Re: [patch] vhost: NULL vs ERR_PTR bug

[Julia Lawall <julia.lawall@lip6.fr>]

On Wed, 15 Jul 2015, walter harms wrote:

>
>
> Am 15.07.2015 13:28, schrieb Michael S. Tsirkin:
> > On Wed, Jul 15, 2015 at 02:16:59PM +0300, Dan Carpenter wrote:
> >> There is only one caller for vhost_kvzalloc() and it expects NULL on
> >> allocation failure.  Most people would probably expect that so let's
> >> change ERR_PTR(-ENOMEM) to NULL.
> >>
> >> Fixes: 4de7255f7d2b ('vhost: extend memory regions allocation to vmalloc')
> >> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> >
> > Ouch. Thanks a lot for noticing this, and it's a good thing
> > you did before Linus merged it.
> > I'll squash this into Igor's patch and redo my pull request.
> >
>
> Is this function needed at all ?
>
> e.g. I followed vzalloc() to __vmalloc_node_range()
>
> a check for size==0 seems to be done there.

At least it looks like one could return the result of vzalloc directly?

julia

>
> re,
>  wh
>
>
> >>
> >> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> >> index a9fe859..99d613b 100644
> >> --- a/drivers/vhost/vhost.c
> >> +++ b/drivers/vhost/vhost.c
> >> @@ -686,7 +686,7 @@ static void *vhost_kvzalloc(unsigned long size)
> >>  	if (!n) {
> >>  		n = vzalloc(size);
> >>  		if (!n)
> >> -			return ERR_PTR(-ENOMEM);
> >> +			return NULL;
> >>  	}
> >>  	return n;
> >>  }
> > --
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