On Sun, Jul 26, 2015 at 10:49:39AM -0700, Dan Williams wrote:
On Sun, Jul 26, 2015 at 10:25 AM, Christoph Hellwig
> On Fri, Jul 24, 2015 at 10:38:42PM -0400, Dan Williams wrote:
>> The behavior change to return NULL on an unsupported request is reserved
>> for a later patch.
This is for drivers like pmem that care about the mapping type. For
example, if pmem can't get a cache-enabled mapping it is potentially
putting the write durability of the persistent media at risk.
I understand that part, but the question is why the old behavior
is retained for now and only changed later.