1 files changed, 100 insertions, 32 deletions

diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 514efb200be..6b26f9d3980 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -60,9 +60,14 @@ struct radix_tree_path {
 };
 
 #define RADIX_TREE_INDEX_BITS  (8 /* CHAR_BIT */ * sizeof(unsigned long))
-#define RADIX_TREE_MAX_PATH (RADIX_TREE_INDEX_BITS/RADIX_TREE_MAP_SHIFT + 2)
+#define RADIX_TREE_MAX_PATH (DIV_ROUND_UP(RADIX_TREE_INDEX_BITS, \
+					  RADIX_TREE_MAP_SHIFT))
 
-static unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH] __read_mostly;
+/*
+ * The height_to_maxindex array needs to be one deeper than the maximum
+ * path as height 0 holds only 1 entry.
+ */
+static unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH + 1] __read_mostly;
 
 /*
  * Radix tree node cache.
@@ -93,7 +98,8 @@ radix_tree_node_alloc(struct radix_tree_root *root)
 	struct radix_tree_node *ret;
 	gfp_t gfp_mask = root_gfp_mask(root);
 
-	ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask);
+	ret = kmem_cache_alloc(radix_tree_node_cachep,
+				set_migrateflags(gfp_mask, __GFP_RECLAIMABLE));
 	if (ret == NULL && !(gfp_mask & __GFP_WAIT)) {
 		struct radix_tree_preload *rtp;
 
@@ -104,7 +110,7 @@ radix_tree_node_alloc(struct radix_tree_root *root)
 			rtp->nr--;
 		}
 	}
-	BUG_ON(radix_tree_is_direct_ptr(ret));
+	BUG_ON(radix_tree_is_indirect_ptr(ret));
 	return ret;
 }
 
@@ -137,7 +143,8 @@ int radix_tree_preload(gfp_t gfp_mask)
 	rtp = &__get_cpu_var(radix_tree_preloads);
 	while (rtp->nr < ARRAY_SIZE(rtp->nodes)) {
 		preempt_enable();
-		node = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask);
+		node = kmem_cache_alloc(radix_tree_node_cachep,
+				set_migrateflags(gfp_mask, __GFP_RECLAIMABLE));
 		if (node == NULL)
 			goto out;
 		preempt_disable();
@@ -240,7 +247,7 @@ static int radix_tree_extend(struct radix_tree_root *root, unsigned long index)
 			return -ENOMEM;
 
 		/* Increase the height.  */
-		node->slots[0] = radix_tree_direct_to_ptr(root->rnode);
+		node->slots[0] = radix_tree_indirect_to_ptr(root->rnode);
 
 		/* Propagate the aggregated tag info into the new root */
 		for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
@@ -251,6 +258,7 @@ static int radix_tree_extend(struct radix_tree_root *root, unsigned long index)
 		newheight = root->height+1;
 		node->height = newheight;
 		node->count = 1;
+		node = radix_tree_ptr_to_indirect(node);
 		rcu_assign_pointer(root->rnode, node);
 		root->height = newheight;
 	} while (height > root->height);
@@ -274,7 +282,7 @@ int radix_tree_insert(struct radix_tree_root *root,
 	int offset;
 	int error;
 
-	BUG_ON(radix_tree_is_direct_ptr(item));
+	BUG_ON(radix_tree_is_indirect_ptr(item));
 
 	/* Make sure the tree is high enough.  */
 	if (index > radix_tree_maxindex(root->height)) {
@@ -283,7 +291,8 @@ int radix_tree_insert(struct radix_tree_root *root,
 			return error;
 	}
 
-	slot = root->rnode;
+	slot = radix_tree_indirect_to_ptr(root->rnode);
+
 	height = root->height;
 	shift = (height-1) * RADIX_TREE_MAP_SHIFT;
 
@@ -298,7 +307,8 @@ int radix_tree_insert(struct radix_tree_root *root,
 				rcu_assign_pointer(node->slots[offset], slot);
 				node->count++;
 			} else
-				rcu_assign_pointer(root->rnode, slot);
+				rcu_assign_pointer(root->rnode,
+					radix_tree_ptr_to_indirect(slot));
 		}
 
