linux-kernel - Re: [net PATCH] net: phy: correctly check soft

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Message-ID: <5d35be32-58bb-465d-91d9-ca3e8029373e@lunn.ch>
Date:   Sun, 19 Nov 2023 17:24:00 +0100
From:   Andrew Lunn <andrew@...n.ch>
To:     Christian Marangi <ansuelsmth@...il.com>
Cc:     Heiner Kallweit <hkallweit1@...il.com>,
        Russell King <linux@...linux.org.uk>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        stable@...r.kernel.org
Subject: Re: [net PATCH] net: phy: correctly check soft_reset ret ONLY if
 defined for PHY

On Sun, Nov 19, 2023 at 04:12:58PM +0100, Christian Marangi wrote:
> soft_reset call for phy_init_hw had multiple revision across the years
> and the implementation goes back to 2014. Originally was a simple call
> to write the generic PHY reset BIT, it was then moved to a dedicated
> function. It was then added the option for PHY driver to define their
> own special way to reset the PHY. Till this change, checking for ret was
> correct as it was always filled by either the generic reset or the
> custom implementation. This changed tho with commit 6e2d85ec0559 ("net:
> phy: Stop with excessive soft reset"), as the generic reset call to PHY
> was dropped but the ret check was never made entirely optional and
> dependent whether soft_reset was defined for the PHY driver or not.
> 
> Luckly nothing was ever added before the soft_reset call so the ret
> check (in the case where a PHY didn't had soft_reset defined) although
> wrong, never caused problems as ret was init 0 at the start of
> phy_init_hw.
> 
> To prevent any kind of problem and to make the function cleaner and more
> robust, correctly move the ret check if the soft_reset section making it
> optional and needed only with the function defined.

I think this should target net-next, not net. It does not appear to be
an problem which actually affects somebody using stable kernels.

The change itself looks O.K.

    Andrew