Commit bbd45f10 authored by Alex Elder's avatar Alex Elder Committed by David S. Miller
Browse files

net: qualcomm: rmnet: rearrange some NOTs 

With the ones' complement arithmetic, the sum of two negated values
is equal to the negation of the sum of the two original values [1].
Rearrange the calculation ip6_payload_sum using this property.

[1] https://tools.ietf.org/html/rfc1071



Signed-off-by: default avatarAlex Elder <elder@linaro.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0e6af897

drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c

+2 −2
Original line number Diff line number Diff line
@@ -140,8 +140,8 @@ rmnet_map_ipv6_dl_csum_trailer(struct sk_buff *skb, 
	 * checksum computed over the pseudo header.

	 */

	ip_header_csum = (__force __be16)ip_fast_csum(ip6h, sizeof(*ip6h) / 4);

	ip6_payload_csum = csum16_sub((__force __sum16)~csum_trailer->csum_value,

				      ~ip_header_csum);

	ip6_payload_csum = ~csum16_sub((__force __sum16)csum_trailer->csum_value,

				       ip_header_csum);



	length = (ip6h->nexthdr == IPPROTO_UDP) ?

		 ntohs(((struct udphdr *)txporthdr)->len) :