linux-kernel - [PATCH net-next 7/8] net: qualcomm: rmnet: drop some unary NOTs

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Date:   Sat, 12 Jun 2021 09:37:35 -0500
From:   Alex Elder <elder@...aro.org>
To:     subashab@...eaurora.org, stranche@...eaurora.org,
        davem@...emloft.net, kuba@...nel.org
Cc:     bjorn.andersson@...aro.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH net-next 7/8] net: qualcomm: rmnet: drop some unary NOTs

We compare a payload checksum with a pseudo checksum value for
equality in rmnet_map_ipv4_dl_csum_trailer().  Both of those values
are computed with a unary NOT (~) operation.  The result of the
comparison is the same if we omit that NOT for both values.

Remove these operations in rmnet_map_ipv6_dl_csum_trailer() also.

Signed-off-by: Alex Elder <elder@...aro.org>
---
 .../net/ethernet/qualcomm/rmnet/rmnet_map_data.c   | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
index 610c8b5a8f46a..ed4737d0043d6 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
@@ -87,11 +87,11 @@ rmnet_map_ipv4_dl_csum_trailer(struct sk_buff *skb,
 	 * header checksum value; it is already accounted for in the
 	 * checksum value found in the trailer.
 	 */
-	ip_payload_csum = ~csum_trailer->csum_value;
+	ip_payload_csum = csum_trailer->csum_value;
 
-	pseudo_csum = ~csum_tcpudp_magic(ip4h->saddr, ip4h->daddr,
-					 ntohs(ip4h->tot_len) - ip4h->ihl * 4,
-					 ip4h->protocol, 0);
+	pseudo_csum = csum_tcpudp_magic(ip4h->saddr, ip4h->daddr,
+					ntohs(ip4h->tot_len) - ip4h->ihl * 4,
+					ip4h->protocol, 0);
 
 	/* The cast is required to ensure only the low 16 bits are examined */
 	if (ip_payload_csum != (__sum16)~pseudo_csum) {
@@ -132,13 +132,13 @@ 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(csum_trailer->csum_value, ip_header_csum);
+	ip6_payload_csum = csum16_sub(csum_trailer->csum_value, ip_header_csum);
 
 	length = (ip6h->nexthdr == IPPROTO_UDP) ?
 		 ntohs(((struct udphdr *)txporthdr)->len) :
 		 ntohs(ip6h->payload_len);
-	pseudo_csum = ~csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
-				       length, ip6h->nexthdr, 0);
+	pseudo_csum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
+				      length, ip6h->nexthdr, 0);
 
 	/* It's sufficient to compare the IP payload checksum with the
 	 * negated pseudo checksum to determine whether the packet
-- 
2.27.0