diff --git a/drivers/nvdimm/btt_devs.c b/drivers/nvdimm/btt_devs.c
index 59ad54a63d9f..cb477518dd0e 100644
--- a/drivers/nvdimm/btt_devs.c
+++ b/drivers/nvdimm/btt_devs.c
@@ -128,13 +128,13 @@ static ssize_t namespace_store(struct device *dev,
 	struct nd_btt *nd_btt = to_nd_btt(dev);
 	ssize_t rc;
 
-	nvdimm_bus_lock(dev);
 	device_lock(dev);
+	nvdimm_bus_lock(dev);
 	rc = nd_namespace_store(dev, &nd_btt->ndns, buf, len);
 	dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
 			rc, buf, buf[len - 1] == '\n' ? "" : "\n");
-	device_unlock(dev);
 	nvdimm_bus_unlock(dev);
+	device_unlock(dev);
 
 	return rc;
 }
diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index 3fd7d0d81a47..71805a1aa0f3 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -148,13 +148,13 @@ static ssize_t namespace_store(struct device *dev,
 	struct nd_pfn *nd_pfn = to_nd_pfn(dev);
 	ssize_t rc;
 
-	nvdimm_bus_lock(dev);
 	device_lock(dev);
+	nvdimm_bus_lock(dev);
 	rc = nd_namespace_store(dev, &nd_pfn->ndns, buf, len);
 	dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
 			rc, buf, buf[len - 1] == '\n' ? "" : "\n");
-	device_unlock(dev);
 	nvdimm_bus_unlock(dev);
+	device_unlock(dev);
 
 	return rc;
 }
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;
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 22ea424ee741..073bb57adab1 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1242,6 +1242,13 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
 				goto out_clear;
 			}
 			bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9);
+			/*
+			 * If the partition is not aligned on a page
+			 * boundary, we can't do dax I/O to it.
+			 */
+			if ((bdev->bd_part->start_sect % (PAGE_SIZE / 512)) ||
+			    (bdev->bd_part->nr_sects % (PAGE_SIZE / 512)))
+				bdev->bd_inode->i_flags &= ~S_DAX;
 		}
 	} else {
 		if (bdev->bd_contains == bdev) {
diff --git a/fs/dax.c b/fs/dax.c
index 93bf2f990ace..7ae6df7ea1d2 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -119,7 +119,8 @@ static ssize_t dax_io(struct inode *inode, struct iov_iter *iter,
 		size_t len;
 		if (pos == max) {
 			unsigned blkbits = inode->i_blkbits;
-			sector_t block = pos >> blkbits;
+			long page = pos >> PAGE_SHIFT;
+			sector_t block = page << (PAGE_SHIFT - blkbits);
 			unsigned first = pos - (block << blkbits);
 			long size;
 
diff --git a/include/asm-generic/memory_model.h b/include/asm-generic/memory_model.h
index f20f407ce45d..4b4b056a6eb0 100644
--- a/include/asm-generic/memory_model.h
+++ b/include/asm-generic/memory_model.h
@@ -73,7 +73,7 @@
  * Convert a physical address to a Page Frame Number and back
  */
 #define	__phys_to_pfn(paddr)	((unsigned long)((paddr) >> PAGE_SHIFT))
-#define	__pfn_to_phys(pfn)	((pfn) << PAGE_SHIFT)
+#define	__pfn_to_phys(pfn)	PFN_PHYS(pfn)
 
 #define page_to_pfn __page_to_pfn
 #define pfn_to_page __pfn_to_page