ACPICA: Update comments for acquire/release mutex interfaces
pdate comments for acquire/release mutex interfaces
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/executer/exmutex.c b/drivers/acpi/executer/exmutex.c
index 0bebe75..32f24a8 100644
--- a/drivers/acpi/executer/exmutex.c
+++ b/drivers/acpi/executer/exmutex.c
@@ -134,7 +134,16 @@
*
* RETURN: Status
*
- * DESCRIPTION: Acquire an AML mutex, low-level interface
+ * DESCRIPTION: Acquire an AML mutex, low-level interface. Provides a common
+ * path that supports multiple acquires by the same thread.
+ *
+ * MUTEX: Interpreter must be locked
+ *
+ * NOTE: This interface is called from three places:
+ * 1) From acpi_ex_acquire_mutex, via an AML Acquire() operator
+ * 2) From acpi_ex_acquire_global_lock when an AML Field access requires the
+ * global lock
+ * 3) From the external interface, acpi_acquire_global_lock
*
******************************************************************************/
@@ -174,7 +183,7 @@
return_ACPI_STATUS(status);
}
- /* Have the mutex: update mutex and save the sync_level */
+ /* Acquired the mutex: update mutex object */
obj_desc->mutex.thread_id = thread_id;
obj_desc->mutex.acquisition_depth = 1;
@@ -211,7 +220,7 @@
return_ACPI_STATUS(AE_BAD_PARAMETER);
}
- /* Sanity check: we must have a valid thread ID */
+ /* Must have a valid thread ID */
if (!walk_state->thread) {
ACPI_ERROR((AE_INFO,
@@ -221,7 +230,7 @@
}
/*
- * Current Sync level must be less than or equal to the sync level of the
+ * Current sync level must be less than or equal to the sync level of the
* mutex. This mechanism provides some deadlock prevention
*/
if (walk_state->thread->current_sync_level > obj_desc->mutex.sync_level) {
@@ -236,6 +245,9 @@
obj_desc,
walk_state->thread->thread_id);
if (ACPI_SUCCESS(status) && obj_desc->mutex.acquisition_depth == 1) {
+
+ /* Save Thread object, original/current sync levels */
+
obj_desc->mutex.owner_thread = walk_state->thread;
obj_desc->mutex.original_sync_level =
walk_state->thread->current_sync_level;
@@ -259,6 +271,16 @@
* RETURN: Status
*
* DESCRIPTION: Release a previously acquired Mutex, low level interface.
+ * Provides a common path that supports multiple releases (after
+ * previous multiple acquires) by the same thread.
+ *
+ * MUTEX: Interpreter must be locked
+ *
+ * NOTE: This interface is called from three places:
+ * 1) From acpi_ex_release_mutex, via an AML Acquire() operator
+ * 2) From acpi_ex_release_global_lock when an AML Field access requires the
+ * global lock
+ * 3) From the external interface, acpi_release_global_lock
*
******************************************************************************/
@@ -294,6 +316,8 @@
acpi_os_release_mutex(obj_desc->mutex.os_mutex);
}
+ /* Clear mutex info */
+
obj_desc->mutex.thread_id = 0;
return_ACPI_STATUS(status);
}
@@ -348,7 +372,7 @@
return_ACPI_STATUS(AE_AML_NOT_OWNER);
}
- /* Sanity check: we must have a valid thread ID */
+ /* Must have a valid thread ID */
if (!walk_state->thread) {
ACPI_ERROR((AE_INFO,
@@ -370,7 +394,7 @@
status = acpi_ex_release_mutex_object(obj_desc);
- /* Restore sync_level */
+ /* Restore the original sync_level */
walk_state->thread->current_sync_level =
obj_desc->mutex.original_sync_level;