Merge branch 'for-5.8' into for-linus

[platform/kernel/linux-starfive.git] / drivers / nvdimm / pfn.h

diff --git a/drivers/nvdimm/pfn.h b/drivers/nvdimm/pfn.h
index acb1951..37cb1b8 100644 (file)
--- a/drivers/nvdimm/pfn.h
+++ b/drivers/nvdimm/pfn.h
@@ -24,6 +24,18 @@ struct nd_pfn_sb {
        __le64 npfns;
        __le32 mode;
        /* minor-version-1 additions for section alignment */
+       /**
+        * @start_pad: Deprecated attribute to pad start-misaligned namespaces
+        *
+        * start_pad is deprecated because the original definition did
+        * not comprehend that dataoff is relative to the base address
+        * of the namespace not the start_pad adjusted base. The result
+        * is that the dax path is broken, but the block-I/O path is
+        * not. The kernel will no longer create namespaces using start
+        * padding, but it still supports block-I/O for legacy
+        * configurations mainly to allow a backup, reconfigure the
+        * namespace, and restore flow to repair dax operation.
+        */
        __le32 start_pad;
        __le32 end_trunc;
        /* minor-version-2 record the base alignment of the mapping */