linux-kernel - Re: [PATCH 2/2] usbip: Use common error handling code in stub_recv_cmd

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Date:   Tue, 5 Dec 2017 15:21:19 -0700
From:   Shuah Khan <shuah@...nel.org>
To:     SF Markus Elfring <elfring@...rs.sourceforge.net>,
        linux-usb@...r.kernel.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Valentina Manea <valentina.manea.m@...il.com>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        kernel-janitors@...r.kernel.org,
        Shuah Khan <shuahkh@....samsung.com>,
        Shuah Khan <shuah@...nel.org>
Subject: Re: [PATCH 2/2] usbip: Use common error handling code in
 stub_recv_cmd_submit()

On 12/05/2017 02:52 PM, SF Markus Elfring wrote:
> From: Markus Elfring <elfring@...rs.sourceforge.net>
> Date: Tue, 5 Dec 2017 22:40:30 +0100
> 
> Add a jump target so that a bit of exception handling can be better reused
> at the end of this function.
> 
> Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
> ---
>  drivers/usb/usbip/stub_rx.c | 22 ++++++++++------------
>  1 file changed, 10 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/usb/usbip/stub_rx.c b/drivers/usb/usbip/stub_rx.c
> index a70eb81823a3..f46d71abd2f9 100644
> --- a/drivers/usb/usbip/stub_rx.c
> +++ b/drivers/usb/usbip/stub_rx.c
> @@ -445,29 +445,23 @@ static void stub_recv_cmd_submit(struct stub_device *sdev,
>  	else
>  		priv->urb = usb_alloc_urb(0, GFP_KERNEL);
>  
> -	if (!priv->urb) {
> -		usbip_event_add(ud, SDEV_EVENT_ERROR_MALLOC);
> -		return;
> -	}
> +	if (!priv->urb)
> +		goto add_event_malloc_failure;
>  
>  	/* allocate urb transfer buffer, if needed */
>  	if (pdu->u.cmd_submit.transfer_buffer_length > 0) {
>  		priv->urb->transfer_buffer =
>  			kzalloc(pdu->u.cmd_submit.transfer_buffer_length,
>  				GFP_KERNEL);
> -		if (!priv->urb->transfer_buffer) {
> -			usbip_event_add(ud, SDEV_EVENT_ERROR_MALLOC);
> -			return;
> -		}
> +		if (!priv->urb->transfer_buffer)
> +			goto add_event_malloc_failure;
>  	}
>  
>  	/* copy urb setup packet */
>  	priv->urb->setup_packet = kmemdup(&pdu->u.cmd_submit.setup, 8,
>  					  GFP_KERNEL);
> -	if (!priv->urb->setup_packet) {
> -		usbip_event_add(ud, SDEV_EVENT_ERROR_MALLOC);

Please see comments on my comments on the previous patch in this series.
This patch depends on the patch that is incorrect.

> -		return;
> -	}
> +	if (!priv->urb->setup_packet)
> +		goto add_event_malloc_failure;
>  
>  	/* set other members from the base header of pdu */
>  	priv->urb->context                = (void *) priv;
> @@ -507,6 +501,10 @@ static void stub_recv_cmd_submit(struct stub_device *sdev,
>  	}
>  
>  	usbip_dbg_stub_rx("Leave\n");
> +	return;
> +
> +add_event_malloc_failure:
> +	usbip_event_add(ud, SDEV_EVENT_ERROR_MALLOC);
>  }
>  
>  /* recv a pdu */
> 

I am restructuring this routine to fix a bug and so it stands now,
I don't see a value in taking this patch that doesn't really fix
any specific bug.

thanks,
-- Shuah