Re: [PATCH v3] libnvdimm, pmem: use REQ_FUA, REQ_FLUSH for nvdimm_flush()

Given that nvdimm_flush() has higher overhead than wmb_pmem() (pointer chasing through nd_region), and that we otherwise assume a platform has ADR capability when flush hints are not present, move nvdimm_flush() to REQ_FLUSH context. Note that we still arrange for nvdimm_flush() to be called even in the ADR case. We need at least once wmb() fence to push buffered writes in the cpu out to the ADR protected domain. Cc: Toshi Kani <toshi.kani(a)hpe.com&gt; Cc: Ross Zwisler <ross.zwisler(a)linux.intel.com&gt; Signed-off-by: Dan Williams <dan.j.williams(a)intel.com&gt;