[patch 26/48] sungem: Soft lockup in sungem on Netra AC200 when switching interface up

Greg KH
2009-02-14T01:38:33Z

[-- Attachment #1: sungem-soft-lockup-in-sungem-on-netra-ac200-when-switching-interface-up.patch --]
[-- Type: text/plain, Size: 2053 bytes --]

2.6.28-stable review patch. If anyone has any objections, please let us know.

------------------

From: Ilkka Virta <itvirta@iki.fi>

[ Upstream commit 71822faa3bc0af5dbf5e333a2d085f1ed7cd809f ]

From: Ilkka Virta <itvirta@iki.fi>

In the lockup situation the driver seems to go off in an eternal storm
of interrupts right after calling request_irq(). It doesn't actually
do anything interesting in the interrupt handler. Since connecting the link
afterwards works, something later in initialization must fix this.

Looking at gem_do_start() and gem_open(), it seems that the only thing
done while opening the device after the request_irq(), is a call to
napi_enable().

I don't know what the ordering requirements are for the
initialization, but I boldly tried to move the napi_enable() call
inside gem_do_start() before the link state is checked and interrupts
subsequently enabled, and it seems to work for me. Doesn't even break
anything too obvious...

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/net/sungem.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/net/sungem.c
+++ b/drivers/net/sungem.c
@@ -2222,6 +2222,8 @@ static int gem_do_start(struct net_devic

gp->running = 1;

+ napi_enable(&gp->napi);
+
if (gp->lstate == link_up) {
netif_carrier_on(gp->dev);
gem_set_link_modes(gp);
@@ -2239,6 +2241,8 @@ static int gem_do_start(struct net_devic
spin_lock_irqsave(&gp->lock, flags);
spin_lock(&gp->tx_lock);

+ napi_disable(&gp->napi);
+
gp->running = 0;
gem_reset(gp);
gem_clean_rings(gp);
@@ -2339,8 +2343,6 @@ static int gem_open(struct net_device *d
if (!gp->asleep)
rc = gem_do_start(dev);
gp->opened = (rc == 0);
- if (gp->opened)
- napi_enable(&gp->napi);

mutex_unlock(&gp->pm_mutex);

@@ -2477,8 +2479,6 @@ static int gem_resume(struct pci_dev *pd

/* Re-attach net device */
netif_device_attach(dev);
-
- napi_enable(&gp->napi);
}

spin_lock_irqsave(&gp->lock, flags);