On Tue, May 03, 2016 at 12:05:56PM -0400, David Miller wrote:

From: Lars Ellenberg <redacted>
Date: Tue, 3 May 2016 12:06:44 +0200

quoted

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 <redacted>
Date: Tue, 3 May 2016 12:06:44 +0200

quoted

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