kernel: backport flow_dissect support for tag_brcm

This change helps BCM4908 SoC. It was capable of 940 Mb/s masq NAT while
using iperf but users reported lower & unstable speeds for HTTP based
tests.

For LibreSpeed tests this bumps NAT speed from ~930 Mb/s to ~990 Mb/s
(not that this value seems real but speed bump definitely is).

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
This commit is contained in:
Rafał Miłecki 2022-11-24 16:39:10 +01:00
parent 079ce0413a
commit 829cc60a28

View File

@ -0,0 +1,62 @@
From 52015366e361a88c569550a285c71f72bb095661 Mon Sep 17 00:00:00 2001
From: Florian Fainelli <f.fainelli@gmail.com>
Date: Sun, 22 Mar 2020 14:09:57 -0700
Subject: [PATCH] net: dsa: Implement flow dissection for tag_brcm.c
Provide a flow_dissect callback which returns the network offset and
where to find the skb protocol, given the tags structure a common
function works for both tagging formats that are supported.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Vivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/dsa/tag_brcm.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
--- a/net/dsa/tag_brcm.c
+++ b/net/dsa/tag_brcm.c
@@ -144,6 +144,27 @@ static struct sk_buff *brcm_tag_rcv_ll(s
return skb;
}
+
+static int brcm_tag_flow_dissect(const struct sk_buff *skb, __be16 *proto,
+ int *offset)
+{
+ /* We have been called on the DSA master network device after
+ * eth_type_trans() which pulled the Ethernet header already.
+ * Frames have one of these two layouts:
+ * -----------------------------------
+ * | MAC DA | MAC SA | 4b tag | Type | DSA_TAG_PROTO_BRCM
+ * -----------------------------------
+ * -----------------------------------
+ * | 4b tag | MAC DA | MAC SA | Type | DSA_TAG_PROTO_BRCM_PREPEND
+ * -----------------------------------
+ * skb->data points 2 bytes before the actual Ethernet type field and
+ * we have an offset of 4bytes between where skb->data and where the
+ * payload starts.
+ */
+ *offset = BRCM_TAG_LEN;
+ *proto = ((__be16 *)skb->data)[1];
+ return 0;
+}
#endif
#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM)
@@ -179,6 +200,7 @@ static const struct dsa_device_ops brcm_
.xmit = brcm_tag_xmit,
.rcv = brcm_tag_rcv,
.overhead = BRCM_TAG_LEN,
+ .flow_dissect = brcm_tag_flow_dissect,
};
DSA_TAG_DRIVER(brcm_netdev_ops);
@@ -207,6 +229,7 @@ static const struct dsa_device_ops brcm_
.xmit = brcm_tag_xmit_prepend,
.rcv = brcm_tag_rcv_prepend,
.overhead = BRCM_TAG_LEN,
+ .flow_dissect = brcm_tag_flow_dissect,
};
DSA_TAG_DRIVER(brcm_prepend_netdev_ops);