Re: [PATCH v3 1/2] usb: gadget: loopback: fix: Don't share qlen and buflen between instances

[Robert Baldyga <r.baldyga@samsung.com>]

On 09/22/2015 08:40 PM, Krzysztof Opasiak wrote:
> Each instance of loopback function may have different qlen
> and buflen attributes values. When linking function to
> configuration those values had been assigned to global
> variables. Linking other instance to config overwrites those
> values.
> 
> This commit moves those values to f_loopback structure
> to avoid overwriting. Now each function has its own instance
> of those values.
> 
> Cc: <stable@vger.kernel.org> # 3.10+
> Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>

Reviewed-by: Robert Baldyga <r.baldyga@samsung.com>

> ---
>  drivers/usb/gadget/function/f_loopback.c |   24 +++++++++++++-----------
>  1 file changed, 13 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/usb/gadget/function/f_loopback.c b/drivers/usb/gadget/function/f_loopback.c
> index 6e2fe63..e4bfed4 100644
> --- a/drivers/usb/gadget/function/f_loopback.c
> +++ b/drivers/usb/gadget/function/f_loopback.c
> @@ -34,6 +34,9 @@ struct f_loopback {
>  
>  	struct usb_ep		*in_ep;
>  	struct usb_ep		*out_ep;
> +
> +	unsigned                qlen;
> +	unsigned                buflen;
>  };
>  
>  static inline struct f_loopback *func_to_loop(struct usb_function *f)
> @@ -41,13 +44,10 @@ static inline struct f_loopback *func_to_loop(struct usb_function *f)
>  	return container_of(f, struct f_loopback, function);
>  }
>  
> -static unsigned qlen;
> -static unsigned buflen;
> -
>  /*-------------------------------------------------------------------------*/
>  
>  static struct usb_interface_descriptor loopback_intf = {
> -	.bLength =		sizeof loopback_intf,
> +	.bLength =		sizeof(loopback_intf),
>  	.bDescriptorType =	USB_DT_INTERFACE,
>  
>  	.bNumEndpoints =	2,
> @@ -253,7 +253,7 @@ static void loopback_complete(struct usb_ep *ep, struct usb_request *req)
>  		}
>  
>  		/* queue the buffer for some later OUT packet */
> -		req->length = buflen;
> +		req->length = loop->buflen;
>  		status = usb_ep_queue(ep, req, GFP_ATOMIC);
>  		if (status == 0)
>  			return;
> @@ -290,7 +290,9 @@ static void disable_loopback(struct f_loopback *loop)
>  
>  static inline struct usb_request *lb_alloc_ep_req(struct usb_ep *ep, int len)
>  {
> -	return alloc_ep_req(ep, len, buflen);
> +	struct f_loopback	*loop = ep->driver_data;
> +
> +	return alloc_ep_req(ep, len, loop->buflen);
>  }
>  
>  static int enable_endpoint(struct usb_composite_dev *cdev, struct f_loopback *loop,
> @@ -317,7 +319,7 @@ static int enable_endpoint(struct usb_composite_dev *cdev, struct f_loopback *lo
>  	 * we buffer at most 'qlen' transfers; fewer if any need more
>  	 * than 'buflen' bytes each.
>  	 */
> -	for (i = 0; i < qlen && result == 0; i++) {
> +	for (i = 0; i < loop->qlen && result == 0; i++) {
>  		req = lb_alloc_ep_req(ep, 0);
>  		if (!req)
>  			goto fail1;
> @@ -391,10 +393,10 @@ static struct usb_function *loopback_alloc(struct usb_function_instance *fi)
>  	lb_opts->refcnt++;
>  	mutex_unlock(&lb_opts->lock);
>  
> -	buflen = lb_opts->bulk_buflen;
> -	qlen = lb_opts->qlen;
> -	if (!qlen)
> -		qlen = 32;
> +	loop->buflen = lb_opts->bulk_buflen;
> +	loop->qlen = lb_opts->qlen;
> +	if (!loop->qlen)
> +		loop->qlen = 32;
>  
>  	loop->function.name = "loopback";
>  	loop->function.bind = loopback_bind;
>