drm/mm: Convert drm_mm_node booleans to bitops

A straightforward conversion of assignment and checking of the boolean
state flags (allocated, scanned) into non-atomic bitops. The caller
remains responsible for all locking around the drm_mm and its nodes.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191003210100.22250-4-chris@chris-wilson.co.uk

drivers/gpu/drm/drm_mm.c

@@ -426,7 +426,7 @@ int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node)
 
 	list_add(&node->node_list, &hole->node_list);
 	drm_mm_interval_tree_add_node(hole, node);
-	node->allocated = true;
+	__set_bit(DRM_MM_NODE_ALLOCATED_BIT, &node->flags);
 	node->hole_size = 0;
 
 	rm_hole(hole);
@@ -545,7 +545,7 @@ int drm_mm_insert_node_in_range(struct drm_mm * const mm,
 
 		list_add(&node->node_list, &hole->node_list);
 		drm_mm_interval_tree_add_node(hole, node);
-		node->allocated = true;
+		__set_bit(DRM_MM_NODE_ALLOCATED_BIT, &node->flags);
 
 		rm_hole(hole);
 		if (adj_start > hole_start)
@@ -563,7 +563,7 @@ EXPORT_SYMBOL(drm_mm_insert_node_in_range);
 
 static inline bool drm_mm_node_scanned_block(const struct drm_mm_node *node)
 {
-	return node->scanned_block;
+	return test_bit(DRM_MM_NODE_SCANNED_BIT, &node->flags);
 }
 
 /**
@@ -589,7 +589,7 @@ void drm_mm_remove_node(struct drm_mm_node *node)
 
 	drm_mm_interval_tree_remove(node, &mm->interval_tree);
 	list_del(&node->node_list);
-	node->allocated = false;
+	__clear_bit(DRM_MM_NODE_ALLOCATED_BIT, &node->flags);
 
 	if (drm_mm_hole_follows(prev_node))
 		rm_hole(prev_node);
@@ -627,8 +627,8 @@ void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new)
 				&mm->holes_addr);
 	}
 
-	old->allocated = false;
-	new->allocated = true;
+	__clear_bit(DRM_MM_NODE_ALLOCATED_BIT, &old->flags);
+	__set_bit(DRM_MM_NODE_ALLOCATED_BIT, &new->flags);
 }
 EXPORT_SYMBOL(drm_mm_replace_node);
 
@@ -738,7 +738,7 @@ bool drm_mm_scan_add_block(struct drm_mm_scan *scan,
 	DRM_MM_BUG_ON(node->mm != mm);
 	DRM_MM_BUG_ON(!drm_mm_node_allocated(node));
 	DRM_MM_BUG_ON(drm_mm_node_scanned_block(node));
-	node->scanned_block = true;
+	__set_bit(DRM_MM_NODE_SCANNED_BIT, &node->flags);
 	mm->scan_active++;
 
 	/* Remove this block from the node_list so that we enlarge the hole
@@ -824,7 +824,7 @@ bool drm_mm_scan_remove_block(struct drm_mm_scan *scan,
 
 	DRM_MM_BUG_ON(node->mm != scan->mm);
 	DRM_MM_BUG_ON(!drm_mm_node_scanned_block(node));
-	node->scanned_block = false;
+	__clear_bit(DRM_MM_NODE_SCANNED_BIT, &node->flags);
 
 	DRM_MM_BUG_ON(!node->mm->scan_active);
 	node->mm->scan_active--;
@@ -922,7 +922,7 @@ void drm_mm_init(struct drm_mm *mm, u64 start, u64 size)
 
 	/* Clever trick to avoid a special case in the free hole tracking. */
 	INIT_LIST_HEAD(&mm->head_node.node_list);
-	mm->head_node.allocated = false;
+	mm->head_node.flags = 0;
 	mm->head_node.mm = mm;
 	mm->head_node.start = start + size;
 	mm->head_node.size = -size;

drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c

@@ -902,7 +902,7 @@ static void reloc_cache_init(struct reloc_cache *cache,
 	cache->use_64bit_reloc = HAS_64BIT_RELOC(i915);
 	cache->has_fence = cache->gen < 4;
 	cache->needs_unfenced = INTEL_INFO(i915)->unfenced_needs_alignment;
-	cache->node.allocated = false;
+	cache->node.flags = 0;
 	cache->rq = NULL;
 	cache->rq_size = 0;
 }

drivers/gpu/drm/i915/i915_gem.c

@@ -351,7 +351,7 @@ i915_gem_gtt_pread(struct drm_i915_gem_object *obj,
 					       PIN_NOEVICT);
 	if (!IS_ERR(vma)) {
 		node.start = i915_ggtt_offset(vma);
-		node.allocated = false;
+		node.flags = 0;
 	} else {
 		ret = insert_mappable_node(ggtt, &node, PAGE_SIZE);
 		if (ret)
@@ -561,7 +561,7 @@ i915_gem_gtt_pwrite_fast(struct drm_i915_gem_object *obj,
 					       PIN_NOEVICT);
 	if (!IS_ERR(vma)) {
 		node.start = i915_ggtt_offset(vma);
-		node.allocated = false;
+		node.flags = 0;
 	} else {
 		ret = insert_mappable_node(ggtt, &node, PAGE_SIZE);
 		if (ret)

include/drm/drm_mm.h

@@ -168,8 +168,9 @@ struct drm_mm_node {
 	struct rb_node rb_hole_addr;
 	u64 __subtree_last;
 	u64 hole_size;
-	bool allocated : 1;
-	bool scanned_block : 1;
+	unsigned long flags;
+#define DRM_MM_NODE_ALLOCATED_BIT	0
+#define DRM_MM_NODE_SCANNED_BIT		1
 #ifdef CONFIG_DRM_DEBUG_MM
 	depot_stack_handle_t stack;
 #endif
@@ -253,7 +254,7 @@ struct drm_mm_scan {
  */
 static inline bool drm_mm_node_allocated(const struct drm_mm_node *node)
 {
-	return node->allocated;
+	return test_bit(DRM_MM_NODE_ALLOCATED_BIT, &node->flags);
 }
 
 /**