Re: [PATCH net-next v6 7/9] net: dsa: microchip: Add error handling for ksz_switch_macaddr_get()

[Vladimir Oltean <olteanv@gmail.com>]

On Thu, Oct 19, 2023 at 02:28:48PM +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@pengutronix.de>
> Reviewed-by: Andrew Lunn <andrew@lunn.ch>
> Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
> ---
>  drivers/net/dsa/microchip/ksz_common.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/dsa/microchip/ksz_common.c b/drivers/net/dsa/microchip/ksz_common.c
> index 7b05de6fe987..79052a54880c 100644
> --- a/drivers/net/dsa/microchip/ksz_common.c
> +++ b/drivers/net/dsa/microchip/ksz_common.c
> @@ -3612,7 +3612,7 @@ 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();
> @@ -3639,8 +3639,11 @@ 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)
> +			return ret;
> +	}

I understand that you intend the error to be fatal, but this leaks memory and a refcount.