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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
29ed1f29b6 (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: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
This commit is contained in:
Rafael J. Wysocki 2014-02-04 00:37:02 +01:00
parent af9d8adc6b
commit 1c0c5443de
1 changed files with 5 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
drivers/pci/hotplug/acpiphp_glue.c
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@ -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));