 at 11:08 PM Gerd Hoffmann <kraxel@xxxxxxxxxx> wrote:
>
> Some helper functions to manage an array of gem objects.
>
> v4: make them virtio-private instead of generic helpers.
>
> Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
> ---
> drivers/gpu/drm/virtio/virtgpu_drv.h | 10 ++++++
> drivers/gpu/drm/virtio/virtgpu_gem.c | 50 ++++++++++++++++++++++++++++
> 2 files changed, 60 insertions(+)
>
> diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
> index 07f6001ea91e..98d646789d23 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_drv.h
> +++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
> @@ -84,6 +84,11 @@ struct virtio_gpu_object {
> #define gem_to_virtio_gpu_obj(gobj) \
> container_of((gobj), struct virtio_gpu_object, gem_base)
>
> +struct virtio_gpu_object_array {
> + u32 nents;
> + struct drm_gem_object *objs[];
> +};
> +
> struct virtio_gpu_vbuffer;
> struct virtio_gpu_device;
>
> @@ -251,6 +256,11 @@ int virtio_gpu_mode_dumb_mmap(struct drm_file *file_priv,
> struct drm_device *dev,
> uint32_t handle, uint64_t *offset_p);
>
> +struct virtio_gpu_object_array *virtio_gpu_array_alloc(u32 nents);
> +struct virtio_gpu_object_array*
> +virtio_gpu_array_from_handles(struct drm_file *drm_file, u32 *handles, u32 nents);
> +void virtio_gpu_array_put_free(struct virtio_gpu_object_array *objs);
> +
> /* virtio vg */
> int virtio_gpu_alloc_vbufs(struct virtio_gpu_device *vgdev);
> void virtio_gpu_free_vbufs(struct virtio_gpu_device *vgdev);
> diff --git a/drivers/gpu/drm/virtio/virtgpu_gem.c b/drivers/gpu/drm/virtio/virtgpu_gem.c
> index 9c9ad3b14080..456cc382ce68 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_gem.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_gem.c
> @@ -169,3 +169,53 @@ void virtio_gpu_gem_object_close(struct drm_gem_object *obj,
> qobj->hw_res_handle);
> virtio_gpu_object_unreserve(qobj);
> }
> +
> +struct virtio_gpu_object_array *virtio_gpu_array_alloc(u32 nents)
> +{
> + struct virtio_gpu_object_array *objs;
> + size_t size = sizeof(*objs) + sizeof(objs->objs[0]) * nents;
> +
> + objs = kzalloc(size, GFP_KERNEL);
It seems unlikely to get wrong. Use kmalloc instead?
> + if (!objs)
> + return NULL;
> +
> + objs->nents = nents;
> + return objs;
> +}
> +
> +static void virtio_gpu_array_free(struct virtio_gpu_object_array *objs)
> +{
> + kfree(objs);
> +}
> +
> +struct virtio_gpu_object_array*
> +virtio_gpu_array_from_handles(struct drm_file *drm_file, u32 *handles, u32 nents)
> +{
> + struct virtio_gpu_object_array *objs;
> + u32 i;
> +
> + objs = virtio_gpu_array_alloc(nents);
> + if (!objs)
> + return NULL;
> +
> + for (i = 0; i < nents; i++) {
> + objs->objs[i] = drm_gem_object_lookup(drm_file, handles[i]);
> + if (!objs->objs[i]) {
> + virtio_gpu_array_put_free(objs);
Set objs->nents to i before calling i915_gem_object_lookup;
> + return NULL;
Should we distinguish ENOMEM and ENOENT?
> + }
> + }
> + return objs;
> +}
> +
> +void virtio_gpu_array_put_free(struct virtio_gpu_object_array *objs)
> +{
> + u32 i;
> +
> + for (i = 0; i < objs->nents; i++) {
> + if (!objs->objs[i])
> + continue;
The check can be removed if the change in virtio_gpu_array_from_handles.
> + drm_gem_object_put_unlocked(objs->objs[i]);
> + }
> + virtio_gpu_array_free(objs);
> +}
> --
> 2.18.1
>
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