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Date: Fri, 6 Dec 2024 08:13:46 -0800
From: Jakub Kicinski <kuba@kernel.org>
To: "Russell King (Oracle)" <linux@armlinux.org.uk>
Cc: Oleksij Rempel <o.rempel@pengutronix.de>, "David S. Miller"
 <davem@davemloft.net>, Eric Dumazet <edumazet@google.com>, Paolo Abeni
 <pabeni@redhat.com>, Andrew Lunn <andrew+netdev@lunn.ch>, Heiner Kallweit
 <hkallweit1@gmail.com>, Jonathan Corbet <corbet@lwn.net>,
 kernel@pengutronix.de, linux-kernel@vger.kernel.org,
 netdev@vger.kernel.org, Simon Horman <horms@kernel.org>, Maxime Chevallier
 <maxime.chevallier@bootlin.com>, linux-doc@vger.kernel.org
Subject: Re: [PATCH net-next v1 1/7] net: ethtool: plumb PHY stats to PHY
 drivers
Message-ID: <20241206081346.2fc81766@kernel.org>
In-Reply-To: <Z1K_xI-0d3JINvlg@shell.armlinux.org.uk>
References: <20241203075622.2452169-1-o.rempel@pengutronix.de>
	<20241203075622.2452169-2-o.rempel@pengutronix.de>
	<Z1GVLf0RaYCP060b@shell.armlinux.org.uk>
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On Fri, 6 Dec 2024 09:11:32 +0000 Russell King (Oracle) wrote:
> Maybe:
> 
>  * The input structure is pre-initialised with ETHTOOL_STAT_NOT_SET and
>  * the implementation must only change implemented statistics.

Yup, that's better!

FWIW I think my brain goes to talking about zero-init because for
per-queue or per-cpu stats some drivers do:

	for each q:
		struct->stat += q->stat;

without first setting to 0. And it _seems_ fine since NOT_SET is -1,
and the off-by-one is hard to spot. But for PHY stats this sort of
iteration is very unlikely.