[SCSI] libfc: add fc_fill_reply_hdr() and fc_fill_hdr()

Add functions to fill in an FC header given a request header.
These reduces code lines in fc_lport and fc_rport and works
without an exchange/sequence assigned.

fc_fill_reply_hdr() fills a header for a final reply frame.

fc_fill_hdr() which is similar but allows specifying the
f_ctl parameter.

Add defines for F_CTL values FC_FCTL_REQ and FC_FCTL_RESP.
These can be used for most request and response sequences.

v2 of patch adds a line to copy the frame encapsulation
info from the received frame.

Signed-off-by: Joe Eykholt <jeykholt@cisco.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
diff --git a/include/scsi/fc_encode.h b/include/scsi/fc_encode.h
index 9b4867c..6d293c8 100644
--- a/include/scsi/fc_encode.h
+++ b/include/scsi/fc_encode.h
@@ -21,6 +21,13 @@
 #define _FC_ENCODE_H_
 #include <asm/unaligned.h>
 
+/*
+ * F_CTL values for simple requests and responses.
+ */
+#define FC_FCTL_REQ	(FC_FC_FIRST_SEQ | FC_FC_END_SEQ | FC_FC_SEQ_INIT)
+#define FC_FCTL_RESP	(FC_FC_EX_CTX | FC_FC_LAST_SEQ | \
+			FC_FC_END_SEQ | FC_FC_SEQ_INIT)
+
 struct fc_ns_rft {
 	struct fc_ns_fid fid;	/* port ID object */
 	struct fc_ns_fts fts;	/* FC4-types object */