Re: [PATCH] soundwire: qcom: handle return correctly in qcom_swrm_transport_params

[Kees Cook]

On Thu, Apr 01, 2021 at 10:15:02AM +0100, Srinivas Kandagatla wrote:
> Looks like return from reg_write is set but not checked.
> Fix this by adding error return path.
> 
> Reported-by: coverity-bot <keescook+coverity-bot@xxxxxxxxxxxx>
> Addresses-Coverity-ID: 1503591 ("UNUSED_VALUE")
> Fixes: 128eaf937adb ("soundwire: qcom: add support to missing transport params")
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>

Thanks for fixing this!

Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

-Kees

> ---
>  drivers/soundwire/qcom.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/soundwire/qcom.c b/drivers/soundwire/qcom.c
> index 5fd4a99cc8ac..348d9a46f850 100644
> --- a/drivers/soundwire/qcom.c
> +++ b/drivers/soundwire/qcom.c
> @@ -731,17 +731,23 @@ static int qcom_swrm_transport_params(struct sdw_bus *bus,
>  	value |= pcfg->si;
>  
>  	ret = ctrl->reg_write(ctrl, reg, value);
> +	if (ret)
> +		goto err;
>  
>  	if (pcfg->lane_control != SWR_INVALID_PARAM) {
>  		reg = SWRM_DP_PORT_CTRL_2_BANK(params->port_num, bank);
>  		value = pcfg->lane_control;
>  		ret = ctrl->reg_write(ctrl, reg, value);
> +		if (ret)
> +			goto err;
>  	}
>  
>  	if (pcfg->blk_group_count != SWR_INVALID_PARAM) {
>  		reg = SWRM_DP_BLOCK_CTRL2_BANK(params->port_num, bank);
>  		value = pcfg->blk_group_count;
>  		ret = ctrl->reg_write(ctrl, reg, value);
> +		if (ret)
> +			goto err;
>  	}
>  
>  	if (pcfg->hstart != SWR_INVALID_PARAM
> @@ -755,11 +761,15 @@ static int qcom_swrm_transport_params(struct sdw_bus *bus,
>  		ret = ctrl->reg_write(ctrl, reg, value);
>  	}
>  
> +	if (ret)
> +		goto err;
> +
>  	if (pcfg->bp_mode != SWR_INVALID_PARAM) {
>  		reg = SWRM_DP_BLOCK_CTRL3_BANK(params->port_num, bank);
>  		ret = ctrl->reg_write(ctrl, reg, pcfg->bp_mode);
>  	}
>  
> +err:
>  	return ret;
>  }
>  
> -- 
> 2.21.0
> 

-- 
Kees Cook