net: cpsw_new: Fix potential unregister of netdev that has not been registered yet

If an error occurs during register_netdev() for the first MAC in
cpsw_register_ports(), even though cpsw->slaves[0].ndev is set to NULL,
cpsw->slaves[1].ndev would remain unchanged. This could later cause
cpsw_unregister_ports() to attempt unregistering the second MAC.
To address this, add a check for ndev->reg_state before calling
unregister_netdev(). With this change, setting cpsw->slaves[i].ndev
to NULL becomes unnecessary and can be removed accordingly.

Fixes: ed3525e ("net: ethernet: ti: introduce cpsw switchdev based driver part 1 - dual-emac")
Signed-off-by: Kevin Hao <[email protected]>
Cc: [email protected]
Reviewed-by: Alexander Sverdlin <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: haokexin

drivers/net/ethernet/ti/cpsw_new.c

@@ -1472,7 +1472,7 @@ static void cpsw_unregister_ports(struct cpsw_common *cpsw)
 
 	for (i = 0; i < cpsw->data.slaves; i++) {
 		ndev = cpsw->slaves[i].ndev;
-		if (!ndev)
+		if (!ndev || ndev->reg_state != NETREG_REGISTERED)
 			continue;
 
 		priv = netdev_priv(ndev);
@@ -1494,7 +1494,6 @@ static int cpsw_register_ports(struct cpsw_common *cpsw)
 		if (ret) {
 			dev_err(cpsw->dev,
 				"cpsw: err registering net device%d\n", i);
-			cpsw->slaves[i].ndev = NULL;
 			break;
 		}
 	}