drm: Wrap drm_mm_node.hole_follows

Insulate users from changes to the internal hole tracking within
struct drm_mm_node by using an accessor for hole_follows.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
[danvet: resolve conflicts in i915_vma.c]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/drm_mm.c

@@ -323,7 +323,7 @@ int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node)
 	}
 
 	hole = list_last_entry(&hole->node_list, typeof(*hole), node_list);
-	if (!hole->hole_follows)
+	if (!drm_mm_hole_follows(hole))
 		return -ENOSPC;
 
 	adj_start = hole_start = __drm_mm_hole_node_start(hole);
@@ -408,7 +408,7 @@ static void drm_mm_insert_helper_range(struct drm_mm_node *hole_node,
 	u64 adj_start = hole_start;
 	u64 adj_end = hole_end;
 
-	DRM_MM_BUG_ON(!hole_node->hole_follows || node->allocated);
+	DRM_MM_BUG_ON(!drm_mm_hole_follows(hole_node) || node->allocated);
 
 	if (adj_start < start)
 		adj_start = start;
@@ -523,16 +523,16 @@ void drm_mm_remove_node(struct drm_mm_node *node)
 	prev_node =
 	    list_entry(node->node_list.prev, struct drm_mm_node, node_list);
 
-	if (node->hole_follows) {
+	if (drm_mm_hole_follows(node)) {
 		DRM_MM_BUG_ON(__drm_mm_hole_node_start(node) ==
 			      __drm_mm_hole_node_end(node));
 		list_del(&node->hole_stack);
-	} else
+	} else {
 		DRM_MM_BUG_ON(__drm_mm_hole_node_start(node) !=
 			      __drm_mm_hole_node_end(node));
+	}
 
-
-	if (!prev_node->hole_follows) {
+	if (!drm_mm_hole_follows(prev_node)) {
 		prev_node->hole_follows = 1;
 		list_add(&prev_node->hole_stack, &mm->hole_stack);
 	} else

drivers/gpu/drm/i915/i915_vma.c

@@ -320,11 +320,11 @@ bool i915_gem_valid_gtt_space(struct i915_vma *vma,
 		return true;
 
 	other = list_entry(gtt_space->node_list.prev, struct drm_mm_node, node_list);
-	if (other->allocated && !other->hole_follows && other->color != cache_level)
+	if (other->allocated && !drm_mm_hole_follows(other) && other->color != cache_level)
 		return false;
 
 	other = list_entry(gtt_space->node_list.next, struct drm_mm_node, node_list);
-	if (other->allocated && !gtt_space->hole_follows && other->color != cache_level)
+	if (other->allocated && !drm_mm_hole_follows(gtt_space) && other->color != cache_level)
 		return false;
 
 	return true;

drivers/gpu/drm/selftests/test-drm_mm.c

@@ -63,7 +63,7 @@ static bool assert_no_holes(const struct drm_mm *mm)
 	}
 
 	drm_mm_for_each_node(hole, mm) {
-		if (hole->hole_follows) {
+		if (drm_mm_hole_follows(hole)) {
 			pr_err("Hole follows node, expected none!\n");
 			return false;
 		}
@@ -125,7 +125,7 @@ static bool assert_continuous(const struct drm_mm *mm, u64 size)
 			return false;
 		}
 
-		if (node->hole_follows) {
+		if (drm_mm_hole_follows(node)) {
 			pr_err("node[%ld] is followed by a hole!\n", n);
 			return false;
 		}
@@ -828,7 +828,8 @@ static bool assert_contiguous_in_range(struct drm_mm *mm,
 			return false;
 		}
 
-		if (node->hole_follows && drm_mm_hole_node_end(node) < end) {
+		if (drm_mm_hole_follows(node) &&
+		    drm_mm_hole_node_end(node) < end) {
 			pr_err("node %d is followed by a hole!\n", n);
 			return false;
 		}
@@ -1337,11 +1338,12 @@ static int evict_something(struct drm_mm *mm,
 		err = -EINVAL;
 	}
 
