[PATCH] mm/nvdimm: Use correct #defines instead of opencoding

[Aneesh Kumar K.V]

On 5/21/19 9:37 PM, Dan Williams wrote:
> On Tue, May 21, 2019 at 2:51 AM Aneesh Kumar K.V
> <aneesh.kumar at linux.ibm.com> wrote:


....

>>
>> Something like the below (Not tested). I am not sure what we will init the page_size
>> for minor version < 3. This will mark the namespace disabled if the
>> PAGE_SIZE and sizeof(struct page) doesn't match with the values used
>> during namespace create.
> 
> Yes, this is on the right track.
> 
> I would special-case page_size == 0 as 4096 and page_struct_size == 0
> as 64. If either of those is non-zero then the info-block version
> needs to be revved and it needs to be crafted to make older kernels
> fail to parse it.
> 

page_size = SZ_4K implies we fail to enable namesepaces created on ppc64 
till now. We do work fine with page_size = PAGE_SIZE. It is a few error 
check and pfn_sb->npfns that got wrong values. We do reserve the correct 
space for the required pfns even when we recorded wrong pfn_sb->npfs.


> There was an earlier attempt to implement minimum info-block versions here:
> 
> https://lore.kernel.org/lkml/155000670159.348031.17631616775326330606.stgit@dwillia2-desk3.amr.corp.intel.com/
> 
> ...but that was dropped in favor of the the "sub-section" patches.
> 

Ok i will pick that too.

-aneesh