Two net_sched fixes for stable

[Cong Wang]

Hi, David

Can you queue the following commits for stable? They fix a
sleep-in-atomic warning reported by Roland.


commit efbf78973978b0d25af59bc26c8013a942af6e64
Author: Cong Wang <xiyou.wangc...@gmail.com>
Date:   Mon Dec 4 10:48:18 2017 -0800

    net_sched: get rid of rcu_barrier() in tcf_block_put_ext()

commit df45bf84e4f5a48f23d4b1a07d21d566e8b587b2
Author: Jiri Pirko <j...@mellanox.com>
Date:   Fri Dec 8 19:27:27 2017 +0100

    net: sched: fix use-after-free in tcf_block_put_ext


This problem was introduced by:

commit e2ef75445340ca7ec2c4558f84ae6c8c5d650fc8
Author: Cong Wang <xiyou.wangc...@gmail.com>
Date:   Mon Sep 11 16:33:31 2017 -0700

    net_sched: fix reference counting of tc filter chain

so should apply to 4.14 too.

For 4.15, they can just apply nearly cleanly. However, it is not
straight-forward to cherry pick them to 4.14 due to some big changes
between 4.14 and 4.15.

Please let me know how you want to handle this for 4.14.

Thanks.