1 files changed, 141 insertions, 121 deletions

diff --git a/fs/btrfs/ulist.c b/fs/btrfs/ulist.c
index b0a523b2c60e..7e16a253fb35 100644
--- a/fs/btrfs/ulist.c
+++ b/fs/btrfs/ulist.c
@@ -1,11 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (C) 2011 STRATO AG
  * written by Arne Jansen <sensille@gmx.net>
- * Distributed under the GNU GPL license version 2.
  */
 
 #include <linux/slab.h>
-#include <linux/export.h>
+#include "messages.h"
 #include "ulist.h"
 
 /*
@@ -14,10 +14,6 @@
  * enumerating it.
  * It is possible to store an auxiliary value along with the key.
  *
- * The implementation is preliminary and can probably be sped up
- * significantly. A first step would be to store the values in an rbtree
- * as soon as ULIST_SIZE is exceeded.
- *
  * A sample usage for ulists is the enumeration of directed graphs without
  * visiting a node twice. The pseudo-code could look like this:
  *
@@ -32,7 +28,7 @@
  * }
  * ulist_free(ulist);
  *
- * This assumes the graph nodes are adressable by u64. This stems from the
+ * This assumes the graph nodes are addressable by u64. This stems from the
  * usage for tree enumeration in btrfs, where the logical addresses are
  * 64 bit.
  *
@@ -41,8 +37,9 @@
  * loop would be similar to the above.
  */
 
-/**
- * ulist_init - freshly initialize a ulist
+/*
+ * Freshly initialize a ulist.
+ *
  * @ulist:	the ulist to initialize
  *
  * Note: don't use this function to init an already used ulist, use
@@ -50,35 +47,37 @@
  */
 void ulist_init(struct ulist *ulist)
 {
-	ulist->nnodes = 0;
-	ulist->nodes = ulist->int_nodes;
-	ulist->nodes_alloced = ULIST_SIZE;
+	INIT_LIST_HEAD(&ulist->nodes);
 	ulist->root = RB_ROOT;
+	ulist->nnodes = 0;
+	ulist->prealloc = NULL;
 }
-EXPORT_SYMBOL(ulist_init);
 
-/**
- * ulist_fini - free up additionally allocated memory for the ulist
+/*
+ * Free up additionally allocated memory for the ulist.
+ *
  * @ulist:	the ulist from which to free the additional memory
  *
  * This is useful in cases where the base 'struct ulist' has been statically
  * allocated.
  */
-void ulist_fini(struct ulist *ulist)
+void ulist_release(struct ulist *ulist)
 {
-	/*
-	 * The first ULIST_SIZE elements are stored inline in struct ulist.
-	 * Only if more elements are alocated they need to be freed.
-	 */
-	if (ulist->nodes_alloced > ULIST_SIZE)
-		kfree(ulist->nodes);
-	ulist->nodes_alloced = 0;	/* in case ulist_fini is called twice */
+	struct ulist_node *node;
+	struct ulist_node *next;
+
+	list_for_each_entry_safe(node, next, &ulist->nodes, list) {
+		kfree(node);
+	}
+	kfree(ulist->prealloc);
+	ulist->prealloc = NULL;
 	ulist->root = RB_ROOT;
+	INIT_LIST_HEAD(&ulist->nodes);
 }
-EXPORT_SYMBOL(ulist_fini);
 
-/**
- * ulist_reinit - prepare a ulist for reuse
+/*
+ * Prepare a ulist for reuse.
+ *
  * @ulist:	ulist to be reused
  *
  * Free up all additional memory allocated for the list elements and reinit
@@ -86,13 +85,13 @@ EXPORT_SYMBOL(ulist_fini);
  */
 void ulist_reinit(struct ulist *ulist)
 {
-	ulist_fini(ulist);
+	ulist_release(ulist);
 	ulist_init(ulist);
 }
-EXPORT_SYMBOL(ulist_reinit);
 
-/**
- * ulist_alloc - dynamically allocate a ulist
+/*
+ * Dynamically allocate a ulist.
+ *
  * @gfp_mask:	allocation flags to for base allocation
  *
  * The allocated ulist will be returned in an initialized state.
@@ -108,64 +107,78 @@ struct ulist *ulist_alloc(gfp_t gfp_mask)
 
 	return ulist;
 }
-EXPORT_SYMBOL(ulist_alloc);
 
