| | 1 | /* |
| | 2 | * include/linux/eventpoll.h ( Efficient event polling implementation ) |
| | 3 | * Copyright (C) 2001,...,2006 Davide Libenzi |
| | 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 | #ifndef _LINUX_EVENTPOLL_H |
| | 14 | #define _LINUX_EVENTPOLL_H |
| | 15 | |
| | 16 | #include <uapi/linux/eventpoll.h> |
| | 17 | #include <uapi/linux/kcmp.h> |
| | 18 | |
| | 19 | |
| | 20 | /* Forward declarations to avoid compiler errors */ |
| | 21 | struct file; |
| | 22 | |
| | 23 | |
| | 24 | #ifdef CONFIG_EPOLL |
| | 25 | |
| | 26 | #ifdef CONFIG_CHECKPOINT_RESTORE |
| | 27 | struct file *get_epoll_tfile_raw_ptr(struct file *file, int tfd, unsigned long toff); |
| | 28 | #endif |
| | 29 | |
| | 30 | /* Used to initialize the epoll bits inside the "struct file" */ |
| | 31 | static inline void eventpoll_init_file(struct file *file) |
| | 32 | { |
| | 33 | INIT_LIST_HEAD(&file->f_ep_links); |
| | 34 | INIT_LIST_HEAD(&file->f_tfile_llink); |
| | 35 | } |
| | 36 | |
| | 37 | |
| | 38 | /* Used to release the epoll bits inside the "struct file" */ |
| | 39 | void eventpoll_release_file(struct file *file); |
| | 40 | |
| | 41 | /* |
| | 42 | * This is called from inside fs/file_table.c:__fput() to unlink files |
| | 43 | * from the eventpoll interface. We need to have this facility to cleanup |
| | 44 | * correctly files that are closed without being removed from the eventpoll |
| | 45 | * interface. |
| | 46 | */ |
| | 47 | static inline void eventpoll_release(struct file *file) |
| | 48 | { |
| | 49 | |
| | 50 | /* |
| | 51 | * Fast check to avoid the get/release of the semaphore. Since |
| | 52 | * we're doing this outside the semaphore lock, it might return |
| | 53 | * false negatives, but we don't care. It'll help in 99.99% of cases |
| | 54 | * to avoid the semaphore lock. False positives simply cannot happen |
| | 55 | * because the file in on the way to be removed and nobody ( but |
| | 56 | * eventpoll ) has still a reference to this file. |
| | 57 | */ |
| | 58 | if (likely(list_empty(&file->f_ep_links))) |
| | 59 | return; |
| | 60 | |
| | 61 | /* |
| | 62 | * The file is being closed while it is still linked to an epoll |
| | 63 | * descriptor. We need to handle this by correctly unlinking it |
| | 64 | * from its containers. |
| | 65 | */ |
| | 66 | eventpoll_release_file(file); |
| | 67 | } |
| | 68 | |
| | 69 | #else |
| | 70 | |
| | 71 | static inline void eventpoll_init_file(struct file *file) {} |
| | 72 | static inline void eventpoll_release(struct file *file) {} |
| | 73 | |
| | 74 | #endif |
| | 75 | |
| | 76 | #endif /* #ifndef _LINUX_EVENTPOLL_H */ |
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