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Davide Libenzie1ad7462007-05-10 22:23:19 -07001/*
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
Ulrich Drepperb087498e2008-07-23 21:29:25 -070011#include <linux/fcntl.h>
Davide Libenzi13389012009-06-30 11:41:11 -070012#include <linux/file.h>
Davide Libenzicb289d62010-01-13 09:34:36 -080013#include <linux/wait.h>
Ulrich Drepperb087498e2008-07-23 21:29:25 -070014
Davide Libenzibcd0b232009-03-31 15:24:18 -070015/*
Martin Sustrik1d730c42013-02-27 17:05:42 -080016 * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
Davide Libenzibcd0b232009-03-31 15:24:18 -070017 * new flags, since they might collide with O_* ones. We want
18 * to re-use O_* flags that couldn't possibly have a meaning
19 * from eventfd, in order to leave a free define-space for
20 * shared O_* flags.
21 */
22#define EFD_SEMAPHORE (1 << 0)
Ulrich Drepperb087498e2008-07-23 21:29:25 -070023#define EFD_CLOEXEC O_CLOEXEC
Ulrich Dreppere7d476d2008-07-23 21:29:38 -070024#define EFD_NONBLOCK O_NONBLOCK
Ulrich Drepperb087498e2008-07-23 21:29:25 -070025
Davide Libenzibcd0b232009-03-31 15:24:18 -070026#define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
27#define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS | EFD_SEMAPHORE)
28
Davide Libenzi13389012009-06-30 11:41:11 -070029#ifdef CONFIG_EVENTFD
30
Davide Libenzi562787a2009-09-22 16:43:57 -070031struct file *eventfd_file_create(unsigned int count, int flags);
Davide Libenzi13389012009-06-30 11:41:11 -070032struct eventfd_ctx *eventfd_ctx_get(struct eventfd_ctx *ctx);
33void eventfd_ctx_put(struct eventfd_ctx *ctx);
Davide Libenzie1ad7462007-05-10 22:23:19 -070034struct file *eventfd_fget(int fd);
Davide Libenzi13389012009-06-30 11:41:11 -070035struct eventfd_ctx *eventfd_ctx_fdget(int fd);
36struct eventfd_ctx *eventfd_ctx_fileget(struct file *file);
Sha Zhengjuee62c6b2012-05-31 16:26:41 -070037__u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n);
Davide Libenzicb289d62010-01-13 09:34:36 -080038ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait, __u64 *cnt);
39int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_t *wait,
40 __u64 *cnt);
Davide Libenzie1ad7462007-05-10 22:23:19 -070041
42#else /* CONFIG_EVENTFD */
43
Davide Libenzi13389012009-06-30 11:41:11 -070044/*
45 * Ugly ugly ugly error layer to support modules that uses eventfd but
46 * pretend to work in !CONFIG_EVENTFD configurations. Namely, AIO.
47 */
Davide Libenzi562787a2009-09-22 16:43:57 -070048static inline struct file *eventfd_file_create(unsigned int count, int flags)
49{
50 return ERR_PTR(-ENOSYS);
51}
52
Davide Libenzi13389012009-06-30 11:41:11 -070053static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd)
54{
55 return ERR_PTR(-ENOSYS);
56}
Davide Libenzie1ad7462007-05-10 22:23:19 -070057
Davide Libenzi13389012009-06-30 11:41:11 -070058static inline int eventfd_signal(struct eventfd_ctx *ctx, int n)
59{
60 return -ENOSYS;
61}
62
63static inline void eventfd_ctx_put(struct eventfd_ctx *ctx)
64{
65
66}
67
Davide Libenzicb289d62010-01-13 09:34:36 -080068static inline ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait,
69 __u64 *cnt)
70{
71 return -ENOSYS;
72}
73
74static inline int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx,
75 wait_queue_t *wait, __u64 *cnt)
76{
77 return -ENOSYS;
78}
79
Davide Libenzi13389012009-06-30 11:41:11 -070080#endif
Davide Libenzie1ad7462007-05-10 22:23:19 -070081
Davide Libenzie1ad7462007-05-10 22:23:19 -070082#endif /* _LINUX_EVENTFD_H */
83