libnvdimm/pfn_dev: Don't clear device memmap area during generic namespace probe

nvdimm core use nd_pfn_validate when looking for devdax or fsdax namespace. In this
case device resources are allocated against nd_namespace_io dev. In-order to
allow remap of range in nd_pfn_clear_memmap_error(), move the device memmap
area clearing while initializing pfn namespace. With this device
resource are allocated against nd_pfn and we can use nd_pfn->dev for remapping.

This also avoids calling nd_pfn_clear_mmap_errors twice. Once while probing the
namespace and second while initializing a pfn namespace.

Signed-off-by: Aneesh Kumar K.V <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Dan Williams <[e-mail]>

drivers/nvdimm/pfn_devs.c

···
 		return -ENXIO;
 	}
 
-	return nd_pfn_clear_memmap_errors(nd_pfn);
+	return 0;
 }
 EXPORT_SYMBOL(nd_pfn_validate);
 
···
 		sig = PFN_SIG;
 
 	rc = nd_pfn_validate(nd_pfn, sig);
+	if (rc == 0)
+		return nd_pfn_clear_memmap_errors(nd_pfn);
 	if (rc != -ENODEV)
 		return rc;
 
···
 	pfn_sb->page_size = cpu_to_le32(PAGE_SIZE);
 	checksum = nd_sb_checksum((struct nd_gen_sb *) pfn_sb);
 	pfn_sb->checksum = cpu_to_le64(checksum);
+
+	rc = nd_pfn_clear_memmap_errors(nd_pfn);
+	if (rc)
+		return rc;
 
 	return nvdimm_write_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb), 0);
 }