Re: [PATCH 2/5] nvme: register ns_id attributes as default sysfs groups

["hch@lst.de" <hch@lst.de>]

On Tue, Aug 14, 2018 at 03:44:57PM +0000, Bart Van Assche wrote:
> On Tue, 2018-08-14 at 17:39 +0200, Hannes Reinecke wrote:
> > While I have considered having nvme_nvm_register_sysfs() returning a
> > pointer I would then have to remove the 'static' declaration from the
> > nvm_dev_attr_group_12/20.
> > Which I didn't really like, either.
> 
> Hmm ... I don't see why the static declaration would have to be removed from
> nvm_dev_attr_group_12/20 if nvme_nvm_register_sysfs() would return a pointer?
> Am I perhaps missing something?

No, I think that would be the preferable approach IFF patching the global
table of groups would be viable.  I don't think it is, though - we can
have both normal NVMe and LightNVM devices in the same system, so we
can't just patch it over.

So we'll need three different attribut group arrays:

const struct attribute_group *nvme_ns_id_attr_groups[] = {
	&nvme_ns_id_attr_group,
	NULL,
};

const struct attribute_group *lightnvm12_ns_id_attr_groups[] = {
	&nvme_ns_id_attr_group,
	&nvm_dev_attr_group_12,
	NULL,
};

const struct attribute_group *lightnvm20_ns_id_attr_groups[] = {
	&nvme_ns_id_attr_group,
	&nvm_dev_attr_group_20,
	NULL,
};

and a function to select which one to use.