Merge tag 'kvm-s390-next-5.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-block.git] / include / linux / eventfd.h
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b2441318 1/* SPDX-License-Identifier: GPL-2.0 */
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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
b087498e 12#include <linux/fcntl.h>
cb289d62 13#include <linux/wait.h>
fa3fc2ad 14#include <linux/err.h>
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15#include <linux/percpu-defs.h>
16#include <linux/percpu.h>
b542e383 17#include <linux/sched.h>
b087498e 18
bcd0b235 19/*
1d730c49 20 * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
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21 * new flags, since they might collide with O_* ones. We want
22 * to re-use O_* flags that couldn't possibly have a meaning
23 * from eventfd, in order to leave a free define-space for
24 * shared O_* flags.
25 */
26#define EFD_SEMAPHORE (1 << 0)
b087498e 27#define EFD_CLOEXEC O_CLOEXEC
e7d476df 28#define EFD_NONBLOCK O_NONBLOCK
b087498e 29
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30#define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
31#define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS | EFD_SEMAPHORE)
32
105f2b70 33struct eventfd_ctx;
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34struct file;
35
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36#ifdef CONFIG_EVENTFD
37
13389010 38void eventfd_ctx_put(struct eventfd_ctx *ctx);
e1ad7468 39struct file *eventfd_fget(int fd);
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40struct eventfd_ctx *eventfd_ctx_fdget(int fd);
41struct eventfd_ctx *eventfd_ctx_fileget(struct file *file);
ee62c6b2 42__u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n);
ac6424b9 43int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *wait,
cb289d62 44 __u64 *cnt);
28f13267 45void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt);
e1ad7468 46
b542e383 47static inline bool eventfd_signal_allowed(void)
b5e683d5 48{
b542e383 49 return !current->in_eventfd_signal;
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50}
51
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52#else /* CONFIG_EVENTFD */
53
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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 */
562787a5 58
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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}
e1ad7468 73
cb289d62 74static inline int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx,
ac6424b9 75 wait_queue_entry_t *wait, __u64 *cnt)
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76{
77 return -ENOSYS;
78}
79
b542e383 80static inline bool eventfd_signal_allowed(void)
b5e683d5 81{
b542e383 82 return true;
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83}
84
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85static inline void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt)
86{
87
88}
89
13389010 90#endif
e1ad7468 91
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92#endif /* _LINUX_EVENTFD_H */
93