projects / mirror_ubuntu-zesty-kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
1 | /* |
| 2 | * include/linux/eventpoll.h ( Efficent 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 | ||
| 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. | |
| d75e26a8 | 34 | * |
| ca5cd877 | 35 | * UML/x86_64 needs the same packing as x86_64 |
| 1da177e4 LT |
36 | */ |
| 37 | #ifdef __x86_64__ | |
| 38 | #define EPOLL_PACKED __attribute__((packed)) | |
| 39 | #else | |
| 40 | #define EPOLL_PACKED | |
| 41 | #endif | |
| 42 | ||
| 43 | struct epoll_event { | |
| 44 | __u32 events; | |
| 45 | __u64 data; | |
| 46 | } EPOLL_PACKED; | |
| 47 | ||
| 48 | #ifdef __KERNEL__ | |
| 49 | ||
| 50 | /* Forward declarations to avoid compiler errors */ | |
| 51 | struct file; | |
| 52 | ||
| 53 | ||
| 54 | #ifdef CONFIG_EPOLL | |
| 55 | ||
| 56 | /* Used to initialize the epoll bits inside the "struct file" */ | |
| 5a6b7951 BL |
57 | static inline void eventpoll_init_file(struct file *file) |
| 58 | { | |
| 59 | INIT_LIST_HEAD(&file->f_ep_links); | |
| 60 | spin_lock_init(&file->f_ep_lock); | |
| 61 | } | |
| 62 | ||
| 1da177e4 LT |
63 | |
| 64 | /* Used to release the epoll bits inside the "struct file" */ | |
| 65 | void eventpoll_release_file(struct file *file); | |
| 66 | ||
| 67 | /* | |
| 68 | * This is called from inside fs/file_table.c:__fput() to unlink files | |
| 69 | * from the eventpoll interface. We need to have this facility to cleanup | |
| 70 | * correctly files that are closed without being removed from the eventpoll | |
| 71 | * interface. | |
| 72 | */ | |
| 73 | static inline void eventpoll_release(struct file *file) | |
| 74 | { | |
| 75 | ||
| 76 | /* | |
| 77 | * Fast check to avoid the get/release of the semaphore. Since | |
| 78 | * we're doing this outside the semaphore lock, it might return | |
| 79 | * false negatives, but we don't care. It'll help in 99.99% of cases | |
| 80 | * to avoid the semaphore lock. False positives simply cannot happen | |
| 81 | * because the file in on the way to be removed and nobody ( but | |
| 82 | * eventpoll ) has still a reference to this file. | |
| 83 | */ | |
| 84 | if (likely(list_empty(&file->f_ep_links))) | |
| 85 | return; | |
| 86 | ||
| 87 | /* | |
| 88 | * The file is being closed while it is still linked to an epoll | |
| 89 | * descriptor. We need to handle this by correctly unlinking it | |
| 90 | * from its containers. | |
| 91 | */ | |
| 92 | eventpoll_release_file(file); | |
| 93 | } | |
| 94 | ||
| 1da177e4 LT |
95 | #else |
| 96 | ||
| 97 | static inline void eventpoll_init_file(struct file *file) {} | |
| 98 | static inline void eventpoll_release(struct file *file) {} | |
| 99 | ||
| 100 | #endif | |
| 101 | ||
| 102 | #endif /* #ifdef __KERNEL__ */ | |
| 103 | ||
| 104 | #endif /* #ifndef _LINUX_EVENTPOLL_H */ | |
| 105 |