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Commit aafdcfd3 authored by Chris Wilson's avatar Chris Wilson Committed by Daniel Vetter
Browse files

drm: Declare that create drm_mm nodes with size 0 is illegal 



At a higher level, all objects are created with definite size i.e. 0 is
illegal. In forthcoming patches, this assumption is dependent upon in
the drm_mm range manager, i.e. trying to create a drm_mm node with size
0 will have undefined behaviour. Add a couple of WARNs upon creating the
drm_mm node to prevent later bugs.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarDavid Herrmann <dh.herrmann@gmail.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1470248788-30873-1-git-send-email-chris@chris-wilson.co.uk
parent a3ccc461

drivers/gpu/drm/drm_mm.c

+9 −0
Original line number Diff line number Diff line
@@ -250,6 +250,9 @@ int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node) 
	struct drm_mm_node *hole;

	u64 hole_start, hole_end;



	if (WARN_ON(node->size == 0))

		return -EINVAL;



	end = node->start + node->size;



	/* Find the relevant hole to add our node to */
@@ -317,6 +320,9 @@ int drm_mm_insert_node_generic(struct drm_mm *mm, struct drm_mm_node *node, 
{

	struct drm_mm_node *hole_node;



	if (WARN_ON(size == 0))

		return -EINVAL;



	hole_node = drm_mm_search_free_generic(mm, size, alignment,

					       color, sflags);

	if (!hole_node)
@@ -419,6 +425,9 @@ int drm_mm_insert_node_in_range_generic(struct drm_mm *mm, struct drm_mm_node *n 
{

	struct drm_mm_node *hole_node;



	if (WARN_ON(size == 0))

		return -EINVAL;



	hole_node = drm_mm_search_free_in_range_generic(mm,

							size, alignment, color,

							start, end, sflags);