From d5af37ae22f0364be9ded773d737dd6e5b207b10 Mon Sep 17 00:00:00 2001
From: Ioana Ciornei <ioana.ciornei@nxp.com>
Date: Thu, 21 Nov 2019 21:15:25 +0200
Subject: [PATCH 3/4] dpaa2-eth: do not hold rtnl_lock on phylink_create() or
 _destroy()

The rtnl_lock should not be held when calling phylink_create() or
phylink_destroy() since it leads to the deadlock listed below:

[   18.656576]  rtnl_lock+0x18/0x20
[   18.659798]  sfp_bus_add_upstream+0x28/0x90
[   18.663974]  phylink_create+0x2cc/0x828
[   18.667803]  dpaa2_mac_connect+0x14c/0x2a8
[   18.671890]  dpaa2_eth_connect_mac+0x94/0xd8

Fix this by moving the _lock() and _unlock() calls just outside of
phylink_of_phy_connect() and phylink_disconnect_phy().

Fixes: 719479230893 ("dpaa2-eth: add MAC/PHY support through phylink")
Reported-by: Russell King <linux@armlinux.org.uk>
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
---
 drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c | 4 ----
 drivers/net/ethernet/freescale/dpaa2/dpaa2-mac.c | 4 ++++
 2 files changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
@@ -4215,12 +4215,10 @@ static irqreturn_t dpni_irq0_handler_thr
 		dpaa2_eth_set_mac_addr(netdev_priv(net_dev));
 		dpaa2_eth_update_tx_fqids(priv);
 
-		rtnl_lock();
 		if (dpaa2_eth_has_mac(priv))
 			dpaa2_eth_disconnect_mac(priv);
 		else
 			dpaa2_eth_connect_mac(priv);
-		rtnl_unlock();
 	}
 
 	return IRQ_HANDLED;
@@ -4516,9 +4514,7 @@ static int dpaa2_eth_remove(struct fsl_m
 #endif
 
 	unregister_netdev(net_dev);
-	rtnl_lock();
 	dpaa2_eth_disconnect_mac(priv);
-	rtnl_unlock();
 
 	dpaa2_eth_dl_port_del(priv);
 	dpaa2_eth_dl_traps_unregister(priv);
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-mac.c
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-mac.c
@@ -357,7 +357,9 @@ int dpaa2_mac_connect(struct dpaa2_mac *
 	if (mac->pcs)
 		phylink_set_pcs(mac->phylink, &mac->pcs->pcs);
 
+	rtnl_lock();
 	err = phylink_fwnode_phy_connect(mac->phylink, dpmac_node, 0);
+	rtnl_unlock();
 	if (err) {
 		netdev_err(net_dev, "phylink_fwnode_phy_connect() = %d\n", err);
 		goto err_phylink_destroy;
@@ -378,7 +380,9 @@ void dpaa2_mac_disconnect(struct dpaa2_m
 	if (!mac->phylink)
 		return;
 
+	rtnl_lock();
 	phylink_disconnect_phy(mac->phylink);
+	rtnl_unlock();
 	phylink_destroy(mac->phylink);
 	dpaa2_pcs_destroy(mac);
 }
