[PATCH] nvme: add namespace paths links

[Sagi Grimberg]

>>>> It is really annoying to always have to loop through the entire
>>>> /sys/block directory just to find the namespace path links for
>>>> a single namespace in libnvme/nvme-cli.
>>>> So provide links to the namespace paths for efficient lookup.
>>>
>>> I think having some form of links would be useful.  Quite a while ago
>>> Thadeu looked into adding some form of relationship for lsblk and
>>> friends.  Maybe it would be good to sync up and make sure whatever
>>> links we are adding would be useful for all users?
>>>
>> Care to elaborate?
>> Using the block device name is the most straightforward way here; we don't
>> have a good enumeration to leverage as the paths are essentially just a
>> linked list.
>>
>> We sure can have a subdirectory 'paths', and stick the links in there.
>> If that helps with lsblk ...
> 
> I personally don't care.  But I've added Thadeu and the util-linux list
> to get everyone on board.

Why not stick to slaves/ like the device mapper?