From 85328240c625f322af9f69c7b60e619717101d77 Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Tue, 26 Nov 2013 06:33:52 +0000 Subject: [PATCH] net: allow netdev_all_upper_get_next_dev_rcu with rtnl lock held It is useful to be able to walk all upper devices when bringing a device online where the RTNL lock is held. In this case it is safe to walk the all_adj_list because the RTNL lock is used to protect the write side as well. This patch adds a check to see if the rtnl lock is held before throwing a warning in netdev_all_upper_get_next_dev_rcu(). Also because we now have a call site for lockdep_rtnl_is_held() outside COFIG_LOCK_PROVING an inline definition returning 1 is needed. Similar to the rcu_read_lock_is_held(). Fixes: 2a47fa45d4df ("ixgbe: enable l2 forwarding acceleration for macvlans") CC: Veaceslav Falico Reported-by: Yuanhan Liu Signed-off-by: John Fastabend Tested-by: Phil Schmitt Signed-off-by: Jeff Kirsher --- include/linux/rtnetlink.h | 5 +++++ net/core/dev.c | 2 +- 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h index 939428ad25ac..8e3e66ac0a52 100644 --- a/include/linux/rtnetlink.h +++ b/include/linux/rtnetlink.h @@ -24,6 +24,11 @@ extern int rtnl_trylock(void); extern int rtnl_is_locked(void); #ifdef CONFIG_PROVE_LOCKING extern int lockdep_rtnl_is_held(void); +#else +static inline int lockdep_rtnl_is_held(void) +{ + return 1; +} #endif /* #ifdef CONFIG_PROVE_LOCKING */ /** diff --git a/net/core/dev.c b/net/core/dev.c index ba3b7ea5ebb3..4fc17221545d 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4500,7 +4500,7 @@ struct net_device *netdev_all_upper_get_next_dev_rcu(struct net_device *dev, { struct netdev_adjacent *upper; - WARN_ON_ONCE(!rcu_read_lock_held()); + WARN_ON_ONCE(!rcu_read_lock_held() && !lockdep_rtnl_is_held()); upper = list_entry_rcu((*iter)->next, struct netdev_adjacent, list); -- 2.20.1