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1 : : /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 : : /* 3 : : * include/linux/eventpoll.h ( Efficient event polling implementation ) 4 : : * Copyright (C) 2001,...,2006 Davide Libenzi 5 : : * 6 : : * Davide Libenzi <davidel@xmailserver.org> 7 : : */ 8 : : #ifndef _LINUX_EVENTPOLL_H 9 : : #define _LINUX_EVENTPOLL_H 10 : : 11 : : #include <uapi/linux/eventpoll.h> 12 : : #include <uapi/linux/kcmp.h> 13 : : 14 : : 15 : : /* Forward declarations to avoid compiler errors */ 16 : : struct file; 17 : : 18 : : 19 : : #ifdef CONFIG_EPOLL 20 : : 21 : : #ifdef CONFIG_CHECKPOINT_RESTORE 22 : : struct file *get_epoll_tfile_raw_ptr(struct file *file, int tfd, unsigned long toff); 23 : : #endif 24 : : 25 : : /* Used to initialize the epoll bits inside the "struct file" */ 26 : 684018 : static inline void eventpoll_init_file(struct file *file) 27 : : { 28 : 684018 : INIT_LIST_HEAD(&file->f_ep_links); 29 : 684018 : INIT_LIST_HEAD(&file->f_tfile_llink); 30 : : } 31 : : 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 : 534156 : 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 [ + + ]: 534156 : 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 : 117 : eventpoll_release_file(file); 62 : : } 63 : : 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 : 11685 : static inline int ep_op_has_event(int op) 69 : : { 70 [ + + + + : 11685 : return op != EPOLL_CTL_DEL; + + ] 71 : : } 72 : : 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 : : 80 : : #endif /* #ifndef _LINUX_EVENTPOLL_H */