Messages in this thread | | | Date | Wed, 4 May 2016 11:05:30 +0200 | From | Lars Ellenberg <> | Subject | Re: [PATCH net-next v2] block/drbd: use nla_put_u64_64bit() |
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On Tue, May 03, 2016 at 12:05:56PM -0400, David Miller wrote: > From: Lars Ellenberg <lars.ellenberg@linbit.com> > Date: Tue, 3 May 2016 12:06:44 +0200 > > > Please just NOT use an additional "field", > > but always use 0 to pad. > > You can't, it doesn't work.
I did, and it *did* work. At least, it appeared to.
I'm not talking about every user of netlink out there. That I don't know. But specifically for DRBD netlink, from what my experiments tell me, it works just fine.
> We are adding a new field to every netlink protocol family that has > this alignment problem.
We don't have an "alignment problem" there, btw. Last time I checked, we did work fine without this alignment magic, we already take care of that, yes, even on affected architectures.
On Tue, May 03, 2016 at 12:06:52PM -0400, David Miller wrote: > From: Lars Ellenberg <lars.ellenberg@linbit.com> > Date: Tue, 3 May 2016 12:06:44 +0200 > > > Whereas using some arbitrary value will be wrong, > > and will needlessly break userland. > > It cannot break userland.
It can, if those tags have been used already. There is DRBD out-of-tree as well, it usually is ahead of in-tree DRBD.
But yes, I could obviously check and assign and reserve some not-yet-used tag to all of them.
I don't see why, though, given that 0 (appearently) works fine.
Can you elaborate why and how that does not work?
Lars
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