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 */
21 struct ulist_iterator {
22 struct list_head *cur_list; /* hint to start search */
23 };
24
25 /*
26 * element of the list
27 */
28 struct 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
36 struct 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
47 void ulist_init(struct ulist *ulist);
48 void ulist_release(struct ulist *ulist);
49 void ulist_reinit(struct ulist *ulist);
50 struct ulist *ulist_alloc(gfp_t gfp_mask);
51 void ulist_prealloc(struct ulist *ulist, gfp_t mask);
52 void ulist_free(struct ulist *ulist);
53 int ulist_add(struct ulist *ulist, u64 val, u64 aux, gfp_t gfp_mask);
54 int ulist_add_merge(struct ulist *ulist, u64 val, u64 aux,
55 u64 *old_aux, gfp_t gfp_mask);
56 int ulist_del(struct ulist *ulist, u64 val, u64 aux);
57
58 /* just like ulist_add_merge() but take a pointer for the aux data */
59 static 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
72 struct 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
78
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