--- zzzz-none-000/linux-3.10.107/fs/btrfs/ulist.h	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/fs/btrfs/ulist.h	2021-02-04 17:41:59.000000000 +0000
@@ -17,18 +17,12 @@
  * 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.
  */
-
-/*
- * number of elements statically allocated inside struct ulist
- */
-#define ULIST_SIZE 16
-
 struct ulist_iterator {
+#ifdef CONFIG_BTRFS_DEBUG
 	int i;
+#endif
+	struct list_head *cur_list;  /* hint to start search */
 };
 
 /*
@@ -37,6 +31,12 @@
 struct ulist_node {
 	u64 val;		/* value to store */
 	u64 aux;		/* auxiliary value saved along with the val */
+
+#ifdef CONFIG_BTRFS_DEBUG
+	int seqnum;		/* sequence number this node is added */
+#endif
+
+	struct list_head list;  /* used to link node */
 	struct rb_node rb_node;	/* used to speed up search */
 };
 
@@ -46,37 +46,36 @@
 	 */
 	unsigned long nnodes;
 
-	/*
-	 * number of nodes we already have room for
-	 */
-	unsigned long nodes_alloced;
-
-	/*
-	 * pointer to the array storing the elements. The first ULIST_SIZE
-	 * elements are stored inline. In this case the it points to int_nodes.
-	 * After exceeding ULIST_SIZE, dynamic memory is allocated.
-	 */
-	struct ulist_node *nodes;
-
+	struct list_head nodes;
 	struct rb_root root;
-
-	/*
-	 * inline storage space for the first ULIST_SIZE entries
-	 */
-	struct ulist_node int_nodes[ULIST_SIZE];
 };
 
 void ulist_init(struct ulist *ulist);
-void ulist_fini(struct ulist *ulist);
 void ulist_reinit(struct ulist *ulist);
 struct ulist *ulist_alloc(gfp_t gfp_mask);
 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,
+				      void **old_aux, gfp_t gfp_mask)
+{
+#if BITS_PER_LONG == 32
+	u64 old64 = (uintptr_t)*old_aux;
+	int ret = ulist_add_merge(ulist, val, (uintptr_t)aux, &old64, gfp_mask);
+	*old_aux = (void *)((uintptr_t)old64);
+	return ret;
+#else
+	return ulist_add_merge(ulist, val, (u64)aux, (u64 *)old_aux, gfp_mask);
+#endif
+}
+
 struct ulist_node *ulist_next(struct ulist *ulist,
 			      struct ulist_iterator *uiter);
 
-#define ULIST_ITER_INIT(uiter) ((uiter)->i = 0)
+#define ULIST_ITER_INIT(uiter) ((uiter)->cur_list = NULL)
 
 #endif