From: Paolo Abeni <pabeni@redhat.com>
Date: Tue, 15 May 2018 16:24:37 +0200
Subject: pfifo_fast: drop unneeded additional lock on dequeue
Patch-mainline: v4.18-rc1
Git-commit: 021a17ed796b62383f7623f4fea73787abddad77
References: bsc#1109837

After the previous patch, for NOLOCK qdiscs, q->seqlock is
always held when the dequeue() is invoked, we can drop
any additional locking to protect such operation.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 include/linux/skb_array.h |    5 +++++
 net/sched/sch_generic.c   |    4 ++--
 2 files changed, 7 insertions(+), 2 deletions(-)

--- a/include/linux/skb_array.h
+++ b/include/linux/skb_array.h
@@ -97,6 +97,11 @@ static inline bool skb_array_empty_any(s
 	return ptr_ring_empty_any(&a->ring);
 }
 
+static inline struct sk_buff *__skb_array_consume(struct skb_array *a)
+{
+	return __ptr_ring_consume(&a->ring);
+}
+
 static inline struct sk_buff *skb_array_consume(struct skb_array *a)
 {
 	return ptr_ring_consume(&a->ring);
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -653,7 +653,7 @@ static struct sk_buff *pfifo_fast_dequeu
 		if (__skb_array_empty(q))
 			continue;
 
-		skb = skb_array_consume_bh(q);
+		skb = __skb_array_consume(q);
 	}
 	if (likely(skb)) {
 		qdisc_qstats_cpu_backlog_dec(qdisc, skb);
@@ -694,7 +694,7 @@ static void pfifo_fast_reset(struct Qdis
 		if (!q->ring.queue)
 			continue;
 
-		while ((skb = skb_array_consume_bh(q)) != NULL)
+		while ((skb = __skb_array_consume(q)) != NULL)
 			kfree_skb(skb);
 	}