Re: [PATCH 4/8] drm: Allow drm_mode_object_find() to look up an object of any type

[Daniel Vetter <daniel@ffwll.ch>]

On Wed, May 28, 2014 at 07:57:21PM -0400, Rob Clark wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> To avoid having to pass object types from userspace for atomic mode
> setting ioctl, allow drm_mode_object_find() to look up an object of any
> type. This will only work as long as the all object types share the ID
> space.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Signed-off-by: Rob Clark <robdclark@gmail.com>

Still NACK. Iirc you only want a boolean "does this exist" so please add a
new function for this. Returning a full pointer for framebuffer is simply
unsafe, allowing that a call for trouble. Yes, I know your current code is
safe but I don't want to freak out and do an ad-hoc audit every time I
stumble over this again.
-Daniel

> ---
>  drivers/gpu/drm/drm_crtc.c | 3 ++-
>  include/drm/drm_crtc.h     | 1 +
>  2 files changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> index c53ddc3..b975575 100644
> --- a/drivers/gpu/drm/drm_crtc.c
> +++ b/drivers/gpu/drm/drm_crtc.c
> @@ -409,7 +409,8 @@ struct drm_mode_object *drm_mode_object_find(struct drm_device *dev,
>  
>  	mutex_lock(&dev->mode_config.idr_mutex);
>  	obj = idr_find(&dev->mode_config.crtc_idr, id);
> -	if (!obj || (obj->type != type) || (obj->id != id))
> +	if (!obj || (type != DRM_MODE_OBJECT_ANY && obj->type != type) ||
> +	    (obj->id != id))
>  		obj = NULL;
>  	mutex_unlock(&dev->mode_config.idr_mutex);
>  
> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> index dbd7954..44d7964 100644
> --- a/include/drm/drm_crtc.h
> +++ b/include/drm/drm_crtc.h
> @@ -50,6 +50,7 @@ struct drm_clip_rect;
>  #define DRM_MODE_OBJECT_BLOB 0xbbbbbbbb
>  #define DRM_MODE_OBJECT_PLANE 0xeeeeeeee
>  #define DRM_MODE_OBJECT_BRIDGE 0xbdbdbdbd
> +#define DRM_MODE_OBJECT_ANY 0
>  
>  struct drm_mode_object {
>  	uint32_t id;
> -- 
> 1.9.3
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch