| /* SPDX-License-Identifier: GPL-2.0 */ |
| /* |
| * include/linux/eventfd.h |
| * |
| * Copyright (C) 2007 Davide Libenzi <davidel@xmailserver.org> |
| * |
| */ |
| |
| #ifndef _LINUX_EVENTFD_H |
| #define _LINUX_EVENTFD_H |
| |
| #include <linux/fcntl.h> |
| #include <linux/wait.h> |
| #include <linux/err.h> |
| #include <linux/percpu-defs.h> |
| #include <linux/percpu.h> |
| #include <linux/sched.h> |
| |
| /* |
| * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining |
| * new flags, since they might collide with O_* ones. We want |
| * to re-use O_* flags that couldn't possibly have a meaning |
| * from eventfd, in order to leave a free define-space for |
| * shared O_* flags. |
| */ |
| #define EFD_SEMAPHORE (1 << 0) |
| #define EFD_CLOEXEC O_CLOEXEC |
| #define EFD_NONBLOCK O_NONBLOCK |
| |
| #define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK) |
| #define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS | EFD_SEMAPHORE) |
| |
| struct eventfd_ctx; |
| struct file; |
| |
| #ifdef CONFIG_EVENTFD |
| |
| void eventfd_ctx_put(struct eventfd_ctx *ctx); |
| struct file *eventfd_fget(int fd); |
| struct eventfd_ctx *eventfd_ctx_fdget(int fd); |
| struct eventfd_ctx *eventfd_ctx_fileget(struct file *file); |
| __u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n); |
| int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *wait, |
| __u64 *cnt); |
| void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt); |
| |
| static inline bool eventfd_signal_allowed(void) |
| { |
| return !current->in_eventfd_signal; |
| } |
| |
| #else /* CONFIG_EVENTFD */ |
| |
| /* |
| * Ugly ugly ugly error layer to support modules that uses eventfd but |
| * pretend to work in !CONFIG_EVENTFD configurations. Namely, AIO. |
| */ |
| |
| static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd) |
| { |
| return ERR_PTR(-ENOSYS); |
| } |
| |
| static inline int eventfd_signal(struct eventfd_ctx *ctx, int n) |
| { |
| return -ENOSYS; |
| } |
| |
| static inline void eventfd_ctx_put(struct eventfd_ctx *ctx) |
| { |
| |
| } |
| |
| static inline int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, |
| wait_queue_entry_t *wait, __u64 *cnt) |
| { |
| return -ENOSYS; |
| } |
| |
| static inline bool eventfd_signal_allowed(void) |
| { |
| return true; |
| } |
| |
| static inline void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt) |
| { |
| |
| } |
| |
| #endif |
| |
| #endif /* _LINUX_EVENTFD_H */ |
| |