Revert "ACPICA: fix AML mutex re-entrancy"

This reverts commit c0d127b.

These changes to AML locking were made to allow
Notify handlers to be called on the stack
and not deadlock.  However, that scheme turns
out to be flawed and was reverted by the previous commit,
so this commit restores the locking to it previous design.

Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/dispatcher/dsmethod.c

@@ -231,8 +231,10 @@ acpi_ds_begin_method_execution(struct acpi_namespace_node *method_node,
 		 * Obtain the method mutex if necessary. Do not acquire mutex for a
 		 * recursive call.
 		 */
-		if (acpi_os_get_thread_id() !=
-		    obj_desc->method.mutex->mutex.owner_thread_id) {
+		if (!walk_state ||
+		    !obj_desc->method.mutex->mutex.owner_thread ||
+		    (walk_state->thread !=
+		     obj_desc->method.mutex->mutex.owner_thread)) {
 			/*
 			 * Acquire the method mutex. This releases the interpreter if we
 			 * block (and reacquires it before it returns)
@@ -246,14 +248,14 @@ acpi_ds_begin_method_execution(struct acpi_namespace_node *method_node,
 			}
 
 			/* Update the mutex and walk info and save the original sync_level */
-			obj_desc->method.mutex->mutex.owner_thread_id =
-				acpi_os_get_thread_id();
 
 			if (walk_state) {
 				obj_desc->method.mutex->mutex.
 				    original_sync_level =
 				    walk_state->thread->current_sync_level;
 
+				obj_desc->method.mutex->mutex.owner_thread =
+				    walk_state->thread;
 				walk_state->thread->current_sync_level =
 				    obj_desc->method.sync_level;
 			} else {
@@ -567,7 +569,7 @@ acpi_ds_terminate_control_method(union acpi_operand_object *method_desc,
 
 			acpi_os_release_mutex(method_desc->method.mutex->mutex.
 					      os_mutex);
-			method_desc->method.mutex->mutex.owner_thread_id = ACPI_MUTEX_NOT_ACQUIRED;
+			method_desc->method.mutex->mutex.owner_thread = NULL;
 		}
 	}
 

drivers/acpi/executer/exdump.c

@@ -134,7 +134,7 @@ static struct acpi_exdump_info acpi_ex_dump_method[8] = {
 static struct acpi_exdump_info acpi_ex_dump_mutex[5] = {
 	{ACPI_EXD_INIT, ACPI_EXD_TABLE_SIZE(acpi_ex_dump_mutex), NULL},
 	{ACPI_EXD_UINT8, ACPI_EXD_OFFSET(mutex.sync_level), "Sync Level"},
-	{ACPI_EXD_POINTER, ACPI_EXD_OFFSET(mutex.owner_thread_id), "Owner Thread"},
+	{ACPI_EXD_POINTER, ACPI_EXD_OFFSET(mutex.owner_thread), "Owner Thread"},
 	{ACPI_EXD_UINT16, ACPI_EXD_OFFSET(mutex.acquisition_depth),
 	 "Acquire Depth"},
 	{ACPI_EXD_POINTER, ACPI_EXD_OFFSET(mutex.os_mutex), "OsMutex"}

drivers/acpi/executer/exmutex.c

@@ -66,9 +66,10 @@ acpi_ex_link_mutex(union acpi_operand_object *obj_desc,
  *
  ******************************************************************************/
 
-void acpi_ex_unlink_mutex(union acpi_operand_object *obj_desc,
-			  struct acpi_thread_state *thread)
+void acpi_ex_unlink_mutex(union acpi_operand_object *obj_desc)
 {
+	struct acpi_thread_state *thread = obj_desc->mutex.owner_thread;
+
 	if (!thread) {
 		return;
 	}
@@ -173,13 +174,16 @@ acpi_ex_acquire_mutex(union acpi_operand_object *time_desc,
 
 	/* Support for multiple acquires by the owning thread */
 
-	if (obj_desc->mutex.owner_thread_id == acpi_os_get_thread_id()) {
-		/*
-		 * The mutex is already owned by this thread, just increment the
-		 * acquisition depth
-		 */
-		obj_desc->mutex.acquisition_depth++;
-		return_ACPI_STATUS(AE_OK);
+	if (obj_desc->mutex.owner_thread) {
+		if (obj_desc->mutex.owner_thread->thread_id ==
+		    walk_state->thread->thread_id) {
+			/*
+			 * The mutex is already owned by this thread, just increment the
+			 * acquisition depth
+			 */
+			obj_desc->mutex.acquisition_depth++;
+			return_ACPI_STATUS(AE_OK);
+		}
 	}
 
 	/* Acquire the mutex, wait if necessary. Special case for Global Lock */
@@ -202,7 +206,7 @@ acpi_ex_acquire_mutex(union acpi_operand_object *time_desc,
 
