From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oskar Schirmer Subject: [PATCH] net/fec: fix link/queue interaction, wake queue iff link is up Date: Wed, 6 Oct 2010 13:31:58 +0200 Message-ID: <1286364718-20070-1-git-send-email-oskar@linutronix.de> Cc: Dan Malek , Sebastian Siewior , "Hans J. Koch" , Oskar Schirmer To: netdev@vger.kernel.org Return-path: Received: from www.tglx.de ([62.245.132.106]:39141 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753072Ab0JFLbu (ORCPT ); Wed, 6 Oct 2010 07:31:50 -0400 Sender: netdev-owner@vger.kernel.org List-ID: with hardware slow in negotiation, the system did freeze while trying to mount root on nfs at boot time. while the driver did report being busy when the link is down or no transmission buffers are available, it did not stop the queue, causing instant retries. furthermore, transmission being triggered with link down was caused by unconditional queue wakes, especially on timeouts. now, wake queue only iff link is up and transmission buffers are available, and dont forget to wake queue when link has been adjusted. next, add stop queue notification upon driver induced transmission problems, so network stack has a chance to handle the situation. Signed-off-by: Oskar Schirmer --- drivers/net/fec.c | 14 ++++++++++---- 1 files changed, 10 insertions(+), 4 deletions(-) diff --git a/drivers/net/fec.c b/drivers/net/fec.c index 768b840..c2da006 100644 --- a/drivers/net/fec.c +++ b/drivers/net/fec.c @@ -222,12 +222,14 @@ fec_enet_start_xmit(struct sk_buff *skb, struct net_device *dev) unsigned short status; unsigned long flags; + spin_lock_irqsave(&fep->hw_lock, flags); if (!fep->link) { /* Link is down or autonegotiation is in progress. */ + netif_stop_queue(dev); + spin_unlock_irqrestore(&fep->hw_lock, flags); return NETDEV_TX_BUSY; } - spin_lock_irqsave(&fep->hw_lock, flags); /* Fill in a Tx ring entry */ bdp = fep->cur_tx; @@ -238,6 +240,7 @@ fec_enet_start_xmit(struct sk_buff *skb, struct net_device *dev) * This should not happen, since dev->tbusy should be set. */ printk("%s: tx queue full!.\n", dev->name); + netif_stop_queue(dev); spin_unlock_irqrestore(&fep->hw_lock, flags); return NETDEV_TX_BUSY; } @@ -309,7 +312,8 @@ fec_timeout(struct net_device *dev) dev->stats.tx_errors++; fec_restart(dev, fep->full_duplex); - netif_wake_queue(dev); + if (fep->link && !fep->tx_full) + netif_wake_queue(dev); } static irqreturn_t @@ -602,9 +606,11 @@ static void fec_enet_adjust_link(struct net_device *dev) /* Link on or off change */ if (phy_dev->link != fep->link) { fep->link = phy_dev->link; - if (phy_dev->link) + if (phy_dev->link) { fec_restart(dev, phy_dev->duplex); - else + if (!fep->tx_full) + netif_wake_queue(dev); + } else fec_stop(dev); status_change = 1; } -- 1.7.0.4