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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/file.h>
13
14/*
15 * CAREFUL: Check include/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
28#ifdef CONFIG_EVENTFD
29
30struct eventfd_ctx *eventfd_ctx_get(struct eventfd_ctx *ctx);
31void eventfd_ctx_put(struct eventfd_ctx *ctx);
32struct file *eventfd_fget(int fd);
33struct eventfd_ctx *eventfd_ctx_fdget(int fd);
34struct eventfd_ctx *eventfd_ctx_fileget(struct file *file);
35int eventfd_signal(struct eventfd_ctx *ctx, int n);
36
37#else /* CONFIG_EVENTFD */
38
39/*
40 * Ugly ugly ugly error layer to support modules that uses eventfd but
41 * pretend to work in !CONFIG_EVENTFD configurations. Namely, AIO.
42 */
43static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd)
44{
45 return ERR_PTR(-ENOSYS);
46}
47
48static inline int eventfd_signal(struct eventfd_ctx *ctx, int n)
49{
50 return -ENOSYS;
51}
52
53static inline void eventfd_ctx_put(struct eventfd_ctx *ctx)
54{
55
56}
57
58#endif
59
60#endif /* _LINUX_EVENTFD_H */
61