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



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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