net: percpu_counter_inc() should not be called in BH-disabled section

Based upon a lockdep report by Alexey Dobriyan.

I checked all per_cpu_counter_xxx() usages in network tree, and I
think all call sites are BH enabled except one in
inet_csk_listen_stop().

commit dd24c001
(net: Use a percpu_counter for orphan_count)
replaced atomic_t orphan_count to a percpu_counter.

atomic_inc()/atomic_dec() can be called from any context, while
percpu_counter_xxx() should be called from a consistent state.

For orphan_count, this context can be the BH-enabled one.
Signed-off-by: NEric Dumazet <dada1@cosmosbay.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/inet_connection_sock.c

@@ -632,6 +632,8 @@ void inet_csk_listen_stop(struct sock *sk)
 
 		acc_req = req->dl_next;
 
+		percpu_counter_inc(sk->sk_prot->orphan_count);
+
 		local_bh_disable();
 		bh_lock_sock(child);
 		WARN_ON(sock_owned_by_user(child));
@@ -641,8 +643,6 @@ void inet_csk_listen_stop(struct sock *sk)
 
 		sock_orphan(child);
 
-		percpu_counter_inc(sk->sk_prot->orphan_count);
-
 		inet_csk_destroy_sock(child);
 
 		bh_unlock_sock(child);