From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
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
29ed1f29b68a (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@xxxxxxxxx>
---
drivers/pci/hotplug/acpiphp_glue.c | 28 +++++-----------------------
1 file changed, 5 insertions(+), 23 deletions(-)
Index: linux-pm/drivers/pci/hotplug/acpiphp_glue.c
===================================================================
--- linux-pm.orig/drivers/pci/hotplug/acpiphp_glue.c
+++ linux-pm/drivers/pci/hotplug/acpiphp_glue.c
@@ -604,32 +604,15 @@ static void __ref enable_slot(struct acp
}
}
-/* 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
@@ -637,10 +620,9 @@ static void disable_slot(struct acpiphp_
* 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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