This is a note to let you know that I've just added the patch titled
s390/pci: remove superfluous zdev->zbus check
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
s390-pci-remove-superfluous-zdev-zbus-check.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From e1bff843cde62a45a287b7f9b4cd5e824e8e49e2 Mon Sep 17 00:00:00 2001
From: Niklas Schnelle <schnelle@xxxxxxxxxxxxx>
Date: Tue, 19 Jan 2021 08:49:37 +0100
Subject: s390/pci: remove superfluous zdev->zbus check
From: Niklas Schnelle <schnelle@xxxxxxxxxxxxx>
commit e1bff843cde62a45a287b7f9b4cd5e824e8e49e2 upstream.
Checking zdev->zbus for NULL in __zpci_event_availability() is
superfluous as it can never be NULL at this point. While harmless this
check causes smatch warnings because we later access zdev->zbus with
only having checked zdev != NULL which is sufficient.
The reason zdev->zbus can never be NULL is since with zdev != NULL given
we know the zdev came from get_zdev_by_fid() and thus the zpci_list.
Now on first glance at zpci_create_device() one may assume that there is
a window where the zdev is in the list without a zdev, however this
window can't overlap with __zpci_event_availability() as
zpci_create_device() either runs on the same kthread as part of
availability events, or during the initial CLP List PCI at which point
the __zpci_event_availability() is not yet called as zPCI is not yet
initialized.
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Niklas Schnelle <schnelle@xxxxxxxxxxxxx>
Signed-off-by: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/s390/pci/pci_event.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/s390/pci/pci_event.c
+++ b/arch/s390/pci/pci_event.c
@@ -80,7 +80,7 @@ static void __zpci_event_availability(st
enum zpci_state state;
int ret;
- if (zdev && zdev->zbus && zdev->zbus->bus)
+ if (zdev && zdev->zbus->bus)
pdev = pci_get_slot(zdev->zbus->bus, zdev->devfn);
zpci_err("avail CCDF:\n");
Patches currently in stable-queue which might be from schnelle@xxxxxxxxxxxxx are
queue-5.10/s390-pci-fix-leak-of-pci-device-structure.patch
queue-5.10/s390-pci-remove-superfluous-zdev-zbus-check.patch
queue-5.10/s390-pci-refactor-zpci_create_device.patch
