iscsi: Add Serial Number Arithmetic LT and GT into iscsi_proto.h

This patch moves the iscsi_sna_lt() and iscsi_sna_lte(), along with
iscsi_sna_gt() and iscsi_sna_gte() from iscsi_target_mod into
static inlines inside of include/scsi/iscsi_proto.h

This patch also includes the ISCSI_HDR_LEN and ISCSI_CRC_LEN
definitions.

(Added JesperJ simpliciation for iscsi_sna_* usage)

Signed-off-by: Mark Rustad <mark.d.rustad@intel.com>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>

1 files changed, 30 insertions, 0 deletions

diff --git a/include/scsi/iscsi_proto.h b/include/scsi/iscsi_proto.h
index f5f83534fc13..988ba06b3ad6 100644
--- a/include/scsi/iscsi_proto.h
+++ b/include/scsi/iscsi_proto.h
@@ -29,10 +29,40 @@
 /* default iSCSI listen port for incoming connections */
 #define ISCSI_LISTEN_PORT       3260
 
+/* iSCSI header length */
+#define ISCSI_HDR_LEN           48
+
+/* iSCSI CRC32C length */
+#define ISCSI_CRC_LEN           4
+
 /* Padding word length */
 #define ISCSI_PAD_LEN           4
 
 /*
+ * Serial Number Arithmetic, 32 bits, RFC1982
+ */
+
+static inline int iscsi_sna_lt(u32 n1, u32 n2)
+{
+        return (s32)(n1 - n2) < 0;
+}
+
+static inline int iscsi_sna_lte(u32 n1, u32 n2)
+{
+        return (s32)(n1 - n2) <= 0;
+}
+
+static inline int iscsi_sna_gt(u32 n1, u32 n2)
+{
+        return (s32)(n1 - n2) > 0;
+}
+
+static inline int iscsi_sna_gte(u32 n1, u32 n2)
+{
+        return (s32)(n1 - n2) >= 0;
+}
+
+/*
  * useful common(control and data pathes) macro
  */
 #define ntoh24(p) (((p)[0] << 16) | ((p)[1] << 8) | ((p)[2]))