ACPI / hotplug / PCI: Move PCI rescan-remove locking to hotplug_event()

Commit 9217a984671e (ACPI / hotplug / PCI: Use global PCI rescan-remove
locking) modified ACPIPHP to protect its PCI device removal and addition
code paths from races against sysfs-driven rescan and remove operations
with the help of PCI rescan-remove locking.  However, it overlooked the
fact that hotplug_event_work() is not the only caller of hotplug_event()
which may also be called by dock_hotplug_event() and that code path
is missing the PCI rescan-remove locking.  This means that, although
the PCI rescan-remove lock is held as appropriate during the handling
of events originating from handle_hotplug_event(), the ACPIPHP's
operations resulting from dock events may still suffer the race
conditions that commit 9217a984671e was supposed to eliminate.

To address that problem, move the PCI rescan-remove locking from
hotplug_event_work() to hotplug_event() so that it is used regardless
of the way that function is invoked.

Revamps: 9217a984671e (ACPI / hotplug / PCI: Use global PCI rescan-remove locking)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
index 6a4b4b7..6e5bd79 100644 (file)
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -852,6 +852,7 @@ static void hotplug_event(acpi_handle handle, u32 type, void *data)
 
        mutex_unlock(&acpiphp_context_lock);
 
+       pci_lock_rescan_remove();
        acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 
        switch (type) {
@@ -905,6 +906,7 @@ static void hotplug_event(acpi_handle handle, u32 type, void *data)
                break;
        }
 
+       pci_unlock_rescan_remove();
        if (bridge)
                put_bridge(bridge);
 }
@@ -915,11 +917,9 @@ static void hotplug_event_work(void *data, u32 type)
        acpi_handle handle = context->handle;
 
        acpi_scan_lock_acquire();
-       pci_lock_rescan_remove();
 
        hotplug_event(handle, type, context);
 
-       pci_unlock_rescan_remove();
        acpi_scan_lock_release();
        acpi_evaluate_hotplug_ost(handle, type, ACPI_OST_SC_SUCCESS, NULL);
        put_bridge(context->func.parent);