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/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 28 struct file; 29 30 #ifdef CONFIG_EVENTFD 31 32 struct file *eventfd_file_create(unsigned int count, int flags); 33 struct eventfd_ctx *eventfd_ctx_get(struct eventfd_ctx *ctx); 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 __u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n); 39 ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait, __u64 *cnt); 40 int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_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 */ 49 static inline struct file *eventfd_file_create(unsigned int count, int flags) 50 { 51 return ERR_PTR(-ENOSYS); 52 } 53 54 static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd) 55 { 56 return ERR_PTR(-ENOSYS); 57 } 58 59 static inline int eventfd_signal(struct eventfd_ctx *ctx, int n) 60 { 61 return -ENOSYS; 62 } 63 64 static inline void eventfd_ctx_put(struct eventfd_ctx *ctx) 65 { 66 67 } 68 69 static inline ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait, 70 __u64 *cnt) 71 { 72 return -ENOSYS; 73 } 74 75 static inline int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, 76 wait_queue_entry_t *wait, __u64 *cnt) 77 { 78 return -ENOSYS; 79 } 80 81 #endif 82 83 #endif /* _LINUX_EVENTFD_H */ 84 85