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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* include/linux/eventpoll.h ( Efficient event polling implementation )
* Copyright (C) 2001,...,2006 Davide Libenzi
*
* Davide Libenzi <davidel@xmailserver.org>
*/
#ifndef _LINUX_EVENTPOLL_H
#define _LINUX_EVENTPOLL_H
#include <uapi/linux/eventpoll.h>
#include <uapi/linux/kcmp.h>
/* Forward declarations to avoid compiler errors */
struct file;
#ifdef CONFIG_EPOLL
#ifdef CONFIG_CHECKPOINT_RESTORE
struct file *get_epoll_tfile_raw_ptr(struct file *file, int tfd, unsigned long toff);
#endif
/* Used to initialize the epoll bits inside the "struct file" */
static inline void eventpoll_init_file(struct file *file)
{
INIT_LIST_HEAD(&file->f_ep_links);
INIT_LIST_HEAD(&file->f_tfile_llink);
}
/* Used to release the epoll bits inside the "struct file" */
void eventpoll_release_file(struct file *file);
/*
* This is called from inside fs/file_table.c:__fput() to unlink files
* from the eventpoll interface. We need to have this facility to cleanup
* correctly files that are closed without being removed from the eventpoll
* interface.
*/
static inline void eventpoll_release(struct file *file)
{
/*
* Fast check to avoid the get/release of the semaphore. Since
* we're doing this outside the semaphore lock, it might return
* false negatives, but we don't care. It'll help in 99.99% of cases
* to avoid the semaphore lock. False positives simply cannot happen
* because the file in on the way to be removed and nobody ( but
* eventpoll ) has still a reference to this file.
*/
if (likely(list_empty(&file->f_ep_links)))
return;
/*
* The file is being closed while it is still linked to an epoll
* descriptor. We need to handle this by correctly unlinking it
* from its containers.
*/
eventpoll_release_file(file);
}
#else
static inline void eventpoll_init_file(struct file *file) {}
static inline void eventpoll_release(struct file *file) {}
#endif
#endif /* #ifndef _LINUX_EVENTPOLL_H */
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