net: introduce netif_addr_lock_nested() and call if when appropriate

dev_uc_sync() and dev_mc_sync() are acquiring netif_addr_lock for
destination device of synchronization. Since netif_addr_lock is
already held at the time for source device, this triggers lockdep
deadlock warning.

There's no way this deadlock can happen so use spin_lock_nested() to
silence the warning.

Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index a1d109590da4..d0522bb2d4a0 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2450,6 +2450,11 @@ static inline void netif_addr_lock(struct net_device *dev)
         spin_lock(&dev->addr_list_lock);
 }
 
+static inline void netif_addr_lock_nested(struct net_device *dev)
+{
+        spin_lock_nested(&dev->addr_list_lock, SINGLE_DEPTH_NESTING);
+}
+
 static inline void netif_addr_lock_bh(struct net_device *dev)
 {
         spin_lock_bh(&dev->addr_list_lock);