[PATCH 3/6] drm/omap: gem: Don't take struct_mutex to get GEM object mmap offset

[Daniel Vetter]

On Mon, Apr 02, 2018 at 09:50:35PM +0300, Laurent Pinchart wrote:
> GEM objects mmap offsets are created by calling
> drm_gem_create_mmap_offset_size() that doesn't need struct_mutex
> protection as it includes its own locking, based on a size that is
> static across the object's life time. Remove the unneeded struct_mutex
> locking.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

It was once required, before the switch to the vma manager thing.

Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>

> ---
>  drivers/gpu/drm/omapdrm/omap_gem.c | 16 ++--------------
>  1 file changed, 2 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/gpu/drm/omapdrm/omap_gem.c b/drivers/gpu/drm/omapdrm/omap_gem.c
> index 13fea207343e..4e727862459f 100644
> --- a/drivers/gpu/drm/omapdrm/omap_gem.c
> +++ b/drivers/gpu/drm/omapdrm/omap_gem.c
> @@ -137,14 +137,12 @@ struct omap_drm_usergart {
>   */
>  
>  /** get mmap offset */
> -static u64 mmap_offset(struct drm_gem_object *obj)
> +u64 omap_gem_mmap_offset(struct drm_gem_object *obj)
>  {
>  	struct drm_device *dev = obj->dev;
>  	int ret;
>  	size_t size;
>  
> -	WARN_ON(!mutex_is_locked(&dev->struct_mutex));
> -
>  	/* Make it mmapable */
>  	size = omap_gem_mmap_size(obj);
>  	ret = drm_gem_create_mmap_offset_size(obj, size);
> @@ -178,7 +176,7 @@ static void omap_gem_evict_entry(struct drm_gem_object *obj,
>  	struct omap_drm_private *priv = obj->dev->dev_private;
>  	int n = priv->usergart[fmt].height;
>  	size_t size = PAGE_SIZE * n;
> -	loff_t off = mmap_offset(obj) +
> +	loff_t off = omap_gem_mmap_offset(obj) +
>  			(entry->obj_pgoff << PAGE_SHIFT);
>  	const int m = DIV_ROUND_UP(omap_obj->width << fmt, PAGE_SIZE);
>  
> @@ -322,16 +320,6 @@ u32 omap_gem_flags(struct drm_gem_object *obj)
>  	return to_omap_bo(obj)->flags;
>  }
>  
> -u64 omap_gem_mmap_offset(struct drm_gem_object *obj)
> -{
> -	u64 offset;
> -
> -	mutex_lock(&obj->dev->struct_mutex);
> -	offset = mmap_offset(obj);
> -	mutex_unlock(&obj->dev->struct_mutex);
> -	return offset;
> -}
> -
>  /** get mmap size */
>  size_t omap_gem_mmap_size(struct drm_gem_object *obj)
>  {
> -- 
> Regards,
> 
> Laurent Pinchart
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch