Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * include/linux/eventpoll.h ( Efficent event polling implementation ) |
| 3 | * Copyright (C) 2001,...,2003 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 | |
| 14 | #ifndef _LINUX_EVENTPOLL_H |
| 15 | #define _LINUX_EVENTPOLL_H |
| 16 | |
| 17 | #include <linux/types.h> |
| 18 | |
| 19 | |
| 20 | /* Valid opcodes to issue to sys_epoll_ctl() */ |
| 21 | #define EPOLL_CTL_ADD 1 |
| 22 | #define EPOLL_CTL_DEL 2 |
| 23 | #define EPOLL_CTL_MOD 3 |
| 24 | |
| 25 | /* Set the One Shot behaviour for the target file descriptor */ |
| 26 | #define EPOLLONESHOT (1 << 30) |
| 27 | |
| 28 | /* Set the Edge Triggered behaviour for the target file descriptor */ |
| 29 | #define EPOLLET (1 << 31) |
| 30 | |
| 31 | /* |
| 32 | * On x86-64 make the 64bit structure have the same alignment as the |
| 33 | * 32bit structure. This makes 32bit emulation easier. |
| 34 | */ |
| 35 | #ifdef __x86_64__ |
| 36 | #define EPOLL_PACKED __attribute__((packed)) |
| 37 | #else |
| 38 | #define EPOLL_PACKED |
| 39 | #endif |
| 40 | |
| 41 | struct epoll_event { |
| 42 | __u32 events; |
| 43 | __u64 data; |
| 44 | } EPOLL_PACKED; |
| 45 | |
| 46 | #ifdef __KERNEL__ |
| 47 | |
| 48 | /* Forward declarations to avoid compiler errors */ |
| 49 | struct file; |
| 50 | |
| 51 | |
| 52 | #ifdef CONFIG_EPOLL |
| 53 | |
| 54 | /* Used to initialize the epoll bits inside the "struct file" */ |
Benjamin LaHaise | 5a6b795 | 2006-03-23 03:01:03 -0800 | [diff] [blame] | 55 | static inline void eventpoll_init_file(struct file *file) |
| 56 | { |
| 57 | INIT_LIST_HEAD(&file->f_ep_links); |
| 58 | spin_lock_init(&file->f_ep_lock); |
| 59 | } |
| 60 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 61 | |
| 62 | /* Used to release the epoll bits inside the "struct file" */ |
| 63 | void eventpoll_release_file(struct file *file); |
| 64 | |
| 65 | /* |
| 66 | * This is called from inside fs/file_table.c:__fput() to unlink files |
| 67 | * from the eventpoll interface. We need to have this facility to cleanup |
| 68 | * correctly files that are closed without being removed from the eventpoll |
| 69 | * interface. |
| 70 | */ |
| 71 | static inline void eventpoll_release(struct file *file) |
| 72 | { |
| 73 | |
| 74 | /* |
| 75 | * Fast check to avoid the get/release of the semaphore. Since |
| 76 | * we're doing this outside the semaphore lock, it might return |
| 77 | * false negatives, but we don't care. It'll help in 99.99% of cases |
| 78 | * to avoid the semaphore lock. False positives simply cannot happen |
| 79 | * because the file in on the way to be removed and nobody ( but |
| 80 | * eventpoll ) has still a reference to this file. |
| 81 | */ |
| 82 | if (likely(list_empty(&file->f_ep_links))) |
| 83 | return; |
| 84 | |
| 85 | /* |
| 86 | * The file is being closed while it is still linked to an epoll |
| 87 | * descriptor. We need to handle this by correctly unlinking it |
| 88 | * from its containers. |
| 89 | */ |
| 90 | eventpoll_release_file(file); |
| 91 | } |
| 92 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 93 | #else |
| 94 | |
| 95 | static inline void eventpoll_init_file(struct file *file) {} |
| 96 | static inline void eventpoll_release(struct file *file) {} |
| 97 | |
| 98 | #endif |
| 99 | |
| 100 | #endif /* #ifdef __KERNEL__ */ |
| 101 | |
| 102 | #endif /* #ifndef _LINUX_EVENTPOLL_H */ |
| 103 | |