[thirdparty/linux.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
	1	/* SPDX-License-Identifier: GPL-2.0 */
	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
	12	#include <linux/wait.h>
	13	#include <linux/err.h>
	14	#include <linux/percpu-defs.h>
	15	#include <linux/percpu.h>
	16	#include <linux/sched.h>
	17	#include <uapi/linux/eventfd.h>
	18
	19	/*
	20	* CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
	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_SHARED_FCNTL_FLAGS (O_CLOEXEC \| O_NONBLOCK)
	27	#define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS \| EFD_SEMAPHORE)
	28
	29	struct eventfd_ctx;
	30	struct file;
	31
	32	#ifdef CONFIG_EVENTFD
	33
	34	void eventfd_ctx_put(struct eventfd_ctx *ctx);
	35	struct file *eventfd_fget(int fd);
	36	struct eventfd_ctx *eventfd_ctx_fdget(int fd);
	37	struct eventfd_ctx eventfd_ctx_fileget(struct file file);
	38	void eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask);
	39	int eventfd_ctx_remove_wait_queue(struct eventfd_ctx ctx, wait_queue_entry_t wait,
	40	__u64 *cnt);
	41	void eventfd_ctx_do_read(struct eventfd_ctx ctx, __u64 cnt);
	42
	43	static inline bool eventfd_signal_allowed(void)
	44	{
	45	return !current->in_eventfd;
	46	}
	47
	48	#else /* CONFIG_EVENTFD */
	49
	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	*/
	54
	55	static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd)
	56	{
	57	return ERR_PTR(-ENOSYS);
	58	}
	59
	60	static inline void eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask)
	61	{
	62	}
	63
	64	static inline void eventfd_ctx_put(struct eventfd_ctx *ctx)
	65	{
	66
	67	}
	68
	69	static inline int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx,
	70	wait_queue_entry_t wait, __u64 cnt)
	71	{
	72	return -ENOSYS;
	73	}
	74
	75	static inline bool eventfd_signal_allowed(void)
	76	{
	77	return true;
	78	}
	79
	80	static inline void eventfd_ctx_do_read(struct eventfd_ctx ctx, __u64 cnt)
	81	{
	82
	83	}
	84
	85	#endif
	86
	87	static inline void eventfd_signal(struct eventfd_ctx *ctx)
	88	{
	89	eventfd_signal_mask(ctx, 0);
	90	}
	91
	92	#endif /* _LINUX_EVENTFD_H */
	93