drm: Extract struct drm_mm_scan from struct drm_mm

The scan state occupies a large proportion of the struct drm_mm and is
rarely used and only contains temporary state. That makes it suitable to
moving to its struct and onto the stack of the callers.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
[danvet: Fix up etnaviv to compile, was missing a BUG_ON.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/drm_mm.c

@@ -574,7 +574,7 @@ static struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm,
 	u64 adj_end;
 	u64 best_size;
 
-	DRM_MM_BUG_ON(mm->scanned_blocks);
+	DRM_MM_BUG_ON(mm->scan_active);
 
 	best = NULL;
 	best_size = ~0UL;
@@ -618,7 +618,7 @@ static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_
 	u64 adj_end;
 	u64 best_size;
 
-	DRM_MM_BUG_ON(mm->scanned_blocks);
+	DRM_MM_BUG_ON(mm->scan_active);
 
 	best = NULL;
 	best_size = ~0UL;
@@ -693,7 +693,7 @@ EXPORT_SYMBOL(drm_mm_replace_node);
  *
  * The DRM range allocator supports this use-case through the scanning
  * interfaces. First a scan operation needs to be initialized with
- * drm_mm_init_scan() or drm_mm_init_scan_with_range(). The driver adds
+ * drm_mm_scan_init() or drm_mm_scan_init_with_range(). The driver adds
  * objects to the roaster (probably by walking an LRU list, but this can be
  * freely implemented) until a suitable hole is found or there's no further
  * evictable object.
@@ -710,7 +710,8 @@ EXPORT_SYMBOL(drm_mm_replace_node);
  */
 
 /**
- * drm_mm_init_scan - initialize lru scanning
+ * drm_mm_scan_init - initialize lru scanning
+ * @scan: scan state
  * @mm: drm_mm to scan
  * @size: size of the allocation
  * @alignment: alignment of the allocation
@@ -724,26 +725,33 @@ EXPORT_SYMBOL(drm_mm_replace_node);
  * As long as the scan list is non-empty, no other operations than
  * adding/removing nodes to/from the scan list are allowed.
  */
-void drm_mm_init_scan(struct drm_mm *mm,
+void drm_mm_scan_init(struct drm_mm_scan *scan,
+		      struct drm_mm *mm,
 		      u64 size,
 		      u64 alignment,
 		      unsigned long color)
 {
 	DRM_MM_BUG_ON(!size);
+	DRM_MM_BUG_ON(mm->scan_active);
 
-	mm->scan_color = color;
-	mm->scan_alignment = alignment;
-	mm->scan_size = size;
-	mm->scanned_blocks = 0;
-	mm->scan_hit_start = 0;
-	mm->scan_hit_end = 0;
-	mm->scan_check_range = 0;
-	mm->prev_scanned_node = NULL;
+	scan->mm = mm;
+
+	scan->color = color;
+	scan->alignment = alignment;
+	scan->size = size;
+
+	scan->check_range = 0;
+
+	scan->hit_start = U64_MAX;
+	scan->hit_end = 0;
+
+	scan->prev_scanned_node = NULL;
 }
-EXPORT_SYMBOL(drm_mm_init_scan);
+EXPORT_SYMBOL(drm_mm_scan_init);
 
 /**
- * drm_mm_init_scan - initialize range-restricted lru scanning
+ * drm_mm_scan_init_with_range - initialize range-restricted lru scanning
+ * @scan: scan state
  * @mm: drm_mm to scan
  * @size: size of the allocation
  * @alignment: alignment of the allocation
@@ -759,7 +767,8 @@ EXPORT_SYMBOL(drm_mm_init_scan);
  * As long as the scan list is non-empty, no other operations than
  * adding/removing nodes to/from the scan list are allowed.
  */
-void drm_mm_init_scan_with_range(struct drm_mm *mm,
+void drm_mm_scan_init_with_range(struct drm_mm_scan *scan,
+				 struct drm_mm *mm,
 				 u64 size,
 				 u64 alignment,
 				 unsigned long color,
@@ -768,19 +777,25 @@ void drm_mm_init_scan_with_range(struct drm_mm *mm,
 {
 	DRM_MM_BUG_ON(start >= end);
 	DRM_MM_BUG_ON(!size || size > end - start);
+	DRM_MM_BUG_ON(mm->scan_active);
+
+	scan->mm = mm;
+
+	scan->color = color;
+	scan->alignment = alignment;
+	scan->size = size;
+
+	DRM_MM_BUG_ON(end <= start);
+	scan->range_start = start;
+	scan->range_end = end;
+	scan->check_range = 1;
+
+	scan->hit_start = U64_MAX;
+	scan->hit_end = 0;
 
