Re: [PATCH] usb: renesas_usbhs: Add error handling for usbhsf_fifo_select()

[Greg KH]

On Wed, Apr 02, 2025 at 08:45:15PM +0800, Wentao Liang wrote:
> In usbhsf_dcp_data_stage_prepare_pop(), the return value of
> usbhsf_fifo_select() needs to be checked. A proper implementation
> can be found in usbhsf_dma_try_pop_with_rx_irq().
> 
> Add an error check and jump to PIO pop when FIFO selection fails.
> 
> Fixes: 9e74d601de8a ("usb: gadget: renesas_usbhs: add data/status stage handler")
> Cc: stable@xxxxxxxxxxxxxxx # v3.2+
> Signed-off-by: Wentao Liang <vulab@xxxxxxxxxxx>
> ---
>  drivers/usb/renesas_usbhs/fifo.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)

How was this tested?



> 
> diff --git a/drivers/usb/renesas_usbhs/fifo.c b/drivers/usb/renesas_usbhs/fifo.c
> index 10607e273879..6cc07ab4782d 100644
> --- a/drivers/usb/renesas_usbhs/fifo.c
> +++ b/drivers/usb/renesas_usbhs/fifo.c
> @@ -466,6 +466,7 @@ static int usbhsf_dcp_data_stage_prepare_pop(struct usbhs_pkt *pkt,
>  	struct usbhs_pipe *pipe = pkt->pipe;
>  	struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
>  	struct usbhs_fifo *fifo = usbhsf_get_cfifo(priv);
> +	int ret;
>  
>  	if (usbhs_pipe_is_busy(pipe))
>  		return 0;
> @@ -480,10 +481,14 @@ static int usbhsf_dcp_data_stage_prepare_pop(struct usbhs_pkt *pkt,
>  
>  	usbhs_pipe_sequence_data1(pipe); /* DATA1 */
>  
> -	usbhsf_fifo_select(pipe, fifo, 0);
> +	ret = usbhsf_fifo_select(pipe, fifo, 0);
> +	if (ret < 0)
> +		goto usbhsf_pio_prepare_pop;
> +
>  	usbhsf_fifo_clear(pipe, fifo);
>  	usbhsf_fifo_unselect(pipe, fifo);
>  
> +usbhsf_pio_prepare_pop:
>  	/*
>  	 * change handler to PIO pop
>  	 */

This change really looks wrong and I would like you to test and verify
tha it actually works before going forward.

thanks,

greg k-h