linux-kernel - Re: [PATCH net-next v8 3/5] net: dsa: microchip: Add error handling for ksz_switch_macaddr

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Message-ID: <20231026095338.o6v6wzrjoyci72jk@skbuf>
Date:   Thu, 26 Oct 2023 12:53:38 +0300
From:   Vladimir Oltean <olteanv@...il.com>
To:     Oleksij Rempel <o.rempel@...gutronix.de>
Cc:     "David S. Miller" <davem@...emloft.net>,
        Andrew Lunn <andrew@...n.ch>,
        Eric Dumazet <edumazet@...gle.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Woojung Huh <woojung.huh@...rochip.com>,
        Arun Ramadoss <arun.ramadoss@...rochip.com>,
        Conor Dooley <conor+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Florian Fainelli <florian.fainelli@...adcom.com>,
        kernel@...gutronix.de, linux-kernel@...r.kernel.org,
        netdev@...r.kernel.org, UNGLinuxDriver@...rochip.com,
        "Russell King (Oracle)" <linux@...linux.org.uk>,
        devicetree@...r.kernel.org
Subject: Re: [PATCH net-next v8 3/5] net: dsa: microchip: Add error handling
 for ksz_switch_macaddr_get()

On Thu, Oct 26, 2023 at 07:10:49AM +0200, Oleksij Rempel wrote:
> Enhance the ksz_switch_macaddr_get() function to handle errors that may
> occur during the call to ksz_write8(). Specifically, this update checks
> the return value of ksz_write8(), which may fail if regmap ranges
> validation is not passed and returns the error code.
> 
> Signed-off-by: Oleksij Rempel <o.rempel@...gutronix.de>
> Reviewed-by: Andrew Lunn <andrew@...n.ch>
> Reviewed-by: Florian Fainelli <florian.fainelli@...adcom.com>
> ---

Reviewed-by: Vladimir Oltean <vladimir.oltean@....com>

>  drivers/net/dsa/microchip/ksz_common.c | 16 +++++++++++++---
>  1 file changed, 13 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/dsa/microchip/ksz_common.c b/drivers/net/dsa/microchip/ksz_common.c
> index 0c3adc389d0b..00be812bef40 100644
> --- a/drivers/net/dsa/microchip/ksz_common.c
> +++ b/drivers/net/dsa/microchip/ksz_common.c
> @@ -3640,7 +3640,7 @@ int ksz_switch_macaddr_get(struct dsa_switch *ds, int port,
>  	struct ksz_switch_macaddr *switch_macaddr;
>  	struct ksz_device *dev = ds->priv;
>  	const u16 *regs = dev->info->regs;
> -	int i;
> +	int i, ret;
>  
>  	/* Make sure concurrent MAC address changes are blocked */
>  	ASSERT_RTNL();
> @@ -3667,10 +3667,20 @@ int ksz_switch_macaddr_get(struct dsa_switch *ds, int port,
>  	dev->switch_macaddr = switch_macaddr;
>  
>  	/* Program the switch MAC address to hardware */
> -	for (i = 0; i < ETH_ALEN; i++)
> -		ksz_write8(dev, regs[REG_SW_MAC_ADDR] + i, addr[i]);
> +	for (i = 0; i < ETH_ALEN; i++) {
> +		ret = ksz_write8(dev, regs[REG_SW_MAC_ADDR] + i, addr[i]);
> +		if (ret)
> +			goto macaddr_drop;
> +	}
>  
>  	return 0;
> +
> +macaddr_drop:
> +	dev->switch_macaddr = NULL;
> +	refcount_set(&switch_macaddr->refcount, 0);

Nitpick: this line doesn't do any harm, but it doesn't do any good, either.
It can be removed in a follow-up patch.

> +	kfree(switch_macaddr);
> +
> +	return ret;
>  }
>  
>  void ksz_switch_macaddr_put(struct dsa_switch *ds)
> -- 
> 2.39.2
>