On Wed, Jul 22, 2015 at 5:55 PM, Luis R. Rodriguez [off-list ref] wrote:

On Wed, Jul 22, 2015 at 04:15:41PM -0700, Dan Williams wrote:
Anyway so why is WB and WT allowed if you are going to remove WC and not add UC?

Because all existing usages of WB and WT mappings are clearly free of
I/O side effect concerns.  The WC and now UC usages are a muddy mix of
"sometimes there's I/O side effects, but it depends by arch and
driver".