1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * include/linux/eventfd.h 4 * 5 * Copyright (C) 2007 Davide Libenzi <[email protected]> 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 29 struct eventfd_ctx; 30 struct file; 31 32 #ifdef CONFIG_EVENTFD 33 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 __u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, __poll_t mask); 40 int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *wait, 41 __u64 *cnt); 42 void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt); 43 44 static inline bool eventfd_signal_allowed(void) 45 { 46 return !current->in_eventfd; 47 } 48 49 #else /* CONFIG_EVENTFD */ 50 51 /* 52 * Ugly ugly ugly error layer to support modules that uses eventfd but 53 * pretend to work in !CONFIG_EVENTFD configurations. Namely, AIO. 54 */ 55 56 static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd) 57 { 58 return ERR_PTR(-ENOSYS); 59 } 60 61 static inline int eventfd_signal(struct eventfd_ctx *ctx, __u64 n) 62 { 63 return -ENOSYS; 64 } 65 66 static inline int eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, 67 unsigned mask) 68 { 69 return -ENOSYS; 70 } 71 72 static inline void eventfd_ctx_put(struct eventfd_ctx *ctx) 73 { 74 75 } 76 77 static inline int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, 78 wait_queue_entry_t *wait, __u64 *cnt) 79 { 80 return -ENOSYS; 81 } 82 83 static inline bool eventfd_signal_allowed(void) 84 { 85 return true; 86 } 87 88 static inline void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt) 89 { 90 91 } 92 93 #endif 94 95 #endif /* _LINUX_EVENTFD_H */ 96 97