[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/wait.h>
#include <linux/err.h>
#include <linux/percpu-defs.h>
#include <linux/percpu.h>
#include <linux/sched.h>
#include <uapi/linux/eventfd.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_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);
void eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t 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 void eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask)
{
}

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

static inline void eventfd_signal(struct eventfd_ctx *ctx)
{
	eventfd_signal_mask(ctx, 0);
}

#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
cb289d62	12	#include <linux/wait.h>
fa3fc2ad	13	#include <linux/err.h>
b5e683d5 JA	14	#include <linux/percpu-defs.h>
b5e683d5 JA	15	#include <linux/percpu.h>
b542e383	16	#include <linux/sched.h>
2d8c9dcf	17	#include <uapi/linux/eventfd.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	*/
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);
b7638ad0	38	void eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask);
ac6424b9	39	int eventfd_ctx_remove_wait_queue(struct eventfd_ctx ctx, wait_queue_entry_t wait,
cb289d62	40	__u64 *cnt);
28f13267	41	void eventfd_ctx_do_read(struct eventfd_ctx ctx, __u64 cnt);
e1ad7468	42
b542e383	43	static inline bool eventfd_signal_allowed(void)
b5e683d5	44	{
9f0deaa1	45	return !current->in_eventfd;
b5e683d5 JA	46	}
b5e683d5 JA	47
e1ad7468 DL	48	#else /* CONFIG_EVENTFD */
e1ad7468 DL	49
13389010 DL	50	/*
	51	* Ugly ugly ugly error layer to support modules that uses eventfd but
	52	* pretend to work in !CONFIG_EVENTFD configurations. Namely, AIO.
	53	*/
562787a5	54
13389010 DL	55	static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd)
	56	{
	57	return ERR_PTR(-ENOSYS);
	58	}
	59
b7638ad0	60	static inline void eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask)
13389010	61	{
03e02acd JA	62	}
03e02acd JA	63
13389010 DL	64	static inline void eventfd_ctx_put(struct eventfd_ctx *ctx)
	65	{
	66
	67	}
e1ad7468	68
cb289d62	69	static inline int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx,
ac6424b9	70	wait_queue_entry_t wait, __u64 cnt)
cb289d62 DL	71	{
	72	return -ENOSYS;
	73	}
	74
b542e383	75	static inline bool eventfd_signal_allowed(void)
b5e683d5	76	{
b542e383	77	return true;
b5e683d5 JA	78	}
b5e683d5 JA	79
28f13267 DW	80	static inline void eventfd_ctx_do_read(struct eventfd_ctx ctx, __u64 cnt)
	81	{
	82
	83	}
	84
13389010	85	#endif
e1ad7468	86
b7638ad0 CB	87	static inline void eventfd_signal(struct eventfd_ctx *ctx)
	88	{
	89	eventfd_signal_mask(ctx, 0);
	90	}
	91
e1ad7468 DL	92	#endif /* _LINUX_EVENTFD_H */
e1ad7468 DL	93