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Commit d391f00f authored by Kenji Kaneshige's avatar Kenji Kaneshige Committed by Jesse Barnes
Browse files

PCI hotplug: fix wrong assumption in acpi_get_hp_hw_control_from_firmware 



Current acpi_get_hp_hw_control_from_firmware() has a assumption that
pci_bus->self is NULL on a PCI root bus. But it might not be true on
some platforms. Because of this wrong assumption, current
acpi_get_hp_hw_control_from_firmware() might cause endless loop. We
must check pci_bus->parent instead.

Signed-off-by: default avatarKenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
parent 267efd7e

drivers/pci/hotplug/acpi_pcihp.c

+12 −22
Original line number Diff line number Diff line
@@ -372,12 +372,10 @@ EXPORT_SYMBOL_GPL(acpi_get_hp_params_from_firmware); 
 *

 * Attempt to take hotplug control from firmware.

 */

int acpi_get_hp_hw_control_from_firmware(struct pci_dev *dev, u32 flags)

int acpi_get_hp_hw_control_from_firmware(struct pci_dev *pdev, u32 flags)

{

	acpi_status status;

	acpi_handle chandle, handle;

	struct pci_dev *pdev = dev;

	struct pci_bus *parent;

	struct acpi_buffer string = { ACPI_ALLOCATE_BUFFER, NULL };



	flags &= (OSC_PCI_EXPRESS_NATIVE_HP_CONTROL |
@@ -409,26 +407,18 @@ int acpi_get_hp_hw_control_from_firmware(struct pci_dev *dev, u32 flags) 
		string = (struct acpi_buffer){ ACPI_ALLOCATE_BUFFER, NULL };

	}



	pdev = dev;

	handle = DEVICE_ACPI_HANDLE(&dev->dev);

	while (!handle) {

	handle = DEVICE_ACPI_HANDLE(&pdev->dev);

	if (!handle) {

		/*

		 * This hotplug controller was not listed in the ACPI name

		 * space at all. Try to get acpi handle of parent pci bus.

		 */

		if (!pdev || !pdev->bus->parent)

		struct pci_bus *pbus;

		for (pbus = pdev->bus; pbus; pbus = pbus->parent) {

			handle = acpi_pci_get_bridge_handle(pbus);

			if (handle)

				break;

		parent = pdev->bus->parent;

		dbg("Could not find %s in acpi namespace, trying parent\n",

		    pci_name(pdev));

		if (!parent->self)

			/* Parent must be a host bridge */

			handle = acpi_get_pci_rootbridge_handle(

					pci_domain_nr(parent),

					parent->number);

		else

			handle = DEVICE_ACPI_HANDLE(&(parent->self->dev));

		pdev = parent->self;

		}

	}



	while (handle) {
@@ -447,13 +437,13 @@ int acpi_get_hp_hw_control_from_firmware(struct pci_dev *dev, u32 flags) 
	}



	dbg("Cannot get control of hotplug hardware for pci %s\n",

	    pci_name(dev));

	    pci_name(pdev));



	kfree(string.pointer);

	return -ENODEV;

got_one:

	dbg("Gained control for hotplug HW for pci %s (%s)\n", pci_name(dev),

			(char *)string.pointer);

	dbg("Gained control for hotplug HW for pci %s (%s)\n",

	    pci_name(pdev), (char *)string.pointer);

	kfree(string.pointer);

	return 0;

}