linux-kernel - [PATCH V2] usb: gadget zero: avoid unnecessary reinit of data in f

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Message-ID: <1355915077-1617-1-git-send-email-armando.visconti@st.com>
Date:	Wed, 19 Dec 2012 12:04:37 +0100
From:	Armando Visconti <armando.visconti@...com>
To:	<balbi@...com>
Cc:	<gregkh@...uxfoundation.org>, <pratyush.anand@...com>,
	<linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<spear-devel@...t.st.com>
Subject: [PATCH V2] usb: gadget zero: avoid unnecessary reinit of data in f_sourcesink

In the IN case, since the USB request is allocated only when
the source/sink function is started and never freed, the USB ept
buffer needs to be initialized only at the beginning. This change
results into a more performant g_zero module, especially when
'pattern=1' is selected.

Signed-off-by: Armando Visconti <armando.visconti@...com>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
---
This is patch V2, after Sbatian's review. Patch is very simple, but
my assumption needs to be cross-verified. This patch has been
quickly tested using a DWC3 controller gadget device.

Felipe, if you can quicly take a look at it..

Armando

 drivers/usb/gadget/f_sourcesink.c |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/f_sourcesink.c b/drivers/usb/gadget/f_sourcesink.c
index 3c126fd..534cf8c 100644
--- a/drivers/usb/gadget/f_sourcesink.c
+++ b/drivers/usb/gadget/f_sourcesink.c
@@ -536,8 +536,7 @@ static void source_sink_complete(struct usb_ep *ep, struct usb_request *req)
 			check_read_data(ss, req);
 			if (pattern != 2)
 				memset(req->buf, 0x55, req->length);
-		} else
-			reinit_write_data(ep, req);
+		}
 		break;
 
 	/* this endpoint is normally active while we're configured */
-- 
1.7.4.4

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