drm: Use drm_mm_nodes() as shorthand for the list of nodes under struct drm_mm

Fairly commonly we want to inspect the node list on the struct drm_mm,
which is buried within an embedded node. Bring it to the surface with a
bit of syntatic sugar.

Note this was intended to be split from commit ad579002 ("drm: Add
drm_mm_for_each_node_safe()") before being applied, but my timing sucks.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20161222083641.2691-3-chris@chris-wilson.co.uk

drivers/gpu/drm/drm_mm.c

@@ -138,7 +138,7 @@ static void show_leaks(struct drm_mm *mm)
 	if (!buf)
 		return;
 
-	list_for_each_entry(node, __drm_mm_nodes(mm), node_list) {
+	list_for_each_entry(node, drm_mm_nodes(mm), node_list) {
 		struct stack_trace trace = {
 			.entries = entries,
 			.max_entries = STACKDEPTH
@@ -320,7 +320,7 @@ int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node)
 		if (hole->start < end)
 			return -ENOSPC;
 	} else {
-		hole = list_entry(__drm_mm_nodes(mm), typeof(*hole), node_list);
+		hole = list_entry(drm_mm_nodes(mm), typeof(*hole), node_list);
 	}
 
 	hole = list_last_entry(&hole->node_list, typeof(*hole), node_list);
@@ -883,7 +883,7 @@ EXPORT_SYMBOL(drm_mm_scan_remove_block);
  */
 bool drm_mm_clean(const struct drm_mm *mm)
 {
-	const struct list_head *head = __drm_mm_nodes(mm);
+	const struct list_head *head = drm_mm_nodes(mm);
 
 	return (head->next->next == head);
 }
@@ -929,7 +929,7 @@ EXPORT_SYMBOL(drm_mm_init);
  */
 void drm_mm_takedown(struct drm_mm *mm)
 {
-	if (WARN(!list_empty(__drm_mm_nodes(mm)),
+	if (WARN(!list_empty(drm_mm_nodes(mm)),
 		 "Memory manager not clean during takedown.\n"))
 		show_leaks(mm);
 

include/drm/drm_mm.h

@@ -180,7 +180,19 @@ static inline u64 drm_mm_hole_node_end(const struct drm_mm_node *hole_node)
 	return __drm_mm_hole_node_end(hole_node);
 }
 
-#define __drm_mm_nodes(mm) (&(mm)->head_node.node_list)
+/**
+ * drm_mm_nodes - list of nodes under the drm_mm range manager
+ * @mm: the struct drm_mm range manger
+ *
+ * As the drm_mm range manager hides its node_list deep with its
+ * structure, extracting it looks painful and repetitive. This is
+ * not expected to be used outside of the drm_mm_for_each_node()
+ * macros and similar internal functions.
+ *
+ * Returns:
+ * The node list, may be empty.
+ */
+#define drm_mm_nodes(mm) (&(mm)->head_node.node_list)
 
 /**
  * drm_mm_for_each_node - iterator to walk over all allocated nodes
@@ -191,7 +203,7 @@ static inline u64 drm_mm_hole_node_end(const struct drm_mm_node *hole_node)
  * with list_for_each, so not save against removal of elements.
  */
 #define drm_mm_for_each_node(entry, mm) \
-	list_for_each_entry(entry, __drm_mm_nodes(mm), node_list)
+	list_for_each_entry(entry, drm_mm_nodes(mm), node_list)
 
 /**
  * drm_mm_for_each_node_safe - iterator to walk over all allocated nodes
@@ -203,7 +215,7 @@ static inline u64 drm_mm_hole_node_end(const struct drm_mm_node *hole_node)
  * with list_for_each_safe, so save against removal of elements.
  */
 #define drm_mm_for_each_node_safe(entry, next, mm) \
-	list_for_each_entry_safe(entry, next, __drm_mm_nodes(mm), node_list)
+	list_for_each_entry_safe(entry, next, drm_mm_nodes(mm), node_list)
 
 #define __drm_mm_for_each_hole(entry, mm, hole_start, hole_end, backwards) \
 	for (entry = list_entry((backwards) ? (mm)->hole_stack.prev : (mm)->hole_stack.next, struct drm_mm_node, hole_stack); \