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From: Alex Elder <elder@linaro.org>
To: subashab@codeaurora.org, stranche@codeaurora.org,
	davem@davemloft.net, kuba@kernel.org
Cc: sharathv@codeaurora.org, bjorn.andersson@linaro.org,
	evgreen@chromium.org, cpratapa@codeaurora.org,
	David.Laight@ACULAB.COM, olteanv@gmail.com, elder@kernel.org,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH net-next v4 2/6] net: qualcomm: rmnet: simplify some byte order logic
Date: Mon, 15 Mar 2021 08:34:51 -0500	[thread overview]
Message-ID: <20210315133455.1576188-3-elder@linaro.org> (raw)
In-Reply-To: <20210315133455.1576188-1-elder@linaro.org>

In rmnet_map_ipv4_ul_csum_header() and rmnet_map_ipv6_ul_csum_header()
the offset within a packet at which checksumming should commence is
calculated.  This calculation involves byte swapping and a forced type
conversion that makes it hard to understand.

Simplify this by computing the offset in host byte order, then
converting the result when assigning it into the header field.

Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---
 .../ethernet/qualcomm/rmnet/rmnet_map_data.c  | 22 ++++++++++---------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
index 21d38167f9618..bd1aa11c9ce59 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
@@ -197,12 +197,13 @@ rmnet_map_ipv4_ul_csum_header(void *iphdr,
 			      struct rmnet_map_ul_csum_header *ul_header,
 			      struct sk_buff *skb)
 {
-	struct iphdr *ip4h = (struct iphdr *)iphdr;
-	__be16 *hdr = (__be16 *)ul_header, offset;
+	__be16 *hdr = (__be16 *)ul_header;
+	struct iphdr *ip4h = iphdr;
+	u16 offset;
+
+	offset = skb_transport_header(skb) - (unsigned char *)iphdr;
+	ul_header->csum_start_offset = htons(offset);
 
-	offset = htons((__force u16)(skb_transport_header(skb) -
-				     (unsigned char *)iphdr));
-	ul_header->csum_start_offset = offset;
 	ul_header->csum_insert_offset = skb->csum_offset;
 	ul_header->csum_enabled = 1;
 	if (ip4h->protocol == IPPROTO_UDP)
@@ -239,12 +240,13 @@ rmnet_map_ipv6_ul_csum_header(void *ip6hdr,
 			      struct rmnet_map_ul_csum_header *ul_header,
 			      struct sk_buff *skb)
 {
-	struct ipv6hdr *ip6h = (struct ipv6hdr *)ip6hdr;
-	__be16 *hdr = (__be16 *)ul_header, offset;
+	__be16 *hdr = (__be16 *)ul_header;
+	struct ipv6hdr *ip6h = ip6hdr;
+	u16 offset;
+
+	offset = skb_transport_header(skb) - (unsigned char *)ip6hdr;
+	ul_header->csum_start_offset = htons(offset);
 
-	offset = htons((__force u16)(skb_transport_header(skb) -
-				     (unsigned char *)ip6hdr));
-	ul_header->csum_start_offset = offset;
 	ul_header->csum_insert_offset = skb->csum_offset;
 	ul_header->csum_enabled = 1;
 
-- 
2.27.0


  parent reply	other threads:[~2021-03-15 13:35 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-15 13:34 [PATCH net-next v4 0/6] net: qualcomm: rmnet: stop using C bit-fields Alex Elder
2021-03-15 13:34 ` [PATCH net-next v4 1/6] net: qualcomm: rmnet: mark trailer field endianness Alex Elder
2021-03-15 13:34 ` Alex Elder [this message]
2021-03-15 16:02   ` [PATCH net-next v4 2/6] net: qualcomm: rmnet: simplify some byte order logic Alexander Duyck
2021-03-15 17:12     ` Alex Elder
2021-03-15 13:34 ` [PATCH net-next v4 3/6] net: qualcomm: rmnet: kill RMNET_MAP_GET_*() accessor macros Alex Elder
2021-03-15 13:34 ` [PATCH net-next v4 4/6] net: qualcomm: rmnet: use masks instead of C bit-fields Alex Elder
2021-03-15 13:34 ` [PATCH net-next v4 5/6] net: qualcomm: rmnet: don't use C bit-fields in rmnet checksum trailer Alex Elder
2021-03-15 13:34 ` [PATCH net-next v4 6/6] net: qualcomm: rmnet: don't use C bit-fields in rmnet checksum header Alex Elder
2021-03-15 16:12 ` [PATCH net-next v4 0/6] net: qualcomm: rmnet: stop using C bit-fields Alexander Duyck

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