Re: [PATCH 2/4] drm/panthor: Add driver IOCTL for setting BO labels

[Boris Brezillon <boris.brezillon@collabora.com>]

On Sun, 16 Mar 2025 21:51:33 +0000
Adrián Larumbe <adrian.larumbe@collabora.com> wrote:

> Allow UM to label a BO for which it possesses a DRM handle.
> 
> Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
> ---
>  drivers/gpu/drm/panthor/panthor_drv.c | 31 +++++++++++++++++++++++++++
>  include/uapi/drm/panthor_drm.h        | 14 ++++++++++++
>  2 files changed, 45 insertions(+)
> 
> diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c
> index 310bb44abe1a..f41b8946258f 100644
> --- a/drivers/gpu/drm/panthor/panthor_drv.c
> +++ b/drivers/gpu/drm/panthor/panthor_drv.c
> @@ -1330,6 +1330,35 @@ static int panthor_ioctl_vm_get_state(struct drm_device *ddev, void *data,
>  	return 0;
>  }
>  
> +static int panthor_ioctl_label_bo(struct drm_device *ddev, void *data,
> +				  struct drm_file *file)
> +{
> +	struct drm_panthor_label_bo *args = data;
> +	struct drm_gem_object *obj;
> +	const char *label;
> +	int ret = 0;
> +
> +	obj = drm_gem_object_lookup(file, args->handle);
> +	if (!obj)
> +		return -ENOENT;
> +
> +	if (args->len && args->label) {
> +		label = strndup_user(u64_to_user_ptr(args->label), args->len + 1);
> +		if (IS_ERR(label)) {
> +			ret = PTR_ERR(label);
> +			goto err_label;
> +		}
> +	} else
> +		label = NULL;
> +
> +	panthor_gem_label_bo(obj, label);
> +
> +err_label:
> +	drm_gem_object_put(obj);
> +
> +	return ret;
> +}
> +
>  static int
>  panthor_open(struct drm_device *ddev, struct drm_file *file)
>  {
> @@ -1399,6 +1428,7 @@ static const struct drm_ioctl_desc panthor_drm_driver_ioctls[] = {
>  	PANTHOR_IOCTL(TILER_HEAP_CREATE, tiler_heap_create, DRM_RENDER_ALLOW),
>  	PANTHOR_IOCTL(TILER_HEAP_DESTROY, tiler_heap_destroy, DRM_RENDER_ALLOW),
>  	PANTHOR_IOCTL(GROUP_SUBMIT, group_submit, DRM_RENDER_ALLOW),
> +	PANTHOR_IOCTL(LABEL_BO, label_bo, DRM_RENDER_ALLOW),
>  };
>  
>  static int panthor_mmap(struct file *filp, struct vm_area_struct *vma)
> @@ -1508,6 +1538,7 @@ static void panthor_debugfs_init(struct drm_minor *minor)
>   * - 1.2 - adds DEV_QUERY_GROUP_PRIORITIES_INFO query
>   *       - adds PANTHOR_GROUP_PRIORITY_REALTIME priority
>   * - 1.3 - adds DRM_PANTHOR_GROUP_STATE_INNOCENT flag
> + * - 1.4 - adds DRM_IOCTL_PANTHOR_LABEL_BO ioctl
>   */
>  static const struct drm_driver panthor_drm_driver = {
>  	.driver_features = DRIVER_RENDER | DRIVER_GEM | DRIVER_SYNCOBJ |
> diff --git a/include/uapi/drm/panthor_drm.h b/include/uapi/drm/panthor_drm.h
> index 97e2c4510e69..1a7ed567d36a 100644
> --- a/include/uapi/drm/panthor_drm.h
> +++ b/include/uapi/drm/panthor_drm.h
> @@ -127,6 +127,9 @@ enum drm_panthor_ioctl_id {
>  
>  	/** @DRM_PANTHOR_TILER_HEAP_DESTROY: Destroy a tiler heap. */
>  	DRM_PANTHOR_TILER_HEAP_DESTROY,
> +
> +	/** @DRM_PANTHOR_LABEL_BO: Label a BO. */
> +	DRM_PANTHOR_LABEL_BO,

DRM_PANTHOR_BO_SET_LABEL to follow the DRM_PANTHOR_<object>_<action>
naming scheme used in this file.

I'd also be tempted to introduce a DRM_PANTHOR_BO_GET_LABEL ioctl while
we're at it.

>  };
>  
>  /**
> @@ -977,6 +980,15 @@ struct drm_panthor_tiler_heap_destroy {
>  	__u32 pad;
>  };
>  
> +/**
> + * struct drm_panthor_label_bo - Arguments passed to DRM_IOCTL_PANTHOR_LABEL_BO
> + */
> +struct drm_panthor_label_bo {
> +	__u32 handle;
> +	__u32 len;
> +	__u64 label;

Can you document these fields?

> +};
> +
>  /**
>   * DRM_IOCTL_PANTHOR() - Build a Panthor IOCTL number
>   * @__access: Access type. Must be R, W or RW.
> @@ -1019,6 +1031,8 @@ enum {
>  		DRM_IOCTL_PANTHOR(WR, TILER_HEAP_CREATE, tiler_heap_create),
>  	DRM_IOCTL_PANTHOR_TILER_HEAP_DESTROY =
>  		DRM_IOCTL_PANTHOR(WR, TILER_HEAP_DESTROY, tiler_heap_destroy),
> +	DRM_IOCTL_PANTHOR_LABEL_BO =
> +		DRM_IOCTL_PANTHOR(WR, LABEL_BO, label_bo),
>  };
>  
>  #if defined(__cplusplus)