-	mm->scan_color = color;
-	mm->scan_alignment = alignment;
-	mm->scan_size = size;
-	mm->scanned_blocks = 0;
-	mm->scan_hit_start = 0;
-	mm->scan_hit_end = 0;
-	mm->scan_start = start;
-	mm->scan_end = end;
-	mm->scan_check_range = 1;
-	mm->prev_scanned_node = NULL;
+	scan->prev_scanned_node = NULL;
 }
-EXPORT_SYMBOL(drm_mm_init_scan_with_range);
+EXPORT_SYMBOL(drm_mm_scan_init_with_range);
 
 /**
  * drm_mm_scan_add_block - add a node to the scan list
@@ -792,46 +807,46 @@ EXPORT_SYMBOL(drm_mm_init_scan_with_range);
  * Returns:
  * True if a hole has been found, false otherwise.
  */
-bool drm_mm_scan_add_block(struct drm_mm_node *node)
+bool drm_mm_scan_add_block(struct drm_mm_scan *scan,
+			   struct drm_mm_node *node)
 {
-	struct drm_mm *mm = node->mm;
+	struct drm_mm *mm = scan->mm;
 	struct drm_mm_node *prev_node;
 	u64 hole_start, hole_end;
 	u64 adj_start, adj_end;
 
-	mm->scanned_blocks++;
-
+	DRM_MM_BUG_ON(node->mm != mm);
+	DRM_MM_BUG_ON(!node->allocated);
 	DRM_MM_BUG_ON(node->scanned_block);
 	node->scanned_block = 1;
+	mm->scan_active++;
 
-	prev_node = list_entry(node->node_list.prev, struct drm_mm_node,
-			       node_list);
+	prev_node = list_prev_entry(node, node_list);
 
 	node->scanned_preceeds_hole = prev_node->hole_follows;
 	prev_node->hole_follows = 1;
 	list_del(&node->node_list);
 	node->node_list.prev = &prev_node->node_list;
-	node->node_list.next = &mm->prev_scanned_node->node_list;
-	mm->prev_scanned_node = node;
+	node->node_list.next = &scan->prev_scanned_node->node_list;
+	scan->prev_scanned_node = node;
 
 	adj_start = hole_start = drm_mm_hole_node_start(prev_node);
 	adj_end = hole_end = drm_mm_hole_node_end(prev_node);
 
-	if (mm->scan_check_range) {
-		if (adj_start < mm->scan_start)
-			adj_start = mm->scan_start;
-		if (adj_end > mm->scan_end)
-			adj_end = mm->scan_end;
+	if (scan->check_range) {
+		if (adj_start < scan->range_start)
+			adj_start = scan->range_start;
+		if (adj_end > scan->range_end)
+			adj_end = scan->range_end;
 	}
 
 	if (mm->color_adjust)
-		mm->color_adjust(prev_node, mm->scan_color,
-				 &adj_start, &adj_end);
+		mm->color_adjust(prev_node, scan->color, &adj_start, &adj_end);
 
 	if (check_free_hole(adj_start, adj_end,
-			    mm->scan_size, mm->scan_alignment)) {
-		mm->scan_hit_start = hole_start;
-		mm->scan_hit_end = hole_end;
+			    scan->size, scan->alignment)) {
+		scan->hit_start = hole_start;
+		scan->hit_end = hole_end;
 		return true;
 	}
 
