Re: [PATCH 1/5] lib/rhashtable: convert param sanitations to WARN_ON

[Davidlohr Bueso]

On Sat, 02 Jun 2018, Herbert Xu wrote:

> On Fri, Jun 01, 2018 at 09:01:21AM -0700, Davidlohr Bueso wrote:
> > For the purpose of making rhashtable_init() unable to fail,
> > we can replace the returning -EINVAL with WARN_ONs whenever
> > the caller passes bogus parameters during initialization.
> >
> > Signed-off-by: Davidlohr Bueso <dbueso@xxxxxxx>
> > ---
> >  lib/rhashtable.c | 9 ++++-----
> >  1 file changed, 4 insertions(+), 5 deletions(-)
> >
> > diff --git a/lib/rhashtable.c b/lib/rhashtable.c
> > index 9427b5766134..05a4b1b8b8ce 100644
> > --- a/lib/rhashtable.c
> > +++ b/lib/rhashtable.c
> > @@ -1024,12 +1024,11 @@ int rhashtable_init(struct rhashtable *ht,
> >
> >  	size = HASH_DEFAULT_SIZE;
> >
> > -	if ((!params->key_len && !params->obj_hashfn) ||
> > -	    (params->obj_hashfn && !params->obj_cmpfn))
> > -		return -EINVAL;
> > +	WARN_ON((!params->key_len && !params->obj_hashfn) ||
> > +		(params->obj_hashfn && !params->obj_cmpfn));
> >
> > -	if (params->nulls_base && params->nulls_base < (1U << RHT_BASE_SHIFT))
> > -		return -EINVAL;
> > +	WARN_ON(params->nulls_base &&
> > +		params->nulls_base < (1U << RHT_BASE_SHIFT));
>
> I still don't like this.
>
> Yes for your use-case you will never crash and a WARN_ON is fine.
> However, rhashtable is used in all sorts of contexts and returning
> an error makes sense for quite a number of them.

Curious, are these users setting up the param structure dynamically
or something that they can pass along bogus values?

If that's the case then yes, I definitely agree.