From ff181e5a4f6b536e5f3f1601cd5c54e792cd9abc Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Sat, 13 Jul 2013 23:27:26 +0200 Subject: [PATCH] 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 Tested-by: Mika Westerberg --- drivers/pci/hotplug/acpiphp_glue.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c index 18c9e54990ee..e4b7f2bc94df 100644 --- a/drivers/pci/hotplug/acpiphp_glue.c +++ b/drivers/pci/hotplug/acpiphp_glue.c @@ -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); } /**