Index: head/sys/net/iflib.c
===================================================================
--- head/sys/net/iflib.c
+++ head/sys/net/iflib.c
@@ -2892,7 +2892,7 @@
 	if_ctx_t ctx;
 	if_shared_ctx_t		sctx;
 	if_softc_ctx_t		scctx;
-	int i, next, pidx, err, maxsegsz, ntxd, count;
+	int i, next, pidx, err, ntxd, count;
 	struct mbuf *m, *tmp, **ifsd_m;
 
 	m = *m0;
@@ -2935,13 +2935,17 @@
 			m = m->m_next;
 		} while (m != NULL);
 	} else {
-		int buflen, sgsize, max_sgsize;
+		int buflen, sgsize, maxsegsz, max_sgsize;
 		vm_offset_t vaddr;
 		vm_paddr_t curaddr;
 
 		count = i = 0;
-		maxsegsz = sctx->isc_tx_maxsize;
 		m = *m0;
+		if (m->m_pkthdr.csum_flags & CSUM_TSO)
+			maxsegsz = scctx->isc_tx_tso_segsize_max;
+		else
+			maxsegsz = sctx->isc_tx_maxsegsize;
+
 		do {
 			if (__predict_false(m->m_len <= 0)) {
 				tmp = m;