[Intel-gfx] [PATCH v2 1/3] drm/mm: Ensure that the entry is not NULL before extracting rb_node

[Vivek Kasireddy <vivek.kasireddy@intel.com>]

While looking for next holes suitable for an allocation, although,
it is highly unlikely, make sure that the DECLARE_NEXT_HOLE_ADDR
macro is using a valid node before it extracts the rb_node from it.

Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Christian König <christian.koenig@amd.com>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
---
 drivers/gpu/drm/drm_mm.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c
index 8257f9d4f619..499d8874e4ed 100644
--- a/drivers/gpu/drm/drm_mm.c
+++ b/drivers/gpu/drm/drm_mm.c
@@ -389,11 +389,12 @@ first_hole(struct drm_mm *mm,
 #define DECLARE_NEXT_HOLE_ADDR(name, first, last)			\
 static struct drm_mm_node *name(struct drm_mm_node *entry, u64 size)	\
 {									\
-	struct rb_node *parent, *node = &entry->rb_hole_addr;		\
+	struct rb_node *parent, *node;					\
 									\
-	if (!entry || RB_EMPTY_NODE(node))				\
+	if (!entry || RB_EMPTY_NODE(&entry->rb_hole_addr))		\
 		return NULL;						\
 									\
+	node = &entry->rb_hole_addr;					\
 	if (usable_hole_addr(node->first, size)) {			\
 		node = node->first;					\
 		while (usable_hole_addr(node->last, size))		\
-- 
2.34.1