Re: [PATCH 09/14] Big kfree NULL check cleanup - misc remaining drivers

[Jesper Juhl <jesper.juhl@gmail.com>]

On 10/13/05, Miller, Mike (OS Dev) <Mike.Miller@hp.com> wrote:
> > From: Jesper Juhl [mailto:jesper.juhl@gmail.com]
> > This is the remaining misc drivers/ part of the big kfree
> > cleanup patch.
> >
> > Remove pointless checks for NULL prior to calling kfree() in
> > misc files in drivers/.
> >
> >
> > --- linux-2.6.14-rc4-orig/drivers/block/cciss.c
> > 2005-10-11 22:41:05.000000000 +0200
> > +++ linux-2.6.14-rc4/drivers/block/cciss.c    2005-10-12
> > 17:43:18.000000000 +0200
> > @@ -1096,14 +1096,11 @@ static int cciss_ioctl(struct inode *ino
> >  cleanup1:
> >               if (buff) {
> >                       for(i=0; i<sg_used; i++)
> > -                             if(buff[i] != NULL)
> > -                                     kfree(buff[i]);
>
> I'm not sure I agree that these are pointless checks. They're not in the
> main code path so nothing is lost by checking first. What if the pointer
> is NULL????
>

If the pointer is NULL then this bit of code in kfree takes care of things :

 void kfree(const void *objp)
 {
...

         if (unlikely(!objp))
                 return;
...

Runtime behaviour is exactely the same.
kfree checks if the pointer passed to it is NULL in any case and just
returns if it is.


--
Jesper Juhl <jesper.juhl@gmail.com>
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