Re: [greybus-dev] PATCH 1/1: greybus/usb: handle unspecified lengths in hub_control

[Greg KH <gregkh@linuxfoundation.org>]

On Wed, Feb 11, 2026 at 11:02:17PM +0100, Jose A. Perez de Azpillaga wrote:
> >From 1e099b581fe475905509b9d600015ea2500b8cf8 Mon Sep 17 00:00:00 2001
> From: "Jose A. Perez de Azpillaga" <azpijr@gmail.com>
> Date: Wed, 11 Feb 2026 22:54:40 +0100
> Subject: [PATCH] greybus/usb: handle unspecified lengths in hub_control

Something went wrong with your email client to include this in the
changelog area.  Perhaps use git send-email instead?

> 
> Fixes the FIXME in hub_control where response length was not handled correctly.

Can you wrap these lines at 72 columns like the editor asks?

> 
> Signed-off-by: Jose A. Perez de Azpillaga <azpijr@gmail.com>
> ---
>  drivers/staging/greybus/usb.c | 16 +++++++++++-----
>  1 file changed, 11 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/staging/greybus/usb.c b/drivers/staging/greybus/usb.c
> index 475f24f20cd4..f5f5a4863ddc 100644
> --- a/drivers/staging/greybus/usb.c
> +++ b/drivers/staging/greybus/usb.c
> @@ -105,8 +105,10 @@ static int hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue, u16 wIndex,
>  	size_t response_size;
>  	int ret;
>  
> -	/* FIXME: handle unspecified lengths */
> -	response_size = sizeof(*response) + wLength;
> +	/* Calculate expected response size */
> +	response_size = sizeof(*response);
> +	if (wLength)
> +		response_size += wLength;

How is this handling an unspecified length?


>  
>  	operation = gb_operation_create(dev->connection,
>  					GB_USB_TYPE_HUB_CONTROL,
> @@ -127,9 +129,13 @@ static int hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue, u16 wIndex,
>  		goto out;
>  
>  	if (wLength) {
> -		/* Greybus core has verified response size */
> -		response = operation->response->payload;
> -		memcpy(buf, response->buf, wLength);
> +		size_t actual_size = operation->response->payload_size - sizeof(*response);
> +		size_t copy_size = min(wLength, actual_size);
> +
> +		if (copy_size) {
> +			response = operation->response->payload;
> +			memcpy(buf, response->buf, copy_size);
> +		}

Sorry, but I do not understand this change.  How was this tested?

thanks,

greg k-h