From 9873cd435afb128336fc45afda43e9fc497314a7 Mon Sep 17 00:00:00 2001
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Wed, 16 Sep 2020 16:15:39 +0200
Subject: [PATCH 107/158] net: Dequeue in dev_cpu_dead() without the lock

Upstream uses skb_dequeue() to acquire lock of `input_pkt_queue'. The reason is
to synchronize against a remote CPU which still thinks that the CPU is online
enqueues packets to this CPU.
There are no guarantees that the packet is enqueued before the callback is run,
it just hope.
RT however complains about an not initialized lock because it uses another lock
for `input_pkt_queue' due to the IRQ-off nature of the context.

Use the unlocked dequeue version for `input_pkt_queue'.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 net/core/dev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-5.15.19-rt29/net/core/dev.c
===================================================================
--- linux-5.15.19-rt29.orig/net/core/dev.c
+++ linux-5.15.19-rt29/net/core/dev.c
@@ -11328,7 +11328,7 @@ static int dev_cpu_dead(unsigned int old
 		netif_rx_ni(skb);
 		input_queue_head_incr(oldsd);
 	}
-	while ((skb = skb_dequeue(&oldsd->input_pkt_queue))) {
+	while ((skb = __skb_dequeue(&oldsd->input_pkt_queue))) {
 		netif_rx_ni(skb);
 		input_queue_head_incr(oldsd);
 	}