 		/* Go a level down */
@@ -318,7 +328,7 @@ int radix_tree_insert(struct radix_tree_root *root,
 		BUG_ON(tag_get(node, 0, offset));
 		BUG_ON(tag_get(node, 1, offset));
 	} else {
-		rcu_assign_pointer(root->rnode, radix_tree_ptr_to_direct(item));
+		rcu_assign_pointer(root->rnode, item);
 		BUG_ON(root_tag_get(root, 0));
 		BUG_ON(root_tag_get(root, 1));
 	}
@@ -350,11 +360,12 @@ void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index)
 	if (node == NULL)
 		return NULL;
 
-	if (radix_tree_is_direct_ptr(node)) {
+	if (!radix_tree_is_indirect_ptr(node)) {
 		if (index > 0)
 			return NULL;
 		return (void **)&root->rnode;
 	}
+	node = radix_tree_indirect_to_ptr(node);
 
 	height = node->height;
 	if (index > radix_tree_maxindex(height))
@@ -398,11 +409,12 @@ void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index)
 	if (node == NULL)
 		return NULL;
 
-	if (radix_tree_is_direct_ptr(node)) {
+	if (!radix_tree_is_indirect_ptr(node)) {
 		if (index > 0)
 			return NULL;
-		return radix_tree_direct_to_ptr(node);
+		return node;
 	}
+	node = radix_tree_indirect_to_ptr(node);
 
 	height = node->height;
 	if (index > radix_tree_maxindex(height))
@@ -447,7 +459,7 @@ void *radix_tree_tag_set(struct radix_tree_root *root,
 	height = root->height;
 	BUG_ON(index > radix_tree_maxindex(height));
 
-	slot = root->rnode;
+	slot = radix_tree_indirect_to_ptr(root->rnode);
 	shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
 
 	while (height > 0) {
@@ -487,7 +499,11 @@ EXPORT_SYMBOL(radix_tree_tag_set);
 void *radix_tree_tag_clear(struct radix_tree_root *root,
 			unsigned long index, unsigned int tag)
 {
-	struct radix_tree_path path[RADIX_TREE_MAX_PATH], *pathp = path;
+	/*
+	 * The radix tree path needs to be one longer than the maximum path
+	 * since the "list" is null terminated.
+	 */
+	struct radix_tree_path path[RADIX_TREE_MAX_PATH + 1], *pathp = path;
 	struct radix_tree_node *slot = NULL;
 	unsigned int height, shift;
 
@@ -497,7 +513,7 @@ void *radix_tree_tag_clear(struct radix_tree_root *root,
 
 	shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
 	pathp->node = NULL;
-	slot = root->rnode;
+	slot = radix_tree_indirect_to_ptr(root->rnode);
 
 	while (height > 0) {
 		int offset;
@@ -562,8 +578,9 @@ int radix_tree_tag_get(struct radix_tree_root *root,
 	if (node == NULL)
 		return 0;
 
-	if (radix_tree_is_direct_ptr(node))
+	if (!radix_tree_is_indirect_ptr(node))
 		return (index == 0);
+	node = radix_tree_indirect_to_ptr(node);
 
 	height = node->height;
 	if (index > radix_tree_maxindex(height))
@@ -599,6 +616,42 @@ int radix_tree_tag_get(struct radix_tree_root *root,
 EXPORT_SYMBOL(radix_tree_tag_get);
 #endif
 
+/**
+ *	radix_tree_next_hole    -    find the next hole (not-present entry)
+ *	@root:		tree root
+ *	@index:		index key
+ *	@max_scan:	maximum range to search
+ *
+ *	Search the set [index, min(index+max_scan-1, MAX_INDEX)] for the lowest
+ *	indexed hole.
+ *
+ *	Returns: the index of the hole if found, otherwise returns an index
+ *	outside of the set specified (in which case 'return - index >= max_scan'
+ *	will be true).
+ *
+ *	radix_tree_next_hole may be called under rcu_read_lock. However, like
+ *	radix_tree_gang_lookup, this will not atomically search a snapshot of the
+ *	tree at a single point in time. For example, if a hole is created at index
+ *	5, then subsequently a hole is created at index 10, radix_tree_next_hole
+ *	covering both indexes may return 10 if called under rcu_read_lock.
+ */
+unsigned long radix_tree_next_hole(struct radix_tree_root *root,
+				unsigned long index, unsigned long max_scan)
+{
+	unsigned long i;
+
+	for (i = 0; i < max_scan; i++) {
+		if (!radix_tree_lookup(root, index))
+			break;
+		index++;
+		if (index == 0)
+			break;
+	}
+
+	return index;
+}
+EXPORT_SYMBOL(radix_tree_next_hole);
+
 static unsigned int
 __lookup(struct radix_tree_node *slot, void **results, unsigned long index,
 	unsigned int max_items, unsigned long *next_index)
@@ -680,13 +733,13 @@ radix_tree_gang_lookup(struct radix_tree_root *root, void **results,
 	if (!node)
 		return 0;
 