-/**
- * ulist_free - free dynamically allocated ulist
+void ulist_prealloc(struct ulist *ulist, gfp_t gfp_mask)
+{
+	if (!ulist->prealloc)
+		ulist->prealloc = kzalloc(sizeof(*ulist->prealloc), gfp_mask);
+}
+
+/*
+ * Free dynamically allocated ulist.
+ *
  * @ulist:	ulist to free
  *
- * It is not necessary to call ulist_fini before.
+ * It is not necessary to call ulist_release before.
  */
 void ulist_free(struct ulist *ulist)
 {
 	if (!ulist)
 		return;
-	ulist_fini(ulist);
+	ulist_release(ulist);
 	kfree(ulist);
 }
-EXPORT_SYMBOL(ulist_free);
+
+static int ulist_node_val_key_cmp(const void *key, const struct rb_node *node)
+{
+	const u64 *val = key;
+	const struct ulist_node *unode = rb_entry(node, struct ulist_node, rb_node);
+
+	if (unode->val < *val)
+		return 1;
+	else if (unode->val > *val)
+		return -1;
+
+	return 0;
+}
 
 static struct ulist_node *ulist_rbtree_search(struct ulist *ulist, u64 val)
 {
-	struct rb_node *n = ulist->root.rb_node;
-	struct ulist_node *u = NULL;
-
-	while (n) {
-		u = rb_entry(n, struct ulist_node, rb_node);
-		if (u->val < val)
-			n = n->rb_right;
-		else if (u->val > val)
-			n = n->rb_left;
-		else
-			return u;
-	}
-	return NULL;
+	struct rb_node *node;
+
+	node = rb_find(&val, &ulist->root, ulist_node_val_key_cmp);
+	return rb_entry_safe(node, struct ulist_node, rb_node);
+}
+
+static void ulist_rbtree_erase(struct ulist *ulist, struct ulist_node *node)
+{
+	rb_erase(&node->rb_node, &ulist->root);
+	list_del(&node->list);
+	kfree(node);
+	BUG_ON(ulist->nnodes == 0);
+	ulist->nnodes--;
+}
+
+static int ulist_node_val_cmp(struct rb_node *new, const struct rb_node *existing)
+{
+	const struct ulist_node *unode = rb_entry(new, struct ulist_node, rb_node);
+
+	return ulist_node_val_key_cmp(&unode->val, existing);
 }
 
 static int ulist_rbtree_insert(struct ulist *ulist, struct ulist_node *ins)
 {
-	struct rb_node **p = &ulist->root.rb_node;
-	struct rb_node *parent = NULL;
-	struct ulist_node *cur = NULL;
-
-	while (*p) {
-		parent = *p;
-		cur = rb_entry(parent, struct ulist_node, rb_node);
-
-		if (cur->val < ins->val)
-			p = &(*p)->rb_right;
-		else if (cur->val > ins->val)
-			p = &(*p)->rb_left;
-		else
-			return -EEXIST;
-	}
-	rb_link_node(&ins->rb_node, parent, p);
-	rb_insert_color(&ins->rb_node, &ulist->root);
+	struct rb_node *node;
+
+	node = rb_find_add(&ins->rb_node, &ulist->root, ulist_node_val_cmp);
+	if (node)
+		return -EEXIST;
 	return 0;
 }
 
-/**
- * ulist_add - add an element to the ulist
+/*
+ * Add an element to the ulist.
+ *
  * @ulist:	ulist to add the element to
  * @val:	value to add to ulist
  * @aux:	auxiliary value to store along with val
@@ -192,8 +205,9 @@ int ulist_add(struct ulist *ulist, u64 val, u64 aux, gfp_t gfp_mask)
 int ulist_add_merge(struct ulist *ulist, u64 val, u64 aux,
 		    u64 *old_aux, gfp_t gfp_mask)
 {
-	int ret = 0;
-	struct ulist_node *node = NULL;
+	int ret;
+	struct ulist_node *node;
+
 	node = ulist_rbtree_search(ulist, val);
 	if (node) {
 		if (old_aux)
@@ -201,57 +215,57 @@ int ulist_add_merge(struct ulist *ulist, u64 val, u64 aux,
 		return 0;
 	}
 
