函数逻辑报告

Linux Kernel

v5.5.9

Brick Technologies Co., Ltd

Source Code:fs\eventpoll.c Create Date:2022-07-29 10:50:58
Last Modify:2020-03-12 14:18:49 Copyright©Brick
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函数名称：Modify the interest event mask by dropping an event if the new mask* has a match in the current file status. Must be called with "mtx" held.

函数原型：static int ep_modify(struct eventpoll *ep, struct epitem *epi, const struct epoll_event *event)

返回类型：int

参数：

类型参数名称
struct eventpoll *ep
struct epitem *epi
const struct epoll_event *event
1611  pwake等于0
1614  lockdep_assert_irqs_enabled()
1616  init_poll_funcptr( & pt, NULL)
1623  events等于events
1624  data等于data
1625  如果events按位与Request the handling of system wakeup events so as to prevent system suspends* from happening while those events are being processed则
1626  如果非ep_has_wakeup_source(epi)则ep_create_wakeup_source(epi)
1628  否则如果ep_has_wakeup_source(epi)则
1629  are code path, only used when EPOLL_CTL_MOD removes a wakeup source
1650  smp_mb()
1658  如果Differs from ep_eventpoll_poll() in that internal callers already have* the ep->mtx so we need to start from depth=1, such that mutex_lock_nested()* is correctly annotated.则
1659  write_lock_irq( & Lock which protects rdllist and ovflist )
1660  如果非Tells us if the item is currently linked 则
1661  添加链表项
1662  all only when ep->mtx is held
1665  如果waitqueue_active -- locklessly test for waiters on the queue*@wq_head: the waitqueue to test for waiters* returns true if the wait list is not empty* NOTE: this function is lockless and requires care, incorrect usage _will_则wake_up( & Wait queue used by sys_epoll_wait() )
1667  如果waitqueue_active -- locklessly test for waiters on the queue*@wq_head: the waitqueue to test for waiters* returns true if the wait list is not empty* NOTE: this function is lockless and requires care, incorrect usage _will_则pwake自加
1670  write_unlock_irq( & Lock which protects rdllist and ovflist )
1674  如果pwake则ep_poll_safewake( & Wait queue used by file->poll() )
1677  返回:0
调用者
名称描述
SYSCALL_DEFINE4The following function implements the controller interface for* the eventpoll file that enables the insertion/removal/change of* file descriptors inside the interest set.