net: sh_eth: Fix missing rtnl lock in suspend/resume path

Fix the suspend/resume path by ensuring the rtnl lock is held where
required. Calls to sh_eth_close, sh_eth_open and wol operations must be
performed under the rtnl lock to prevent conflicts with ongoing ndo
operations.

Fixes: b71af04 ("sh_eth: add more PM methods")
Tested-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Author: kmaincent

drivers/net/ethernet/renesas/sh_eth.c

@@ -3494,10 +3494,12 @@ static int sh_eth_suspend(struct device *dev)
 
 	netif_device_detach(ndev);
 
+	rtnl_lock();
 	if (mdp->wol_enabled)
 		ret = sh_eth_wol_setup(ndev);
 	else
 		ret = sh_eth_close(ndev);
+	rtnl_unlock();
 
 	return ret;
 }
@@ -3511,10 +3513,12 @@ static int sh_eth_resume(struct device *dev)
 	if (!netif_running(ndev))
 		return 0;
 
+	rtnl_lock();
 	if (mdp->wol_enabled)
 		ret = sh_eth_wol_restore(ndev);
 	else
 		ret = sh_eth_open(ndev);
+	rtnl_unlock();
 
 	if (ret < 0)
 		return ret;