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@xxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/drm_mm.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c
index cb39f45d6a16..e8c15795386d 100644
--- a/drivers/gpu/drm/drm_mm.c
+++ b/drivers/gpu/drm/drm_mm.c
@@ -185,6 +185,9 @@ int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node)
BUG_ON(node == NULL);
+ if (WARN_ON(node->size == 0))
+ return -EINVAL;
+
end = node->start + node->size;
/* Find the relevant hole to add our node to */
@@ -239,6 +242,9 @@ 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)
@@ -340,6 +346,9 @@ 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);
--
2.8.1
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