您是否需要在del_timer()之后再次调用init_timer() [英] Do you need to call init_timer() again after a del_timer()

问题描述

我有一个Linux模块，它创建计时器，其中一些计时器可能会在其处理程序功能中再次添加自己.

I have a Linux module which creates timers, some of which may add themselves again during their handler function.

在其他情况下，使用del_timer_sync()删除计时器(可能在关闭计时器之前).

In some other cases, the timer is removed (perhaps before it's gone off) using del_timer_sync().

在那种情况下，我是否需要在下一个add_timer(之前在结构上再次执行init_timer()调用)，还是浪费了(宝贵的)中断延迟?

In that case, do I need to do the init_timer() call again on the struct before I next add_timer() or is that just a waste of (precious) interrupt latency?

推荐答案

要回答我自己的问题，我想如果我打算访问任何del_timer()或del_timer_sync()之后，确实需要在自己的结构上初始化init_timer().再次进行结构化-例如，在执行timer_pending()或在模块清理过程中执行某些操作时.

To answer my own question, I believe I do need to init_timer() my struct after any del_timer() or del_timer_sync() if I ever intend to access the struct again - for example, when doing a timer_pending() or something during module cleanup.

我认为在编写可能重复使用计时器的内核模块的情况下，最好的做法是:

I think in the case of writing a kernel module which potentially re-uses a timer, the best thing to do is:

static struct timer_list my_timer;

...

static void remove_my_timer(void)
{
  if (timer_pending(&my_timer))
  {
    del_timer_sync(&my_timer);
    init_timer(&my_timer);
  }
}

static void arm_my_timer(...)
{
  remove_my_timer();
  my_timer.expires  = ...;
  my_timer.data     = ...;
  my_timer.function = ...;
  add_timer(&my_timer);
}

...

int __init init_my_device(void)
{
  ...
  init_timer(&my_timer);
  ...
}

void __exit cleanup_my_device(void)
{
  ...
  remove_my_timer();
  ...
}

希望对以后的人有所帮助.

Hope that helps someone else in future.

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