net: Silence a W=1 compiler warning

Avoid that the following compiler warning is reported when building with W=1:

include/linux/netdevice.h: In function 'netif_addr_lock_nested':
include/linux/netdevice.h:2865:6: warning: variable 'subclass' set but not used [-Wunused-but-set-variable]

  int subclass = SINGLE_DEPTH_NESTING;
      ^

This patch does not change any functionality.

---
 include/linux/netdevice.h | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

index abe3de1..3c0a2e7 100644
@@ -2951,12 +2951,10 @@ static inline void netif_addr_lock(struct net_device *dev)
 
 static inline void netif_addr_lock_nested(struct net_device *dev)
 {
-	int subclass = SINGLE_DEPTH_NESTING;
-
-	if (dev->netdev_ops->ndo_get_lock_subclass)
-		subclass = dev->netdev_ops->ndo_get_lock_subclass(dev);
-
-	spin_lock_nested(&dev->addr_list_lock, subclass);
+	spin_lock_nested(&dev->addr_list_lock,
+			 dev->netdev_ops->ndo_get_lock_subclass ?
+			 dev->netdev_ops->ndo_get_lock_subclass(dev) :
+			 SINGLE_DEPTH_NESTING);
 }
 
 static inline void netif_addr_lock_bh(struct net_device *dev)

1.8.4.5

From: Bart Van Assche <[email protected]>
Date: Fri, 13 Jun 2014 16:12:49 +0200

This has already been discussed.

The spin_lock_nested() with your configuration should be adjusted to mark the argument as used.

There is nothing wrong with this code, it should not warn, it's simply the spin locking macros that need to be fixed.

I'm not applying this patch, sorry.