1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  *	klist.h - Some generic list helpers, extending struct list_head a bit.
4  *
5  *	Implementations are found in lib/klist.c
6  *
7  *	Copyright (C) 2005 Patrick Mochel
8  */
9 
10 #ifndef _LINUX_KLIST_H
11 #define _LINUX_KLIST_H
12 
13 #include <linux/spinlock.h>
14 #include <linux/kref.h>
15 #include <linux/list.h>
16 
17 struct klist_node;
18 struct klist {
19 	spinlock_t		k_lock;
20 	struct list_head	k_list;
21 	void			(*get)(struct klist_node *);
22 	void			(*put)(struct klist_node *);
23 } __attribute__ ((aligned (sizeof(void *))));
24 
25 #define KLIST_INIT(_name, _get, _put)					\
26 	{ .k_lock	= __SPIN_LOCK_UNLOCKED(_name.k_lock),		\
27 	  .k_list	= LIST_HEAD_INIT(_name.k_list),			\
28 	  .get		= _get,						\
29 	  .put		= _put, }
30 
31 #define DEFINE_KLIST(_name, _get, _put)					\
32 	struct klist _name = KLIST_INIT(_name, _get, _put)
33 
34 extern void klist_init(struct klist *k, void (*get)(struct klist_node *),
35 		       void (*put)(struct klist_node *));
36 
37 struct klist_node {
38 	void			*n_klist;	/* never access directly */
39 	struct list_head	n_node;
40 	struct kref		n_ref;
41 };
42 
43 extern void klist_add_tail(struct klist_node *n, struct klist *k);
44 extern void klist_add_head(struct klist_node *n, struct klist *k);
45 extern void klist_add_behind(struct klist_node *n, struct klist_node *pos);
46 extern void klist_add_before(struct klist_node *n, struct klist_node *pos);
47 
48 extern void klist_del(struct klist_node *n);
49 extern void klist_remove(struct klist_node *n);
50 
51 extern int klist_node_attached(struct klist_node *n);
52 
53 
54 struct klist_iter {
55 	struct klist		*i_klist;
56 	struct klist_node	*i_cur;
57 };
58 
59 
60 extern void klist_iter_init(struct klist *k, struct klist_iter *i);
61 extern void klist_iter_init_node(struct klist *k, struct klist_iter *i,
62 				 struct klist_node *n);
63 extern void klist_iter_exit(struct klist_iter *i);
64 extern struct klist_node *klist_prev(struct klist_iter *i);
65 extern struct klist_node *klist_next(struct klist_iter *i);
66 
67 #endif
68