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Date:   Sun, 18 Apr 2021 08:06:23 -0700
From:   Richard Cochran <richardcochran@gmail.com>
To:     Yangbo Lu <yangbo.lu@nxp.com>
Cc:     netdev@vger.kernel.org, Vladimir Oltean <vladimir.oltean@nxp.com>,
        "David S . Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Kurt Kanzenbach <kurt@linutronix.de>,
        Andrew Lunn <andrew@lunn.ch>,
        Vivien Didelot <vivien.didelot@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Claudiu Manoil <claudiu.manoil@nxp.com>,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        UNGLinuxDriver@microchip.com, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [net-next 1/3] net: dsa: optimize tx timestamp request handling
Message-ID: <20210418150623.GA24506@hoboy.vegasvil.org>
References: <20210416123655.42783-1-yangbo.lu@nxp.com>
 <20210416123655.42783-2-yangbo.lu@nxp.com>
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On Fri, Apr 16, 2021 at 08:36:53PM +0800, Yangbo Lu wrote:
> Optimization could be done on dsa_skb_tx_timestamp(), and dsa device
> drivers should adapt to it.
> 
> - Check SKBTX_HW_TSTAMP request flag at the very beginning, instead of in
>   port_txtstamp, so that most skbs not requiring tx timestamp just return.
> 
> - No longer to identify PTP packets, and limit tx timestamping only for PTP
>   packets. If device driver likes, let device driver do.
> 
> - It is a waste to clone skb directly in dsa_skb_tx_timestamp().
>   For one-step timestamping, a clone is not needed. For any failure of
>   port_txtstamp (this may usually happen), the skb clone has to be freed.
>   So put skb cloning into port_txtstamp where it really needs.

This patch changes three things ^^^ at once.  These are AFAICT
independent changes, and so please break this one patch into three for
easier review.

Thanks,
Richard