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-rw-r--r--include/linux/notifier.h96
1 files changed, 89 insertions, 7 deletions
diff --git a/include/linux/notifier.h b/include/linux/notifier.h
index 5937dd6053c3..51dbab9710c7 100644
--- a/include/linux/notifier.h
+++ b/include/linux/notifier.h
@@ -10,25 +10,107 @@
10#ifndef _LINUX_NOTIFIER_H 10#ifndef _LINUX_NOTIFIER_H
11#define _LINUX_NOTIFIER_H 11#define _LINUX_NOTIFIER_H
12#include <linux/errno.h> 12#include <linux/errno.h>
13#include <linux/mutex.h>
14#include <linux/rwsem.h>
13 15
14struct notifier_block 16/*
15{ 17 * Notifier chains are of three types:
16 int (*notifier_call)(struct notifier_block *self, unsigned long, void *); 18 *
19 * Atomic notifier chains: Chain callbacks run in interrupt/atomic
20 * context. Callouts are not allowed to block.
21 * Blocking notifier chains: Chain callbacks run in process context.
22 * Callouts are allowed to block.
23 * Raw notifier chains: There are no restrictions on callbacks,
24 * registration, or unregistration. All locking and protection
25 * must be provided by the caller.
26 *
27 * atomic_notifier_chain_register() may be called from an atomic context,
28 * but blocking_notifier_chain_register() must be called from a process
29 * context. Ditto for the corresponding _unregister() routines.
30 *
31 * atomic_notifier_chain_unregister() and blocking_notifier_chain_unregister()
32 * _must not_ be called from within the call chain.
33 */
34
35struct notifier_block {
36 int (*notifier_call)(struct notifier_block *, unsigned long, void *);
17 struct notifier_block *next; 37 struct notifier_block *next;
18 int priority; 38 int priority;
19}; 39};
20 40
41struct atomic_notifier_head {
42 spinlock_t lock;
43 struct notifier_block *head;
44};
45
46struct blocking_notifier_head {
47 struct rw_semaphore rwsem;
48 struct notifier_block *head;
49};
50
51struct raw_notifier_head {
52 struct notifier_block *head;
53};
54
55#define ATOMIC_INIT_NOTIFIER_HEAD(name) do { \
56 spin_lock_init(&(name)->lock); \
57 (name)->head = NULL; \
58 } while (0)
59#define BLOCKING_INIT_NOTIFIER_HEAD(name) do { \
60 init_rwsem(&(name)->rwsem); \
61 (name)->head = NULL; \
62 } while (0)
63#define RAW_INIT_NOTIFIER_HEAD(name) do { \
64 (name)->head = NULL; \
65 } while (0)
66
67#define ATOMIC_NOTIFIER_INIT(name) { \
68 .lock = SPIN_LOCK_UNLOCKED, \
69 .head = NULL }
70#define BLOCKING_NOTIFIER_INIT(name) { \
71 .rwsem = __RWSEM_INITIALIZER((name).rwsem), \
72 .head = NULL }
73#define RAW_NOTIFIER_INIT(name) { \
74 .head = NULL }
75
76#define ATOMIC_NOTIFIER_HEAD(name) \
77 struct atomic_notifier_head name = \
78 ATOMIC_NOTIFIER_INIT(name)
79#define BLOCKING_NOTIFIER_HEAD(name) \
80 struct blocking_notifier_head name = \
81 BLOCKING_NOTIFIER_INIT(name)
82#define RAW_NOTIFIER_HEAD(name) \
83 struct raw_notifier_head name = \
84 RAW_NOTIFIER_INIT(name)
21 85
22#ifdef __KERNEL__ 86#ifdef __KERNEL__
23 87
24extern int notifier_chain_register(struct notifier_block **list, struct notifier_block *n); 88extern int atomic_notifier_chain_register(struct atomic_notifier_head *,
25extern int notifier_chain_unregister(struct notifier_block **nl, struct notifier_block *n); 89 struct notifier_block *);
26extern int notifier_call_chain(struct notifier_block **n, unsigned long val, void *v); 90extern int blocking_notifier_chain_register(struct blocking_notifier_head *,
91 struct notifier_block *);
92extern int raw_notifier_chain_register(struct raw_notifier_head *,
93 struct notifier_block *);
94
95extern int atomic_notifier_chain_unregister(struct atomic_notifier_head *,
96 struct notifier_block *);
97extern int blocking_notifier_chain_unregister(struct blocking_notifier_head *,
98 struct notifier_block *);
99extern int raw_notifier_chain_unregister(struct raw_notifier_head *,
100 struct notifier_block *);
101
102extern int atomic_notifier_call_chain(struct atomic_notifier_head *,
103 unsigned long val, void *v);
104extern int blocking_notifier_call_chain(struct blocking_notifier_head *,
105 unsigned long val, void *v);
106extern int raw_notifier_call_chain(struct raw_notifier_head *,
107 unsigned long val, void *v);
27 108
28#define NOTIFY_DONE 0x0000 /* Don't care */ 109#define NOTIFY_DONE 0x0000 /* Don't care */
29#define NOTIFY_OK 0x0001 /* Suits me */ 110#define NOTIFY_OK 0x0001 /* Suits me */
30#define NOTIFY_STOP_MASK 0x8000 /* Don't call further */ 111#define NOTIFY_STOP_MASK 0x8000 /* Don't call further */
31#define NOTIFY_BAD (NOTIFY_STOP_MASK|0x0002) /* Bad/Veto action */ 112#define NOTIFY_BAD (NOTIFY_STOP_MASK|0x0002)
113 /* Bad/Veto action */
32/* 114/*
33 * Clean way to return from the notifier and stop further calls. 115 * Clean way to return from the notifier and stop further calls.
34 */ 116 */
generated by cgit v1.2.2 (git 2.25.0) at 2024-09-30 14:30:25 -0400