[RFC] wireless: check against default_ethtool_ops

Since:

commit 2c60db037034d27f8c636403355d52872da92f81
Author: Eric Dumazet [off-list ref]
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, and avoid assigning ethtool_ops on each individual cfg80211
driver, we check against default_ethool_ops pointer instead of NULL in
wireless core.

Signed-off-by: Stanislaw Gruszka <redacted>
---
 include/linux/netdevice.h |    2 ++
 net/core/dev.c            |    3 ++-
 net/wireless/core.c       |    2 +-
 3 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index f8eda02..c98e1c3 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h

@@ -60,6 +60,8 @@ struct wireless_dev;
 #define SET_ETHTOOL_OPS(netdev,ops) \
 	( (netdev)->ethtool_ops = (ops) )
 
+extern const struct ethtool_ops default_ethtool_ops;
+
 /* hardware address assignment types */
 #define NET_ADDR_PERM		0	/* address is permanent (default) */
 #define NET_ADDR_RANDOM		1	/* address is generated randomly */

diff --git a/net/core/dev.c b/net/core/dev.c
index c0946cb..4cd2168 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c

@@ -6008,7 +6008,8 @@ struct netdev_queue *dev_ingress_queue_create(struct net_device *dev)
 	return queue;
 }
 
-static const struct ethtool_ops default_ethtool_ops;
+const struct ethtool_ops default_ethtool_ops;
+EXPORT_SYMBOL_GPL(default_ethtool_ops);
 
 /**
  *	alloc_netdev_mqs - allocate network device

diff --git a/net/wireless/core.c b/net/wireless/core.c
index 14d9904..90915d4 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c

@@ -866,7 +866,7 @@ static int cfg80211_netdev_notifier_call(struct notifier_block *nb,
 		/* allow mac80211 to determine the timeout */
 		wdev->ps_timeout = -1;
 
-		if (!dev->ethtool_ops)
+		if (dev->ethtool_ops == &default_ethtool_ops)
 			dev->ethtool_ops = &cfg80211_ethtool_ops;
 
 		if ((wdev->iftype == NL80211_IFTYPE_STATION ||

-- 
1.7.1

On Fri, 2012-12-07 at 13:16 +0100, Stanislaw Gruszka wrote:

Since:

commit 2c60db037034d27f8c636403355d52872da92f81
Author: Eric Dumazet [off-list ref]
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, and avoid assigning ethtool_ops on each individual cfg80211
driver, we check against default_ethool_ops pointer instead of NULL in
wireless core.

Signed-off-by: Stanislaw Gruszka <redacted>

[...]
Acked-by: Ben Hutchings <redacted>

Ideally you could do this assignment unconditionally in the setup
function for the device, but it doesn't seem like there's a common
allocation path that you could do that in.

Ben.

-- 
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.