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

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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>
This commit is contained in:
Chris Wilson 2016-08-03 19:26:28 +01:00 • committed by Sushmita Susheelendra
parent e4cf5a0425
commit ffc435160c
1 changed files with 11 additions and 0 deletions
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11
drivers/gpu/drm/drm_mm.c
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@ -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);