Commit | Line | Data |
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2874c5fd | 1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
1da177e4 | 2 | /* |
25985edc | 3 | * include/linux/eventpoll.h ( Efficient event polling implementation ) |
3419b23a | 4 | * Copyright (C) 2001,...,2006 Davide Libenzi |
1da177e4 | 5 | * |
1da177e4 | 6 | * Davide Libenzi <davidel@xmailserver.org> |
1da177e4 | 7 | */ |
1da177e4 LT |
8 | #ifndef _LINUX_EVENTPOLL_H |
9 | #define _LINUX_EVENTPOLL_H | |
10 | ||
607ca46e | 11 | #include <uapi/linux/eventpoll.h> |
0791e364 | 12 | #include <uapi/linux/kcmp.h> |
1da177e4 | 13 | |
1da177e4 LT |
14 | |
15 | /* Forward declarations to avoid compiler errors */ | |
16 | struct file; | |
17 | ||
18 | ||
19 | #ifdef CONFIG_EPOLL | |
20 | ||
92ef6da3 | 21 | #ifdef CONFIG_CHECKPOINT_RESTORE |
0791e364 | 22 | struct file *get_epoll_tfile_raw_ptr(struct file *file, int tfd, unsigned long toff); |
92ef6da3 | 23 | #endif |
0791e364 | 24 | |
1da177e4 | 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 | ||
39220e8d JA |
64 | int do_epoll_ctl(int epfd, int op, int fd, struct epoll_event *epds, |
65 | bool nonblock); | |
66 | ||
67 | /* Tells if the epoll_ctl(2) operation needs an event copy from userspace */ | |
68 | static inline int ep_op_has_event(int op) | |
69 | { | |
70 | return op != EPOLL_CTL_DEL; | |
71 | } | |
72 | ||
1da177e4 LT |
73 | #else |
74 | ||
75 | static inline void eventpoll_init_file(struct file *file) {} | |
76 | static inline void eventpoll_release(struct file *file) {} | |
77 | ||
78 | #endif | |
79 | ||
1da177e4 | 80 | #endif /* #ifndef _LINUX_EVENTPOLL_H */ |