xref: /openbmc/linux/fs/btrfs/ulist.h (revision feac8c8b)
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  */
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 };
45 
46 void ulist_init(struct ulist *ulist);
47 void ulist_release(struct ulist *ulist);
48 void ulist_reinit(struct ulist *ulist);
49 struct ulist *ulist_alloc(gfp_t gfp_mask);
50 void ulist_free(struct ulist *ulist);
51 int ulist_add(struct ulist *ulist, u64 val, u64 aux, gfp_t gfp_mask);
52 int ulist_add_merge(struct ulist *ulist, u64 val, u64 aux,
53 		    u64 *old_aux, gfp_t gfp_mask);
54 int ulist_del(struct ulist *ulist, u64 val, u64 aux);
55 
56 /* just like ulist_add_merge() but take a pointer for the aux data */
57 static inline int ulist_add_merge_ptr(struct ulist *ulist, u64 val, void *aux,
58 				      void **old_aux, gfp_t gfp_mask)
59 {
60 #if BITS_PER_LONG == 32
61 	u64 old64 = (uintptr_t)*old_aux;
62 	int ret = ulist_add_merge(ulist, val, (uintptr_t)aux, &old64, gfp_mask);
63 	*old_aux = (void *)((uintptr_t)old64);
64 	return ret;
65 #else
66 	return ulist_add_merge(ulist, val, (u64)aux, (u64 *)old_aux, gfp_mask);
67 #endif
68 }
69 
70 struct ulist_node *ulist_next(struct ulist *ulist,
71 			      struct ulist_iterator *uiter);
72 
73 #define ULIST_ITER_INIT(uiter) ((uiter)->cur_list = NULL)
74 
75 #endif
76