1/*
2 * Copyright (C) 2011 STRATO AG
3 * written by Arne Jansen <sensille@gmx.net>
4 * Distributed under the GNU GPL license version 2.
5 *
6 */
7
8#ifndef __ULIST__
9#define __ULIST__
10
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#ifdef CONFIG_BTRFS_DEBUG
23	int i;
24#endif
25	struct list_head *cur_list;  /* hint to start search */
26};
27
28/*
29 * element of the list
30 */
31struct ulist_node {
32	u64 val;		/* value to store */
33	u64 aux;		/* auxiliary value saved along with the val */
34
35#ifdef CONFIG_BTRFS_DEBUG
36	int seqnum;		/* sequence number this node is added */
37#endif
38
39	struct list_head list;  /* used to link node */
40	struct rb_node rb_node;	/* used to speed up search */
41};
42
43struct ulist {
44	/*
45	 * number of elements stored in list
46	 */
47	unsigned long nnodes;
48
49	struct list_head nodes;
50	struct rb_root root;
51};
52
53void ulist_init(struct ulist *ulist);
54void ulist_reinit(struct ulist *ulist);
55struct ulist *ulist_alloc(gfp_t gfp_mask);
56void ulist_free(struct ulist *ulist);
57int ulist_add(struct ulist *ulist, u64 val, u64 aux, gfp_t gfp_mask);
58int ulist_add_merge(struct ulist *ulist, u64 val, u64 aux,
59		    u64 *old_aux, gfp_t gfp_mask);
60
61/* just like ulist_add_merge() but take a pointer for the aux data */
62static inline int ulist_add_merge_ptr(struct ulist *ulist, u64 val, void *aux,
63				      void **old_aux, gfp_t gfp_mask)
64{
65#if BITS_PER_LONG == 32
66	u64 old64 = (uintptr_t)*old_aux;
67	int ret = ulist_add_merge(ulist, val, (uintptr_t)aux, &old64, gfp_mask);
68	*old_aux = (void *)((uintptr_t)old64);
69	return ret;
70#else
71	return ulist_add_merge(ulist, val, (u64)aux, (u64 *)old_aux, gfp_mask);
72#endif
73}
74
75struct ulist_node *ulist_next(struct ulist *ulist,
76			      struct ulist_iterator *uiter);
77
78#define ULIST_ITER_INIT(uiter) ((uiter)->cur_list = NULL)
79
80#endif
81