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git.proxmox.com Git - mirror_ubuntu-jammy-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
18 #include <linux/fcntl.h>
19 #include <linux/types.h>
21 /* Flags for epoll_create1. */
22 #define EPOLL_CLOEXEC O_CLOEXEC
24 /* Valid opcodes to issue to sys_epoll_ctl() */
25 #define EPOLL_CTL_ADD 1
26 #define EPOLL_CTL_DEL 2
27 #define EPOLL_CTL_MOD 3
29 /* Set the One Shot behaviour for the target file descriptor */
30 #define EPOLLONESHOT (1 << 30)
32 /* Set the Edge Triggered behaviour for the target file descriptor */
33 #define EPOLLET (1 << 31)
36 * On x86-64 make the 64bit structure have the same alignment as the
37 * 32bit structure. This makes 32bit emulation easier.
39 * UML/x86_64 needs the same packing as x86_64
42 #define EPOLL_PACKED __attribute__((packed))
54 /* Forward declarations to avoid compiler errors */
60 /* Used to initialize the epoll bits inside the "struct file" */
61 static inline void eventpoll_init_file(struct file
*file
)
63 INIT_LIST_HEAD(&file
->f_ep_links
);
67 /* Used to release the epoll bits inside the "struct file" */
68 void eventpoll_release_file(struct file
*file
);
71 * This is called from inside fs/file_table.c:__fput() to unlink files
72 * from the eventpoll interface. We need to have this facility to cleanup
73 * correctly files that are closed without being removed from the eventpoll
76 static inline void eventpoll_release(struct file
*file
)
80 * Fast check to avoid the get/release of the semaphore. Since
81 * we're doing this outside the semaphore lock, it might return
82 * false negatives, but we don't care. It'll help in 99.99% of cases
83 * to avoid the semaphore lock. False positives simply cannot happen
84 * because the file in on the way to be removed and nobody ( but
85 * eventpoll ) has still a reference to this file.
87 if (likely(list_empty(&file
->f_ep_links
)))
91 * The file is being closed while it is still linked to an epoll
92 * descriptor. We need to handle this by correctly unlinking it
93 * from its containers.
95 eventpoll_release_file(file
);
100 static inline void eventpoll_init_file(struct file
*file
) {}
101 static inline void eventpoll_release(struct file
*file
) {}
105 #endif /* #ifdef __KERNEL__ */
107 #endif /* #ifndef _LINUX_EVENTPOLL_H */