hsr: Disable netpoll.

The hsr device is a software device. Its
net_device_ops::ndo_start_xmit() routine will process the packet and
then pass the resulting skb to dev_queue_xmit().
During processing, hsr acquires a lock with spin_lock_bh()
(hsr_add_node()) which needs to be promoted to the _irq() suffix in
order to avoid a potential deadlock.
Then there are the warnings in dev_queue_xmit() (due to
local_bh_disable() with disabled interrupts) left.

Instead trying to address those (there is qdisc and…) for netpoll sake,
just disable netpoll on hsr.

Disable netpoll on hsr and replace the _irqsave() locking with _bh().

Fixes: f421436a ("net/hsr: Add support for the High-availability Seamless Redundancy protocol (HSRv0)")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/hsr/hsr_device.c

@@ -278,7 +278,6 @@ static void send_hsr_supervision_frame(struct hsr_port *master,
 	__u8 type = HSR_TLV_LIFE_CHECK;
 	struct hsr_sup_payload *hsr_sp;
 	struct hsr_sup_tag *hsr_stag;
-	unsigned long irqflags;
 	struct sk_buff *skb;
 
 	*interval = msecs_to_jiffies(HSR_LIFE_CHECK_INTERVAL);
@@ -299,7 +298,7 @@ static void send_hsr_supervision_frame(struct hsr_port *master,
 	set_hsr_stag_HSR_ver(hsr_stag, hsr->prot_version);
 
 	/* From HSRv1 on we have separate supervision sequence numbers. */
-	spin_lock_irqsave(&master->hsr->seqnr_lock, irqflags);
+	spin_lock_bh(&hsr->seqnr_lock);
 	if (hsr->prot_version > 0) {
 		hsr_stag->sequence_nr = htons(hsr->sup_sequence_nr);
 		hsr->sup_sequence_nr++;
@@ -307,7 +306,7 @@ static void send_hsr_supervision_frame(struct hsr_port *master,
 		hsr_stag->sequence_nr = htons(hsr->sequence_nr);
 		hsr->sequence_nr++;
 	}
-	spin_unlock_irqrestore(&master->hsr->seqnr_lock, irqflags);
+	spin_unlock_bh(&hsr->seqnr_lock);
 
 	hsr_stag->tlv.HSR_TLV_type = type;
 	/* TODO: Why 12 in HSRv0? */
@@ -332,7 +331,6 @@ static void send_prp_supervision_frame(struct hsr_port *master,
 	struct hsr_priv *hsr = master->hsr;
 	struct hsr_sup_payload *hsr_sp;
 	struct hsr_sup_tag *hsr_stag;
-	unsigned long irqflags;
 	struct sk_buff *skb;
 
 	skb = hsr_init_skb(master);
@@ -347,7 +345,7 @@ static void send_prp_supervision_frame(struct hsr_port *master,
 	set_hsr_stag_HSR_ver(hsr_stag, (hsr->prot_version ? 1 : 0));
 
 	/* From HSRv1 on we have separate supervision sequence numbers. */
-	spin_lock_irqsave(&master->hsr->seqnr_lock, irqflags);
+	spin_lock_bh(&hsr->seqnr_lock);
 	hsr_stag->sequence_nr = htons(hsr->sup_sequence_nr);
 	hsr->sup_sequence_nr++;
 	hsr_stag->tlv.HSR_TLV_type = PRP_TLV_LIFE_CHECK_DD;
@@ -358,11 +356,11 @@ static void send_prp_supervision_frame(struct hsr_port *master,
 	ether_addr_copy(hsr_sp->macaddress_A, master->dev->dev_addr);
 
 	if (skb_put_padto(skb, ETH_ZLEN)) {
-		spin_unlock_irqrestore(&master->hsr->seqnr_lock, irqflags);
+		spin_unlock_bh(&hsr->seqnr_lock);
 		return;
 	}
 
-	spin_unlock_irqrestore(&master->hsr->seqnr_lock, irqflags);
+	spin_unlock_bh(&hsr->seqnr_lock);
 
 	hsr_forward_skb(skb, master);
 }
@@ -444,7 +442,7 @@ void hsr_dev_setup(struct net_device *dev)
 	dev->header_ops = &hsr_header_ops;
 	dev->netdev_ops = &hsr_device_ops;
 	SET_NETDEV_DEVTYPE(dev, &hsr_type);
-	dev->priv_flags |= IFF_NO_QUEUE;
+	dev->priv_flags |= IFF_NO_QUEUE | IFF_DISABLE_NETPOLL;
 
 	dev->needs_free_netdev = true;
 

net/hsr/hsr_forward.c

@@ -500,7 +500,6 @@ static void handle_std_frame(struct sk_buff *skb,
 {
 	struct hsr_port *port = frame->port_rcv;
 	struct hsr_priv *hsr = port->hsr;
-	unsigned long irqflags;
 
 	frame->skb_hsr = NULL;
 	frame->skb_prp = NULL;
@@ -510,10 +509,10 @@ static void handle_std_frame(struct sk_buff *skb,
 		frame->is_from_san = true;
 	} else {
 		/* Sequence nr for the master node */
-		spin_lock_irqsave(&hsr->seqnr_lock, irqflags);
+		spin_lock_bh(&hsr->seqnr_lock);
 		frame->sequence_nr = hsr->sequence_nr;
 		hsr->sequence_nr++;
-		spin_unlock_irqrestore(&hsr->seqnr_lock, irqflags);
+		spin_unlock_bh(&hsr->seqnr_lock);
 	}
 }