Commit | Line | Data |
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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 | |
03a7beb5 | 28 | #define EPOLL_CTL_DISABLE 4 |
1da177e4 | 29 | |
4d7e30d9 AH |
30 | /* |
31 | * Request the handling of system wakeup events so as to prevent system suspends | |
32 | * from happening while those events are being processed. | |
33 | * | |
34 | * Assuming neither EPOLLET nor EPOLLONESHOT is set, system suspends will not be | |
35 | * re-allowed until epoll_wait is called again after consuming the wakeup | |
36 | * event(s). | |
37 | * | |
d9914cf6 | 38 | * Requires CAP_BLOCK_SUSPEND |
4d7e30d9 AH |
39 | */ |
40 | #define EPOLLWAKEUP (1 << 29) | |
41 | ||
1da177e4 LT |
42 | /* Set the One Shot behaviour for the target file descriptor */ |
43 | #define EPOLLONESHOT (1 << 30) | |
44 | ||
45 | /* Set the Edge Triggered behaviour for the target file descriptor */ | |
46 | #define EPOLLET (1 << 31) | |
47 | ||
48 | /* | |
49 | * On x86-64 make the 64bit structure have the same alignment as the | |
50 | * 32bit structure. This makes 32bit emulation easier. | |
d75e26a8 | 51 | * |
ca5cd877 | 52 | * UML/x86_64 needs the same packing as x86_64 |
1da177e4 LT |
53 | */ |
54 | #ifdef __x86_64__ | |
55 | #define EPOLL_PACKED __attribute__((packed)) | |
56 | #else | |
57 | #define EPOLL_PACKED | |
58 | #endif | |
59 | ||
60 | struct epoll_event { | |
61 | __u32 events; | |
62 | __u64 data; | |
63 | } EPOLL_PACKED; | |
64 | ||
65 | #ifdef __KERNEL__ | |
66 | ||
67 | /* Forward declarations to avoid compiler errors */ | |
68 | struct file; | |
69 | ||
70 | ||
71 | #ifdef CONFIG_EPOLL | |
72 | ||
73 | /* Used to initialize the epoll bits inside the "struct file" */ | |
5a6b7951 BL |
74 | static inline void eventpoll_init_file(struct file *file) |
75 | { | |
76 | INIT_LIST_HEAD(&file->f_ep_links); | |
28d82dc1 | 77 | INIT_LIST_HEAD(&file->f_tfile_llink); |
5a6b7951 BL |
78 | } |
79 | ||
1da177e4 LT |
80 | |
81 | /* Used to release the epoll bits inside the "struct file" */ | |
82 | void eventpoll_release_file(struct file *file); | |
83 | ||
84 | /* | |
85 | * This is called from inside fs/file_table.c:__fput() to unlink files | |
86 | * from the eventpoll interface. We need to have this facility to cleanup | |
87 | * correctly files that are closed without being removed from the eventpoll | |
88 | * interface. | |
89 | */ | |
90 | static inline void eventpoll_release(struct file *file) | |
91 | { | |
92 | ||
93 | /* | |
94 | * Fast check to avoid the get/release of the semaphore. Since | |
95 | * we're doing this outside the semaphore lock, it might return | |
96 | * false negatives, but we don't care. It'll help in 99.99% of cases | |
97 | * to avoid the semaphore lock. False positives simply cannot happen | |
98 | * because the file in on the way to be removed and nobody ( but | |
99 | * eventpoll ) has still a reference to this file. | |
100 | */ | |
101 | if (likely(list_empty(&file->f_ep_links))) | |
102 | return; | |
103 | ||
104 | /* | |
105 | * The file is being closed while it is still linked to an epoll | |
106 | * descriptor. We need to handle this by correctly unlinking it | |
107 | * from its containers. | |
108 | */ | |
109 | eventpoll_release_file(file); | |
110 | } | |
111 | ||
1da177e4 LT |
112 | #else |
113 | ||
114 | static inline void eventpoll_init_file(struct file *file) {} | |
115 | static inline void eventpoll_release(struct file *file) {} | |
116 | ||
117 | #endif | |
118 | ||
119 | #endif /* #ifdef __KERNEL__ */ | |
120 | ||
121 | #endif /* #ifndef _LINUX_EVENTPOLL_H */ | |
122 |