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git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/blob - include/linux/eventpoll.h
2 * include/linux/eventpoll.h ( Efficent event polling implementation )
3 * Copyright (C) 2001,...,2006 Davide Libenzi
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 * Davide Libenzi <davidel@xmailserver.org>
14 #ifndef _LINUX_EVENTPOLL_H
15 #define _LINUX_EVENTPOLL_H
17 #include <linux/types.h>
20 /* Valid opcodes to issue to sys_epoll_ctl() */
21 #define EPOLL_CTL_ADD 1
22 #define EPOLL_CTL_DEL 2
23 #define EPOLL_CTL_MOD 3
25 /* Set the One Shot behaviour for the target file descriptor */
26 #define EPOLLONESHOT (1 << 30)
28 /* Set the Edge Triggered behaviour for the target file descriptor */
29 #define EPOLLET (1 << 31)
32 * On x86-64 make the 64bit structure have the same alignment as the
33 * 32bit structure. This makes 32bit emulation easier.
36 #define EPOLL_PACKED __attribute__((packed))
48 /* Forward declarations to avoid compiler errors */
54 /* Used to initialize the epoll bits inside the "struct file" */
55 static inline void eventpoll_init_file(struct file
*file
)
57 INIT_LIST_HEAD(&file
->f_ep_links
);
58 spin_lock_init(&file
->f_ep_lock
);
62 /* Used to release the epoll bits inside the "struct file" */
63 void eventpoll_release_file(struct file
*file
);
66 * This is called from inside fs/file_table.c:__fput() to unlink files
67 * from the eventpoll interface. We need to have this facility to cleanup
68 * correctly files that are closed without being removed from the eventpoll
71 static inline void eventpoll_release(struct file
*file
)
75 * Fast check to avoid the get/release of the semaphore. Since
76 * we're doing this outside the semaphore lock, it might return
77 * false negatives, but we don't care. It'll help in 99.99% of cases
78 * to avoid the semaphore lock. False positives simply cannot happen
79 * because the file in on the way to be removed and nobody ( but
80 * eventpoll ) has still a reference to this file.
82 if (likely(list_empty(&file
->f_ep_links
)))
86 * The file is being closed while it is still linked to an epoll
87 * descriptor. We need to handle this by correctly unlinking it
88 * from its containers.
90 eventpoll_release_file(file
);
95 static inline void eventpoll_init_file(struct file
*file
) {}
96 static inline void eventpoll_release(struct file
*file
) {}
100 #endif /* #ifdef __KERNEL__ */
102 #endif /* #ifndef _LINUX_EVENTPOLL_H */