1 /* SPDX-License-Identifier: GPL-2.0-or-later */
3 * include/linux/eventpoll.h ( Efficient event polling implementation )
4 * Copyright (C) 2001,...,2006 Davide Libenzi
6 * Davide Libenzi <davidel@xmailserver.org>
8 #ifndef _LINUX_EVENTPOLL_H
9 #define _LINUX_EVENTPOLL_H
11 #include <uapi/linux/eventpoll.h>
12 #include <uapi/linux/kcmp.h>
15 /* Forward declarations to avoid compiler errors */
22 struct file *get_epoll_tfile_raw_ptr(struct file *file, int tfd, unsigned long toff);
25 /* Used to release the epoll bits inside the "struct file" */
26 void eventpoll_release_file(struct file *file);
29 * This is called from inside fs/file_table.c:__fput() to unlink files
30 * from the eventpoll interface. We need to have this facility to cleanup
31 * correctly files that are closed without being removed from the eventpoll
34 static inline void eventpoll_release(struct file *file)
38 * Fast check to avoid the get/release of the semaphore. Since
39 * we're doing this outside the semaphore lock, it might return
40 * false negatives, but we don't care. It'll help in 99.99% of cases
41 * to avoid the semaphore lock. False positives simply cannot happen
42 * because the file in on the way to be removed and nobody ( but
43 * eventpoll ) has still a reference to this file.
45 if (likely(!file->f_ep))
49 * The file is being closed while it is still linked to an epoll
50 * descriptor. We need to handle this by correctly unlinking it
51 * from its containers.
53 eventpoll_release_file(file);
56 int do_epoll_ctl(int epfd, int op, int fd, struct epoll_event *epds,
59 /* Tells if the epoll_ctl(2) operation needs an event copy from userspace */
60 static inline int ep_op_has_event(int op)
62 return op != EPOLL_CTL_DEL;
67 static inline void eventpoll_release(struct file *file) {}
71 #endif /* #ifndef _LINUX_EVENTPOLL_H */