Le 03/05/2016 12:06, Lars Ellenberg a écrit :

On Tue, May 03, 2016 at 11:39:18AM +0200, Nicolas Dichtel wrote:

quoted

Two new handlers have been defined in genl_magic_ headers:
 - __field2: the corresponding nla_put() function (nla_put_flag()) takes
             only two args
 - __field4: the corresponding nla_put() function (nla_put_u64_64bit())
             takes four args

__field2 allows us to define __unspec_field for padding attribute.
__field4 allows us to update the definition of __u64_field: the pad
attribute should now be specified.

Please just NOT use an additional "field",
but always use 0 to pad.

Patch is much shorter as well, see below.

I don't think that the goal is to make the shortest patch...
But frankly, I don't care. The goal was to use the new interface in a proper
way, like every other subsystem.

Attribute type "0" is not used,
and will never be of semantic value,
but always be ignored in the DRBD netlink family.

Whereas using some arbitrary value will be wrong,
and will needlessly break userland.

An application should always ignore unknown attribute, this is a golden rule.
Now if you know that this patch will break applications (which one exactly?), we
can use your proposal.


Regards,
Nicolas