diff --git a/net/appletalk/ddp.c b/net/appletalk/ddp.c
index 31fca64d17a2b9cea30cf162834fe1cb6fea35f2..b631cc7345403bd5fd8b1ef104475afcf870b3b2 100644
--- a/net/appletalk/ddp.c
+++ b/net/appletalk/ddp.c
@@ -922,13 +922,8 @@ static unsigned long atalk_sum_partial(const unsigned char *data,
 {
 	/* This ought to be unwrapped neatly. I'll trust gcc for now */
 	while (len--) {
-		sum += *data;
-		sum <<= 1;
-		if (sum & 0x10000) {
-			sum++;
-			sum &= 0xffff;
-		}
-		data++;
+		sum += *data++;
+		sum = rol16(sum, 1);
 	}
 	return sum;
 }