From: Andrew Lunn <andrew@lunn.ch>
To: John Crispin <john@phrozen.org>
Cc: Vivien Didelot <vivien.didelot@savoirfairelinux.com>,
Florian Fainelli <f.fainelli@gmail.com>,
"David S . Miller" <davem@davemloft.net>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH V2 3/4] net-next: dsa: fix flow dissection
Date: Wed, 26 Jul 2017 17:10:13 +0200 [thread overview]
Message-ID: <20170726151013.GD12049@lunn.ch> (raw)
In-Reply-To: <20170721085813.30789-3-john@phrozen.org>
On Fri, Jul 21, 2017 at 10:58:12AM +0200, John Crispin wrote:
> RPS and probably other kernel features are currently broken on some if not
> all DSA devices. The root cause of this is that skb_hash will call the
> flow_dissector. At this point the skb still contains the magic switch header
> and the skb->protocol field is not set up to the correct 802.3 value yet.
> By the time the tag specific code is called, removing the header and
> properly setting the protocol an invalid hash is already set. In the case
> of the mt7530 this will result in all flows always having the same hash.
>
> This patch makes the flow dissector honour the nh and protocol offset
> defined by the dsa tag driver thus fixing dissection, hashing and RPS.
>
> Signed-off-by: John Crispin <john@phrozen.org>
> ---
> net/core/flow_dissector.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
> index fc5fc4594c90..1268ae75c3b3 100644
> --- a/net/core/flow_dissector.c
> +++ b/net/core/flow_dissector.c
> @@ -4,6 +4,7 @@
> #include <linux/ip.h>
> #include <linux/ipv6.h>
> #include <linux/if_vlan.h>
> +#include <net/dsa.h>
> #include <net/ip.h>
> #include <net/ipv6.h>
> #include <net/gre.h>
> @@ -440,6 +441,17 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
> skb->vlan_proto : skb->protocol;
> nhoff = skb_network_offset(skb);
> hlen = skb_headlen(skb);
> +
> + if (unlikely(netdev_uses_dsa(skb->dev))) {
> + const struct dsa_device_ops *ops;
> + u8 *p = (u8 *)data;
> +
> + ops = skb->dev->dsa_ptr->tag_ops;
> + if (ops->hash_proto_off)
> + proto = (u16)p[ops->hash_proto_off];
Hi John
Unfortunately, this is not generic enough to work for DSA and EDSA
tagging. With these tagging protocols, the size of the tag depends on
the presence or not of a VLAN header.
To make this work for all tagging protocols, we are going to need to
add an a new op to tag_ops.
Andrew
next prev parent reply other threads:[~2017-07-26 15:10 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-21 8:58 [PATCH V2 1/4] net-next: dsa: move struct dsa_device_ops to the global header file John Crispin
2017-07-21 8:58 ` [PATCH V2 2/4] net-next: dsa: add 802.3 protocol offset to struct dsa_device_ops John Crispin
2017-07-21 8:58 ` [PATCH V2 3/4] net-next: dsa: fix flow dissection John Crispin
2017-07-23 20:26 ` kbuild test robot
2017-07-26 15:10 ` Andrew Lunn [this message]
2017-07-28 19:40 ` John Crispin
2017-07-28 21:25 ` Andrew Lunn
2017-07-21 8:58 ` [PATCH V2 4/4] net-next: tag_mtk: add nh and proto offsets to the ops struct John Crispin
2017-07-21 19:12 ` [PATCH V2 1/4] net-next: dsa: move struct dsa_device_ops to the global header file David Miller
2017-07-26 14:53 ` Andrew Lunn
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