[mirror_ubuntu-bionic-kernel.git] / include / linux / eventfd.h

/* 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/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 file;

#ifdef CONFIG_EVENTFD

struct file *eventfd_file_create(unsigned int count, int flags);
struct eventfd_ctx *eventfd_ctx_get(struct eventfd_ctx *ctx);
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);
ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait, __u64 *cnt);
int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *wait,
				  __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 file *eventfd_file_create(unsigned int count, int flags)
{
	return ERR_PTR(-ENOSYS);
}

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 ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait,
				       __u64 *cnt)
{
	return -ENOSYS;
}

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;
}

#endif

#endif /* _LINUX_EVENTFD_H */
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
e1ad7468 DL	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>
fde5fd9c JA	14	#include <linux/percpu-defs.h>
fde5fd9c JA	15	#include <linux/percpu.h>
b087498e	16
bcd0b235	17	/*
1d730c49	18	* CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
bcd0b235 DL	19	* new flags, since they might collide with O_* ones. We want
	20	* to re-use O_* flags that couldn't possibly have a meaning
	21	* from eventfd, in order to leave a free define-space for
	22	* shared O_* flags.
	23	*/
	24	#define EFD_SEMAPHORE (1 << 0)
b087498e	25	#define EFD_CLOEXEC O_CLOEXEC
e7d476df	26	#define EFD_NONBLOCK O_NONBLOCK
b087498e	27
bcd0b235 DL	28	#define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC \| O_NONBLOCK)
	29	#define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS \| EFD_SEMAPHORE)
	30
4e10f3c9 AV	31	struct file;
4e10f3c9 AV	32
13389010 DL	33	#ifdef CONFIG_EVENTFD
13389010 DL	34
562787a5	35	struct file *eventfd_file_create(unsigned int count, int flags);
13389010 DL	36	struct eventfd_ctx eventfd_ctx_get(struct eventfd_ctx ctx);
13389010 DL	37	void eventfd_ctx_put(struct eventfd_ctx *ctx);
e1ad7468	38	struct file *eventfd_fget(int fd);
13389010 DL	39	struct eventfd_ctx *eventfd_ctx_fdget(int fd);
13389010 DL	40	struct eventfd_ctx eventfd_ctx_fileget(struct file file);
ee62c6b2	41	__u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n);
cb289d62	42	ssize_t eventfd_ctx_read(struct eventfd_ctx ctx, int no_wait, __u64 cnt);
ac6424b9	43	int eventfd_ctx_remove_wait_queue(struct eventfd_ctx ctx, wait_queue_entry_t wait,
cb289d62	44	__u64 *cnt);
e1ad7468	45
fde5fd9c JA	46	DECLARE_PER_CPU(int, eventfd_wake_count);
	47
	48	static inline bool eventfd_signal_count(void)
	49	{
	50	return this_cpu_read(eventfd_wake_count);
	51	}
	52
e1ad7468 DL	53	#else /* CONFIG_EVENTFD */
e1ad7468 DL	54
13389010 DL	55	/*
	56	* Ugly ugly ugly error layer to support modules that uses eventfd but
	57	* pretend to work in !CONFIG_EVENTFD configurations. Namely, AIO.
	58	*/
562787a5 DL	59	static inline struct file *eventfd_file_create(unsigned int count, int flags)
	60	{
	61	return ERR_PTR(-ENOSYS);
	62	}
	63
13389010 DL	64	static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd)
	65	{
	66	return ERR_PTR(-ENOSYS);
	67	}
	68
	69	static inline int eventfd_signal(struct eventfd_ctx *ctx, int n)
	70	{
	71	return -ENOSYS;
	72	}
	73
	74	static inline void eventfd_ctx_put(struct eventfd_ctx *ctx)
	75	{
	76
	77	}
e1ad7468	78
cb289d62 DL	79	static inline ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait,
	80	__u64 *cnt)
	81	{
	82	return -ENOSYS;
	83	}
	84
	85	static inline int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx,
ac6424b9	86	wait_queue_entry_t wait, __u64 cnt)
cb289d62 DL	87	{
	88	return -ENOSYS;
	89	}
	90
fde5fd9c JA	91	static inline bool eventfd_signal_count(void)
	92	{
	93	return false;
	94	}
	95
13389010	96	#endif
e1ad7468	97
e1ad7468 DL	98	#endif /* _LINUX_EVENTFD_H */
e1ad7468 DL	99