[PATCH 2/9] ACPI / PCI: Use global PCI rescan-remove locking in PCI root hotplug

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

Multiple race conditions are possible between the addition and
removal of PCI devices during ACPI PCI host bridge hotplug and the
generic PCI bus rescan and device removal that can be triggered via
sysfs.

To avoid those race conditions make the ACPI PCI host bridge addition
and removal code use global PCI rescan-remove locking.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
 drivers/acpi/pci_root.c |    6 ++++++
 1 file changed, 6 insertions(+)

Index: linux-pm/drivers/acpi/pci_root.c
===================================================================
--- linux-pm.orig/drivers/acpi/pci_root.c
+++ linux-pm/drivers/acpi/pci_root.c
@@ -604,7 +604,9 @@ static int acpi_pci_root_add(struct acpi
 		pci_assign_unassigned_root_bus_resources(root->bus);
 	}
 
+	pci_lock_rescan_remove();
 	pci_bus_add_devices(root->bus);
+	pci_unlock_rescan_remove();
 	return 1;
 
 end:
@@ -616,6 +618,8 @@ static void acpi_pci_root_remove(struct
 {
 	struct acpi_pci_root *root = acpi_driver_data(device);
 
+	pci_lock_rescan_remove();
+
 	pci_stop_root_bus(root->bus);
 
 	device_set_run_wake(root->bus->bridge, false);
@@ -623,6 +627,8 @@ static void acpi_pci_root_remove(struct
 
 	pci_remove_root_bus(root->bus);
 
+	pci_unlock_rescan_remove();
+
 	kfree(root);
 }
 

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