[PATCH] drm: document that blobs are ref'counted

[Jonas Ådahl]

Thanks for this!

I can't review the correctness, but the description looks clear to me
so,

Reviewed-by: Jonas Ådahl <jadahl at gmail.com>


Jonas

On Thu, Oct 22, 2020 at 09:38:05AM +0000, Simon Ser wrote:
> User-space doesn't need to keep track of blobs that might be in use by
> the kernel. User-space can just destroy blobs as soon as they don't need
> them anymore.
> 
> Signed-off-by: Simon Ser <contact at emersion.fr>
> Cc: Pekka Paalanen <ppaalanen at gmail.com>
> Cc: Daniel Vetter <daniel at ffwll.ch>
> Cc: Jonas Ådahl <jadahl at gmail.com>
> ---
>  include/uapi/drm/drm_mode.h | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
> index 863eda048265..f7c41aa4b5eb 100644
> --- a/include/uapi/drm/drm_mode.h
> +++ b/include/uapi/drm/drm_mode.h
> @@ -924,6 +924,10 @@ struct drm_mode_create_blob {
>   * struct drm_mode_destroy_blob - Destroy user blob
>   * @blob_id: blob_id to destroy
>   * Destroy a user-created blob property.
> + *
> + * Blobs are reference-counted by the kernel, so user-space can destroy them as
> + * soon as they're done with them.  For instance user-space can destroy a blob
> + * used in an atomic commit right after performing the atomic commit ioctl.
>   */
>  struct drm_mode_destroy_blob {
>  	__u32 blob_id;
> -- 
> 2.28.0
> 
>