netdev - Re: [net-next PATCH] net: phy: correctly check soft

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Date: Tue, 21 Nov 2023 10:09:01 +0100
From: Larysa Zaremba <larysa.zaremba@...el.com>
To: Christian Marangi <ansuelsmth@...il.com>
CC: Andrew Lunn <andrew@...n.ch>, 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>
Subject: Re: [net-next PATCH] net: phy: correctly check soft_reset ret ONLY
 if defined for PHY

On Mon, Nov 20, 2023 at 05:49:28PM +0100, Christian Marangi wrote:
> On Mon, Nov 20, 2023 at 06:15:43PM +0100, Larysa Zaremba wrote:
> > On Mon, Nov 20, 2023 at 02:15:40PM +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.
> > > 
> > > Fixes: 6e2d85ec0559 ("net: phy: Stop with excessive soft reset")
> > > Signed-off-by: Christian Marangi <ansuelsmth@...il.com>
> > > ---
> > >  drivers/net/phy/phy_device.c | 9 ++++-----
> > >  1 file changed, 4 insertions(+), 5 deletions(-)
> > > 
> > > diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
> > > index 2ce74593d6e4..478126f6b5bc 100644
> > > --- a/drivers/net/phy/phy_device.c
> > > +++ b/drivers/net/phy/phy_device.c
> > > @@ -1235,14 +1235,13 @@ int phy_init_hw(struct phy_device *phydev)
> > >  
> > >  	if (phydev->drv->soft_reset) {
> > >  		ret = phydev->drv->soft_reset(phydev);
> > > +		if (ret < 0)
> > > +			return ret;
> > > +
> > >  		/* see comment in genphy_soft_reset for an explanation */
> > > -		if (!ret)
> > > -			phydev->suspended = 0;
> > > +		phydev->suspended = 0;
> > 
> > Are you sure 'suspended' should not be cleared, if soft_reset fails?
> > 
> > >  	}
> 
> Idea is not change current implementation... And before this, suspended
> was cleared only with reset not failing.
> 

Ah, OK. I should not do reviews that late.
If the change is purely cosmetic though, I think Fixes tag does not apply here.

Other than that:

Reviewed-by: Larysa Zaremba <larysa.zaremba@...el.com>

But I am also not certain, if maintainers would take such small of a change.

> > >  
> > > -	if (ret < 0)
> > > -		return ret;
> > > -
> > >  	ret = phy_scan_fixups(phydev);
> > >  	if (ret < 0)
> > >  		return ret;
> > > -- 
> > > 2.40.1
> > > 
> > > 
> 
> -- 
> 	Ansuel
>