linux-kernel - Re: [PATCH net v2 2/2] smsc911x: avoid PHY being resumed when interface is not up

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Date:   Tue, 21 Mar 2023 15:39:05 +0100
From:   Paolo Abeni <pabeni@...hat.com>
To:     Wolfram Sang <wsa+renesas@...g-engineering.com>,
        netdev@...r.kernel.org
Cc:     linux-renesas-soc@...r.kernel.org,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Steve Glendinning <steve.glendinning@...well.net>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Florian Fainelli <f.fainelli@...il.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH net v2 2/2] smsc911x: avoid PHY being resumed when
 interface is not up

On Mon, 2023-03-20 at 10:20 +0100, Wolfram Sang wrote:
> SMSC911x doesn't need mdiobus suspend/resume, that's why it sets
> 'mac_managed_pm'. However, setting it needs to be moved from init to
> probe, so mdiobus PM functions will really never be called (e.g. when
> the interface is not up yet during suspend/resume). The errno is changed
> because ENODEV has a special meaning when returned in probe().
> 
> Fixes: 3ce9f2bef755 ("net: smsc911x: Stop and start PHY during suspend and resume")
> Suggested-by: Heiner Kallweit <hkallweit1@...il.com>
> Signed-off-by: Wolfram Sang <wsa+renesas@...g-engineering.com>
> ---
> Changes since v1:
> * no change
> 
> In smsc911x_mii_probe(), I remove the sanity check for 'phydev' because
> it was already done in smsc911x_mii_init(). Let me know if this is
> acceptable or if a more defensive approach is favoured.

Since this is a fix, I would keep the old check, too.

> @@ -1108,6 +1102,15 @@ static int smsc911x_mii_init(struct platform_device *pdev,
>  		goto err_out_free_bus_2;
>  	}
>  
> +	phydev = phy_find_first(pdata->mii_bus);
> +	if (!phydev) {
> +		netdev_err(dev, "no PHY found\n");
> +		err = -ENOENT;
> +		goto err_out_free_bus_2;

Why don't you call mdiobus_unregister() in this error path?

mdiobus_register() completed successfully a few lines above.

Cheers,

Paolo