[PATCH net 2/2] net: stmmac: fix system hang if change mac address after interface ifdown

[Joakim Zhang]

Fix system hang with below sequences:
~# ifconfig ethx down
~# ifconfig ethx hw ether xx:xx:xx:xx:xx:xx

After ethx down, stmmac all clocks gated off and then register access causes
system hang.

Fixes: 5ec55823438e ("net: stmmac: add clocks management for gmac driver")
Signed-off-by: Joakim Zhang <qiangqing.zhang@xxxxxxx>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index df4ce5977fad..5d956a553434 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -5891,12 +5891,21 @@ static int stmmac_set_mac_address(struct net_device *ndev, void *addr)
 	struct stmmac_priv *priv = netdev_priv(ndev);
 	int ret = 0;
 
+	ret = pm_runtime_get_sync(priv->device);
+	if (ret < 0) {
+		pm_runtime_put_noidle(priv->device);
+		return ret;
+	}
+
 	ret = eth_mac_addr(ndev, addr);
 	if (ret)
-		return ret;
+		goto set_mac_error;
 
 	stmmac_set_umac_addr(priv, priv->hw, ndev->dev_addr, 0);
 
+set_mac_error:
+	pm_runtime_put(priv->device);
+
 	return ret;
 }
 
-- 
2.17.1