Merge tag 'drm-misc-next-fixes-2023-09-11' of git://anongit.freedesktop.org/drm/drm-misc into drm-fixes

Short summary of fixes pull:

 * nouveau: Lockdep workaround
 * fbdev/g364fb: Build fix

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
From: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230911141915.GA983@linux-uq9g

2 files changed, 32 insertions, 5 deletions

diff --git a/drivers/gpu/drm/drm_exec.c b/drivers/gpu/drm/drm_exec.c
index ff69cf0fb42aab..5d2809de4517ca 100644
--- a/drivers/gpu/drm/drm_exec.c
+++ b/drivers/gpu/drm/drm_exec.c
@@ -56,7 +56,7 @@ static void drm_exec_unlock_all(struct drm_exec *exec)
 	struct drm_gem_object *obj;
 	unsigned long index;
 
-	drm_exec_for_each_locked_object(exec, index, obj) {
+	drm_exec_for_each_locked_object_reverse(exec, index, obj) {
 		dma_resv_unlock(obj->resv);
 		drm_gem_object_put(obj);
 	}
diff --git a/include/drm/drm_exec.h b/include/drm/drm_exec.h
index e0462361adf9ed..b5bf0b6da791c1 100644
--- a/include/drm/drm_exec.h
+++ b/include/drm/drm_exec.h
@@ -52,6 +52,20 @@ struct drm_exec {
 };
 
 /**
+ * drm_exec_obj() - Return the object for a give drm_exec index
+ * @exec: Pointer to the drm_exec context
+ * @index: The index.
+ *
+ * Return: Pointer to the locked object corresponding to @index if
+ * index is within the number of locked objects. NULL otherwise.
+ */
+static inline struct drm_gem_object *
+drm_exec_obj(struct drm_exec *exec, unsigned long index)
+{
+	return index < exec->num_objects ? exec->objects[index] : NULL;
+}
+
+/**
  * drm_exec_for_each_locked_object - iterate over all the locked objects
  * @exec: drm_exec object
  * @index: unsigned long index for the iteration
@@ -59,10 +73,23 @@ struct drm_exec {
  *
  * Iterate over all the locked GEM objects inside the drm_exec object.
  */
-#define drm_exec_for_each_locked_object(exec, index, obj)	\
-	for (index = 0, obj = (exec)->objects[0];		\
-	     index < (exec)->num_objects;			\
-	     ++index, obj = (exec)->objects[index])
+#define drm_exec_for_each_locked_object(exec, index, obj)		\
+	for ((index) = 0; ((obj) = drm_exec_obj(exec, index)); ++(index))
+
+/**
+ * drm_exec_for_each_locked_object_reverse - iterate over all the locked
+ * objects in reverse locking order
+ * @exec: drm_exec object
+ * @index: unsigned long index for the iteration
+ * @obj: the current GEM object
+ *
+ * Iterate over all the locked GEM objects inside the drm_exec object in
+ * reverse locking order. Note that @index may go below zero and wrap,
+ * but that will be caught by drm_exec_obj(), returning a NULL object.
+ */
+#define drm_exec_for_each_locked_object_reverse(exec, index, obj)	\
+	for ((index) = (exec)->num_objects - 1;				\
+	     ((obj) = drm_exec_obj(exec, index)); --(index))
 
 /**
  * drm_exec_until_all_locked - loop until all GEM objects are locked