1 /* 2 * include/linux/eventfd.h 3 * 4 * Copyright (C) 2007 Davide Libenzi <[email protected]> 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 31 struct file *eventfd_file_create(unsigned int count, int flags); 32 struct eventfd_ctx *eventfd_ctx_get(struct eventfd_ctx *ctx); 33 void eventfd_ctx_put(struct eventfd_ctx *ctx); 34 struct file *eventfd_fget(int fd); 35 struct eventfd_ctx *eventfd_ctx_fdget(int fd); 36 struct eventfd_ctx *eventfd_ctx_fileget(struct file *file); 37 __u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n); 38 ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait, __u64 *cnt); 39 int 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 */ 48 static inline struct file *eventfd_file_create(unsigned int count, int flags) 49 { 50 return ERR_PTR(-ENOSYS); 51 } 52 53 static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd) 54 { 55 return ERR_PTR(-ENOSYS); 56 } 57 58 static inline int eventfd_signal(struct eventfd_ctx *ctx, int n) 59 { 60 return -ENOSYS; 61 } 62 63 static inline void eventfd_ctx_put(struct eventfd_ctx *ctx) 64 { 65 66 } 67 68 static inline ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait, 69 __u64 *cnt) 70 { 71 return -ENOSYS; 72 } 73 74 static 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