[SCSI] iscsi_tcp: drop session when itt does not match any command

A target should never send us a itt that does not match a running
task. If it does we do not really know what is coming down after the header,
unless we evaluate the hdr and do some guessing sometimes. However,
even if we know what is coming we probably do not have buffers for it or we
cannot respond (if it is a r2t for example), so just drop the session.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

drivers/scsi/iscsi_tcp.c

@@ -755,11 +755,7 @@ iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
 	opcode = hdr->opcode & ISCSI_OPCODE_MASK;
 	/* verify itt (itt encoding: age+cid+itt) */
 	rc = iscsi_verify_itt(conn, hdr, &itt);
-	if (rc == ISCSI_ERR_NO_SCSI_CMD) {
-		/* XXX: what does this do? */
-		tcp_conn->in.datalen = 0; /* force drop */
-		return 0;
-	} else if (rc)
+	if (rc)
 		return rc;
 
 	debug_tcp("opcode 0x%x ahslen %d datalen %d\n",