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 29struct eventfd_ctx; 30struct file; 31 32#ifdef CONFIG_EVENTFD 33 34void eventfd_ctx_put(struct eventfd_ctx *ctx); 35struct file *eventfd_fget(int fd); 36struct eventfd_ctx *eventfd_ctx_fdget(int fd); 37struct eventfd_ctx *eventfd_ctx_fileget(struct file *file); 38void eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask); 39int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *wait, 40 __u64 *cnt); 41void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt); 42 43static 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 55static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd) 56{ 57 return ERR_PTR(-ENOSYS); 58} 59 60static inline void eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask) 61{ 62} 63 64static inline void eventfd_ctx_put(struct eventfd_ctx *ctx) 65{ 66 67} 68 69static 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 75static inline bool eventfd_signal_allowed(void) 76{ 77 return true; 78} 79 80static inline void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt) 81{ 82 83} 84 85#endif 86 87static inline void eventfd_signal(struct eventfd_ctx *ctx) 88{ 89 eventfd_signal_mask(ctx, 0); 90} 91 92#endif /* _LINUX_EVENTFD_H */ 93 94