From: Niklas Schnelle <schnelle@linux.ibm.com>
Date: Fri, 6 Aug 2021 12:12:11 +0200
Subject: s390/pci: reset zdev->zbus on registration failure
Git-commit: 81a076171e72dcb6545a8a508b800aec59d6e82b
Patch-mainline: v5.15-rc1
References: jsc#PED-600

On failure to register a struct zpci_dev with a struct zpci_bus we left
a dangling pointer in zdev->zbus. As zpci_create_device() bails if
zpci_bus_device_register() fails this is of no consequence but still bad
practice.

Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 arch/s390/pci/pci_bus.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/arch/s390/pci/pci_bus.c
+++ b/arch/s390/pci/pci_bus.c
@@ -343,11 +343,11 @@ static int zpci_bus_add_device(struct zp
 {
 	int rc = -EINVAL;
 
-	zdev->zbus = zbus;
 	if (zbus->function[zdev->devfn]) {
 		pr_err("devfn %04x is already assigned\n", zdev->devfn);
 		return rc;
 	}
+	zdev->zbus = zbus;
 	zbus->function[zdev->devfn] = zdev;
 	zpci_nb_devices++;
 
@@ -367,6 +367,7 @@ static int zpci_bus_add_device(struct zp
 
 error:
 	zbus->function[zdev->devfn] = NULL;
+	zdev->zbus = NULL;
 	zpci_nb_devices--;
 	return rc;
 }