igc: reinit_locked() should be called with rtnl_lock

This commit applies to the igc_reset_task the same changes that
were applied to the igb driver in commit 024a816 ("igb:
reinit_locked() should be called with rtnl_lock")
and fix possible race in reset subtask.

Fixes: 0507ef8 ("igc: Add transmit and receive fastpath and interrupt handlers")
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Neftin <sasha.neftin@intel.com>
Tested-by: Dvora Fuxbrumer <dvorax.fuxbrumer@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/igc/igc_main.c

@@ -3831,10 +3831,19 @@ static void igc_reset_task(struct work_struct *work)
 
 	adapter = container_of(work, struct igc_adapter, reset_task);
 
+	rtnl_lock();
+	/* If we're already down or resetting, just bail */
+	if (test_bit(__IGC_DOWN, &adapter->state) ||
+	    test_bit(__IGC_RESETTING, &adapter->state)) {
+		rtnl_unlock();
+		return;
+	}
+
 	igc_rings_dump(adapter);
 	igc_regs_dump(adapter);
 	netdev_err(adapter->netdev, "Reset adapter\n");
 	igc_reinit_locked(adapter);
+	rtnl_unlock();
 }
 
 /**