Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block

[safe/jmp/linux-2.6] / drivers / block / cciss_cmd.h

diff --git a/drivers/block/cciss_cmd.h b/drivers/block/cciss_cmd.h
index 25f9762..e624ff9 100644 (file)
--- a/drivers/block/cciss_cmd.h
+++ b/drivers/block/cciss_cmd.h
@@ -167,10 +167,18 @@ typedef struct _SGDescriptor_struct {
 #define CMD_MSG_TIMEOUT 0x05
 #define CMD_MSG_STALE  0xff
 
-/* This structure needs to be divisible by 8 for new
- * indexing method.
+/* This structure needs to be divisible by COMMANDLIST_ALIGNMENT
+ * because low bits of the address are used to to indicate that
+ * whether the tag contains an index or an address.  PAD_32 and
+ * PAD_64 can be adjusted independently as needed for 32-bit
+ * and 64-bits systems.
  */
-#define PADSIZE (sizeof(long) - 4)
+#define COMMANDLIST_ALIGNMENT (8)
+#define IS_64_BIT ((sizeof(long) - 4)/4)
+#define IS_32_BIT (!IS_64_BIT)
+#define PAD_32 (0)
+#define PAD_64 (4)
+#define PADSIZE (IS_32_BIT * PAD_32 + IS_64_BIT * PAD_64)
 typedef struct _CommandList_struct {
   CommandListHeader_struct Header;
   RequestBlock_struct      Request;