libnvdimm, dax: record the specified alignment of a dax-device instance
We want to use the alignment as the allocation and mapping unit.
Previously this information was only useful for establishing the data
offset, but now it is important to remember the granularity for the
later use.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/nvdimm/pfn.h b/drivers/nvdimm/pfn.h
index 8e343a3..9d2704c 100644
--- a/drivers/nvdimm/pfn.h
+++ b/drivers/nvdimm/pfn.h
@@ -33,7 +33,9 @@
/* minor-version-1 additions for section alignment */
__le32 start_pad;
__le32 end_trunc;
- u8 padding[4004];
+ /* minor-version-2 record the base alignment of the mapping */
+ __le32 align;
+ u8 padding[4000];
__le64 checksum;
};