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From: Alex Elder <elder@linaro.org>
To: subashab@codeaurora.org, stranche@codeaurora.org,
	davem@davemloft.net, kuba@kernel.org
Cc: bjorn.andersson@linaro.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH net-next 1/8] net: qualcomm: rmnet: remove some local variables
Date: Sat, 12 Jun 2021 09:37:29 -0500	[thread overview]
Message-ID: <20210612143736.3498712-2-elder@linaro.org> (raw)
In-Reply-To: <20210612143736.3498712-1-elder@linaro.org>

In rmnet_map_ipv4_dl_csum_trailer(), remove the "csum_temp" and
"addend" local variables, and simplify a few lines of code.

Remove the "csum_temp", "csum_value", "ip6_hdr_csum", and "addend"
local variables in rmnet_map_ipv6_dl_csum_trailer(), and simplify a
few lines of code there as well.

Signed-off-by: Alex Elder <elder@linaro.org>
---
 .../ethernet/qualcomm/rmnet/rmnet_map_data.c  | 37 +++++++------------
 1 file changed, 13 insertions(+), 24 deletions(-)

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
index d4d23ab446ef5..3e6feef0fd252 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
@@ -35,10 +35,9 @@ rmnet_map_ipv4_dl_csum_trailer(struct sk_buff *skb,
 {
 	struct iphdr *ip4h = (struct iphdr *)skb->data;
 	void *txporthdr = skb->data + ip4h->ihl * 4;
-	__sum16 *csum_field, csum_temp, pseudo_csum;
+	__sum16 *csum_field, pseudo_csum;
 	__sum16 ip_payload_csum;
-	u16 csum_value_final;
-	__be16 addend;
+	__sum16 csum_value_final;
 
 	/* Computing the checksum over just the IPv4 header--including its
 	 * checksum field--should yield 0.  If it doesn't, the IP header
@@ -83,14 +82,11 @@ rmnet_map_ipv4_dl_csum_trailer(struct sk_buff *skb,
 	pseudo_csum = ~csum_tcpudp_magic(ip4h->saddr, ip4h->daddr,
 					 ntohs(ip4h->tot_len) - ip4h->ihl * 4,
 					 ip4h->protocol, 0);
-	addend = (__force __be16)pseudo_csum;
-	pseudo_csum = csum16_add(ip_payload_csum, addend);
+	pseudo_csum = csum16_add(ip_payload_csum, (__force __be16)pseudo_csum);
 
-	addend = (__force __be16)*csum_field;
-	csum_temp = ~csum16_sub(pseudo_csum, addend);
-	csum_value_final = (__force u16)csum_temp;
+	csum_value_final = ~csum16_sub(pseudo_csum, (__force __be16)*csum_field);
 
-	if (unlikely(csum_value_final == 0)) {
+	if (unlikely(!csum_value_final)) {
 		switch (ip4h->protocol) {
 		case IPPROTO_UDP:
 			/* RFC 768 - DL4 1's complement rule for UDP csum 0 */
@@ -105,7 +101,7 @@ rmnet_map_ipv4_dl_csum_trailer(struct sk_buff *skb,
 		}
 	}
 
-	if (csum_value_final == (__force u16)*csum_field) {
+	if (csum_value_final == *csum_field) {
 		priv->stats.csum_ok++;
 		return 0;
 	} else {
@@ -122,12 +118,10 @@ rmnet_map_ipv6_dl_csum_trailer(struct sk_buff *skb,
 {
 	struct ipv6hdr *ip6h = (struct ipv6hdr *)skb->data;
 	void *txporthdr = skb->data + sizeof(*ip6h);
-	__sum16 *csum_field, pseudo_csum, csum_temp;
-	__be16 ip6_hdr_csum, addend;
+	__sum16 *csum_field, pseudo_csum;
 	__sum16 ip6_payload_csum;
 	__be16 ip_header_csum;
-	u16 csum_value_final;
-	__be16 csum_value;
+	__sum16 csum_value_final;
 	u32 length;
 
 	/* Checksum offload is only supported for UDP and TCP protocols;
@@ -145,23 +139,18 @@ rmnet_map_ipv6_dl_csum_trailer(struct sk_buff *skb,
 	 * of the IP header from the trailer checksum.  We then add the
 	 * checksum computed over the pseudo header.
 	 */
-	csum_value = ~csum_trailer->csum_value;
 	ip_header_csum = (__force __be16)ip_fast_csum(ip6h, sizeof(*ip6h) / 4);
-	ip6_hdr_csum = (__force __be16)~ip_header_csum;
-	ip6_payload_csum = csum16_sub((__force __sum16)csum_value,
-				      ip6_hdr_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) :
 		 ntohs(ip6h->payload_len);
 	pseudo_csum = ~csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
 				       length, ip6h->nexthdr, 0);
-	addend = (__force __be16)pseudo_csum;
-	pseudo_csum = csum16_add(ip6_payload_csum, addend);
+	pseudo_csum = csum16_add(ip6_payload_csum, (__force __be16)pseudo_csum);
 
-	addend = (__force __be16)*csum_field;
-	csum_temp = ~csum16_sub(pseudo_csum, addend);
-	csum_value_final = (__force u16)csum_temp;
+	csum_value_final = ~csum16_sub(pseudo_csum, (__force __be16)*csum_field);
 
 	if (unlikely(csum_value_final == 0)) {
 		switch (ip6h->nexthdr) {
@@ -180,7 +169,7 @@ rmnet_map_ipv6_dl_csum_trailer(struct sk_buff *skb,
 		}
 	}
 
-	if (csum_value_final == (__force u16)*csum_field) {
+	if (csum_value_final == *csum_field) {
 		priv->stats.csum_ok++;
 		return 0;
 	} else {
-- 
2.27.0


  reply	other threads:[~2021-06-12 14:39 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-12 14:37 [PATCH net-next 0/8] net: qualcomm: rmnet: MAPv4 download checksum cleanup, part 2 Alex Elder
2021-06-12 14:37 ` Alex Elder [this message]
2021-06-12 14:37 ` [PATCH net-next 2/8] net: qualcomm: rmnet: rearrange some NOTs Alex Elder
2021-06-12 14:37 ` [PATCH net-next 3/8] net: qualcomm: rmnet: show that an intermediate sum is zero Alex Elder
2021-06-12 14:37 ` [PATCH net-next 4/8] net: qualcomm: rmnet: return earlier for bad checksum Alex Elder
2021-06-12 14:37 ` [PATCH net-next 5/8] net: qualcomm: rmnet: remove unneeded code Alex Elder
2021-06-12 14:37 ` [PATCH net-next 6/8] net: qualcomm: rmnet: trailer value is a checksum Alex Elder
2021-06-12 14:37 ` [PATCH net-next 7/8] net: qualcomm: rmnet: drop some unary NOTs Alex Elder
2021-06-12 14:37 ` [PATCH net-next 8/8] net: qualcomm: rmnet: IPv6 payload length is simple Alex Elder

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