1/* SPDX-License-Identifier: GPL-2.0 */
 2/*
 3 *  include/linux/eventfd.h
 4 *
 5 *  Copyright (C) 2007  Davide Libenzi <davidel@xmailserver.org>
 6 *
 7 */
 8
 9#ifndef _LINUX_EVENTFD_H
10#define _LINUX_EVENTFD_H
11
12#include <linux/fcntl.h>
13#include <linux/wait.h>
14#include <linux/err.h>
15#include <linux/percpu-defs.h>
16#include <linux/percpu.h>
17
18/*
19 * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
20 * new flags, since they might collide with O_* ones. We want
21 * to re-use O_* flags that couldn't possibly have a meaning
22 * from eventfd, in order to leave a free define-space for
23 * shared O_* flags.
24 */
25#define EFD_SEMAPHORE (1 << 0)
26#define EFD_CLOEXEC O_CLOEXEC
27#define EFD_NONBLOCK O_NONBLOCK
28
29#define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
30#define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS | EFD_SEMAPHORE)
31
32struct eventfd_ctx;
33struct file;
34
35#ifdef CONFIG_EVENTFD
36
 
 
37void eventfd_ctx_put(struct eventfd_ctx *ctx);
38struct file *eventfd_fget(int fd);
39struct eventfd_ctx *eventfd_ctx_fdget(int fd);
40struct eventfd_ctx *eventfd_ctx_fileget(struct file *file);
41__u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n);
42int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *wait,
 
43				  __u64 *cnt);
44
45DECLARE_PER_CPU(int, eventfd_wake_count);
46
47static inline bool eventfd_signal_count(void)
48{
49	return this_cpu_read(eventfd_wake_count);
50}
51
52#else /* CONFIG_EVENTFD */
53
54/*
55 * Ugly ugly ugly error layer to support modules that uses eventfd but
56 * pretend to work in !CONFIG_EVENTFD configurations. Namely, AIO.
57 */
 
 
 
 
58
59static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd)
60{
61	return ERR_PTR(-ENOSYS);
62}
63
64static inline int eventfd_signal(struct eventfd_ctx *ctx, int n)
65{
66	return -ENOSYS;
67}
68
69static inline void eventfd_ctx_put(struct eventfd_ctx *ctx)
70{
71
72}
73
74static inline int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx,
75						wait_queue_entry_t *wait, __u64 *cnt)
76{
77	return -ENOSYS;
78}
79
80static inline bool eventfd_signal_count(void)
 
81{
82	return false;
83}
84
85#endif
86
87#endif /* _LINUX_EVENTFD_H */
88

 
 1/*
 2 *  include/linux/eventfd.h
 3 *
 4 *  Copyright (C) 2007  Davide Libenzi <davidel@xmailserver.org>
 5 *
 6 */
 7
 8#ifndef _LINUX_EVENTFD_H
 9#define _LINUX_EVENTFD_H
10
11#include <linux/fcntl.h>
12#include <linux/wait.h>
 
 
 
13
14/*
15 * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
16 * new flags, since they might collide with O_* ones. We want
17 * to re-use O_* flags that couldn't possibly have a meaning
18 * from eventfd, in order to leave a free define-space for
19 * shared O_* flags.
20 */
21#define EFD_SEMAPHORE (1 << 0)
22#define EFD_CLOEXEC O_CLOEXEC
23#define EFD_NONBLOCK O_NONBLOCK
24
25#define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
26#define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS | EFD_SEMAPHORE)
27
 
28struct file;
29
30#ifdef CONFIG_EVENTFD
31
32struct file *eventfd_file_create(unsigned int count, int flags);
33struct eventfd_ctx *eventfd_ctx_get(struct eventfd_ctx *ctx);
34void eventfd_ctx_put(struct eventfd_ctx *ctx);
35struct file *eventfd_fget(int fd);
36struct eventfd_ctx *eventfd_ctx_fdget(int fd);
37struct eventfd_ctx *eventfd_ctx_fileget(struct file *file);
38__u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n);
39ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait, __u64 *cnt);
40int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_t *wait,
41				  __u64 *cnt);
42
 
 
 
 
 
 
 
43#else /* CONFIG_EVENTFD */
44
45/*
46 * Ugly ugly ugly error layer to support modules that uses eventfd but
47 * pretend to work in !CONFIG_EVENTFD configurations. Namely, AIO.
48 */
49static inline struct file *eventfd_file_create(unsigned int count, int flags)
50{
51	return ERR_PTR(-ENOSYS);
52}
53
54static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd)
55{
56	return ERR_PTR(-ENOSYS);
57}
58
59static inline int eventfd_signal(struct eventfd_ctx *ctx, int n)
60{
61	return -ENOSYS;
62}
63
64static inline void eventfd_ctx_put(struct eventfd_ctx *ctx)
65{
66
67}
68
69static inline ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait,
70				       __u64 *cnt)
71{
72	return -ENOSYS;
73}
74
75static inline int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx,
76						wait_queue_t *wait, __u64 *cnt)
77{
78	return -ENOSYS;
79}
80
81#endif
82
83#endif /* _LINUX_EVENTFD_H */
84