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net: qualcomm: rmnet: drop some unary NOTs
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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@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Alex Elder authored and David S. Miller committed Jun 12, 2021
1 parent be754f6 commit 411a795
Showing 1 changed file with 7 additions and 7 deletions.
14 changes: 7 additions & 7 deletions drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
Original file line number Diff line number Diff line change
@@ -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

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