From: Heiner Kallweit <hkallweit1@gmail.com>
To: Florian Fainelli <f.fainelli@gmail.com>,
Kunihiko Hayashi <hayashi.kunihiko@socionext.com>,
Andrew Lunn <andrew@lunn.ch>,
"David S. Miller" <davem@davemloft.net>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH net v2] net: phy: Fix the issue that netif always links up after resuming
Date: Fri, 30 Nov 2018 19:47:37 +0100 [thread overview]
Message-ID: <47b5606c-564c-2fe8-0683-65288dafe028@gmail.com> (raw)
In-Reply-To: <26e04d2e-16e5-ac0b-daab-931b8f5a0103@gmail.com>
On 30.11.2018 18:46, Florian Fainelli wrote:
>
>
> On 11/30/2018 1:25 AM, Kunihiko Hayashi wrote:
>> Even though the link is down before entering hibernation,
>> there is an issue that the network interface always links up after resuming
>> from hibernation.
>>
>> The phydev->state is PHY_READY before enabling the network interface, so
>> the link is down. After resuming from hibernation, the phydev->state is
>> forcibly set to PHY_UP in mdio_bus_phy_restore(), and the link becomes up.
>>
>> This patch adds a new convenient function to check whether the PHY is in
>> a started state, and expects to solve the issue by changing phydev->state
>> to PHY_UP and calling phy_start_machine() only when the PHY is started.
>>
>> Suggested-by: Heiner Kallweit <hkallweit1@gmail.com>
>> Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
>> ---
>> drivers/net/phy/phy.c | 2 +-
>> drivers/net/phy/phy_device.c | 9 +++++----
>> include/linux/phy.h | 10 ++++++++++
>> 3 files changed, 16 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
>> index 1d73ac3..f484d03 100644
>> --- a/drivers/net/phy/phy.c
>> +++ b/drivers/net/phy/phy.c
>> @@ -670,7 +670,7 @@ void phy_stop_machine(struct phy_device *phydev)
>> cancel_delayed_work_sync(&phydev->state_queue);
>>
>> mutex_lock(&phydev->lock);
>> - if (phydev->state > PHY_UP && phydev->state != PHY_HALTED)
>> + if (phy_is_started(phydev))
>> phydev->state = PHY_UP;
>> mutex_unlock(&phydev->lock);
>> }
>> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
>> index ab33d17..2c39717 100644
>> --- a/drivers/net/phy/phy_device.c
>> +++ b/drivers/net/phy/phy_device.c
>> @@ -309,10 +309,11 @@ static int mdio_bus_phy_restore(struct device *dev)
>> return ret;
>>
>> /* The PHY needs to renegotiate. */
>> - phydev->link = 0;
>> - phydev->state = PHY_UP;
>> -
>> - phy_start_machine(phydev);
>> + if (phy_is_started(phydev)) {
>> + phydev->link = 0;
>> + phydev->state = PHY_UP;
>> + phy_start_machine(phydev);
>> + }
>
> Don't you need some of these steps to be performed under phydev->lock
> being held? See comment below.
>
Yes, locking should be done. The old code sets phydev->state
w/o holding the lock, I'd says this was wrong.
>>
>> return 0;
>> }
>> diff --git a/include/linux/phy.h b/include/linux/phy.h
>> index 3ea87f7..c194b45 100644
>> --- a/include/linux/phy.h
>> +++ b/include/linux/phy.h
>> @@ -898,6 +898,16 @@ static inline bool phy_is_pseudo_fixed_link(struct phy_device *phydev)
>> }
>>
>> /**
>> + * phy_is_started - Convenience function for testing whether a PHY is in
>> + * a started state
>> + * @phydev: the phy_device struct
>> + */
>> +static inline bool phy_is_started(struct phy_device *phydev)
>> +{
>
> An assert with the phydev->lock mutex being held here would greatly
> help, because otherwise this is possibly racy.
>
Have a look at __phy_resume() to see what is meant with this comment.
>> + return phydev->state >= PHY_UP && phydev->state != PHY_HALTED;
>> +}
>> +
>> +/**
>> * phy_write_mmd - Convenience function for writing a register
>> * on an MMD on a given PHY.
>> * @phydev: The phy_device struct
>>
>
next prev parent reply other threads:[~2018-11-30 18:47 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-30 9:25 [RFC PATCH net v2] net: phy: Fix the issue that netif always links up after resuming Kunihiko Hayashi
2018-11-30 17:46 ` Florian Fainelli
2018-11-30 18:47 ` Heiner Kallweit [this message]
2018-12-03 4:35 ` Kunihiko Hayashi
2018-12-03 7:20 ` Heiner Kallweit
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