linux/fs/eventpoll.c

48  * 2) ep->mtx (mutex)
59  * mutex (ep->mtx). It is acquired during the event transfer loop,
68  * It is necessary to acquire multiple "ep->mtx"es at once in the
71  * epoll_ctl(e1, EPOLL_CTL_ADD, e2), e1->mtx will always be acquired
72  * before e2->mtx). Since we disallow cycles of epoll file
77  * It is possible to drop the "ep->mtx" and to use the global
79  * but having "ep->mtx" will make the interface more scalable.
81  * normal operations the epoll private "ep->mtx" will guarantee
186 	struct mutex mtx;
685  * descriptor.  Must be called with "mtx" held.
699 /* call only when ep->mtx is held */
702 	return rcu_dereference_check(epi->ws, lockdep_is_held(&epi->ep->mtx));
705 /* call only when ep->mtx is held */
719 /* call when ep->mtx cannot be held (ep_poll_callback) */
822 	mutex_destroy(&ep->mtx);
831  * all the associated resources. Must be called with "mtx" held.
885 	 * ep->mtx. The rcu read side, reverse_path_check_proc(), does not make
912 	mutex_lock(&ep->mtx);
939 	mutex_unlock(&ep->mtx);
994 	mutex_lock_nested(&ep->mtx, depth);
1011 	mutex_unlock(&ep->mtx);
1023  * But for epoll, users hold the ep->mtx mutex, and as such any file in
1045  * the ep->mtx so we need to start from depth=1, such that mutex_lock_nested()
1081 	mutex_lock(&ep->mtx);
1095 	mutex_unlock(&ep->mtx);
1125 	 * the ep->mtx.
1139 		mutex_lock(&ep->mtx);
1141 		mutex_unlock(&ep->mtx);
1158 	mutex_init(&ep->mtx);
1175  * are protected by the "mtx" mutex, and ep_find() must be called with
1176  * "mtx" held.
1234 	mutex_lock(&ep->mtx);
1240 	mutex_unlock(&ep->mtx);
1566  * Must be called with "mtx" held.
1600 		mutex_lock_nested(&tep->mtx, 1);
1604 			mutex_unlock(&tep->mtx);
1615 	 * protected by "mtx", and ep_insert() is called with "mtx" held.
1619 		mutex_unlock(&tep->mtx);
1693  * has a match in the current file status. Must be called with "mtx" held.
1711 	epi->event.data = event->data; /* protected by mtx */
1785 	mutex_lock(&ep->mtx);
1790 	 * Items cannot vanish during the loop we are holding ep->mtx.
1819 		 * deliver the event to userspace. Again, we are holding ep->mtx,
1846 			 * ep_send_events() holding "mtx" and the
1854 	mutex_unlock(&ep->mtx);
2080 	mutex_lock_nested(&ep->mtx, depth + 1);
2106 	mutex_unlock(&ep->mtx);
2309 	error = epoll_mutex_lock(&ep->mtx, 0, nonblock);
2315 			mutex_unlock(&ep->mtx);
2327 			error = epoll_mutex_lock(&ep->mtx, 0, nonblock);
2334 	 * Try to lookup the file inside our RB tree. Since we grabbed "mtx"
2371 	mutex_unlock(&ep->mtx);