| Message ID | 1286364718-20070-1-git-send-email-oskar@linutronix.de |
|---|---|
| State | Rejected, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Oskar Schirmer <oskar@linutronix.de> Date: Wed, 6 Oct 2010 13:31:58 +0200 > 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 <oskar@linutronix.de> You should never have to do this. As long as netif_carrier_on() and netif_carrier_off() are invoked properly by the driver, the core networking will never send you packets when netif_carrier_ok() is false. I am not applying this patch, drivers should not manage tx queue state using link status as a condition, that's the job of the core networking. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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; }
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 <oskar@linutronix.de> --- drivers/net/fec.c | 14 ++++++++++---- 1 files changed, 10 insertions(+), 4 deletions(-)