pmem: add proper fencing to pmem_rw_page()

pmem_rw_page() needs to call wmb_pmem() on writes to make sure that the
newly written data is durable.  This flow was added to pmem_rw_bytes()
and pmem_make_request() with this commit:

commit 61031952f4c8 ("arch, x86: pmem api for ensuring durability of
	persistent memory updates")

...the pmem_rw_page() path was missed.

Cc: <stable@vger.kernel.org>
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index b9525385c0dc..0ba6a978f227 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -92,6 +92,8 @@ static int pmem_rw_page(struct block_device *bdev, sector_t sector,
         struct pmem_device *pmem = bdev->bd_disk->private_data;
 
         pmem_do_bvec(pmem, page, PAGE_CACHE_SIZE, 0, rw, sector);
+        if (rw & WRITE)
+                wmb_pmem();
         page_endio(page, rw & WRITE, 0);
 
         return 0;