Re: [PATCH 04/23] usb: gadget: f_loopback: free requests in loopback_disable()

[Felipe Ferreri Tonello <eu@felipetonello.com>]

Hi Robert,

On 03/11/15 12:53, Robert Baldyga wrote:
> USB requests in Loopback function are allocated in loopback_get_alt()
> function, so we prefer to free them rather in loopback_disable() than
> in loopback_complete() when request is completed with error. It provides
> better symetry in resource management and improves code readability.

Are we doing this for all functions? Because I see that several
functions does the same thing, they free IN/OUT ep requests on
complete() instead of disable().

I also prefer this, but then we need to refactor most function code.

> 
> Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
> ---
>  drivers/usb/gadget/function/f_loopback.c | 58 +++++++++++++-------------------
>  1 file changed, 23 insertions(+), 35 deletions(-)
> 
> diff --git a/drivers/usb/gadget/function/f_loopback.c b/drivers/usb/gadget/function/f_loopback.c
> index 6b2102b..41464ae 100644
> --- a/drivers/usb/gadget/function/f_loopback.c
> +++ b/drivers/usb/gadget/function/f_loopback.c
> @@ -35,6 +35,9 @@ struct f_loopback {
>  	struct usb_ep		*in_ep;
>  	struct usb_ep		*out_ep;
>  
> +	struct usb_request	*in_req;
> +	struct usb_request	*out_req;
> +
>  	unsigned                qlen;
>  	unsigned                buflen;
>  };
> @@ -249,30 +252,25 @@ static void loopback_complete(struct usb_ep *ep, struct usb_request *req)
>  			 * We received some data from the host so let's
>  			 * queue it so host can read the from our in ep
>  			 */
> -			struct usb_request *in_req = req->context;
> -
> -			in_req->zero = (req->actual < req->length);
> -			in_req->length = req->actual;
> +			loop->in_req->zero = (req->actual < req->length);
> +			loop->in_req->length = req->actual;
> +			req = loop->in_req;
>  			ep = loop->in_ep;
> -			req = in_req;
>  		} else {
>  			/*
>  			 * We have just looped back a bunch of data
>  			 * to host. Now let's wait for some more data.
>  			 */
> -			req = req->context;
> +			req = loop->out_req;
>  			ep = loop->out_ep;
>  		}
>  
>  		/* queue the buffer back to host or for next bunch of data */
>  		status = usb_ep_queue(ep, req, GFP_ATOMIC);
> -		if (status == 0) {
> -			return;
> -		} else {
> +		if (status < 0)
>  			ERROR(cdev, "Unable to loop back buffer to %s: %d\n",
>  			      ep->name, status);
> -			goto free_req;
> -		}
> +		break;
>  
>  		/* "should never get here" */
>  	default:
> @@ -280,20 +278,10 @@ static void loopback_complete(struct usb_ep *ep, struct usb_request *req)
>  				status, req->actual, req->length);
>  		/* FALLTHROUGH */
>  
> -	/* NOTE:  since this driver doesn't maintain an explicit record
> -	 * of requests it submitted (just maintains qlen count), we
> -	 * rely on the hardware driver to clean up on disconnect or
> -	 * endpoint disable.
> -	 */
>  	case -ECONNABORTED:		/* hardware forced ep reset */
>  	case -ECONNRESET:		/* request dequeued */
>  	case -ESHUTDOWN:		/* disconnect from host */
> -free_req:
> -		usb_ep_free_request(ep == loop->in_ep ?
> -				    loop->out_ep : loop->in_ep,
> -				    req->context);
> -		free_ep_req(ep, req);
> -		return;
> +		break;
>  	}
>  }
>  
> @@ -316,7 +304,6 @@ static inline struct usb_request *lb_alloc_ep_req(struct usb_ep *ep, int len)
>  static int alloc_requests(struct usb_composite_dev *cdev,
>  			  struct f_loopback *loop)
>  {
> -	struct usb_request *in_req, *out_req;
>  	int i;
>  	int result = 0;
>  
> @@ -329,23 +316,21 @@ static int alloc_requests(struct usb_composite_dev *cdev,
>  	for (i = 0; i < loop->qlen && result == 0; i++) {
>  		result = -ENOMEM;
>  
> -		in_req = usb_ep_alloc_request(loop->in_ep, GFP_KERNEL);
> -		if (!in_req)
> +		loop->in_req = usb_ep_alloc_request(loop->in_ep, GFP_KERNEL);
> +		if (!loop->in_req)
>  			goto fail;
>  
> -		out_req = lb_alloc_ep_req(loop->out_ep, 0);
> -		if (!out_req)
> +		loop->out_req = lb_alloc_ep_req(loop->out_ep, 0);
> +		if (!loop->out_req)
>  			goto fail_in;
>  
> -		in_req->complete = loopback_complete;
> -		out_req->complete = loopback_complete;
> +		loop->in_req->complete = loopback_complete;
> +		loop->out_req->complete = loopback_complete;
>  
> -		in_req->buf = out_req->buf;
> +		loop->in_req->buf = loop->out_req->buf;
>  		/* length will be set in complete routine */
> -		in_req->context = out_req;
> -		out_req->context = in_req;
>  
> -		result = usb_ep_queue(loop->out_ep, out_req, GFP_ATOMIC);
> +		result = usb_ep_queue(loop->out_ep, loop->out_req, GFP_ATOMIC);
>  		if (result) {
>  			ERROR(cdev, "%s queue req --> %d\n",
>  					loop->out_ep->name, result);
> @@ -356,9 +341,9 @@ static int alloc_requests(struct usb_composite_dev *cdev,
>  	return 0;
>  
>  fail_out:
> -	free_ep_req(loop->out_ep, out_req);
> +	free_ep_req(loop->out_ep, loop->out_req);
>  fail_in:
> -	usb_ep_free_request(loop->in_ep, in_req);
> +	usb_ep_free_request(loop->in_ep, loop->in_req);
>  fail:
>  	return result;
>  }
> @@ -426,6 +411,9 @@ static void loopback_disable(struct usb_function *f)
>  	struct f_loopback	*loop = func_to_loop(f);
>  
>  	disable_loopback(loop);
> +
> +	free_ep_req(loop->out_ep, loop->out_req);
> +	usb_ep_free_request(loop->in_ep, loop->in_req);
>  }
>  
>  static struct usb_function *loopback_alloc(struct usb_function_instance *fi)
> 

-- 
Felipe