| /* |
| * include/linux/eventpoll.h ( Efficent event polling implementation ) |
| * Copyright (C) 2001,...,2003 Davide Libenzi |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * Davide Libenzi <davidel@xmailserver.org> |
| * |
| */ |
| |
| #ifndef _LINUX_EVENTPOLL_H |
| #define _LINUX_EVENTPOLL_H |
| |
| #include <linux/types.h> |
| |
| |
| /* Valid opcodes to issue to sys_epoll_ctl() */ |
| #define EPOLL_CTL_ADD 1 |
| #define EPOLL_CTL_DEL 2 |
| #define EPOLL_CTL_MOD 3 |
| |
| /* Set the One Shot behaviour for the target file descriptor */ |
| #define EPOLLONESHOT (1 << 30) |
| |
| /* Set the Edge Triggered behaviour for the target file descriptor */ |
| #define EPOLLET (1 << 31) |
| |
| /* |
| * On x86-64 make the 64bit structure have the same alignment as the |
| * 32bit structure. This makes 32bit emulation easier. |
| */ |
| #ifdef __x86_64__ |
| #define EPOLL_PACKED __attribute__((packed)) |
| #else |
| #define EPOLL_PACKED |
| #endif |
| |
| struct epoll_event { |
| __u32 events; |
| __u64 data; |
| } EPOLL_PACKED; |
| |
| #ifdef __KERNEL__ |
| |
| /* Forward declarations to avoid compiler errors */ |
| struct file; |
| |
| |
| #ifdef CONFIG_EPOLL |
| |
| /* Used to initialize the epoll bits inside the "struct file" */ |
| static inline void eventpoll_init_file(struct file *file) |
| { |
| INIT_LIST_HEAD(&file->f_ep_links); |
| spin_lock_init(&file->f_ep_lock); |
| } |
| |
| |
| /* Used to release the epoll bits inside the "struct file" */ |
| void eventpoll_release_file(struct file *file); |
| |
| /* |
| * This is called from inside fs/file_table.c:__fput() to unlink files |
| * from the eventpoll interface. We need to have this facility to cleanup |
| * correctly files that are closed without being removed from the eventpoll |
| * interface. |
| */ |
| static inline void eventpoll_release(struct file *file) |
| { |
| |
| /* |
| * Fast check to avoid the get/release of the semaphore. Since |
| * we're doing this outside the semaphore lock, it might return |
| * false negatives, but we don't care. It'll help in 99.99% of cases |
| * to avoid the semaphore lock. False positives simply cannot happen |
| * because the file in on the way to be removed and nobody ( but |
| * eventpoll ) has still a reference to this file. |
| */ |
| if (likely(list_empty(&file->f_ep_links))) |
| return; |
| |
| /* |
| * The file is being closed while it is still linked to an epoll |
| * descriptor. We need to handle this by correctly unlinking it |
| * from its containers. |
| */ |
| eventpoll_release_file(file); |
| } |
| |
| #else |
| |
| static inline void eventpoll_init_file(struct file *file) {} |
| static inline void eventpoll_release(struct file *file) {} |
| |
| #endif |
| |
| #endif /* #ifdef __KERNEL__ */ |
| |
| #endif /* #ifndef _LINUX_EVENTPOLL_H */ |
| |