Re: [PATCH net-next v5 1/3] net: devmem: allow rx-buf-size > PAGE_SIZE per dmabuf binding

[Bobby Eshleman <bobbyeshleman@gmail.com>]

On Fri, Jul 24, 2026 at 12:58:17PM -0700, Jakub Kicinski wrote:
> On Fri, 24 Jul 2026 09:39:54 -0700 Bobby Eshleman wrote:
> > > BTW did you add both min and max checks? Cause the only risk with using
> > > a dummy value would be that the policy will be rendered inline, and
> > > inline policy is u16 so 64k wouldn't fit. But your sample above has a
> > > max of u32_max which forces the out-of-line policy, which is what we
> > > want.  
> > 
> > Yep, u32_max:
> > 
> > +	 name: rx-page-size
> > ...
> > +        checks:
> > +          min: page-size
> > +          max: u32-max
> > 
> > Sorry, probably should have just sent the whole patch instead of
> > replying hunk-by-hunk.
> 
> Ack, LG, just double checking.
> 
> > BTW, how expressive do we want these policies? For example, would
> > absorbing the power_of_2 check into a policy be valid in the future? or
> > is that too bespoke?
> 
> Power-of-2 could be useful (it's implicitly one bit set, which is also
> potentially useful for validating one-hot flags). The trickiness is
> combining power-of-2 and the min check :S We have one validation per
> field. I was wondering if we would be better off defining the field
> as a shift instead, then we only have to check min. But I thought
> that it'd be a little unusual for uAPI and possibly maybe one day
> we will want the non-power of 2? So I figured checking min using
> the existing facilities and open coding power of two check is good
> enough for now.

SGTM.