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 | */ | |
1da177e4 LT |
13 | #ifndef _LINUX_EVENTPOLL_H |
14 | #define _LINUX_EVENTPOLL_H | |
15 | ||
607ca46e | 16 | #include <uapi/linux/eventpoll.h> |
1da177e4 | 17 | |
1da177e4 LT |
18 | |
19 | /* Forward declarations to avoid compiler errors */ | |
20 | struct file; | |
21 | ||
22 | ||
23 | #ifdef CONFIG_EPOLL | |
24 | ||
25 | /* Used to initialize the epoll bits inside the "struct file" */ | |
5a6b7951 BL |
26 | static inline void eventpoll_init_file(struct file *file) |
27 | { | |
28 | INIT_LIST_HEAD(&file->f_ep_links); | |
28d82dc1 | 29 | INIT_LIST_HEAD(&file->f_tfile_llink); |
5a6b7951 BL |
30 | } |
31 | ||
1da177e4 LT |
32 | |
33 | /* Used to release the epoll bits inside the "struct file" */ | |
34 | void eventpoll_release_file(struct file *file); | |
35 | ||
36 | /* | |
37 | * This is called from inside fs/file_table.c:__fput() to unlink files | |
38 | * from the eventpoll interface. We need to have this facility to cleanup | |
39 | * correctly files that are closed without being removed from the eventpoll | |
40 | * interface. | |
41 | */ | |
42 | static inline void eventpoll_release(struct file *file) | |
43 | { | |
44 | ||
45 | /* | |
46 | * Fast check to avoid the get/release of the semaphore. Since | |
47 | * we're doing this outside the semaphore lock, it might return | |
48 | * false negatives, but we don't care. It'll help in 99.99% of cases | |
49 | * to avoid the semaphore lock. False positives simply cannot happen | |
50 | * because the file in on the way to be removed and nobody ( but | |
51 | * eventpoll ) has still a reference to this file. | |
52 | */ | |
53 | if (likely(list_empty(&file->f_ep_links))) | |
54 | return; | |
55 | ||
56 | /* | |
57 | * The file is being closed while it is still linked to an epoll | |
58 | * descriptor. We need to handle this by correctly unlinking it | |
59 | * from its containers. | |
60 | */ | |
61 | eventpoll_release_file(file); | |
62 | } | |
63 | ||
1da177e4 LT |
64 | #else |
65 | ||
66 | static inline void eventpoll_init_file(struct file *file) {} | |
67 | static inline void eventpoll_release(struct file *file) {} | |
68 | ||
69 | #endif | |
70 | ||
1da177e4 | 71 | #endif /* #ifndef _LINUX_EVENTPOLL_H */ |