-	if (!assert_node(&tmp, mm, size, alignment, 0) || tmp.hole_follows) {
+	if (!assert_node(&tmp, mm, size, alignment, 0) ||
+	    drm_mm_hole_follows(&tmp)) {
 		pr_err("Inserted did not fill the eviction hole: size=%lld [%d], align=%d [rem=%lld], start=%llx, hole-follows?=%d\n",
 		       tmp.size, size,
 		       alignment, misalignment(&tmp, alignment),
-		       tmp.start, tmp.hole_follows);
+		       tmp.start, drm_mm_hole_follows(&tmp));
 		err = -EINVAL;
 	}
 
@@ -1618,7 +1620,7 @@ static int igt_topdown(void *ignored)
 				goto out;
 			}
 
-			if (nodes[n].hole_follows) {
+			if (drm_mm_hole_follows(&nodes[n])) {
 				pr_err("hole after topdown insert %d, start=%llx\n, size=%u",
 				       n, nodes[n].start, size);
 				goto out;
@@ -1650,7 +1652,7 @@ static int igt_topdown(void *ignored)
 					goto out;
 				}
 
-				if (node->hole_follows) {
+				if (drm_mm_hole_follows(node)) {
 					pr_err("hole after topdown insert %d/%d, start=%llx\n",
 					       m, n, node->start);
 					goto out;
@@ -1705,7 +1707,7 @@ static void separate_adjacent_colors(const struct drm_mm_node *node,
 
 static bool colors_abutt(const struct drm_mm_node *node)
 {
-	if (!node->hole_follows &&
+	if (!drm_mm_hole_follows(node) &&
 	    list_next_entry(node, node_list)->allocated) {
 		pr_err("colors abutt; %ld [%llx + %llx] is next to %ld [%llx + %llx]!\n",
 		       node->color, node->start, node->size,

include/drm/drm_mm.h

@@ -155,6 +155,22 @@ static inline bool drm_mm_initialized(const struct drm_mm *mm)
 	return mm->hole_stack.next;
 }
 
+/**
+ * drm_mm_hole_follows - checks whether a hole follows this node
+ * @node: drm_mm_node to check
+ *
+ * Holes are embedded into the drm_mm using the tail of a drm_mm_node.
+ * If you wish to know whether a hole follows this particular node,
+ * query this function.
+ *
+ * Returns:
+ * True if a hole follows the @node.
+ */
+static inline bool drm_mm_hole_follows(const struct drm_mm_node *node)
+{
+	return node->hole_follows;
+}
+
 static inline u64 __drm_mm_hole_node_start(const struct drm_mm_node *hole_node)
 {
 	return hole_node->start + hole_node->size;
@@ -166,14 +182,14 @@ static inline u64 __drm_mm_hole_node_start(const struct drm_mm_node *hole_node)
  *
  * This is useful for driver-specific debug dumpers. Otherwise drivers should
  * not inspect holes themselves. Drivers must check first whether a hole indeed
- * follows by looking at node->hole_follows.
+ * follows by looking at drm_mm_hole_follows()
  *
  * Returns:
  * Start of the subsequent hole.
  */
 static inline u64 drm_mm_hole_node_start(const struct drm_mm_node *hole_node)
 {
-	DRM_MM_BUG_ON(!hole_node->hole_follows);
+	DRM_MM_BUG_ON(!drm_mm_hole_follows(hole_node));
 	return __drm_mm_hole_node_start(hole_node);
 }
 
@@ -188,7 +204,7 @@ static inline u64 __drm_mm_hole_node_end(const struct drm_mm_node *hole_node)
  *
  * This is useful for driver-specific debug dumpers. Otherwise drivers should
  * not inspect holes themselves. Drivers must check first whether a hole indeed
- * follows by looking at node->hole_follows.
+ * follows by looking at drm_mm_hole_follows().
  *
  * Returns:
  * End of the subsequent hole.