[linux-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>
#include <linux/percpu-defs.h>
#include <linux/percpu.h>
#include <linux/sched.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);
__u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, unsigned mask);
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);

static inline bool eventfd_signal_allowed(void)
{
	return !current->in_eventfd;
}

#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, __u64 n)
{
	return -ENOSYS;
}

static inline int eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n,
				      unsigned mask)
{
	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_allowed(void)
{
	return true;
}

static inline void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt)
{

}

#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>
b5e683d5 JA	15	#include <linux/percpu-defs.h>
b5e683d5 JA	16	#include <linux/percpu.h>
b542e383	17	#include <linux/sched.h>
b087498e	18
bcd0b235	19	/*
1d730c49	20	* CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
bcd0b235 DL	21	* new flags, since they might collide with O_* ones. We want
	22	* to re-use O_* flags that couldn't possibly have a meaning
	23	* from eventfd, in order to leave a free define-space for
	24	* shared O_* flags.
	25	*/
	26	#define EFD_SEMAPHORE (1 << 0)
b087498e	27	#define EFD_CLOEXEC O_CLOEXEC
e7d476df	28	#define EFD_NONBLOCK O_NONBLOCK
b087498e	29
bcd0b235 DL	30	#define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC \| O_NONBLOCK)
	31	#define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS \| EFD_SEMAPHORE)
	32
105f2b70	33	struct eventfd_ctx;
4e10f3c9 AV	34	struct file;
4e10f3c9 AV	35
13389010 DL	36	#ifdef CONFIG_EVENTFD
13389010 DL	37
13389010	38	void eventfd_ctx_put(struct eventfd_ctx *ctx);
e1ad7468	39	struct file *eventfd_fget(int fd);
13389010 DL	40	struct eventfd_ctx *eventfd_ctx_fdget(int fd);
13389010 DL	41	struct eventfd_ctx eventfd_ctx_fileget(struct file file);
ee62c6b2	42	__u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n);
03e02acd	43	__u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, unsigned mask);
ac6424b9	44	int eventfd_ctx_remove_wait_queue(struct eventfd_ctx ctx, wait_queue_entry_t wait,
cb289d62	45	__u64 *cnt);
28f13267	46	void eventfd_ctx_do_read(struct eventfd_ctx ctx, __u64 cnt);
e1ad7468	47
b542e383	48	static inline bool eventfd_signal_allowed(void)
b5e683d5	49	{
9f0deaa1	50	return !current->in_eventfd;
b5e683d5 JA	51	}
b5e683d5 JA	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	59
13389010 DL	60	static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd)
	61	{
	62	return ERR_PTR(-ENOSYS);
	63	}
	64
fd4e60bf	65	static inline int eventfd_signal(struct eventfd_ctx *ctx, __u64 n)
13389010 DL	66	{
	67	return -ENOSYS;
	68	}
	69
03e02acd JA	70	static inline int eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n,
	71	unsigned mask)
	72	{
	73	return -ENOSYS;
	74	}
	75
13389010 DL	76	static inline void eventfd_ctx_put(struct eventfd_ctx *ctx)
	77	{
	78
	79	}
e1ad7468	80
cb289d62	81	static inline int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx,
ac6424b9	82	wait_queue_entry_t wait, __u64 cnt)
cb289d62 DL	83	{
	84	return -ENOSYS;
	85	}
	86
b542e383	87	static inline bool eventfd_signal_allowed(void)
b5e683d5	88	{
b542e383	89	return true;
b5e683d5 JA	90	}
b5e683d5 JA	91
28f13267 DW	92	static inline void eventfd_ctx_do_read(struct eventfd_ctx ctx, __u64 cnt)
	93	{
	94
	95	}
	96
13389010	97	#endif
e1ad7468	98
e1ad7468 DL	99	#endif /* _LINUX_EVENTFD_H */
e1ad7468 DL	100