Commit 1c0c5443 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

ACPI / hotplug / PCI: Simplify disable_slot() 



After recent PCI core changes related to the rescan/remove locking,
the ACPIPHP's disable_slot() function is only called under the
general PCI rescan/remove lock, so it doesn't have to use
dev_in_slot() any more to avoid race conditions.  Make it simply
walk the devices on the bus and drop the ones in the slot being
disabled and drop dev_in_slot() which has no more users.

Moreover, to avoid problems described in the changelog of commit
29ed1f29 (PCI: pciehp: Fix null pointer deref when hot-removing
SR-IOV device), make disable_slot() carry out the list walk in
reverse order.

Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
parent af9d8adc

drivers/pci/hotplug/acpiphp_glue.c

+5 −23
Original line number Diff line number Diff line
@@ -625,32 +625,15 @@ static void __ref enable_slot(struct acpiphp_slot *slot) 
	}

}



/* return first device in slot, acquiring a reference on it */

static struct pci_dev *dev_in_slot(struct acpiphp_slot *slot)

{

	struct pci_bus *bus = slot->bus;

	struct pci_dev *dev;

	struct pci_dev *ret = NULL;



	down_read(&pci_bus_sem);

	list_for_each_entry(dev, &bus->devices, bus_list)

		if (PCI_SLOT(dev->devfn) == slot->device) {

			ret = pci_dev_get(dev);

			break;

		}

	up_read(&pci_bus_sem);



	return ret;

}



/**

 * disable_slot - disable a slot

 * @slot: ACPI PHP slot

 */

static void disable_slot(struct acpiphp_slot *slot)

{

	struct pci_bus *bus = slot->bus;

	struct pci_dev *dev, *prev;

	struct acpiphp_func *func;

	struct pci_dev *pdev;



	/*

	 * enable_slot() enumerates all functions in this device via
@@ -658,10 +641,9 @@ static void disable_slot(struct acpiphp_slot *slot) 
	 * methods (_EJ0, etc.) or not.  Therefore, we remove all functions

	 * here.

	 */

	while ((pdev = dev_in_slot(slot))) {

		pci_stop_and_remove_bus_device(pdev);

		pci_dev_put(pdev);

	}

	list_for_each_entry_safe_reverse(dev, prev, &bus->devices, bus_list)

		if (PCI_SLOT(dev->devfn) == slot->device)

			pci_stop_and_remove_bus_device(dev);



	list_for_each_entry(func, &slot->funcs, sibling)

		acpiphp_bus_trim(func_to_handle(func));

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