1/* SPDX-License-Identifier: GPL-2.0 */
 2/*
 3 * Copyright (C) 2011 STRATO AG
 4 * written by Arne Jansen <sensille@gmx.net>
 5 */
 6
 7#ifndef BTRFS_ULIST_H
 8#define BTRFS_ULIST_H
 9
10#include <linux/types.h>
11#include <linux/list.h>
12#include <linux/rbtree.h>
13
14/*
15 * ulist is a generic data structure to hold a collection of unique u64
16 * values. The only operations it supports is adding to the list and
17 * enumerating it.
18 * It is possible to store an auxiliary value along with the key.
19 *
20 */
21struct ulist_iterator {
22	struct list_head *cur_list;  /* hint to start search */
23};
24
25/*
26 * element of the list
27 */
28struct ulist_node {
29	u64 val;		/* value to store */
30	u64 aux;		/* auxiliary value saved along with the val */
31
32	struct list_head list;  /* used to link node */
33	struct rb_node rb_node;	/* used to speed up search */
34};
35
36struct ulist {
37	/*
38	 * number of elements stored in list
39	 */
40	unsigned long nnodes;
41
42	struct list_head nodes;
43	struct rb_root root;
44	struct ulist_node *prealloc;
45};
46
47void ulist_init(struct ulist *ulist);
48void ulist_release(struct ulist *ulist);
49void ulist_reinit(struct ulist *ulist);
50struct ulist *ulist_alloc(gfp_t gfp_mask);
51void ulist_prealloc(struct ulist *ulist, gfp_t mask);
52void ulist_free(struct ulist *ulist);
53int ulist_add(struct ulist *ulist, u64 val, u64 aux, gfp_t gfp_mask);
54int ulist_add_merge(struct ulist *ulist, u64 val, u64 aux,
55		    u64 *old_aux, gfp_t gfp_mask);
56int ulist_del(struct ulist *ulist, u64 val, u64 aux);
57
58/* just like ulist_add_merge() but take a pointer for the aux data */
59static inline int ulist_add_merge_ptr(struct ulist *ulist, u64 val, void *aux,
60				      void **old_aux, gfp_t gfp_mask)
61{
62#if BITS_PER_LONG == 32
63	u64 old64 = (uintptr_t)*old_aux;
64	int ret = ulist_add_merge(ulist, val, (uintptr_t)aux, &old64, gfp_mask);
65	*old_aux = (void *)((uintptr_t)old64);
66	return ret;
67#else
68	return ulist_add_merge(ulist, val, (u64)aux, (u64 *)old_aux, gfp_mask);
69#endif
70}
71
72struct ulist_node *ulist_next(const struct ulist *ulist,
73			      struct ulist_iterator *uiter);
74
75#define ULIST_ITER_INIT(uiter) ((uiter)->cur_list = NULL)
76
77#endif