linux-kernel - RE: [EXT] Re: [PATCH net] net: mvpp2: Add TCAM entry to drop flow control pause frames

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Date:   Thu, 17 Dec 2020 18:08:44 +0000
From:   Stefan Chulski <stefanc@...vell.com>
To:     Antoine Tenart <atenart@...hat.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
CC:     "thomas.petazzoni@...tlin.com" <thomas.petazzoni@...tlin.com>,
        "davem@...emloft.net" <davem@...emloft.net>,
        Nadav Haklai <nadavh@...vell.com>,
        Yan Markman <ymarkman@...vell.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "kuba@...nel.org" <kuba@...nel.org>,
        "linux@...linux.org.uk" <linux@...linux.org.uk>,
        "mw@...ihalf.com" <mw@...ihalf.com>,
        "andrew@...n.ch" <andrew@...n.ch>,
        "rmk+kernel@...linux.org.uk" <rmk+kernel@...linux.org.uk>,
        "atenart@...nel.org" <atenart@...nel.org>
Subject: RE: [EXT] Re: [PATCH net] net: mvpp2: Add TCAM entry to drop flow
 control pause frames

> Quoting stefanc@...vell.com (2020-12-17 18:45:06)
> > From: Stefan Chulski <stefanc@...vell.com>
> >
> > Issue:
> > Flow control frame used to pause GoP(MAC) was delivered to the CPU and
> > created a load on the CPU. Since XOFF/XON frames are used only by MAC,
> > these frames should be dropped inside MAC.
> >
> > Fix:
> > According to 802.3-2012 - IEEE Standard for Ethernet pause frame has
> > unique destination MAC address 01-80-C2-00-00-01.
> > Add TCAM parser entry to track and drop pause frames by destination MAC.
> >
> > Fixes: db9d7d36eecc ("net: mvpp2: Split the PPv2 driver to a dedicated
> > directory")
> 
> Same here, you should go further in the git history.
> 
> Also, was that introduced when the TCAM support landed in (overriding its
> default configuration?)? Or is that the behaviour since the beginning? I'm
> asking because while this could very be a fix, it could also fall in the
> improvements category.

I believe this behavior since the beginning of the driver.
I would repost this with fixes tag with patch that introduced this driver.

Regards.