linux-kernel - Re: [PATCH] s390/process: Delete an unnecessary check before the function call "kfree"

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Date:	Thu, 25 Jun 2015 13:37:12 +0200
From:	Heiko Carstens <heiko.carstens@...ibm.com>
To:	walter harms <wharms@....de>
Cc:	SF Markus Elfring <elfring@...rs.sourceforge.net>,
	Martin Schwidefsky <schwidefsky@...ibm.com>,
	linux390@...ibm.com, linux-s390@...r.kernel.org,
	LKML <linux-kernel@...r.kernel.org>,
	kernel-janitors@...r.kernel.org,
	Julia Lawall <julia.lawall@...6.fr>
Subject: Re: [PATCH] s390/process: Delete an unnecessary check before the
 function call "kfree"

On Thu, Jun 25, 2015 at 12:02:28PM +0200, walter harms wrote:
> 
> Am 24.06.2015 22:48, schrieb SF Markus Elfring:
> > From: Markus Elfring <elfring@...rs.sourceforge.net>
> > Date: Wed, 24 Jun 2015 22:40:30 +0200
> > 
> > The kfree() function tests whether its argument is NULL and then
> > returns immediately. Thus the test around the call is not needed.
> > 
> > This issue was detected by using the Coccinelle software.
> > 
> > Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
> > ---
> >  arch/s390/kernel/process.c | 3 +--
> >  1 file changed, 1 insertion(+), 2 deletions(-)
> > 
> > diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
> > index dc5edc2..22e6448 100644
> > --- a/arch/s390/kernel/process.c
> > +++ b/arch/s390/kernel/process.c
> > @@ -81,8 +81,7 @@ void release_thread(struct task_struct *dead_task)
> >  
> >  void arch_release_task_struct(struct task_struct *tsk)
> >  {
> > -	if (tsk->thread.vxrs)
> > -		kfree(tsk->thread.vxrs);
> > +	kfree(tsk->thread.vxrs);
> >  }

This code will be changed soon anyway. So it would be rather pointless
to apply your patch now. Thanks anyway!

> >  int copy_thread(unsigned long clone_flags, unsigned long new_stackp,
> maybe the intention was to check tsk != NULL ?

No.

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