@@ -856,24 +871,25 @@ EXPORT_SYMBOL(drm_mm_scan_add_block);
  * True if this block should be evicted, false otherwise. Will always
  * return false when no hole has been found.
  */
-bool drm_mm_scan_remove_block(struct drm_mm_node *node)
+bool drm_mm_scan_remove_block(struct drm_mm_scan *scan,
+			      struct drm_mm_node *node)
 {
-	struct drm_mm *mm = node->mm;
 	struct drm_mm_node *prev_node;
 
-	mm->scanned_blocks--;
-
+	DRM_MM_BUG_ON(node->mm != scan->mm);
 	DRM_MM_BUG_ON(!node->scanned_block);
 	node->scanned_block = 0;
 
-	prev_node = list_entry(node->node_list.prev, struct drm_mm_node,
-			       node_list);
+	DRM_MM_BUG_ON(!node->mm->scan_active);
+	node->mm->scan_active--;
+
+	prev_node = list_prev_entry(node, node_list);
 
 	prev_node->hole_follows = node->scanned_preceeds_hole;
 	list_add(&node->node_list, &prev_node->node_list);
 
-	 return (drm_mm_hole_node_end(node) > mm->scan_hit_start &&
-		 node->start < mm->scan_hit_end);
+	return (drm_mm_hole_node_end(node) > scan->hit_start &&
+		node->start < scan->hit_end);
 }
 EXPORT_SYMBOL(drm_mm_scan_remove_block);
 
@@ -890,7 +906,7 @@ void drm_mm_init(struct drm_mm *mm, u64 start, u64 size)
 	DRM_MM_BUG_ON(start + size <= start);
 
 	INIT_LIST_HEAD(&mm->hole_stack);
-	mm->scanned_blocks = 0;
+	mm->scan_active = 0;
 
 	/* Clever trick to avoid a special case in the free hole tracking. */
 	INIT_LIST_HEAD(&mm->head_node.node_list);

drivers/gpu/drm/etnaviv/etnaviv_mmu.c

@@ -113,6 +113,7 @@ static int etnaviv_iommu_find_iova(struct etnaviv_iommu *mmu,
 
 	while (1) {
 		struct etnaviv_vram_mapping *m, *n;
+		struct drm_mm_scan scan;
 		struct list_head list;
 		bool found;
 
@@ -134,7 +135,7 @@ static int etnaviv_iommu_find_iova(struct etnaviv_iommu *mmu,
 		}
 
 		/* Try to retire some entries */
-		drm_mm_init_scan(&mmu->mm, size, 0, 0);
+		drm_mm_scan_init(&scan, &mmu->mm, size, 0, 0);
 
 		found = 0;
 		INIT_LIST_HEAD(&list);
@@ -151,7 +152,7 @@ static int etnaviv_iommu_find_iova(struct etnaviv_iommu *mmu,
 				continue;
 
 			list_add(&free->scan_node, &list);
-			if (drm_mm_scan_add_block(&free->vram_node)) {
+			if (drm_mm_scan_add_block(&scan, &free->vram_node)) {
 				found = true;
 				break;
 			}
@@ -160,7 +161,7 @@ static int etnaviv_iommu_find_iova(struct etnaviv_iommu *mmu,
 		if (!found) {
 			/* Nothing found, clean up and fail */
 			list_for_each_entry_safe(m, n, &list, scan_node)
-				BUG_ON(drm_mm_scan_remove_block(&m->vram_node));
+				BUG_ON(drm_mm_scan_remove_block(&scan, &m->vram_node));
 			break;
 		}
 
@@ -171,7 +172,7 @@ static int etnaviv_iommu_find_iova(struct etnaviv_iommu *mmu,
 		 * can leave the block pinned.
 		 */
 		list_for_each_entry_safe(m, n, &list, scan_node)
-			if (!drm_mm_scan_remove_block(&m->vram_node))
+			if (!drm_mm_scan_remove_block(&scan, &m->vram_node))
 				list_del_init(&m->scan_node);
 
