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71 lines
2.0 KiB
71 lines
2.0 KiB
/* |
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* include/linux/eventpoll.h ( Efficient event polling implementation ) |
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* Copyright (C) 2001,...,2006 Davide Libenzi |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation; either version 2 of the License, or |
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* (at your option) any later version. |
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* |
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* Davide Libenzi <[email protected]> |
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* |
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*/ |
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#ifndef _LINUX_EVENTPOLL_H |
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#define _LINUX_EVENTPOLL_H |
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#include <uapi/linux/eventpoll.h> |
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/* Forward declarations to avoid compiler errors */ |
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struct file; |
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#ifdef CONFIG_EPOLL |
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/* Used to initialize the epoll bits inside the "struct file" */ |
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static inline void eventpoll_init_file(struct file *file) |
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{ |
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INIT_LIST_HEAD(&file->f_ep_links); |
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INIT_LIST_HEAD(&file->f_tfile_llink); |
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} |
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/* Used to release the epoll bits inside the "struct file" */ |
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void eventpoll_release_file(struct file *file); |
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/* |
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* This is called from inside fs/file_table.c:__fput() to unlink files |
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* from the eventpoll interface. We need to have this facility to cleanup |
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* correctly files that are closed without being removed from the eventpoll |
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* interface. |
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*/ |
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static inline void eventpoll_release(struct file *file) |
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{ |
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/* |
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* Fast check to avoid the get/release of the semaphore. Since |
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* we're doing this outside the semaphore lock, it might return |
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* false negatives, but we don't care. It'll help in 99.99% of cases |
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* to avoid the semaphore lock. False positives simply cannot happen |
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* because the file in on the way to be removed and nobody ( but |
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* eventpoll ) has still a reference to this file. |
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*/ |
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if (likely(list_empty(&file->f_ep_links))) |
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return; |
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/* |
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* The file is being closed while it is still linked to an epoll |
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* descriptor. We need to handle this by correctly unlinking it |
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* from its containers. |
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*/ |
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eventpoll_release_file(file); |
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} |
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#else |
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static inline void eventpoll_init_file(struct file *file) {} |
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static inline void eventpoll_release(struct file *file) {} |
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#endif |
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#endif /* #ifndef _LINUX_EVENTPOLL_H */
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