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 --- 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);