 		/*

drivers/gpu/drm/i915/i915_gem_evict.c

@@ -51,7 +51,10 @@ static bool ggtt_is_idle(struct drm_i915_private *dev_priv)
 }
 
 static bool
-mark_free(struct i915_vma *vma, unsigned int flags, struct list_head *unwind)
+mark_free(struct drm_mm_scan *scan,
+	  struct i915_vma *vma,
+	  unsigned int flags,
+	  struct list_head *unwind)
 {
 	if (i915_vma_is_pinned(vma))
 		return false;
@@ -63,7 +66,7 @@ mark_free(struct i915_vma *vma, unsigned int flags, struct list_head *unwind)
 		return false;
 
 	list_add(&vma->exec_list, unwind);
-	return drm_mm_scan_add_block(&vma->node);
+	return drm_mm_scan_add_block(scan, &vma->node);
 }
 
 /**
@@ -97,6 +100,7 @@ i915_gem_evict_something(struct i915_address_space *vm,
 			 unsigned flags)
 {
 	struct drm_i915_private *dev_priv = to_i915(vm->dev);
+	struct drm_mm_scan scan;
 	struct list_head eviction_list;
 	struct list_head *phases[] = {
 		&vm->inactive_list,
@@ -123,11 +127,12 @@ i915_gem_evict_something(struct i915_address_space *vm,
 	 * object on the TAIL.
 	 */
 	if (start != 0 || end != vm->total) {
-		drm_mm_init_scan_with_range(&vm->mm, min_size,
+		drm_mm_scan_init_with_range(&scan, &vm->mm, min_size,
 					    alignment, cache_level,
 					    start, end);
 	} else
-		drm_mm_init_scan(&vm->mm, min_size, alignment, cache_level);
+		drm_mm_scan_init(&scan, &vm->mm, min_size,
+				 alignment, cache_level);
 
 	if (flags & PIN_NONBLOCK)
 		phases[1] = NULL;
@@ -137,13 +142,13 @@ i915_gem_evict_something(struct i915_address_space *vm,
 	phase = phases;
 	do {
 		list_for_each_entry(vma, *phase, vm_link)
-			if (mark_free(vma, flags, &eviction_list))
+			if (mark_free(&scan, vma, flags, &eviction_list))
 				goto found;
 	} while (*++phase);
 
 	/* Nothing found, clean up and bail out! */
 	list_for_each_entry_safe(vma, next, &eviction_list, exec_list) {
-		ret = drm_mm_scan_remove_block(&vma->node);
+		ret = drm_mm_scan_remove_block(&scan, &vma->node);
 		BUG_ON(ret);
 
 		INIT_LIST_HEAD(&vma->exec_list);
@@ -192,7 +197,7 @@ i915_gem_evict_something(struct i915_address_space *vm,
 	 * of any of our objects, thus corrupting the list).
 	 */
 	list_for_each_entry_safe(vma, next, &eviction_list, exec_list) {
-		if (drm_mm_scan_remove_block(&vma->node))
+		if (drm_mm_scan_remove_block(&scan, &vma->node))
 			__i915_vma_pin(vma);
 		else
 			list_del_init(&vma->exec_list);

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

@@ -1114,11 +1114,11 @@ static int igt_align64(void *ignored)
 	return igt_align_pot(64);
 }
 
-static void show_scan(const struct drm_mm *scan)
+static void show_scan(const struct drm_mm_scan *scan)
 {
 	pr_info("scan: hit [%llx, %llx], size=%lld, align=%lld, color=%ld\n",
-		scan->scan_hit_start, scan->scan_hit_end,
-		scan->scan_size, scan->scan_alignment, scan->scan_color);
+		scan->hit_start, scan->hit_end,
+		scan->size, scan->alignment, scan->color);
 }
 
 static void show_holes(const struct drm_mm *mm, int count)
@@ -1158,7 +1158,7 @@ struct evict_node {
 	struct list_head link;
 };
 
