pkt_sched: fq: do not hold qdisc lock while allocating memory

pkt_sched: fq: do not hold qdisc lock while allocating memory

[ Upstream commit 2d8d40afd187bced0a3d056366fb58d66fe845e3 ]

Resizing fq hash table allocates memory while holding qdisc spinlock,
with BH disabled.

This is definitely not good, as allocation might sleep.

We can drop the lock and get it when needed, we hold RTNL so no other
changes can happen at the same time.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Fixes: afe4fd062416 ("pkt_sched: fq: Fair Queue packet scheduler")
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>