From: David Miller <davem@xxxxxxxxxxxxx> Date: Thu, 10 Jan 2013 02:07:29 -0800 (PST) > From: Stanislaw Gruszka <sgruszka@xxxxxxxxxx> > Date: Thu, 10 Jan 2013 09:36:42 +0100 > >> On Wed, Jan 09, 2013 at 11:57:38PM -0800, David Miller wrote: >>> From: Stanislaw Gruszka <sgruszka@xxxxxxxxxx> >>> Date: Tue, 8 Jan 2013 16:38:51 +0100 >>> >>> > Since: >>> > >>> > commit 2c60db037034d27f8c636403355d52872da92f81 >>> > Author: Eric Dumazet <edumazet@xxxxxxxxxx> >>> > Date: Sun Sep 16 09:17:26 2012 +0000 >>> > >>> > net: provide a default dev->ethtool_ops >>> > >>> > wireless core does not correctly assign ethtool_ops. In order to fix >>> > the problem, move assignement of default_ethtool_ops to >>> > register_netdevice(). This is safe because both register_netdevice() >>> > and dev_ethtool() are protected by RTNL lock. >>> > >>> > Patch is besed on hint of Michał Mirosław. >>> > >>> > Signed-off-by: Stanislaw Gruszka <sgruszka@xxxxxxxxxx> >>> > Cc: stable@xxxxxxxxxxxxxxx # 3.7+ >>> > --- >>> > v1 -> v2: change order of default_ethtool_ops initialization to avoid >>> > the problem. Change the subject accordingly. >>> >>> I don't understand this. Why is the assignment of default_ethtool_ops >>> at netdev allocation time not working? Is wireless really not using >>> alloc_netdev*()? >> >> It does. This is done on individual cfg80211 drivers , i.e. on mac80211 >> or full mac drivers. After alloc_netdev*() call, some cfg80211 drivers >> provide they own ethtool_ops, but some do not. For them, wireless core >> provide generic cfg80211_ethtool_ops, which is assigned in >> NETDEV_REGISTER notify call: >> >> if (!dev->ethtool_ops) >> dev->ethtool_ops = &cfg80211_ethtool_ops; >> >> But after Eric's commit, dev->ethtool_ops is no longer NULL (on cfg80211 >> drivers without custom ethtool_ops), but points to &default_ethtool_ops. > > The whole idea is to remove these kinds of NULL tests against > dev->ethtool_ops, thus creating the invariant that given any netdev > one must never be able to see a non-NULL value there. Of course I meant that we should never see a NULL value in dev->ethtool_ops. I would suggest fixing this by making the wireless core express it's intentions, that it wants to use a different default ethtool ops, to the netdev allocation layer. You have two way to do this: 1) Add default_ethtool_ops argument to alloc_netdev*(). 2) Add a "netdev_set_default_ethtool_ops(netdev, ops)" -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
