[SCSI] libosd: OSD2r05: Prepare for rev5 attribute list changes

In OSD2r05 draft each attribute list element header was changed
so attribute-value would be 8 bytes aligned. In OSD2r01-r04
it was aligned on 2 bytes. (This is because in OSD2r01 the complete
element was 8 bytes padded at end but the header was not adjusted
and caused permanent miss-alignment.)

OSD1 elements are not padded and might be or might not be aligned.
OSD1 is still supported.

In this code we do all the code re-factoring to separate OSD1/OSD2
differences but do not change actual wire format. All wire format
changes will happen in one patch later, for bisect-ability.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 15 insertions, 5 deletions

diff --git a/include/scsi/osd_protocol.h b/include/scsi/osd_protocol.h
index cd3cbf764650..fa8343ce3ca2 100644
--- a/include/scsi/osd_protocol.h
+++ b/include/scsi/osd_protocol.h
@@ -301,14 +301,24 @@ struct osd_attributes_list_attrid {
 } __packed;
 
 /*
+ * NOTE: v1: is not aligned.
+ */
+struct osdv1_attributes_list_element {
+        __be32 attr_page;
+        __be32 attr_id;
+        __be16 attr_bytes; /* valid bytes at attr_val without padding */
+        u8 attr_val[0];
+} __packed;
+
+/*
  * osd2r03: 7.1.3.3 List entry format for retrieved attributes and
  *                  for setting attributes
- * NOTE: v2 is 8-bytes aligned, v1 is not aligned.
+ * NOTE: v2 is 8-bytes aligned
  */
-struct osd_attributes_list_element {
+struct osdv2_attributes_list_element {
         __be32 attr_page;
         __be32 attr_id;
-        __be16 attr_bytes;
+        __be16 attr_bytes; /* valid bytes at attr_val without padding */
         u8 attr_val[0];
 } __packed;
 
@@ -324,13 +334,13 @@ enum {
 
 static inline unsigned osdv1_attr_list_elem_size(unsigned len)
 {
-        return ALIGN(len + sizeof(struct osd_attributes_list_element),
+        return ALIGN(len + sizeof(struct osdv1_attributes_list_element),
                      OSDv1_ATTRIBUTES_ELEM_ALIGN);
 }
 
 static inline unsigned osdv2_attr_list_elem_size(unsigned len)
 {
-        return ALIGN(len + sizeof(struct osd_attributes_list_element),
+        return ALIGN(len + sizeof(struct osdv2_attributes_list_element),
                      OSD_ATTRIBUTES_ELEM_ALIGN);
 }