net: sched: fix qdisc->running lockdep annotations

1) qdisc_run_begin() is really using the equivalent of a trylock.
  Instead of using write_seqcount_begin(), use a combination of
  raw_write_seqcount_begin() and correct lockdep annotation.

2) sch_direct_xmit() should use regular spin_lock(root_lock)

Fixes: f9eb8aea2a1e ("net_sched: transform qdisc running bit into a seqcount")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index cebea73..cad810b 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -137,10 +137,10 @@
 
 		HARD_TX_UNLOCK(dev, txq);
 	} else {
-		spin_lock_nested(root_lock, SINGLE_DEPTH_NESTING);
+		spin_lock(root_lock);
 		return qdisc_qlen(q);
 	}
-	spin_lock_nested(root_lock, SINGLE_DEPTH_NESTING);
+	spin_lock(root_lock);
 
 	if (dev_xmit_complete(ret)) {
 		/* Driver sent out skb successfully or skb was consumed */