-	if (radix_tree_is_direct_ptr(node)) {
+	if (!radix_tree_is_indirect_ptr(node)) {
 		if (first_index > 0)
 			return 0;
-		node = radix_tree_direct_to_ptr(node);
-		results[0] = rcu_dereference(node);
+		results[0] = node;
 		return 1;
 	}
+	node = radix_tree_indirect_to_ptr(node);
 
 	max_index = radix_tree_maxindex(node->height);
 
@@ -808,13 +861,13 @@ radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results,
 	if (!node)
 		return 0;
 
-	if (radix_tree_is_direct_ptr(node)) {
+	if (!radix_tree_is_indirect_ptr(node)) {
 		if (first_index > 0)
 			return 0;
-		node = radix_tree_direct_to_ptr(node);
-		results[0] = rcu_dereference(node);
+		results[0] = node;
 		return 1;
 	}
+	node = radix_tree_indirect_to_ptr(node);
 
 	max_index = radix_tree_maxindex(node->height);
 
@@ -844,12 +897,22 @@ EXPORT_SYMBOL(radix_tree_gang_lookup_tag);
 static inline void radix_tree_shrink(struct radix_tree_root *root)
 {
 	/* try to shrink tree height */
-	while (root->height > 0 &&
-			root->rnode->count == 1 &&
-			root->rnode->slots[0]) {
+	while (root->height > 0) {
 		struct radix_tree_node *to_free = root->rnode;
 		void *newptr;
 
+		BUG_ON(!radix_tree_is_indirect_ptr(to_free));
+		to_free = radix_tree_indirect_to_ptr(to_free);
+
+		/*
+		 * The candidate node has more than one child, or its child
+		 * is not at the leftmost slot, we cannot shrink.
+		 */
+		if (to_free->count != 1)
+			break;
+		if (!to_free->slots[0])
+			break;
+
 		/*
 		 * We don't need rcu_assign_pointer(), since we are simply
 		 * moving the node from one part of the tree to another. If
@@ -858,8 +921,8 @@ static inline void radix_tree_shrink(struct radix_tree_root *root)
 		 * one (root->rnode).
 		 */
 		newptr = to_free->slots[0];
-		if (root->height == 1)
-			newptr = radix_tree_ptr_to_direct(newptr);
+		if (root->height > 1)
+			newptr = radix_tree_ptr_to_indirect(newptr);
 		root->rnode = newptr;
 		root->height--;
 		/* must only free zeroed nodes into the slab */
@@ -882,7 +945,11 @@ static inline void radix_tree_shrink(struct radix_tree_root *root)
  */
 void *radix_tree_delete(struct radix_tree_root *root, unsigned long index)
 {
-	struct radix_tree_path path[RADIX_TREE_MAX_PATH], *pathp = path;
+	/*
+	 * The radix tree path needs to be one longer than the maximum path
+	 * since the "list" is null terminated.
+	 */
+	struct radix_tree_path path[RADIX_TREE_MAX_PATH + 1], *pathp = path;
 	struct radix_tree_node *slot = NULL;
 	struct radix_tree_node *to_free;
 	unsigned int height, shift;
@@ -894,12 +961,12 @@ void *radix_tree_delete(struct radix_tree_root *root, unsigned long index)
 		goto out;
 
 	slot = root->rnode;
-	if (height == 0 && root->rnode) {
-		slot = radix_tree_direct_to_ptr(slot);
+	if (height == 0) {
 		root_tag_clear_all(root);
 		root->rnode = NULL;
 		goto out;
 	}
+	slot = radix_tree_indirect_to_ptr(slot);
 
 	shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
 	pathp->node = NULL;
@@ -941,7 +1008,8 @@ void *radix_tree_delete(struct radix_tree_root *root, unsigned long index)
 			radix_tree_node_free(to_free);
 
 		if (pathp->node->count) {
-			if (pathp->node == root->rnode)
+			if (pathp->node ==
+					radix_tree_indirect_to_ptr(root->rnode))
 				radix_tree_shrink(root);
 			goto out;
 		}