drm/omap: gem: Don't take struct_mutex to get GEM object mmap offset

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@ideasonboard.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

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);
 
@@ -319,16 +317,6 @@ 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)
 {