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/* SPDX-License-Identifier: GPL-2.0 */
/*
* include/linux/eventfd.h
*
* Copyright (C) 2007 Davide Libenzi <davidel@xmailserver.org>
*
*/
#ifndef _LINUX_EVENTFD_H
#define _LINUX_EVENTFD_H
#include <linux/fcntl.h>
#include <linux/wait.h>
#include <linux/err.h>
#include <linux/percpu-defs.h>
#include <linux/percpu.h>
/*
* CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
* new flags, since they might collide with O_* ones. We want
* to re-use O_* flags that couldn't possibly have a meaning
* from eventfd, in order to leave a free define-space for
* shared O_* flags.
*/
#define EFD_SEMAPHORE (1 << 0)
#define EFD_CLOEXEC O_CLOEXEC
#define EFD_NONBLOCK O_NONBLOCK
#define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
#define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS | EFD_SEMAPHORE)
struct eventfd_ctx;
struct file;
#ifdef CONFIG_EVENTFD
void eventfd_ctx_put(struct eventfd_ctx *ctx);
struct file *eventfd_fget(int fd);
struct eventfd_ctx *eventfd_ctx_fdget(int fd);
struct eventfd_ctx *eventfd_ctx_fileget(struct file *file);
__u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n);
int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *wait,
__u64 *cnt);
void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt);
DECLARE_PER_CPU(int, eventfd_wake_count);
static inline bool eventfd_signal_count(void)
{
return this_cpu_read(eventfd_wake_count);
}
#else /* CONFIG_EVENTFD */
/*
* Ugly ugly ugly error layer to support modules that uses eventfd but
* pretend to work in !CONFIG_EVENTFD configurations. Namely, AIO.
*/
static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd)
{
return ERR_PTR(-ENOSYS);
}
static inline int eventfd_signal(struct eventfd_ctx *ctx, int n)
{
return -ENOSYS;
}
static inline void eventfd_ctx_put(struct eventfd_ctx *ctx)
{
}
static inline int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx,
wait_queue_entry_t *wait, __u64 *cnt)
{
return -ENOSYS;
}
static inline bool eventfd_signal_count(void)
{
return false;
}
static inline void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt)
{
}
#endif
#endif /* _LINUX_EVENTFD_H */
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