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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: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
This commit is contained in:
Rafael J. Wysocki 2013-07-13 23:27:26 +02:00
parent a1d0abcea8
commit ff181e5a4f
1 changed files with 7 additions and 7 deletions
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14
drivers/pci/hotplug/acpiphp_glue.c
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@ -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);
}
/**