From 19cd847ab24fefe9e50101ec94479e0400a08650 Mon Sep 17 00:00:00 2001 From: Zhang Rui Date: Thu, 28 Aug 2008 10:05:06 +0800 Subject: [PATCH] ACPI: fix hotplug race The hotplug notification handler and drivers' notification handler all run in one workqueue. Before hotplug removes an acpi device, the device driver's notification handler is already be recorded to run just after global notification handler. After hotplug notification handler runs, acpica will notice a NULL notification handler and crash. So now we run run hotplug in another workqueue and wait for all acpi notication handlers finish. This was found in battery hotplug, but actually all hotplug can be affected. Signed-off-by: Zhang Rui Signed-off-by: Shaohua Li Signed-off-by: Len Brown --- drivers/acpi/dock.c | 25 +++++++++++++++++++++- drivers/acpi/osl.c | 46 ++++++++++++++++++++++++++++++++++++----- include/acpi/acpiosxf.h | 3 +++ 3 files changed, 68 insertions(+), 6 deletions(-) diff --git a/drivers/acpi/dock.c b/drivers/acpi/dock.c index 2563bc62987d..4b395b1e61b2 100644 --- a/drivers/acpi/dock.c +++ b/drivers/acpi/dock.c @@ -748,6 +748,20 @@ static void dock_notify(acpi_handle handle, u32 event, void *data) } } +struct dock_data { + acpi_handle handle; + unsigned long event; + struct dock_station *ds; +}; + +static void acpi_dock_deferred_cb(void *context) +{ + struct dock_data *data = (struct dock_data *)context; + + dock_notify(data->handle, data->event, data->ds); + kfree(data); +} + static int acpi_dock_notifier_call(struct notifier_block *this, unsigned long event, void *data) { @@ -759,7 +773,16 @@ static int acpi_dock_notifier_call(struct notifier_block *this, return 0; list_for_each_entry(dock_station, &dock_stations, sibiling) { if (dock_station->handle == handle) { - dock_notify(handle, event, dock_station); + struct dock_data *dock_data; + + dock_data = kmalloc(sizeof(*dock_data), GFP_KERNEL); + if (!dock_data) + return 0; + dock_data->handle = handle; + dock_data->event = event; + dock_data->ds = dock_station; + acpi_os_hotplug_execute(acpi_dock_deferred_cb, + dock_data); return 0 ; } } diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c index 235a1386888a..750e0df15604 100644 --- a/drivers/acpi/osl.c +++ b/drivers/acpi/osl.c @@ -682,6 +682,22 @@ static void acpi_os_execute_deferred(struct work_struct *work) return; } +static void acpi_os_execute_hp_deferred(struct work_struct *work) +{ + struct acpi_os_dpc *dpc = container_of(work, struct acpi_os_dpc, work); + if (!dpc) { + printk(KERN_ERR PREFIX "Invalid (NULL) context\n"); + return; + } + + acpi_os_wait_events_complete(NULL); + + dpc->function(dpc->context); + kfree(dpc); + + return; +} + /******************************************************************************* * * FUNCTION: acpi_os_execute @@ -697,12 +713,13 @@ static void acpi_os_execute_deferred(struct work_struct *work) * ******************************************************************************/ -acpi_status acpi_os_execute(acpi_execute_type type, - acpi_osd_exec_callback function, void *context) +static acpi_status __acpi_os_execute(acpi_execute_type type, + acpi_osd_exec_callback function, void *context, int hp) { acpi_status status = AE_OK; struct acpi_os_dpc *dpc; struct workqueue_struct *queue; + int ret; ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Scheduling function [%p(%p)] for deferred execution.\n", function, context)); @@ -726,9 +743,17 @@ acpi_status acpi_os_execute(acpi_execute_type type, dpc->function = function; dpc->context = context; - INIT_WORK(&dpc->work, acpi_os_execute_deferred); - queue = (type == OSL_NOTIFY_HANDLER) ? kacpi_notify_wq : kacpid_wq; - if (!queue_work(queue, &dpc->work)) { + if (!hp) { + INIT_WORK(&dpc->work, acpi_os_execute_deferred); + queue = (type == OSL_NOTIFY_HANDLER) ? + kacpi_notify_wq : kacpid_wq; + ret = queue_work(queue, &dpc->work); + } else { + INIT_WORK(&dpc->work, acpi_os_execute_hp_deferred); + ret = schedule_work(&dpc->work); + } + + if (!ret) { ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Call to queue_work() failed.\n")); status = AE_ERROR; @@ -737,8 +762,19 @@ acpi_status acpi_os_execute(acpi_execute_type type, return_ACPI_STATUS(status); } +acpi_status acpi_os_execute(acpi_execute_type type, + acpi_osd_exec_callback function, void *context) +{ + return __acpi_os_execute(type, function, context, 0); +} EXPORT_SYMBOL(acpi_os_execute); +acpi_status acpi_os_hotplug_execute(acpi_osd_exec_callback function, + void *context) +{ + return __acpi_os_execute(0, function, context, 1); +} + void acpi_os_wait_events_complete(void *context) { flush_workqueue(kacpid_wq); diff --git a/include/acpi/acpiosxf.h b/include/acpi/acpiosxf.h index 3f93a6b4e17f..b91440ac0d16 100644 --- a/include/acpi/acpiosxf.h +++ b/include/acpi/acpiosxf.h @@ -193,6 +193,9 @@ acpi_status acpi_os_execute(acpi_execute_type type, acpi_osd_exec_callback function, void *context); +acpi_status +acpi_os_hotplug_execute(acpi_osd_exec_callback function, void *context); + void acpi_os_wait_events_complete(void *context); void acpi_os_sleep(acpi_integer milliseconds);