Re: [PATCH v1 2/3] (to be folded into): uuid: hoist uuid_is_null() helper from libnvdimm

[Christoph Hellwig <hch@xxxxxx>]

>  static inline bool guid_is_null(guid_t *guid)
>  {
> -	return guid_equal(guid, &guid_null);
> +	return guid_equal(guid, &NULL_GUID);

Given that NULL_UUID/GUID are macros I wouldn't expect this to work,
and in fact the compiler throws pages of warnings at me with this
change..