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1da177e4 | 1 | /* |
25985edc | 2 | * include/linux/eventpoll.h ( Efficient event polling implementation ) |
3419b23a | 3 | * Copyright (C) 2001,...,2006 Davide Libenzi |
1da177e4 LT |
4 | * |
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. | |
9 | * | |
10 | * Davide Libenzi <davidel@xmailserver.org> | |
11 | * | |
12 | */ | |
13 | ||
14 | #ifndef _LINUX_EVENTPOLL_H | |
15 | #define _LINUX_EVENTPOLL_H | |
16 | ||
a0998b50 UD |
17 | /* For O_CLOEXEC */ |
18 | #include <linux/fcntl.h> | |
1da177e4 LT |
19 | #include <linux/types.h> |
20 | ||
9fe5ad9c | 21 | /* Flags for epoll_create1. */ |
a0998b50 | 22 | #define EPOLL_CLOEXEC O_CLOEXEC |
1da177e4 LT |
23 | |
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 | |
28 | ||
29 | /* Set the One Shot behaviour for the target file descriptor */ | |
30 | #define EPOLLONESHOT (1 << 30) | |
31 | ||
32 | /* Set the Edge Triggered behaviour for the target file descriptor */ | |
33 | #define EPOLLET (1 << 31) | |
34 | ||
35 | /* | |
36 | * On x86-64 make the 64bit structure have the same alignment as the | |
37 | * 32bit structure. This makes 32bit emulation easier. | |
d75e26a8 | 38 | * |
ca5cd877 | 39 | * UML/x86_64 needs the same packing as x86_64 |
1da177e4 LT |
40 | */ |
41 | #ifdef __x86_64__ | |
42 | #define EPOLL_PACKED __attribute__((packed)) | |
43 | #else | |
44 | #define EPOLL_PACKED | |
45 | #endif | |
46 | ||
47 | struct epoll_event { | |
48 | __u32 events; | |
49 | __u64 data; | |
50 | } EPOLL_PACKED; | |
51 | ||
52 | #ifdef __KERNEL__ | |
53 | ||
54 | /* Forward declarations to avoid compiler errors */ | |
55 | struct file; | |
56 | ||
57 | ||
58 | #ifdef CONFIG_EPOLL | |
59 | ||
60 | /* Used to initialize the epoll bits inside the "struct file" */ | |
5a6b7951 BL |
61 | static inline void eventpoll_init_file(struct file *file) |
62 | { | |
63 | INIT_LIST_HEAD(&file->f_ep_links); | |
5a6b7951 BL |
64 | } |
65 | ||
1da177e4 LT |
66 | |
67 | /* Used to release the epoll bits inside the "struct file" */ | |
68 | void eventpoll_release_file(struct file *file); | |
69 | ||
70 | /* | |
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 | |
74 | * interface. | |
75 | */ | |
76 | static inline void eventpoll_release(struct file *file) | |
77 | { | |
78 | ||
79 | /* | |
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. | |
86 | */ | |
87 | if (likely(list_empty(&file->f_ep_links))) | |
88 | return; | |
89 | ||
90 | /* | |
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. | |
94 | */ | |
95 | eventpoll_release_file(file); | |
96 | } | |
97 | ||
1da177e4 LT |
98 | #else |
99 | ||
100 | static inline void eventpoll_init_file(struct file *file) {} | |
101 | static inline void eventpoll_release(struct file *file) {} | |
102 | ||
103 | #endif | |
104 | ||
105 | #endif /* #ifdef __KERNEL__ */ | |
106 | ||
107 | #endif /* #ifndef _LINUX_EVENTPOLL_H */ | |
108 |