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/wait.h> 13 14/* 15 * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining 16 * new flags, since they might collide with O_* ones. We want 17 * to re-use O_* flags that couldn't possibly have a meaning 18 * from eventfd, in order to leave a free define-space for 19 * shared O_* flags. 20 */ 21#define EFD_SEMAPHORE (1 << 0) 22#define EFD_CLOEXEC O_CLOEXEC 23#define EFD_NONBLOCK O_NONBLOCK 24 25#define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK) 26#define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS | EFD_SEMAPHORE) 27 28struct file; 29 30#ifdef CONFIG_EVENTFD 31 32struct file *eventfd_file_create(unsigned int count, int flags); 33struct eventfd_ctx *eventfd_ctx_get(struct eventfd_ctx *ctx); 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); 38__u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n); 39ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait, __u64 *cnt); 40int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_t *wait, 41 __u64 *cnt); 42 43#else /* CONFIG_EVENTFD */ 44 45/* 46 * Ugly ugly ugly error layer to support modules that uses eventfd but 47 * pretend to work in !CONFIG_EVENTFD configurations. Namely, AIO. 48 */ 49static inline struct file *eventfd_file_create(unsigned int count, int flags) 50{ 51 return ERR_PTR(-ENOSYS); 52} 53 54static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd) 55{ 56 return ERR_PTR(-ENOSYS); 57} 58 59static inline int eventfd_signal(struct eventfd_ctx *ctx, int n) 60{ 61 return -ENOSYS; 62} 63 64static inline void eventfd_ctx_put(struct eventfd_ctx *ctx) 65{ 66 67} 68 69static inline ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait, 70 __u64 *cnt) 71{ 72 return -ENOSYS; 73} 74 75static inline int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, 76 wait_queue_t *wait, __u64 *cnt) 77{ 78 return -ENOSYS; 79} 80 81#endif 82 83#endif /* _LINUX_EVENTFD_H */ 84 85