From mboxrd@z Thu Jan  1 00:00:00 1970
From: Neil Horman <nhorman@tuxdriver.com>
Subject: Re: [net PATCH] atl1c: Fix misuse of netdev_alloc_skb in refilling
 rx ring
Date: Fri, 26 Jul 2013 13:02:51 -0400
Message-ID: <20130726170251.GC11633@hmsreliant.think-freely.org>
References: <1374857234-1442-1-git-send-email-nhorman@tuxdriver.com>
 <8761vxfefj.fsf@canonical.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Cc: netdev@vger.kernel.org, Jay Cliburn <jcliburn@gmail.com>,
	"David S. Miller" <davem@davemloft.net>, stable@vger.kernel.org
To: Luis Henriques <luis.henriques@canonical.com>
Return-path: <stable-owner@vger.kernel.org>
Content-Disposition: inline
In-Reply-To: <8761vxfefj.fsf@canonical.com>
Sender: stable-owner@vger.kernel.org
List-Id: netdev.vger.kernel.org

On Fri, Jul 26, 2013 at 05:56:16PM +0100, Luis Henriques wrote:
> Neil Horman <nhorman@tuxdriver.com> writes:
> 
> > atl1c uses netdev_alloc_skb to refill its rx dma ring, but that call makes no
> > guarantees about the suitability of the memory for use in DMA.  As a result
> > we've gotten reports of atl1c drivers occasionally hanging and needing to be
> > reset:
> > https://bugzilla.kernel.org/show_bug.cgi?id=54021
> >
> > Fix this by modifying the call to use the internal version __netdev_alloc_skb,
> > where you can set the gfp_mask explicitly to include GFP_DMA.
> >
> > Tested by two reporters in the above bug, who have the hardware to validate it.
> > Both report immediate cessation of the problem with this patch
> >
> > Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
> > CC: Jay Cliburn <jcliburn@gmail.com>
> > CC: "David S. Miller" <davem@davemloft.net>
> > CC: stable@vger.kernel.org
> > Tested-by: Luis Henrix <luis.henrix@gmail.com>
> 
> Thanks Neil!
> 
> Would it be possible for you to update my name and email?  (I've just
> updated my bz account to remove my gmail account address -- I thought
> I had done this ages ago.)
> 
> Tested-by: Luis Henriques <luis.henriques@canonical.com>
> 
I'm sure if Dave has time, he will square that up.
Neil

> Cheers,
> -- 
> Luis
> 
> 
> > Tested-by: Vincent Alquier <vincent.alquier@gmail.com> ---
> > drivers/net/ethernet/atheros/atl1c/atl1c_main.c | 2 +- 1 file
> > changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/ethernet/atheros/atl1c/atl1c_main.c b/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
> > index 786a874..d5e38d1 100644
> > --- a/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
> > +++ b/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
> > @@ -1660,7 +1660,7 @@ static int atl1c_alloc_rx_buffer(struct atl1c_adapter *adapter)
> >  	while (next_info->flags & ATL1C_BUFFER_FREE) {
> >  		rfd_desc = ATL1C_RFD_DESC(rfd_ring, rfd_next_to_use);
> >  
> > -		skb = netdev_alloc_skb(adapter->netdev, adapter->rx_buffer_len);
> > +		skb = __netdev_alloc_skb(adapter->netdev, adapter->rx_buffer_len, GFP_ATOMIC|GFP_DMA);
> >  		if (unlikely(!skb)) {
> >  			if (netif_msg_rx_err(adapter))
> >  				dev_warn(&pdev->dev, "alloc rx buffer failed\n");
> 
>