[net-next PATCH] net: phy: correctly check soft_reset ret ONLY if defined for PHY

[net-next PATCH] net: phy: correctly check soft_reset ret ONLY if defined for PHY

[Christian Marangi]

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@gmail.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;
 	}
 
-	if (ret < 0)
-		return ret;
-
 	ret = phy_scan_fixups(phydev);
 	if (ret < 0)
 		return ret;
-- 
2.40.1

Re: [net-next PATCH] net: phy: correctly check soft_reset ret ONLY if defined for PHY

[Christian Marangi]

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@gmail.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.

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

-- 
	Ansuel

Re: [net-next PATCH] net: phy: correctly check soft_reset ret ONLY if defined for PHY

[Christian Marangi]

On Mon, Nov 20, 2023 at 09:42:34AM -0800, Jakub Kicinski wrote:
> On Mon, 20 Nov 2023 14:15:40 +0100 Christian Marangi wrote:
> > 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.
> 
> not currently a bug => no Fixes tag, please

I know it's not a bug but still the referenced commit was wrong. Can I
at least use Ref to reference it?

Due to the changes done to this function, it's hard to catch where the
problem arised with a git blame.

-- 
	Ansuel

Re: [net-next PATCH] net: phy: correctly check soft_reset ret ONLY if defined for PHY

[Larysa Zaremba]

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@gmail.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?

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

Re: [net-next PATCH] net: phy: correctly check soft_reset ret ONLY if defined for PHY

[Jakub Kicinski]

On Mon, 20 Nov 2023 14:15:40 +0100 Christian Marangi wrote:
> 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.

not currently a bug => no Fixes tag, please
-- 
pw-bot: cr

Re: [net-next PATCH] net: phy: correctly check soft_reset ret ONLY if defined for PHY

[Jakub Kicinski]

On Mon, 20 Nov 2023 17:50:53 +0100 Christian Marangi wrote:
> On Mon, Nov 20, 2023 at 09:42:34AM -0800, Jakub Kicinski wrote:
> > On Mon, 20 Nov 2023 14:15:40 +0100 Christian Marangi wrote:  
> > > 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.  
> > 
> > not currently a bug => no Fixes tag, please  
> 
> I know it's not a bug but still the referenced commit was wrong. Can I
> at least use Ref to reference it?

Not sure what you mean by "Ref"

> Due to the changes done to this function, it's hard to catch where the
> problem arised with a git blame.

Right, and you already quote the commit in the body. No objections to
repeating that if you want, maybe:

Introduced by commit 6e2d85ec0559 ("net: phy: Stop with excessive soft
reset").

but as a part of the "body" of the commit message, not tags.

Re: [net-next PATCH] net: phy: correctly check soft_reset ret ONLY if defined for PHY

[Larysa Zaremba]

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@gmail.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@intel.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
>