libata: clear drvdata in ata_host_release(), take#2

Clearing drvdata in ->remove_one causes NULL pointer deference.  Clear
drvdata only in ata_host_release() after all resources are freed.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/ata/libata-core.c

@@ -5680,6 +5680,8 @@ static void ata_host_release(struct device *gendev, void *res)
 
 	if (host->ops->host_stop)
 		host->ops->host_stop(host);
+
+	dev_set_drvdata(gendev, NULL);
 }
 
 /**
@@ -5902,7 +5904,6 @@ int ata_device_add(const struct ata_probe_ent *ent)
 
  err_out:
 	devres_release_group(dev, ata_device_add);
-	dev_set_drvdata(dev, NULL);
 	VPRINTK("EXIT, returning %d\n", rc);
 	return 0;
 }

drivers/ata/pata_cs5520.c

@@ -306,7 +306,6 @@ static void __devexit cs5520_remove_one(struct pci_dev *pdev)
 	struct ata_host *host = dev_get_drvdata(dev);
 
 	ata_host_detach(host);
-	dev_set_drvdata(dev, NULL);
 }
 
 /**

drivers/ata/pata_isapnp.c

@@ -128,7 +128,6 @@ static void isapnp_remove_one(struct pnp_dev *idev)
 	struct ata_host *host = dev_get_drvdata(dev);
 
 	ata_host_detach(host);
-	dev_set_drvdata(dev, NULL);
 }
 
 static struct pnp_device_id isapnp_devices[] = {

drivers/ata/pata_platform.c

@@ -228,7 +228,6 @@ static int __devexit pata_platform_remove(struct platform_device *pdev)
 	struct ata_host *host = dev_get_drvdata(dev);
 
 	ata_host_detach(host);
-	dev_set_drvdata(dev, NULL);
 
 	return 0;
 }