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 11#include <linux/fcntl.h> 12#include <linux/file.h> 13#include <linux/wait.h> 14 15/* 16 * CAREFUL: Check include/asm-generic/fcntl.h when defining 17 * new flags, since they might collide with O_* ones. We want 18 * to re-use O_* flags that couldn't possibly have a meaning 19 * from eventfd, in order to leave a free define-space for 20 * shared O_* flags. 21 */ 22#define EFD_SEMAPHORE (1 << 0) 23#define EFD_CLOEXEC O_CLOEXEC 24#define EFD_NONBLOCK O_NONBLOCK 25 26#define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK) 27#define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS | EFD_SEMAPHORE) 28 29#ifdef CONFIG_EVENTFD 30 31struct file *eventfd_file_create(unsigned int count, int flags); 32struct eventfd_ctx *eventfd_ctx_get(struct eventfd_ctx *ctx); 33void eventfd_ctx_put(struct eventfd_ctx *ctx); 34struct file *eventfd_fget(int fd); 35struct eventfd_ctx *eventfd_ctx_fdget(int fd); 36struct eventfd_ctx *eventfd_ctx_fileget(struct file *file); 37int eventfd_signal(struct eventfd_ctx *ctx, int n); 38ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait, __u64 *cnt); 39int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_t *wait, 40 __u64 *cnt); 41 42#else /* CONFIG_EVENTFD */ 43 44/* 45 * Ugly ugly ugly error layer to support modules that uses eventfd but 46 * pretend to work in !CONFIG_EVENTFD configurations. Namely, AIO. 47 */ 48static inline struct file *eventfd_file_create(unsigned int count, int flags) 49{ 50 return ERR_PTR(-ENOSYS); 51} 52 53static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd) 54{ 55 return ERR_PTR(-ENOSYS); 56} 57 58static inline int eventfd_signal(struct eventfd_ctx *ctx, int n) 59{ 60 return -ENOSYS; 61} 62 63static inline void eventfd_ctx_put(struct eventfd_ctx *ctx) 64{ 65 66} 67 68static inline ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait, 69 __u64 *cnt) 70{ 71 return -ENOSYS; 72} 73 74static inline int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, 75 wait_queue_t *wait, __u64 *cnt) 76{ 77 return -ENOSYS; 78} 79 80#endif 81 82#endif /* _LINUX_EVENTFD_H */ 83 84