Re: [Xen-devel] find_next{,_zero}_bit() inconsistencies

[Julien Grall <julien.grall@xxxxxxx>]

Hi Jan,

On 30/08/16 11:08, Jan Beulich wrote:
> > > > On 30.08.16 at 11:26, <david.vrabel@xxxxxxxxxx> wrote:
> > On 29/08/16 12:59, Jan Beulich wrote:
> > > Hello,
> > >
> > > in the context of
> > > https://lists.xenproject.org/archives/html/xen-devel/2016-08/msg03068.html
> > > I once again came across the different behavior our various
> > > implementations of the $subject functions, in particular their varying
> > > handling of the offset argument being greater / greater-or-equal
> > > the size argument. Shouldn't we settle on a single, uniform model,
> > > which might be
> > > 1) offset >= size is valid, returns size,
> > > 2) offset == size is valid, returns size, offset > size is invalid,
> > > 3) offset >= size is invalid.
> > What does the linux implementation do?
> Their generic implementation follows 1). I didn't go and check arch
> overrides.
The ARM64 implementation of find_next_*_bit is a verbatim copy for the 
generic Linux implementation.
ARM32 has its own implementation of find_next_*_bit and follows 1).

So I would lean towards option 1.

Regards,

--
Julien Grall

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