netdev - Re: ne driver crashes when unloaded in 2.6.22.6

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Date:	Sun, 09 Sep 2007 17:55:58 -0400
From:	Dan Williams <dcbw@...hat.com>
To:	Chris Rankin <rankincj@...oo.com>
Cc:	netdev@...r.kernel.org
Subject: Re: ne driver crashes when unloaded in 2.6.22.6

On Sun, 2007-09-09 at 20:46 +0100, Chris Rankin wrote:
> Hi,
> 
> While trying to get my NE2000 ISA card working with NetworkManager and Linux 2.6.22.6, I
> discovered that the ne module will cause the kernel to oops when it is unloaded. The problem is
> that the module's clean-up function tries to unregister a platform driver unconditionally,
> although the platform driver may never have been registered in the first place. I have created a
> patch which seems to work OK. The idea behind the patch is to de-initialise the unregistered
> ne_driver structure to the point where the unregister function will abort without error:
> 
> --- drivers/net/ne.c.orig       2007-07-21 17:00:52.000000000 +0100
> +++ drivers/net/ne.c    2007-09-09 20:04:28.000000000 +0100
> @@ -272,6 +272,7 @@
>                                 pnp_device_detach(idev);
>                                 return -ENXIO;
>                         }
> +                       SET_NETDEV_DEV(dev, &idev->dev);
>                         ei_status.priv = (unsigned long)idev;
>                         break;
>                 }
> @@ -827,6 +828,7 @@
>                 free_netdev(dev);
>                 return err;
>         }
> +       SET_NETDEV_DEV(dev, &pdev->dev);
>         platform_set_drvdata(pdev, dev);
>         return 0;
>  }
> @@ -909,11 +911,14 @@
>  is at boot) and so the probe will get confused by any other 8390 cards.
>  ISA device autoprobes on a running machine are not recommended anyway. */
>  
> int __init init_module(void)
>  {
>         int this_dev, found = 0;
>         int plat_found = !ne_init();
>  
> +       if ( !plat_found )
> +               ne_driver.driver.bus = NULL;
> +
>         for (this_dev = 0; this_dev < MAX_NE_CARDS; this_dev++) {
>                 struct net_device *dev = alloc_ei_netdev();
>                 if (!dev)
> 
> The patch also contains a few SET_NETDEV_DEV() statements, which I am hoping will help these
> network cards work with NetworkManager. This isn't a complete solution because it still doesn't
> address the non-PnP ISA case. However, I think it's a start... At the moment, my eth device
> appears in /sys/class/net but is also completely ignored by lshal.

Awesome.  SET_NETDEV_DEV is required because it establishes the 'device'
link in sysfs that HAL uses for additional information about the card.
At some point all drivers should get audited for SET_NETDEV_DEV (or
rather lack of it) and get fixed if they don't have it.

Offhand question, does your ne2000 card support carrier detection?

Dan


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