Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
Lucas De Marchi | 25985ed | 2011-03-30 22:57:33 -0300 | [diff] [blame] | 2 | * include/linux/eventpoll.h ( Efficient event polling implementation ) |
Davide Libenzi | 3419b23 | 2006-06-25 05:48:14 -0700 | [diff] [blame] | 3 | * Copyright (C) 2001,...,2006 Davide Libenzi |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | |
Ulrich Drepper | a0998b5 | 2008-07-23 21:29:27 -0700 | [diff] [blame] | 17 | /* For O_CLOEXEC */ |
| 18 | #include <linux/fcntl.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 19 | #include <linux/types.h> |
| 20 | |
Ulrich Drepper | 9fe5ad9 | 2008-07-23 21:29:43 -0700 | [diff] [blame] | 21 | /* Flags for epoll_create1. */ |
Ulrich Drepper | a0998b5 | 2008-07-23 21:29:27 -0700 | [diff] [blame] | 22 | #define EPOLL_CLOEXEC O_CLOEXEC |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | |
Arve Hjønnevåg | 4d7e30d | 2012-05-01 21:33:34 +0200 | [diff] [blame] | 29 | /* |
| 30 | * Request the handling of system wakeup events so as to prevent system suspends |
| 31 | * from happening while those events are being processed. |
| 32 | * |
| 33 | * Assuming neither EPOLLET nor EPOLLONESHOT is set, system suspends will not be |
| 34 | * re-allowed until epoll_wait is called again after consuming the wakeup |
| 35 | * event(s). |
| 36 | * |
| 37 | * Requires CAP_EPOLLWAKEUP |
| 38 | */ |
| 39 | #define EPOLLWAKEUP (1 << 29) |
| 40 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 41 | /* Set the One Shot behaviour for the target file descriptor */ |
| 42 | #define EPOLLONESHOT (1 << 30) |
| 43 | |
| 44 | /* Set the Edge Triggered behaviour for the target file descriptor */ |
| 45 | #define EPOLLET (1 << 31) |
| 46 | |
| 47 | /* |
| 48 | * On x86-64 make the 64bit structure have the same alignment as the |
| 49 | * 32bit structure. This makes 32bit emulation easier. |
Jeff Dike | d75e26a | 2007-03-26 21:32:20 -0800 | [diff] [blame] | 50 | * |
Al Viro | ca5cd87 | 2007-10-29 04:31:16 +0000 | [diff] [blame] | 51 | * UML/x86_64 needs the same packing as x86_64 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 52 | */ |
| 53 | #ifdef __x86_64__ |
| 54 | #define EPOLL_PACKED __attribute__((packed)) |
| 55 | #else |
| 56 | #define EPOLL_PACKED |
| 57 | #endif |
| 58 | |
| 59 | struct epoll_event { |
| 60 | __u32 events; |
| 61 | __u64 data; |
| 62 | } EPOLL_PACKED; |
| 63 | |
| 64 | #ifdef __KERNEL__ |
| 65 | |
| 66 | /* Forward declarations to avoid compiler errors */ |
| 67 | struct file; |
| 68 | |
| 69 | |
| 70 | #ifdef CONFIG_EPOLL |
| 71 | |
| 72 | /* Used to initialize the epoll bits inside the "struct file" */ |
Benjamin LaHaise | 5a6b7951 | 2006-03-23 03:01:03 -0800 | [diff] [blame] | 73 | static inline void eventpoll_init_file(struct file *file) |
| 74 | { |
| 75 | INIT_LIST_HEAD(&file->f_ep_links); |
Jason Baron | 28d82dc | 2012-01-12 17:17:43 -0800 | [diff] [blame] | 76 | INIT_LIST_HEAD(&file->f_tfile_llink); |
Benjamin LaHaise | 5a6b7951 | 2006-03-23 03:01:03 -0800 | [diff] [blame] | 77 | } |
| 78 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 79 | |
| 80 | /* Used to release the epoll bits inside the "struct file" */ |
| 81 | void eventpoll_release_file(struct file *file); |
| 82 | |
| 83 | /* |
| 84 | * This is called from inside fs/file_table.c:__fput() to unlink files |
| 85 | * from the eventpoll interface. We need to have this facility to cleanup |
| 86 | * correctly files that are closed without being removed from the eventpoll |
| 87 | * interface. |
| 88 | */ |
| 89 | static inline void eventpoll_release(struct file *file) |
| 90 | { |
| 91 | |
| 92 | /* |
| 93 | * Fast check to avoid the get/release of the semaphore. Since |
| 94 | * we're doing this outside the semaphore lock, it might return |
| 95 | * false negatives, but we don't care. It'll help in 99.99% of cases |
| 96 | * to avoid the semaphore lock. False positives simply cannot happen |
| 97 | * because the file in on the way to be removed and nobody ( but |
| 98 | * eventpoll ) has still a reference to this file. |
| 99 | */ |
| 100 | if (likely(list_empty(&file->f_ep_links))) |
| 101 | return; |
| 102 | |
| 103 | /* |
| 104 | * The file is being closed while it is still linked to an epoll |
| 105 | * descriptor. We need to handle this by correctly unlinking it |
| 106 | * from its containers. |
| 107 | */ |
| 108 | eventpoll_release_file(file); |
| 109 | } |
| 110 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 111 | #else |
| 112 | |
| 113 | static inline void eventpoll_init_file(struct file *file) {} |
| 114 | static inline void eventpoll_release(struct file *file) {} |
| 115 | |
| 116 | #endif |
| 117 | |
| 118 | #endif /* #ifdef __KERNEL__ */ |
| 119 | |
| 120 | #endif /* #ifndef _LINUX_EVENTPOLL_H */ |
| 121 | |