Commit ffc43516 authored Aug 03, 2016 by Chris Wilson Committed by Sushmita Susheelendra May 31, 2017

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.

Change-Id: Ieb81a8ef5a05a32dd37dfc040ea3f78243b59161
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
Git-commit: aafdcfd3f9aa3c9f77ae4e9385f21bf9ae120d3e
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

Signed-off-by: Sushmita Susheelendra <ssusheel@codeaurora.org>

parent e4cf5a04

drivers/gpu/drm/drm_mm.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -250,6 +250,11 @@ 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 */
		hole = drm_mm_interval_tree_iter_first(&mm->interval_tree,
		node->start, ~(u64)0);
		@@ -315,6 +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)
		@@ -417,6 +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);