Re: [PATCH net-next 03/14] net: rtnetlink: RTM_GETSTATS: Allow filtering inside nests

Jakub Kicinski [off-list ref] writes:

On Fri, 25 Feb 2022 09:22:19 +0100 Petr Machata wrote:

quoted

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Why use bitfield if we only use the .value, a u32 would do?  

The bitfield validates the mask as well, thereby making sure that
userspace and the kernel are in sync WRT which bits are meaningful.

Specifically in case of filtering, all meaningful bits are always going
to be the set ones. So it should be OK to just handroll the check that
value doesn't include any bits that we don't know about, and we don't
really need the mask.

Nothing that NLA_POLICY_MASK() can't do, right?

I see, so no need to even handroll.

Or do you mean that we can when user space requests _not_ to have a
group reported?

Can't parse this, but I do not think unset bit X will mean anything else
than "do not include X+1 in the response".

quoted

So I can redo this as u32 if you prefer.

I think that'd be better, simplest tool for the job.

NP.