From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: [RFC][PATCH 30/30] ACPI / hotplug / PCI: Clean up bridge_mutex usage Date: Fri, 12 Jul 2013 02:07:53 +0200 Message-ID: <1556050.sitoT3kI8H@vostro.rjw.lan> References: <26431283.HJCKsss0rt@vostro.rjw.lan> <3718119.FLASu5DBx8@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <3718119.FLASu5DBx8@vostro.rjw.lan> Sender: linux-pci-owner@vger.kernel.org To: ACPI Devel Maling List Cc: Bjorn Helgaas , LKML , Linux PCI , Yinghai Lu , Jiang Liu , Mika Westerberg List-Id: linux-acpi@vger.kernel.org From: Rafael J. Wysocki 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 --- drivers/pci/hotplug/acpiphp_glue.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) Index: linux-pm/drivers/pci/hotplug/acpiphp_glue.c =================================================================== --- linux-pm.orig/drivers/pci/hotplug/acpiphp_glue.c +++ linux-pm/drivers/pci/hotplug/acpiphp_glue.c @@ -324,9 +324,7 @@ static acpi_status register_slot(acpi_ha 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)) { @@ -357,9 +355,7 @@ static acpi_status register_slot(acpi_ha 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)) @@ -997,17 +993,21 @@ void acpiphp_enumerate_slots(struct pci_ /* 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); } /**