/* *  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" */void eventpoll_init_file(struct file *file); /* 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 */