linux-kernel - Re: [PATCH 2/3] usb: gadget: f_midi: free usb request when done

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Date:	Wed, 23 Sep 2015 11:10:40 +0800
From:	Peter Chen <peter.chen@...escale.com>
To:	"Felipe F. Tonello" <eu@...ipetonello.com>
CC:	<linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	"Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
	Felipe Balbi <balbi@...com>,
	Andrzej Pietrasiewicz <andrzej.p@...sung.com>
Subject: Re: [PATCH 2/3] usb: gadget: f_midi: free usb request when done

On Tue, Sep 22, 2015 at 07:59:09PM +0100, Felipe F. Tonello wrote:
> req->actual == req->length means that there is no data left to enqueue,
> so free the request.
> 
> Signed-off-by: Felipe F. Tonello <eu@...ipetonello.com>
> ---
>  drivers/usb/gadget/function/f_midi.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
> index edb84ca..e92aff5 100644
> --- a/drivers/usb/gadget/function/f_midi.c
> +++ b/drivers/usb/gadget/function/f_midi.c
> @@ -258,7 +258,10 @@ f_midi_complete(struct usb_ep *ep, struct usb_request *req)
>  		} else if (ep == midi->in_ep) {
>  			/* Our transmit completed. See if there's more to go.
>  			 * f_midi_transmit eats req, don't queue it again. */
> -			f_midi_transmit(midi, req);
> +			if (req->actual < req->length)
> +				f_midi_transmit(midi, req);
> +			else
> +				free_ep_req(ep, req);
>  			return;
>  		}

It is incorrect, if no reqeust in queue, how device knows when
the host sends data?

-- 

Best Regards,
Peter Chen
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