-	if (ulist->nnodes >= ulist->nodes_alloced) {
-		u64 new_alloced = ulist->nodes_alloced + 128;
-		struct ulist_node *new_nodes;
-		void *old = NULL;
-		int i;
-
-		for (i = 0; i < ulist->nnodes; i++)
-			rb_erase(&ulist->nodes[i].rb_node, &ulist->root);
-
-		/*
-		 * if nodes_alloced == ULIST_SIZE no memory has been allocated
-		 * yet, so pass NULL to krealloc
-		 */
-		if (ulist->nodes_alloced > ULIST_SIZE)
-			old = ulist->nodes;
-
-		new_nodes = krealloc(old, sizeof(*new_nodes) * new_alloced,
-				     gfp_mask);
-		if (!new_nodes)
+	if (ulist->prealloc) {
+		node = ulist->prealloc;
+		ulist->prealloc = NULL;
+	} else {
+		node = kmalloc(sizeof(*node), gfp_mask);
+		if (!node)
 			return -ENOMEM;
-
-		if (!old)
-			memcpy(new_nodes, ulist->int_nodes,
-			       sizeof(ulist->int_nodes));
-
-		ulist->nodes = new_nodes;
-		ulist->nodes_alloced = new_alloced;
-
-		/*
-		 * krealloc actually uses memcpy, which does not copy rb_node
-		 * pointers, so we have to do it ourselves.  Otherwise we may
-		 * be bitten by crashes.
-		 */
-		for (i = 0; i < ulist->nnodes; i++) {
-			ret = ulist_rbtree_insert(ulist, &ulist->nodes[i]);
-			if (ret < 0)
-				return ret;
-		}
 	}
-	ulist->nodes[ulist->nnodes].val = val;
-	ulist->nodes[ulist->nnodes].aux = aux;
-	ret = ulist_rbtree_insert(ulist, &ulist->nodes[ulist->nnodes]);
-	BUG_ON(ret);
-	++ulist->nnodes;
+
+	node->val = val;
+	node->aux = aux;
+
+	ret = ulist_rbtree_insert(ulist, node);
+	ASSERT(!ret);
+	list_add_tail(&node->list, &ulist->nodes);
+	ulist->nnodes++;
 
 	return 1;
 }
-EXPORT_SYMBOL(ulist_add);
 
-/**
- * ulist_next - iterate ulist
+/*
+ * Delete one node from ulist.
+ *
+ * @ulist:	ulist to remove node from
+ * @val:	value to delete
+ * @aux:	aux to delete
+ *
+ * The deletion will only be done when *BOTH* val and aux matches.
+ * Return 0 for successful delete.
+ * Return > 0 for not found.
+ */
+int ulist_del(struct ulist *ulist, u64 val, u64 aux)
+{
+	struct ulist_node *node;
+
+	node = ulist_rbtree_search(ulist, val);
+	/* Not found */
+	if (!node)
+		return 1;
+
+	if (node->aux != aux)
+		return 1;
+
+	/* Found and delete */
+	ulist_rbtree_erase(ulist, node);
+	return 0;
+}
+
+/*
+ * Iterate ulist.
+ *
  * @ulist:	ulist to iterate
  * @uiter:	iterator variable, initialized with ULIST_ITER_INIT(&iterator)
  *
@@ -266,13 +280,19 @@ EXPORT_SYMBOL(ulist_add);
  * It is allowed to call ulist_add during an enumeration. Newly added items
  * are guaranteed to show up in the running enumeration.
  */
-struct ulist_node *ulist_next(struct ulist *ulist, struct ulist_iterator *uiter)
+struct ulist_node *ulist_next(const struct ulist *ulist, struct ulist_iterator *uiter)
 {
-	if (ulist->nnodes == 0)
+	struct ulist_node *node;
+
+	if (list_empty(&ulist->nodes))
 		return NULL;
-	if (uiter->i < 0 || uiter->i >= ulist->nnodes)
+	if (uiter->cur_list && uiter->cur_list->next == &ulist->nodes)
 		return NULL;
-
-	return &ulist->nodes[uiter->i++];
+	if (uiter->cur_list) {
+		uiter->cur_list = uiter->cur_list->next;
+	} else {
+		uiter->cur_list = ulist->nodes.next;
+	}
+	node = list_entry(uiter->cur_list, struct ulist_node, list);
+	return node;
 }
-EXPORT_SYMBOL(ulist_next);