Re: [PATCH v1] platform/surface: aggregator: fix recv_buf() return value

[Maximilian Luz <luzmaximilian@gmail.com>]

On 11/28/23 20:49, Francesco Dolcini wrote:
> From: Francesco Dolcini <francesco.dolcini@toradex.com>
> 
> Serdev recv_buf() callback is supposed to return the amount of bytes
> consumed, therefore an int in between 0 and count.
> 
> Do not return negative number in case of issue, when
> ssam_controller_receive_buf() returns ESHUTDOWN just returns 0, e.g. no
> bytes consumed, this keep the exact same behavior as it was before.
> 
> This fixes a potential WARN in serdev-ttyport.c:ttyport_receive_buf().
> 
> Cc: <stable@vger.kernel.org>
> Fixes: c167b9c7e3d6 ("platform/surface: Add Surface Aggregator subsystem")
> Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>

Thanks! Looks good to me.

Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com>

> ---
>   drivers/platform/surface/aggregator/core.c | 5 ++++-
>   1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/platform/surface/aggregator/core.c b/drivers/platform/surface/aggregator/core.c
> index 1a6373dea109..6152be38398c 100644
> --- a/drivers/platform/surface/aggregator/core.c
> +++ b/drivers/platform/surface/aggregator/core.c
> @@ -231,9 +231,12 @@ static int ssam_receive_buf(struct serdev_device *dev, const unsigned char *buf,
>   			    size_t n)
>   {
>   	struct ssam_controller *ctrl;
> +	int ret;
>   
>   	ctrl = serdev_device_get_drvdata(dev);
> -	return ssam_controller_receive_buf(ctrl, buf, n);
> +	ret = ssam_controller_receive_buf(ctrl, buf, n);
> +
> +	return ret < 0 ? 0 : ret;
>   }
>   
>   static void ssam_write_wakeup(struct serdev_device *dev)