openvswitch: Optimize operation for key comparison

In the current implement when comparing two flow keys, we will return
result after comparing the whole key from start to end.

In our optimization, we will return result in the first none-zero
comparison, then we will improve the flow table looking up efficiency.

Signed-off-by: Baowen Zheng <baowen.zheng@corigine.com>
Signed-off-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/openvswitch/flow_table.c

@@ -670,13 +670,13 @@ static bool cmp_key(const struct sw_flow_key *key1,
 {
 	const long *cp1 = (const long *)((const u8 *)key1 + key_start);
 	const long *cp2 = (const long *)((const u8 *)key2 + key_start);
-	long diffs = 0;
 	int i;
 
 	for (i = key_start; i < key_end; i += sizeof(long))
-		diffs |= *cp1++ ^ *cp2++;
+		if (*cp1++ ^ *cp2++)
+			return false;
 
-	return diffs == 0;
+	return true;
 }
 
 static bool flow_cmp_masked_key(const struct sw_flow *flow,