[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>
#include <linux/err.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>
fa3fc2ad	14	#include <linux/err.h>
b087498e	15
bcd0b235	16	/*
1d730c49	17	* CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
bcd0b235 DL	18	* new flags, since they might collide with O_* ones. We want
	19	* to re-use O_* flags that couldn't possibly have a meaning
	20	* from eventfd, in order to leave a free define-space for
	21	* shared O_* flags.
	22	*/
	23	#define EFD_SEMAPHORE (1 << 0)
b087498e	24	#define EFD_CLOEXEC O_CLOEXEC
e7d476df	25	#define EFD_NONBLOCK O_NONBLOCK
b087498e	26
bcd0b235 DL	27	#define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC \| O_NONBLOCK)
	28	#define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS \| EFD_SEMAPHORE)
	29
105f2b70	30	struct eventfd_ctx;
4e10f3c9 AV	31	struct file;
4e10f3c9 AV	32
13389010 DL	33	#ifdef CONFIG_EVENTFD
13389010 DL	34
13389010	35	void eventfd_ctx_put(struct eventfd_ctx *ctx);
e1ad7468	36	struct file *eventfd_fget(int fd);
13389010 DL	37	struct eventfd_ctx *eventfd_ctx_fdget(int fd);
13389010 DL	38	struct eventfd_ctx eventfd_ctx_fileget(struct file file);
ee62c6b2	39	__u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n);
ac6424b9	40	int eventfd_ctx_remove_wait_queue(struct eventfd_ctx ctx, wait_queue_entry_t wait,
cb289d62	41	__u64 *cnt);
e1ad7468 DL	42
	43	#else /* CONFIG_EVENTFD */
	44
13389010 DL	45	/*
	46	* Ugly ugly ugly error layer to support modules that uses eventfd but
	47	* pretend to work in !CONFIG_EVENTFD configurations. Namely, AIO.
	48	*/
562787a5	49
13389010 DL	50	static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd)
	51	{
	52	return ERR_PTR(-ENOSYS);
	53	}
	54
	55	static inline int eventfd_signal(struct eventfd_ctx *ctx, int n)
	56	{
	57	return -ENOSYS;
	58	}
	59
	60	static inline void eventfd_ctx_put(struct eventfd_ctx *ctx)
	61	{
	62
	63	}
e1ad7468	64
cb289d62	65	static inline int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx,
ac6424b9	66	wait_queue_entry_t wait, __u64 cnt)
cb289d62 DL	67	{
	68	return -ENOSYS;
	69	}
	70
13389010	71	#endif
e1ad7468	72
e1ad7468 DL	73	#endif /* _LINUX_EVENTFD_H */
e1ad7468 DL	74