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