From: Niklas Schnelle <schnelle@xxxxxxxxxxxxx> commit df057c914a9c219ac8b8ed22caf7da2f80c1fe26 upstream. In the initial MIO support introduced in commit 71ba41c9b1d9 ("s390/pci: provide support for MIO instructions") zpci_map_resource() and zpci_setup_resources() default to using the mio_wb address as the resource's start address. This means users of the mapping, which includes most drivers, will get write combining on PCI Stores. This may lead to problems when drivers expect write through behavior when not using an explicit ioremap_wc(). Cc: stable@xxxxxxxxxxxxxxx Fixes: 71ba41c9b1d9 ("s390/pci: provide support for MIO instructions") Signed-off-by: Niklas Schnelle <schnelle@xxxxxxxxxxxxx> Reviewed-by: Pierre Morel <pmorel@xxxxxxxxxxxxx> Signed-off-by: Vasily Gorbik <gor@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/s390/pci/pci.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/arch/s390/pci/pci.c +++ b/arch/s390/pci/pci.c @@ -423,7 +423,7 @@ static void zpci_map_resources(struct pc if (zpci_use_mio(zdev)) pdev->resource[i].start = - (resource_size_t __force) zdev->bars[i].mio_wb; + (resource_size_t __force) zdev->bars[i].mio_wt; else pdev->resource[i].start = (resource_size_t __force) pci_iomap_range_fh(pdev, i, 0, 0); @@ -530,7 +530,7 @@ static int zpci_setup_bus_resources(stru flags |= IORESOURCE_MEM_64; if (zpci_use_mio(zdev)) - addr = (unsigned long) zdev->bars[i].mio_wb; + addr = (unsigned long) zdev->bars[i].mio_wt; else addr = ZPCI_ADDR(entry); size = 1UL << zdev->bars[i].size;