drm: Declare that create drm_mm nodes with size 0 is illegal (aafdcfd3) · Commits · 戴 / test

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:

Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by:

David Herrmann <dh.herrmann@gmail.com> Signed-off-by:

Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/1470248788-30873-1-git-send-email-chris@chris-wilson.co.uk

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);

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