Function report

Linux Kernel

v5.5.9

Brick Technologies Co., Ltd

Source Code:fs\eventpoll.c Create Date:2022-07-28 20:19:08
Last Modify:2020-03-12 14:18:49 Copyright©Brick
home page Tree
Annotation kernel can get tool activityDownload SCCTChinese

Name: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.

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

Type:int

Parameter:

TypeParameterName
struct eventpoll *ep
struct epitem *epi
const struct epoll_event *event
1611  pwake = 0
1614  lockdep_assert_irqs_enabled()
1616  init_poll_funcptr( & pt, NULL)
1623  events = events
1624  data = data
1625  If events & Request the handling of system wakeup events so as to prevent system suspends* from happening while those events are being processed Then
1626  If Not ep_has_wakeup_source(epi) Then ep_create_wakeup_source(epi)
1628  Else if ep_has_wakeup_source(epi) Then
1629  are code path, only used when EPOLL_CTL_MOD removes a wakeup source
1650  smp_mb()
1658  If 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. Then
1659  write_lock_irq( & Lock which protects rdllist and ovflist )
1660  If Not Tells us if the item is currently linked Then
1661  list_add_tail - add a new entry*@new: new entry to be added*@head: list head to add it before* Insert a new entry before the specified head.* This is useful for implementing queues.
1662  all only when ep->mtx is held
1665  If 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_ Then wake_up( & Wait queue used by sys_epoll_wait() )
1667  If 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_ Then pwake++
1670  write_unlock_irq( & Lock which protects rdllist and ovflist )
1674  If pwake Then ep_poll_safewake( & Wait queue used by file->poll() )
1677  Return 0
Caller
NameDescribe
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.