Index: head/sys/net/iflib.c
===================================================================
--- head/sys/net/iflib.c
+++ head/sys/net/iflib.c
@@ -2975,6 +2975,8 @@
 #endif
 			ifsd_m[next] = m;
 			while (buflen > 0) {
+				if (i >= max_segs)
+					goto err;
 				max_sgsize = MIN(buflen, maxsegsz);
 				curaddr = pmap_kextract(vaddr);
 				sgsize = PAGE_SIZE - (curaddr & PAGE_MASK);
@@ -2984,8 +2986,6 @@
 				vaddr += sgsize;
 				buflen -= sgsize;
 				i++;
-				if (i >= max_segs)
-					goto err;
 			}
 			count++;
 			tmp = m;