netdev - Re: [PATCH 2/5] net/cpsw: don't continue if we miss to allocate rx skbs

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Date:	Tue, 23 Apr 2013 23:11:13 +0530
From:	Mugunthan V N <mugunthanvnm@...com>
To:	Sebastian Andrzej Siewior <bigeasy@...utronix.de>
CC:	<netdev@...r.kernel.org>, "David S. Miller" <davem@...emloft.net>,
	<tglx@...utronix.de>
Subject: Re: [PATCH 2/5] net/cpsw: don't continue if we miss to allocate rx
 skbs

On 4/23/2013 11:01 PM, Sebastian Andrzej Siewior wrote:
> if during "ifconfig up" we run out of mem we continue regardless how
> many skbs we got. In worst case we have zero RX skbs and can't ever
> receive further packets since the RX skbs are never reallocated. If
> cpdma_chan_submit() fails we even leak the skb.
> This patch changes the behavior here:
> If we fail to allocate an skb during bring up we don't continue and
> report that error. Same goes for errors from cpdma_chan_submit().
> While here I changed to __netdev_alloc_skb_ip_align() so GFP_KERNEL can
> be used.
>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
> ---
>   drivers/net/ethernet/ti/cpsw.c |   35 ++++++++++++++++++++++-------------
>   1 file changed, 22 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c
> index e2ba702..29700fb 100644
> --- a/drivers/net/ethernet/ti/cpsw.c
> +++ b/drivers/net/ethernet/ti/cpsw.c
> @@ -867,6 +867,15 @@ static void cpsw_init_host_port(struct cpsw_priv *priv)
>   	}
>   }
>   
> +static void cpsw_slave_stop(struct cpsw_slave *slave, struct cpsw_priv *priv)
> +{
> +	if (!slave->phy)
> +		return;
> +	phy_stop(slave->phy);
> +	phy_disconnect(slave->phy);
> +	slave->phy = NULL;
> +}
> +
>   static int cpsw_ndo_open(struct net_device *ndev)
>   {
>   	struct cpsw_priv *priv = netdev_priv(ndev);
> @@ -912,14 +921,16 @@ static int cpsw_ndo_open(struct net_device *ndev)
>   			struct sk_buff *skb;
>   
>   			ret = -ENOMEM;
> -			skb = netdev_alloc_skb_ip_align(priv->ndev,
> -							priv->rx_packet_max);
> +			skb = __netdev_alloc_skb_ip_align(priv->ndev,
> +					priv->rx_packet_max, GFP_KERNEL);
>   			if (!skb)
> -				break;
> +				goto err_cleanup;
>   			ret = cpdma_chan_submit(priv->rxch, skb, skb->data,
>   					skb_tailroom(skb), 0, GFP_KERNEL);
> -			if (WARN_ON(ret < 0))
> -				break;
> +			if (ret < 0) {
> +				kfree_skb(skb);
> +				goto err_cleanup;
> +			}
>   		}
>   		/* continue even if we didn't manage to submit all
>   		 * receive descs
> @@ -944,15 +955,13 @@ static int cpsw_ndo_open(struct net_device *ndev)
>   	if (priv->data.dual_emac)
>   		priv->slaves[priv->emac_port].open_stat = true;
>   	return 0;
> -}
>   
> -static void cpsw_slave_stop(struct cpsw_slave *slave, struct cpsw_priv *priv)
> -{
> -	if (!slave->phy)
> -		return;
> -	phy_stop(slave->phy);
> -	phy_disconnect(slave->phy);
> -	slave->phy = NULL;
> +err_cleanup:
> +	cpdma_ctlr_stop(priv->dma);
> +	for_each_slave(priv, cpsw_slave_stop, priv);
> +	pm_runtime_put_sync(&priv->pdev->dev);
> +	netif_carrier_off(priv->ndev);
> +	return ret;
>   }
>   
>   static int cpsw_ndo_stop(struct net_device *ndev)
Acked-by: Mugunthan V N <mugunthanvnm@...com>

Regards
Mugunthan V N
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