-static bool evict_nodes(struct drm_mm *mm,
+static bool evict_nodes(struct drm_mm_scan *scan,
 			struct evict_node *nodes,
 			unsigned int *order,
 			unsigned int count,
@@ -1170,18 +1170,16 @@ static bool evict_nodes(struct drm_mm *mm,
 	for (i = 0; i < count; i++) {
 		e = &nodes[order ? order[i] : i];
 		list_add(&e->link, evict_list);
-		if (drm_mm_scan_add_block(&e->node))
+		if (drm_mm_scan_add_block(scan, &e->node))
 			break;
 	}
 	list_for_each_entry_safe(e, en, evict_list, link) {
-		if (!drm_mm_scan_remove_block(&e->node))
+		if (!drm_mm_scan_remove_block(scan, &e->node))
 			list_del(&e->link);
 	}
 	if (list_empty(evict_list)) {
 		pr_err("Failed to find eviction: size=%lld [avail=%d], align=%lld (color=%lu)\n",
-		       mm->scan_size, count,
-		       mm->scan_alignment,
-		       mm->scan_color);
+		       scan->size, count, scan->alignment, scan->color);
 		return false;
 	}
 
@@ -1195,19 +1193,20 @@ static bool evict_nothing(struct drm_mm *mm,
 			  unsigned int total_size,
 			  struct evict_node *nodes)
 {
+	struct drm_mm_scan scan;
 	LIST_HEAD(evict_list);
 	struct evict_node *e;
 	struct drm_mm_node *node;
 	unsigned int n;
 
-	drm_mm_init_scan(mm, 1, 0, 0);
+	drm_mm_scan_init(&scan, mm, 1, 0, 0);
 	for (n = 0; n < total_size; n++) {
 		e = &nodes[n];
 		list_add(&e->link, &evict_list);
-		drm_mm_scan_add_block(&e->node);
+		drm_mm_scan_add_block(&scan, &e->node);
 	}
 	list_for_each_entry(e, &evict_list, link)
-		drm_mm_scan_remove_block(&e->node);
+		drm_mm_scan_remove_block(&scan, &e->node);
 
 	for (n = 0; n < total_size; n++) {
 		e = &nodes[n];
@@ -1241,19 +1240,21 @@ static bool evict_everything(struct drm_mm *mm,
 			     unsigned int total_size,
 			     struct evict_node *nodes)
 {
+	struct drm_mm_scan scan;
 	LIST_HEAD(evict_list);
 	struct evict_node *e;
 	unsigned int n;
 	int err;
 
-	drm_mm_init_scan(mm, total_size, 0, 0);
+	drm_mm_scan_init(&scan, mm, total_size, 0, 0);
 	for (n = 0; n < total_size; n++) {
 		e = &nodes[n];
 		list_add(&e->link, &evict_list);
-		drm_mm_scan_add_block(&e->node);
+		if (drm_mm_scan_add_block(&scan, &e->node))
+			break;
 	}
 	list_for_each_entry(e, &evict_list, link) {
-		if (!drm_mm_scan_remove_block(&e->node)) {
+		if (!drm_mm_scan_remove_block(&scan, &e->node)) {
 			pr_err("Node %lld not marked for eviction!\n",
 			       e->node.start);
 			list_del(&e->link);
@@ -1287,15 +1288,16 @@ static int evict_something(struct drm_mm *mm,
 			   unsigned int alignment,
 			   const struct insert_mode *mode)
 {
+	struct drm_mm_scan scan;
 	LIST_HEAD(evict_list);
 	struct evict_node *e;
 	struct drm_mm_node tmp;
 	int err;
 
