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Message-ID: <18320.41737.651384.808195@robur.slu.se>
Date: Fri, 18 Jan 2008 14:00:57 +0100
From: Robert Olsson <Robert.Olsson@...a.slu.se>
To: David Miller <davem@...emloft.net>
Cc: Robert.Olsson@...a.slu.se, elendil@...net.nl,
jesse.brandeburg@...el.com, slavon@...telecom.ru,
netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [REGRESSION] 2.6.24-rc7: e1000: Detected Tx Unit Hang
David Miller writes:
> > eth0 e1000_irq_enable sem = 1 <- ifconfig eth0 down
> > eth0 e1000_irq_disable sem = 2
> >
> > **e1000_open <- ifconfig eth0 up
> > eth0 e1000_irq_disable sem = 3 Dead. irq's can't be enabled
> > e1000_irq_enable miss
> > eth0 e1000_irq_enable sem = 2
> > e1000_irq_enable miss
> > eth0 e1000_irq_enable sem = 1
> > ADDRCONF(NETDEV_UP): eth0: link is not ready
>
> Yes, this semaphore thing is highly problematic. In the most crucial
> areas where network driver consistency matters the most for ease of
> understanding and debugging, the Intel drivers choose to be different
I don't understand the idea with semaphore for enabling/disabling
irq's either the overall logic must safer/better without it.
> The way the napi_disable() logic breaks out from high packet load in
> net_rx_action() is it simply returns even leaving interrupts disabled
> when a pending napi_disable() is pending.
>
> This is what trips up the semaphore logic.
>
> Robert, give this patch a try.
>
> In the long term this semaphore should be completely eliminated,
> there is no justification for it.
It's on the testing list...
Cheers
--ro
>
> Signed-off-by: David S. Miller <davem@...emloft.net>
>
> diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c
> index 0c9a6f7..76c0fa6 100644
> --- a/drivers/net/e1000/e1000_main.c
> +++ b/drivers/net/e1000/e1000_main.c
> @@ -632,6 +632,7 @@ e1000_down(struct e1000_adapter *adapter)
>
> #ifdef CONFIG_E1000_NAPI
> napi_disable(&adapter->napi);
> + atomic_set(&adapter->irq_sem, 0);
> #endif
> e1000_irq_disable(adapter);
>
> diff --git a/drivers/net/e1000e/netdev.c b/drivers/net/e1000e/netdev.c
> index 2ab3bfb..9cc5a6b 100644
> --- a/drivers/net/e1000e/netdev.c
> +++ b/drivers/net/e1000e/netdev.c
> @@ -2183,6 +2183,7 @@ void e1000e_down(struct e1000_adapter *adapter)
> msleep(10);
>
> napi_disable(&adapter->napi);
> + atomic_set(&adapter->irq_sem, 0);
> e1000_irq_disable(adapter);
>
> del_timer_sync(&adapter->watchdog_timer);
> diff --git a/drivers/net/ixgb/ixgb_main.c b/drivers/net/ixgb/ixgb_main.c
> index d2fb88d..4f63839 100644
> --- a/drivers/net/ixgb/ixgb_main.c
> +++ b/drivers/net/ixgb/ixgb_main.c
> @@ -296,6 +296,11 @@ ixgb_down(struct ixgb_adapter *adapter, boolean_t kill_watchdog)
> {
> struct net_device *netdev = adapter->netdev;
>
> +#ifdef CONFIG_IXGB_NAPI
> + napi_disable(&adapter->napi);
> + atomic_set(&adapter->irq_sem, 0);
> +#endif
> +
> ixgb_irq_disable(adapter);
> free_irq(adapter->pdev->irq, netdev);
>
> @@ -304,9 +309,7 @@ ixgb_down(struct ixgb_adapter *adapter, boolean_t kill_watchdog)
>
> if(kill_watchdog)
> del_timer_sync(&adapter->watchdog_timer);
> -#ifdef CONFIG_IXGB_NAPI
> - napi_disable(&adapter->napi);
> -#endif
> +
> adapter->link_speed = 0;
> adapter->link_duplex = 0;
> netif_carrier_off(netdev);
> diff --git a/drivers/net/ixgbe/ixgbe_main.c b/drivers/net/ixgbe/ixgbe_main.c
> index de3f45e..a4265bc 100644
> --- a/drivers/net/ixgbe/ixgbe_main.c
> +++ b/drivers/net/ixgbe/ixgbe_main.c
> @@ -1409,9 +1409,11 @@ void ixgbe_down(struct ixgbe_adapter *adapter)
> IXGBE_WRITE_FLUSH(&adapter->hw);
> msleep(10);
>
> + napi_disable(&adapter->napi);
> + atomic_set(&adapter->irq_sem, 0);
> +
> ixgbe_irq_disable(adapter);
>
> - napi_disable(&adapter->napi);
> del_timer_sync(&adapter->watchdog_timer);
>
> netif_carrier_off(netdev);
> --
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