diff --git a/sys/dev/iwm/if_iwm_util.c b/sys/dev/iwm/if_iwm_util.c
index 2ecfa2f42e11..1190c5871ca8 100644
--- a/sys/dev/iwm/if_iwm_util.c
+++ b/sys/dev/iwm/if_iwm_util.c
@@ -163,7 +163,7 @@ iwm_dma_map_mem(void *arg, bus_dma_segment_t *segs, int nsegs, int error)
 	KASSERT(nsegs <= 2, ("too many DMA segments, %d should be <= 2",
 	    nsegs));
 	if (nsegs > 1)
-		KASSERT(segs[1].ds_addr == segs[0].ds_addr + segs[0].ds_size,
+		KASSERT(segs[1].ds_addr == segs[0].ds_addr + segs[0].ds_len,
 		    ("fragmented DMA memory"));
 	*(bus_addr_t *)arg = segs[0].ds_addr;
 }
@@ -402,4 +402,3 @@ iwm_free_resp(struct iwm_softc *sc, struct iwm_host_cmd *hcmd)
 	sc->sc_wantresp = -1;
 	wakeup(&sc->sc_wantresp);
 }
-