-	drm_mm_init_scan_with_range(mm,
+	drm_mm_scan_init_with_range(&scan, mm,
 				    size, alignment, 0,
 				    range_start, range_end);
-	if (!evict_nodes(mm,
+	if (!evict_nodes(&scan,
 			 nodes, order, count,
 			 &evict_list))
 		return -EINVAL;
@@ -1307,7 +1309,7 @@ static int evict_something(struct drm_mm *mm,
 	if (err) {
 		pr_err("Failed to insert into eviction hole: size=%d, align=%d\n",
 		       size, alignment);
-		show_scan(mm);
+		show_scan(&scan);
 		show_holes(mm, 3);
 		return err;
 	}
@@ -1864,15 +1866,16 @@ static int evict_color(struct drm_mm *mm,
 		       unsigned long color,
 		       const struct insert_mode *mode)
 {
+	struct drm_mm_scan scan;
 	LIST_HEAD(evict_list);
 	struct evict_node *e;
 	struct drm_mm_node tmp;
 	int err;
 
-	drm_mm_init_scan_with_range(mm,
+	drm_mm_scan_init_with_range(&scan, mm,
 				    size, alignment, color,
 				    range_start, range_end);
-	if (!evict_nodes(mm,
+	if (!evict_nodes(&scan,
 			 nodes, order, count,
 			 &evict_list))
 		return -EINVAL;
@@ -1884,7 +1887,7 @@ static int evict_color(struct drm_mm *mm,
 	if (err) {
 		pr_err("Failed to insert into eviction hole: size=%d, align=%d, color=%lu, err=%d\n",
 		       size, alignment, color, err);
-		show_scan(mm);
+		show_scan(&scan);
 		show_holes(mm, 3);
 		return err;
 	}

include/drm/drm_mm.h

@@ -98,20 +98,29 @@ struct drm_mm {
 	/* Keep an interval_tree for fast lookup of drm_mm_nodes by address. */
 	struct rb_root interval_tree;
 
-	unsigned int scan_check_range : 1;
-	unsigned int scanned_blocks;
-	unsigned long scan_color;
-	u64 scan_alignment;
-	u64 scan_size;
-	u64 scan_hit_start;
-	u64 scan_hit_end;
-	u64 scan_start;
-	u64 scan_end;
-	struct drm_mm_node *prev_scanned_node;
-
 	void (*color_adjust)(const struct drm_mm_node *node,
 			     unsigned long color,
 			     u64 *start, u64 *end);
+
+	unsigned long scan_active;
+};
+
+struct drm_mm_scan {
+	struct drm_mm *mm;
+
+	u64 size;
+	u64 alignment;
+
+	u64 range_start;
+	u64 range_end;
+
+	u64 hit_start;
+	u64 hit_end;
+
+	struct drm_mm_node *prev_scanned_node;
+
+	unsigned long color;
+	bool check_range : 1;
 };
 
 /**
@@ -378,18 +387,22 @@ __drm_mm_interval_first(const struct drm_mm *mm, u64 start, u64 last);
 	     node__ && node__->start < (end__);				\
 	     node__ = list_next_entry(node__, node_list))
 
-void drm_mm_init_scan(struct drm_mm *mm,
+void drm_mm_scan_init(struct drm_mm_scan *scan,
+		      struct drm_mm *mm,
 		      u64 size,
 		      u64 alignment,
 		      unsigned long color);
-void drm_mm_init_scan_with_range(struct drm_mm *mm,
+void drm_mm_scan_init_with_range(struct drm_mm_scan *scan,
+				 struct drm_mm *mm,
 				 u64 size,
 				 u64 alignment,
 				 unsigned long color,
 				 u64 start,
 				 u64 end);
-bool drm_mm_scan_add_block(struct drm_mm_node *node);
-bool drm_mm_scan_remove_block(struct drm_mm_node *node);
+bool drm_mm_scan_add_block(struct drm_mm_scan *scan,
+			   struct drm_mm_node *node);
+bool drm_mm_scan_remove_block(struct drm_mm_scan *scan,
+			      struct drm_mm_node *node);
 
 void drm_mm_debug_table(const struct drm_mm *mm, const char *prefix);
 #ifdef CONFIG_DEBUG_FS