linux-kernel - Re: [PATCH 2/2] task_work: check callback if it's NULL

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Date:	Fri, 15 Mar 2013 08:20:34 +0800
From:	li guang <lig.fnst@...fujitsu.com>
To:	Oleg Nesterov <oleg@...hat.com>
Cc:	viro@...iv.linux.org.uk, edumazet@...gle.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] task_work: check callback if it's NULL

在 2013-03-14四的 15:43 +0100，Oleg Nesterov写道：
> On 03/14, liguang wrote:
> >
> > Signed-off-by: liguang <lig.fnst@...fujitsu.com>
> > ---
> >  kernel/task_work.c |    3 ++-
> >  1 files changed, 2 insertions(+), 1 deletions(-)
> >
> > diff --git a/kernel/task_work.c b/kernel/task_work.c
> > index 0bf4258..f458b08 100644
> > --- a/kernel/task_work.c
> > +++ b/kernel/task_work.c
> > @@ -75,7 +75,8 @@ void task_work_run(void)
> >
> >  		do {
> >  			next = work->next;
> > -			work->func(work);
> > +			if (unlikely(work->func))
> > +				work->func(work);
> 
> Why?
> 
> Oleg.
> 

can we believe a callback always be call-able?
can it happened to be 0? e.g. wrong initialized.
of course, we can complain the caller, be why don't
we easily make it more safer?

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