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

From	Michal Hocko <mhocko@kernel.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded variants
Date	2017-01-25 14:10 +0100
Message-ID	<t3vuO-2ag-13@gated-at.bofh.it> (permalink)
References	(2 earlier) <sYRmi-6IL-17@gated-at.bofh.it> <sYRvY-6LY-39@gated-at.bofh.it> <t1HTs-7WH-19@gated-at.bofh.it> <t3aTo-5Sx-31@gated-at.bofh.it> <t3tMl-136-1@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Wed 25-01-17 12:15:59, Vlastimil Babka wrote:
> 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?

how kcalloc hides the GFP_ZERO and the name doesn't reflect that.
 
> [...]
> > 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.

fixed, thanks!

-- 
Michal Hocko
SUSE Labs

Thread

Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded  variants Vlastimil Babka <vbabka@suse.cz> - 2017-01-20 15:00 +0100
  Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded  variants Michal Hocko <mhocko@kernel.org> - 2017-01-24 16:10 +0100
    Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded  variants Vlastimil Babka <vbabka@suse.cz> - 2017-01-25 12:20 +0100
      Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded  variants Michal Hocko <mhocko@kernel.org> - 2017-01-25 14:10 +0100
        Re: [PATCH 5/6] treewide: use kv[mz]alloc* rather than opencoded variants Ilya Dryomov <idryomov@gmail.com> - 2017-01-25 14:50 +0100

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