[deliverable/linux.git] / include / linux / eventfd.h

/*
 *  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 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_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 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_t *wait, __u64 *cnt)
{
	return -ENOSYS;
}

#endif

#endif /* _LINUX_EVENTFD_H */
Commit	Line	Data
e1ad7468 DL	1	/*
	2	* include/linux/eventfd.h
	3	*
	4	* Copyright (C) 2007 Davide Libenzi <davidel@xmailserver.org>
	5	*
	6	*/
	7
	8	#ifndef _LINUX_EVENTFD_H
	9	#define _LINUX_EVENTFD_H
	10
b087498e	11	#include <linux/fcntl.h>
cb289d62	12	#include <linux/wait.h>
b087498e	13
bcd0b235	14	/*
1d730c49	15	* CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
bcd0b235 DL	16	* new flags, since they might collide with O_* ones. We want
	17	* to re-use O_* flags that couldn't possibly have a meaning
	18	* from eventfd, in order to leave a free define-space for
	19	* shared O_* flags.
	20	*/
	21	#define EFD_SEMAPHORE (1 << 0)
b087498e	22	#define EFD_CLOEXEC O_CLOEXEC
e7d476df	23	#define EFD_NONBLOCK O_NONBLOCK
b087498e	24
bcd0b235 DL	25	#define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC \| O_NONBLOCK)
	26	#define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS \| EFD_SEMAPHORE)
	27
4e10f3c9 AV	28	struct file;
4e10f3c9 AV	29
13389010 DL	30	#ifdef CONFIG_EVENTFD
13389010 DL	31
562787a5	32	struct file *eventfd_file_create(unsigned int count, int flags);
13389010 DL	33	struct eventfd_ctx eventfd_ctx_get(struct eventfd_ctx ctx);
13389010 DL	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);
cb289d62 DL	39	ssize_t eventfd_ctx_read(struct eventfd_ctx ctx, int no_wait, __u64 cnt);
	40	int eventfd_ctx_remove_wait_queue(struct eventfd_ctx ctx, wait_queue_t wait,
	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 DL	49	static inline struct file *eventfd_file_create(unsigned int count, int flags)
	50	{
	51	return ERR_PTR(-ENOSYS);
	52	}
	53
13389010 DL	54	static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd)
	55	{
	56	return ERR_PTR(-ENOSYS);
	57	}
	58
	59	static inline int eventfd_signal(struct eventfd_ctx *ctx, int n)
	60	{
	61	return -ENOSYS;
	62	}
	63
	64	static inline void eventfd_ctx_put(struct eventfd_ctx *ctx)
	65	{
	66
	67	}
e1ad7468	68
cb289d62 DL	69	static inline ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait,
	70	__u64 *cnt)
	71	{
	72	return -ENOSYS;
	73	}
	74
	75	static inline int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx,
	76	wait_queue_t wait, __u64 cnt)
	77	{
	78	return -ENOSYS;
	79	}
	80
13389010	81	#endif
e1ad7468	82
e1ad7468 DL	83	#endif /* _LINUX_EVENTFD_H */
e1ad7468 DL	84