From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Date: Fri, 10 Jan 2014 14:23:14 +0000 (+0100)
Subject: ACPI / PCI: Use global PCI rescan-remove locking in PCI root hotplug
X-Git-Tag: v3.14-rc1~132^2~2^2~8
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=7a3bb55ebd1cb04f08dd68cf60af24b434f8cc2a;p=linux.git

ACPI / PCI: Use global PCI rescan-remove locking in PCI root hotplug

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@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 0703bff5e60e..07ee02aa3c51 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -596,7 +596,9 @@ static int acpi_pci_root_add(struct acpi_device *device,
 		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:
@@ -608,6 +610,8 @@ static void acpi_pci_root_remove(struct acpi_device *device)
 {
 	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);
@@ -615,6 +619,8 @@ static void acpi_pci_root_remove(struct acpi_device *device)
 
 	pci_remove_root_bus(root->bus);
 
+	pci_unlock_rescan_remove();
+
 	kfree(root);
 }