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Commit ff181e5a authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

ACPI / hotplug / PCI: Clean up bridge_mutex usage 



Do not acquire bridge_mutex around the addition of a slot to its
bridge's list of slots and arount the addition of a function to
its slot's list of functions, because that doesn't help anything
right now (those lists are walked without any locking anyway).

However, acquire bridge_mutex around the list walk in
acpiphp_remove_slots() and use list_for_each_entry() there,
because we terminate the walk as soon as we find the first matching
entry.  This prevents that list walk from colliding with bridge
addition and removal.

Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
parent a1d0abce

drivers/pci/hotplug/acpiphp_glue.c

+7 −7
Original line number Diff line number Diff line
@@ -323,9 +323,7 @@ static acpi_status register_slot(acpi_handle handle, u32 lvl, void *data, 
	INIT_LIST_HEAD(&slot->funcs);

	mutex_init(&slot->crit_sect);



	mutex_lock(&bridge_mutex);

	list_add_tail(&slot->node, &bridge->slots);

	mutex_unlock(&bridge_mutex);



	/* Register slots for ejectable funtions only. */

	if (acpi_pci_check_ejectable(pbus, handle)  || is_dock_device(handle)) {
@@ -355,9 +353,7 @@ static acpi_status register_slot(acpi_handle handle, u32 lvl, void *data, 


 slot_found:

	newfunc->slot = slot;

	mutex_lock(&bridge_mutex);

	list_add_tail(&newfunc->sibling, &slot->funcs);

	mutex_unlock(&bridge_mutex);



	if (pci_bus_read_dev_vendor_id(pbus, PCI_DEVFN(device, function),

				       &val, 60*1000))
@@ -1025,17 +1021,21 @@ void acpiphp_enumerate_slots(struct pci_bus *bus) 
/* Destroy hotplug slots associated with the PCI bus */

void acpiphp_remove_slots(struct pci_bus *bus)

{

	struct acpiphp_bridge *bridge, *tmp;

	struct acpiphp_bridge *bridge;



	if (acpiphp_disabled)

		return;



	list_for_each_entry_safe(bridge, tmp, &bridge_list, list)

	mutex_lock(&bridge_mutex);

	list_for_each_entry(bridge, &bridge_list, list)

		if (bridge->pci_bus == bus) {

			mutex_unlock(&bridge_mutex);

			cleanup_bridge(bridge);

			put_bridge(bridge);

			break;

			return;

		}



	mutex_unlock(&bridge_mutex);

}



/**