2 files changed, 9 insertions, 3 deletions

diff --git a/drivers/nvdimm/pfn.h b/drivers/nvdimm/pfn.h
index 8e343a3ca873..9d2704c83fa7 100644
--- a/drivers/nvdimm/pfn.h
+++ b/drivers/nvdimm/pfn.h
@@ -33,7 +33,9 @@ struct nd_pfn_sb {
         /* 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;
 };
 
diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index ca396c8f2cd5..58740d7ce81b 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -394,6 +394,9 @@ int nd_pfn_validate(struct nd_pfn *nd_pfn)
                 pfn_sb->end_trunc = 0;
         }
 
+        if (__le16_to_cpu(pfn_sb->version_minor) < 2)
+                pfn_sb->align = 0;
+
         switch (le32_to_cpu(pfn_sb->mode)) {
         case PFN_MODE_RAM:
         case PFN_MODE_PMEM:
@@ -433,7 +436,7 @@ int nd_pfn_validate(struct nd_pfn *nd_pfn)
                 return -EBUSY;
         }
 
-        nd_pfn->align = 1UL << ilog2(offset);
+        nd_pfn->align = le32_to_cpu(pfn_sb->align);
         if (!is_power_of_2(offset) || offset < PAGE_SIZE) {
                 dev_err(&nd_pfn->dev, "bad offset: %#llx dax disabled\n",
                                 offset);
@@ -629,9 +632,10 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn)
         memcpy(pfn_sb->uuid, nd_pfn->uuid, 16);
         memcpy(pfn_sb->parent_uuid, nd_dev_to_uuid(&ndns->dev), 16);
         pfn_sb->version_major = cpu_to_le16(1);
-        pfn_sb->version_minor = cpu_to_le16(1);
+        pfn_sb->version_minor = cpu_to_le16(2);
         pfn_sb->start_pad = cpu_to_le32(start_pad);
         pfn_sb->end_trunc = cpu_to_le32(end_trunc);
+        pfn_sb->align = cpu_to_le32(nd_pfn->align);
         checksum = nd_sb_checksum((struct nd_gen_sb *) pfn_sb);
         pfn_sb->checksum = cpu_to_le64(checksum);