net_sched: hold tcf_lock in netdevice notifier
net_sched: hold tcf_lock in netdevice notifier

We modify mirred action (m->tcfm_dev) in netdev event, we need to
prevent on-going mirred actions from reading freed m->tcfm_dev.
So we need to acquire this spin lock.

Cc: Jamal Hadi Salim <15cac6df0dbdaecca5b04ed6c5cc9ad59098d331@mojatatu.com>
Cc: "David S. Miller" <fe08d3c717adf2ae63592e4c9aec6e3e404d8e3e@davemloft.net>
Signed-off-by: Cong Wang <2b3b59efb30d692c772b2f93c636eba69bba4f54@twopensource.com>
Signed-off-by: Cong Wang <0f114804888b88d50037b04b42e57b858d851b87@gmail.com>
Signed-off-by: David S. Miller <fe08d3c717adf2ae63592e4c9aec6e3e404d8e3e@davemloft.net>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs