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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2012-11-02 13:09:08 +0100
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2012-11-15 00:18:20 +0100
commit3ae45a27df74358b4bcd3d5a67e47ad734a48945 (patch)
tree17ffd507fd96a4567fa2d6076b497298384d0945
parentc5b18e22e74dc7dbd3f7729997a3a553ce761d2b (diff)
downloadlinux-3ae45a27df74358b4bcd3d5a67e47ad734a48945.tar.bz2
ACPI: Make seemingly useless check in osl.c more understandable
There is a seemingly useless check in drivers/acpi/osl.c added by commit bc73675 (ACPI: fixes a false alarm from lockdep), which really is necessary to avoid false positive lockdep complaints. Document this and rearrange the code related to it so that it makes fewer checks. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Yinghai Lu <yinghai@kernel.org>
-rw-r--r--drivers/acpi/osl.c21
1 files changed, 13 insertions, 8 deletions
diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 7dfe91d0173e..6dc4a2b1e956 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -932,7 +932,7 @@ static acpi_status __acpi_os_execute(acpi_execute_type type,
* having a static work_struct.
*/
- dpc = kmalloc(sizeof(struct acpi_os_dpc), GFP_ATOMIC);
+ dpc = kzalloc(sizeof(struct acpi_os_dpc), GFP_ATOMIC);
if (!dpc)
return AE_NO_MEMORY;
@@ -944,17 +944,22 @@ static acpi_status __acpi_os_execute(acpi_execute_type type,
* because the hotplug code may call driver .remove() functions,
* which invoke flush_scheduled_work/acpi_os_wait_events_complete
* to flush these workqueues.
+ *
+ * To prevent lockdep from complaining unnecessarily, make sure that
+ * there is a different static lockdep key for each workqueue by using
+ * INIT_WORK() for each of them separately.
*/
- queue = hp ? kacpi_hotplug_wq :
- (type == OSL_NOTIFY_HANDLER ? kacpi_notify_wq : kacpid_wq);
- dpc->wait = hp ? 1 : 0;
-
- if (queue == kacpi_hotplug_wq)
+ if (hp) {
+ queue = kacpi_hotplug_wq;
+ dpc->wait = 1;
INIT_WORK(&dpc->work, acpi_os_execute_deferred);
- else if (queue == kacpi_notify_wq)
+ } else if (type == OSL_NOTIFY_HANDLER) {
+ queue = kacpi_notify_wq;
INIT_WORK(&dpc->work, acpi_os_execute_deferred);
- else
+ } else {
+ queue = kacpid_wq;
INIT_WORK(&dpc->work, acpi_os_execute_deferred);
+ }
/*
* On some machines, a software-initiated SMI causes corruption unless