comment in commit b566a22c23327f18ce941ffad0ca907e50a53d41
("PCI: disable Bus Master on PCI device shutdown") says:| Disable Bus Master bit on the device in pci_device_shutdown() to ensure PCI | devices do not continue to DMA data after shutdown. This can cause memory | corruption in case of a kexec where the current kernel shuts down and | transfers control to a new kernel while a PCI device continues to DMA to | memory that does not belong to it any more in the new kernel. Seems like pci_clear_master() must be used here instead of pci_disable_device(), because it disables Bus Muster unconditionally and doesn't changes enable_cnt. Signed-off-by: Konstantin Khlebnikov <[email protected]> Cc: [email protected] Cc: Bjorn Helgaas <[email protected]> Cc: Khalid Aziz <[email protected]> --- drivers/pci/pci-driver.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index 030dbf0..853d605 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -392,7 +392,7 @@ static void pci_device_shutdown(struct device *dev) * Turn off Bus Master bit on the device to tell it to not * continue to do DMA */ - pci_disable_device(pci_dev); + pci_clear_master(pci_dev); } #ifdef CONFIG_PM -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
