[linux-2.6-block.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>

/*
 * 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);

#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;
}

#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>
b087498e	14
bcd0b235	15	/*
1d730c49	16	* CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
bcd0b235 DL	17	* 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)
b087498e	23	#define EFD_CLOEXEC O_CLOEXEC
e7d476df	24	#define EFD_NONBLOCK O_NONBLOCK
b087498e	25
bcd0b235 DL	26	#define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC \| O_NONBLOCK)
	27	#define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS \| EFD_SEMAPHORE)
	28
105f2b70	29	struct eventfd_ctx;
4e10f3c9 AV	30	struct file;
4e10f3c9 AV	31
13389010 DL	32	#ifdef CONFIG_EVENTFD
13389010 DL	33
13389010	34	void eventfd_ctx_put(struct eventfd_ctx *ctx);
e1ad7468	35	struct file *eventfd_fget(int fd);
13389010 DL	36	struct eventfd_ctx *eventfd_ctx_fdget(int fd);
13389010 DL	37	struct eventfd_ctx eventfd_ctx_fileget(struct file file);
ee62c6b2	38	__u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n);
ac6424b9	39	int eventfd_ctx_remove_wait_queue(struct eventfd_ctx ctx, wait_queue_entry_t wait,
cb289d62	40	__u64 *cnt);
e1ad7468 DL	41
	42	#else /* CONFIG_EVENTFD */
	43
13389010 DL	44	/*
	45	* Ugly ugly ugly error layer to support modules that uses eventfd but
	46	* pretend to work in !CONFIG_EVENTFD configurations. Namely, AIO.
	47	*/
562787a5	48
13389010 DL	49	static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd)
	50	{
	51	return ERR_PTR(-ENOSYS);
	52	}
	53
	54	static inline int eventfd_signal(struct eventfd_ctx *ctx, int n)
	55	{
	56	return -ENOSYS;
	57	}
	58
	59	static inline void eventfd_ctx_put(struct eventfd_ctx *ctx)
	60	{
	61
	62	}
e1ad7468	63
cb289d62	64	static inline int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx,
ac6424b9	65	wait_queue_entry_t wait, __u64 cnt)
cb289d62 DL	66	{
	67	return -ENOSYS;
	68	}
	69
13389010	70	#endif
e1ad7468	71
e1ad7468 DL	72	#endif /* _LINUX_EVENTFD_H */
e1ad7468 DL	73