| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.11 014/120] s390/pci: remove superfluous zdev->zbus check | Date | Mon, 22 Mar 2021 13:26:37 +0100 |
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From: Niklas Schnelle <schnelle@linux.ibm.com>
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@intel.com> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- 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");
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