linux-kernel - Re: [PATCH 03/23] usb: gadget: f_sourcesink: free requests in sourcesink

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Date:	Tue, 10 Nov 2015 10:02:57 +0800
From:	Peter Chen <peter.chen@...escale.com>
To:	Krzysztof Opasiak <k.opasiak@...sung.com>
CC:	Robert Baldyga <r.baldyga@...sung.com>, <balbi@...com>,
	<gregkh@...uxfoundation.org>, <andrzej.p@...sung.com>,
	<m.szyprowski@...sung.com>, <b.zolnierkie@...sung.com>,
	<linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 03/23] usb: gadget: f_sourcesink: free requests in
 sourcesink_disable()

On Fri, Nov 06, 2015 at 10:58:39AM +0100, Krzysztof Opasiak wrote:
> 
> 
> On 11/06/2015 10:48 AM, Peter Chen wrote:
> >On Fri, Nov 06, 2015 at 09:50:11AM +0100, Robert Baldyga wrote:
> >>On 11/06/2015 09:15 AM, Peter Chen wrote:
> >>>On Tue, Nov 03, 2015 at 01:53:42PM +0100, Robert Baldyga wrote:
> >>>>USB requests in SourceSink function are allocated in sourcesink_get_alt()
> >>>>function, so we prefer to free them rather in sourcesink_disable() than
> >>>>in source_sink_complete() when request is completed with error. It provides
> >>>>better symetry in resource management and improves code readability.
> >>>>
> >>>>Signed-off-by: Robert Baldyga <r.baldyga@...sung.com>
> >>>>---
> >>>>  drivers/usb/gadget/function/f_sourcesink.c | 33 +++++++++++++++++++++++++++---
> >>>>  1 file changed, 30 insertions(+), 3 deletions(-)
> >>>>
> >>>>diff --git a/drivers/usb/gadget/function/f_sourcesink.c b/drivers/usb/gadget/function/f_sourcesink.c
> >>>>index a8b68c6..d8f5f56 100644
> >>>>--- a/drivers/usb/gadget/function/f_sourcesink.c
> >>>>+++ b/drivers/usb/gadget/function/f_sourcesink.c
> >>>>@@ -22,6 +22,8 @@
> >>>>  #include "g_zero.h"
> >>>>  #include "u_f.h"
> >>>>
> >>>>+#define REQ_CNT	8
> >>>>+
> >>>
> >>>It would be buffer if we can have module parameter for this like
> >>>qlen at f_loopback.
> >>>>@@ -561,7 +568,6 @@ static void source_sink_complete(struct usb_ep *ep, struct usb_request *req)
> >>>>  				req->actual, req->length);
> >>>>  		if (ep == ss->out_ep)
> >>>>  			check_read_data(ss, req);
> >>>>-		free_ep_req(ep, req);
> >>>
> >>>I find the current code may cause memory leak, since above code
> >>>is only called one time.
> >>>
> >>
> >>I don't see what you mean. Can you explain a bit more in which situation
> >>can memory leak take place?
> >
> >Oh, sorry, I have not seen there is a "break;" at the source_sink_start_ep for
> >none-iso endpoint, so, I am wrong, no memory leak here.
> >
> >I have tried changing bulk for 8 requests, the performance improves
> >greatly, but still a little problem for OUT,  I will see what's the matter.
> >Besides, it will be better we can have a qlen parameters like f_loopback,
> >in that case, we can improve the performance for gadget, and get the best performance
> >when testing with usbtest, I will do it later.
> >
> 
> Moreover, I would suggest to add qlen and iso_qlen params not only
> qlen as even now we are using different qlen for bulk and iso.
> 

Krzysztof, would you know why we have different qlen for bulk and iso now?

-- 

Best Regards,
Peter Chen
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