[PATCH DRAFT] net: cirrus: ep93xx: fix probe error unwind

[박명훈 <mhun512@gmail.com>]

From: Myeonghun Pak <mhun512@gmail.com>

ep93xx_eth_probe() uses ep93xx_eth_remove() as common error unwind
after setting driver data. When register_netdev() fails, this calls
unregister_netdev() for a net_device that was never registered. The
net core treats that as a driver bug and emits WARN_ON(1).

The shared remove path also fails to unmap the register mapping on
earlier allocation and resource-reservation failures, because
ep->base_addr is only assigned after request_mem_region() succeeds.

Unwind probe failures directly and publish driver data only after the
netdev is registered. This keeps .remove() for successful probes only,
releases the memory region on late failures, frees the net_device, and
unmaps the registers.

Fixes: 1d22e05df818 ("[PATCH] Cirrus Logic ep93xx ethernet driver")
Co-developed-by: Ijae Kim <ae878000@gmail.com>
Signed-off-by: Ijae Kim <ae878000@gmail.com>
Signed-off-by: Myeonghun Pak <mhun512@gmail.com>
---
diff --git a/drivers/net/ethernet/cirrus/ep93xx_eth.c b/drivers/net/ethernet/cirrus/ep93xx_eth.c
index a4972457ed..4e98b76ec7 100644
--- a/drivers/net/ethernet/cirrus/ep93xx_eth.c
+++ b/drivers/net/ethernet/cirrus/ep93xx_eth.c
@@ -800,7 +800,7 @@ static int ep93xx_eth_probe(struct platform_device *pdev)
 	dev = alloc_etherdev(sizeof(struct ep93xx_priv));
 	if (dev == NULL) {
 		err = -ENOMEM;
-		goto err_out;
+		goto err_iounmap;
 	}
 
 	memcpy_fromio(addr, base_addr + 0x50, ETH_ALEN);
@@ -814,14 +814,12 @@ static int ep93xx_eth_probe(struct platform_device *pdev)
 	SET_NETDEV_DEV(dev, &pdev->dev);
 	netif_napi_add(dev, &ep->napi, ep93xx_poll);
 
-	platform_set_drvdata(pdev, dev);
-
 	ep->res = request_mem_region(mem->start, resource_size(mem),
 				     dev_name(&pdev->dev));
 	if (ep->res == NULL) {
 		dev_err(&pdev->dev, "Could not reserve memory region\n");
 		err = -ENOMEM;
-		goto err_out;
+		goto err_free_netdev;
 	}
 
 	ep->base_addr = base_addr;
@@ -841,16 +839,22 @@ static int ep93xx_eth_probe(struct platform_device *pdev)
 	err = register_netdev(dev);
 	if (err) {
 		dev_err(&pdev->dev, "Failed to register netdev\n");
-		goto err_out;
+		goto err_release_mem;
 	}
 
+	platform_set_drvdata(pdev, dev);
+
 	printk(KERN_INFO "%s: ep93xx on-chip ethernet, IRQ %d, %pM\n",
 			dev->name, ep->irq, dev->dev_addr);
 
 	return 0;
 
-err_out:
-	ep93xx_eth_remove(pdev);
+err_release_mem:
+	release_mem_region(mem->start, resource_size(mem));
+err_free_netdev:
+	free_netdev(dev);
+err_iounmap:
+	iounmap(base_addr);
 	return err;
 }