Index: sys/netinet/khelp/h_ertt.c
===================================================================
--- sys/netinet/khelp/h_ertt.c
+++ sys/netinet/khelp/h_ertt.c
@@ -83,7 +83,7 @@
  */
 struct txseginfo {
 	/* Segment length. */
-	long		len;
+	uint32_t	len;
 	/* Segment sequence number. */
 	tcp_seq		seq;
 	/* Time stamp indicating when the packet was sent. */
@@ -366,8 +366,8 @@
 				    &rtt_bytes_adjust, CORRECT_ACK);
 
 			if (txsi->flags & TXSI_TSO) {
-				txsi->len -= acked;
-				if (txsi->len > 0) {
+				if (txsi->len > acked) {
+					txsi->len -= acked;
 					/*
 					 * This presumes ack for first bytes in
 					 * txsi, this may not be true but it
@@ -400,6 +400,7 @@
 					 */
 					break;
 				}
+				txsi->len = 0;
 			}
 
 			TAILQ_REMOVE(&e_t->txsegi_q, txsi, txsegi_lnk);
@@ -435,7 +436,7 @@
 	struct tcpopt *to;
 	struct tcp_hhook_data *thdp;
 	struct txseginfo *txsi;
-	long len;
+	uint32_t len;
 	int tso;
 
 	KASSERT(ctx_data != NULL, ("%s: ctx_data is NULL!", __func__));
Index: sys/netinet/tcp_output.c
===================================================================
--- sys/netinet/tcp_output.c
+++ sys/netinet/tcp_output.c
@@ -142,7 +142,7 @@
 
 static void inline	hhook_run_tcp_est_out(struct tcpcb *tp,
 			    struct tcphdr *th, struct tcpopt *to,
-			    long len, int tso);
+			    uint32_t len, int tso);
 static void inline	cc_after_idle(struct tcpcb *tp);
 
 /*
@@ -150,7 +150,7 @@
  */
 static void inline
 hhook_run_tcp_est_out(struct tcpcb *tp, struct tcphdr *th,
-    struct tcpopt *to, long len, int tso)
+    struct tcpopt *to, uint32_t len, int tso)
 {
 	struct tcp_hhook_data hhook_data;
 
Index: sys/netinet/tcp_var.h
===================================================================
--- sys/netinet/tcp_var.h
+++ sys/netinet/tcp_var.h
@@ -644,7 +644,7 @@
 	struct tcpcb	*tp;
 	struct tcphdr	*th;
 	struct tcpopt	*to;
-	long		len;
+	uint32_t	len;
 	int		tso;
 	tcp_seq		curack;
 };