Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded variants

[Vlastimil Babka]

On 01/24/2017 04:00 PM, Michal Hocko wrote:
> > > Well, I am not opposed to kvmalloc_array but I would argue that this
> > > conversion cannot introduce new overflow issues. The code would have
> > > to be broken already because even though kmalloc_array checks for the
> > > overflow but vmalloc fallback doesn't...
> >
> > Yeah I agree, but if some of the places were really wrong, after the
> > conversion we won't see them anymore.
> >
> > > If there is a general interest for this API I can add it.
> >
> > I think it would be better, yes.
>
> OK, fair enough. I will fold the following into the original patch. I
> was little bit reluctant to create kvcalloc so I've made the original
> callers more talkative and added | __GFP_ZERO.

Fair enough,

> To be honest I do not
> really like how kcalloc...

how kcalloc what?

[...]
> diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
> index cdc55d5ee4ad..eca16612b1ae 100644
> --- a/net/netfilter/x_tables.c
> +++ b/net/netfilter/x_tables.c
> @@ -712,10 +712,7 @@ EXPORT_SYMBOL(xt_check_entry_offsets);
>   */
>  unsigned int *xt_alloc_entry_offsets(unsigned int size)
>  {
> -	if (size < (SIZE_MAX / sizeof(unsigned int)))
> -		return kvzalloc(size * sizeof(unsigned int), GFP_KERNEL);
> -
> -	return NULL;
> +	return kvmalloc_array(size * sizeof(unsigned int), GFP_KERNEL | __GFP_ZERO);

This one wouldn't compile.