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>

4 files changed, 37 insertions, 19 deletions

diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c
index b59978fe4c6e..c0024719f32b 100644
--- a/drivers/gpu/drm/drm_mm.c
+++ b/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
diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index a792dcb902b5..325b917c5ad7 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/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;
diff --git a/drivers/gpu/drm/selftests/test-drm_mm.c b/drivers/gpu/drm/selftests/test-drm_mm.c
index f609e4f1eeaf..2ce92f4dcfc7 100644
--- a/drivers/gpu/drm/selftests/test-drm_mm.c
+++ b/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,
diff --git a/include/drm/drm_mm.h b/include/drm/drm_mm.h
index aed93cbc4bde..7da7a171d6d5 100644
--- a/include/drm/drm_mm.h
+++ b/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.