From 4049542d4ffc92e4e12c7a7d03984afbeeff15bb Mon Sep 17 00:00:00 2001
From: David Sterba <dsterba@suse.com>
Date: Thu, 9 Feb 2017 16:16:02 +0100
Subject: [PATCH] btrfs-progs: shared: copy ulist_del from kernel

Signed-off-by: David Sterba <dsterba@suse.com>
---
 kernel-shared/ulist.c | 36 ++++++++++++++++++++++++++++++++++++
 kernel-shared/ulist.h |  1 +
 2 files changed, 37 insertions(+)

diff --git a/kernel-shared/ulist.c b/kernel-shared/ulist.c
index c5eca45..e25af2d 100644
--- a/kernel-shared/ulist.c
+++ b/kernel-shared/ulist.c
@@ -134,6 +134,15 @@ static struct ulist_node *ulist_rbtree_search(struct ulist *ulist, u64 val)
 	return NULL;
 }
 
+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_rbtree_insert(struct ulist *ulist, struct ulist_node *ins)
 {
 	struct rb_node **p = &ulist->root.rb_node;
@@ -211,6 +220,33 @@ int ulist_add_merge(struct ulist *ulist, u64 val, u64 aux,
 	return 1;
 }
 
+/*
+ * ulist_del - 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;
+}
+
 /**
  * ulist_next - iterate ulist
  * @ulist:	ulist to iterate
diff --git a/kernel-shared/ulist.h b/kernel-shared/ulist.h
index 88f5b82..aa172c5 100644
--- a/kernel-shared/ulist.h
+++ b/kernel-shared/ulist.h
@@ -58,6 +58,7 @@ void ulist_free(struct ulist *ulist);
 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 ulist_del(struct ulist *ulist, u64 val, u64 aux);
 
 /* just like ulist_add_merge() but take a pointer for the aux data */
 static inline int ulist_add_merge_ptr(struct ulist *ulist, u64 val, void *aux,
-- 
2.7.4