Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964837AbZLHEbt (ORCPT ); Mon, 7 Dec 2009 23:31:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S934501AbZLHEbs (ORCPT ); Mon, 7 Dec 2009 23:31:48 -0500 Received: from az33egw02.freescale.net ([192.88.158.103]:43054 "EHLO az33egw02.freescale.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757123AbZLHEbr convert rfc822-to-8bit (ORCPT ); Mon, 7 Dec 2009 23:31:47 -0500 x-mimeole: Produced By Microsoft Exchange V6.5 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 8BIT Subject: RE: [RFC][PATCH 06/10] fec: fix uninitialized rx buffer usage Date: Mon, 7 Dec 2009 21:31:49 -0700 Message-ID: In-Reply-To: <20091204111346.GL15126@pengutronix.de> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [RFC][PATCH 06/10] fec: fix uninitialized rx buffer usage Thread-Index: Acp00uG0lBMdCzFnSDGEhlr4FhW/ZwC6qbFA References: <7a49f4c0ea2f5030068729978c2cb173a6e15857.1259893118.git.amit.kucheria@canonical.com> <20091204111346.GL15126@pengutronix.de> From: "Herring Robert-RA7055" To: "Sascha Hauer" , "Amit Kucheria" Cc: "List Linux Kernel" , "David S. Miller" , , , , , , "Nguyen Dinh-R00091" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4899 Lines: 165 Sascha, > -----Original Message----- > From: Sascha Hauer [mailto:s.hauer@pengutronix.de] > Sent: Friday, December 04, 2009 5:14 AM > To: Amit Kucheria > Cc: List Linux Kernel; Herring Robert-RA7055; David S. > Miller; netdev@vger.kernel.org; > linux-arm-kernel@lists.infradead.org; > valentin.longchamp@epfl.ch; daniel@caiaq.de; > grant.likely@secretlab.ca; Nguyen Dinh-R00091 > Subject: Re: [RFC][PATCH 06/10] fec: fix uninitialized rx buffer usage > > On Fri, Dec 04, 2009 at 04:47:06AM +0200, Amit Kucheria wrote: > > From: Rob Herring > > > > The fec driver was enabling receive buffer descriptor > without allocating > > the buffers. Make sure the buffer descriptors are initialized to not > > start receiving packets. > > > > Signed-off-by: Rob Herring > > Signed-off-by: Amit Kucheria > > Cc: David S. Miller > > Cc: netdev@vger.kernel.org > > --- > > drivers/net/fec.c | 57 > +++++++++++++++++++++++++++-------------------------- > > 1 files changed, 29 insertions(+), 28 deletions(-) > > > > diff --git a/drivers/net/fec.c b/drivers/net/fec.c > > index 16a1d58..9a8743d 100644 > > --- a/drivers/net/fec.c > > +++ b/drivers/net/fec.c > > @@ -1658,6 +1658,7 @@ static int fec_enet_init(struct > net_device *dev, int index) > > { > > struct fec_enet_private *fep = netdev_priv(dev); > > struct bufdesc *cbd_base; > > + struct bufdesc *bdp; > > int i; > > > > /* Allocate memory for buffer descriptors. */ > > @@ -1710,6 +1711,34 @@ static int fec_enet_init(struct > net_device *dev, int index) > > /* Set MII speed to 2.5 MHz */ > > fep->phy_speed = ((((clk_get_rate(fep->clk) / 2 + 4999999) > > / 2500000) / 2) & 0x3F) << 1; > > + > > + /* Initialize the receive buffer descriptors. */ > > + bdp = fep->rx_bd_base; > > + for (i = 0; i < RX_RING_SIZE; i++) { > > + > > + /* Initialize the BD for every fragment in the page. */ > > + bdp->cbd_sc = 0; > > + bdp++; > > + } > > + > > + /* Set the last buffer to wrap */ > > + bdp--; > > + bdp->cbd_sc |= BD_SC_WRAP; > > + > > + /* ...and the same for transmit */ > > + bdp = fep->tx_bd_base; > > + for (i = 0; i < TX_RING_SIZE; i++) { > > + > > + /* Initialize the BD for every fragment in the page. */ > > + bdp->cbd_sc = 0; > > + bdp->cbd_bufaddr = 0; > > + bdp++; > > + } > > + > > + /* Set the last buffer to wrap */ > > + bdp--; > > + bdp->cbd_sc |= BD_SC_WRAP; > > + > > fec_restart(dev, 0); > > I do not really understand why this patch is needed. You move > the buffer > initialisation from fec_restart to fec_enet_init, but fec_restart is > called directly after the initialisation, so this shouldn't > change much. > > I don't need this patch on my boards, so I wonder what is really going > wrong here. It is because open also calls fec_restart after the rx buffers are allocated. With the code in fec_restart, it zeroes out the buffer descriptors that have just been setup. I can't explain how it would work for you. Regards, Rob > > Sascha > > > > > > /* Queue up command to detect the PHY and initialize the > > @@ -1730,7 +1759,6 @@ static void > > fec_restart(struct net_device *dev, int duplex) > > { > > struct fec_enet_private *fep = netdev_priv(dev); > > - struct bufdesc *bdp; > > int i; > > > > /* Whack a reset. We should wait for this. */ > > @@ -1768,33 +1796,6 @@ fec_restart(struct net_device *dev, > int duplex) > > } > > } > > > > - /* Initialize the receive buffer descriptors. */ > > - bdp = fep->rx_bd_base; > > - for (i = 0; i < RX_RING_SIZE; i++) { > > - > > - /* Initialize the BD for every fragment in the page. */ > > - bdp->cbd_sc = BD_ENET_RX_EMPTY; > > - bdp++; > > - } > > - > > - /* Set the last buffer to wrap */ > > - bdp--; > > - bdp->cbd_sc |= BD_SC_WRAP; > > - > > - /* ...and the same for transmit */ > > - bdp = fep->tx_bd_base; > > - for (i = 0; i < TX_RING_SIZE; i++) { > > - > > - /* Initialize the BD for every fragment in the page. */ > > - bdp->cbd_sc = 0; > > - bdp->cbd_bufaddr = 0; > > - bdp++; > > - } > > - > > - /* Set the last buffer to wrap */ > > - bdp--; > > - bdp->cbd_sc |= BD_SC_WRAP; > > - > > /* Enable MII mode */ > > if (duplex) { > > /* MII enable / FD enable */ > > -- > > 1.6.3.3 > > > > > > -- > Pengutronix e.K. | > | > Industrial Linux Solutions | > http://www.pengutronix.de/ | > Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: > +49-5121-206917-0 | > Amtsgericht Hildesheim, HRA 2686 | Fax: > +49-5121-206917-5555 | > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/