 	/* Have the mutex: update mutex and walk info and save the sync_level */
 
-	obj_desc->mutex.owner_thread_id = acpi_os_get_thread_id();
+	obj_desc->mutex.owner_thread = walk_state->thread;
 	obj_desc->mutex.acquisition_depth = 1;
 	obj_desc->mutex.original_sync_level =
 	    walk_state->thread->current_sync_level;
@@ -242,7 +246,7 @@ acpi_ex_release_mutex(union acpi_operand_object *obj_desc,
 
 	/* The mutex must have been previously acquired in order to release it */
 
-	if (!obj_desc->mutex.owner_thread_id) {
+	if (!obj_desc->mutex.owner_thread) {
 		ACPI_ERROR((AE_INFO,
 			    "Cannot release Mutex [%4.4s], not acquired",
 			    acpi_ut_get_node_name(obj_desc->mutex.node)));
@@ -262,14 +266,14 @@ acpi_ex_release_mutex(union acpi_operand_object *obj_desc,
 	 * The Mutex is owned, but this thread must be the owner.
 	 * Special case for Global Lock, any thread can release
 	 */
-	if ((obj_desc->mutex.owner_thread_id !=
+	if ((obj_desc->mutex.owner_thread->thread_id !=
 	     walk_state->thread->thread_id)
 	    && (obj_desc->mutex.os_mutex != acpi_gbl_global_lock_mutex)) {
 		ACPI_ERROR((AE_INFO,
 			    "Thread %lX cannot release Mutex [%4.4s] acquired by thread %lX",
 			    (unsigned long)walk_state->thread->thread_id,
 			    acpi_ut_get_node_name(obj_desc->mutex.node),
-			    (unsigned long)obj_desc->mutex.owner_thread_id));
+			    (unsigned long)obj_desc->mutex.owner_thread->thread_id));
 		return_ACPI_STATUS(AE_AML_NOT_OWNER);
 	}
 
@@ -296,7 +300,7 @@ acpi_ex_release_mutex(union acpi_operand_object *obj_desc,
 
 	/* Unlink the mutex from the owner's list */
 
-	acpi_ex_unlink_mutex(obj_desc, walk_state->thread);
+	acpi_ex_unlink_mutex(obj_desc);
 
 	/* Release the mutex, special case for Global Lock */
 
@@ -308,7 +312,7 @@ acpi_ex_release_mutex(union acpi_operand_object *obj_desc,
 
 	/* Update the mutex and restore sync_level */
 
-	obj_desc->mutex.owner_thread_id = ACPI_MUTEX_NOT_ACQUIRED;
+	obj_desc->mutex.owner_thread = NULL;
 	walk_state->thread->current_sync_level =
 	    obj_desc->mutex.original_sync_level;
 
@@ -363,7 +367,7 @@ void acpi_ex_release_all_mutexes(struct acpi_thread_state *thread)
 
 		/* Mark mutex unowned */
 
-		obj_desc->mutex.owner_thread_id = ACPI_MUTEX_NOT_ACQUIRED;
+		obj_desc->mutex.owner_thread = NULL;
 
 		/* Update Thread sync_level (Last mutex is the important one) */
 

drivers/acpi/utilities/utdelete.c

@@ -170,6 +170,7 @@ static void acpi_ut_delete_internal_obj(union acpi_operand_object *object)
 			acpi_os_delete_mutex(object->mutex.os_mutex);
 			acpi_gbl_global_lock_mutex = NULL;
 		} else {
+			acpi_ex_unlink_mutex(object);
 			acpi_os_delete_mutex(object->mutex.os_mutex);
 		}
 		break;

include/acpi/acinterp.h

@@ -253,8 +253,7 @@ acpi_ex_release_mutex(union acpi_operand_object *obj_desc,
 
 void acpi_ex_release_all_mutexes(struct acpi_thread_state *thread);
 
-void acpi_ex_unlink_mutex(union acpi_operand_object *obj_desc,
-			  struct acpi_thread_state *thread);
+void acpi_ex_unlink_mutex(union acpi_operand_object *obj_desc);
 
 /*
  * exprep - ACPI AML execution - prep utilities

include/acpi/acobject.h

@@ -155,7 +155,7 @@ struct acpi_object_event {
 struct acpi_object_mutex {
 	ACPI_OBJECT_COMMON_HEADER u8 sync_level;	/* 0-15, specified in Mutex() call */
 	u16 acquisition_depth;	/* Allow multiple Acquires, same thread */
-	acpi_thread_id owner_thread_id;	/* Current owner of the mutex */
+	struct acpi_thread_state *owner_thread;	/* Current owner of the mutex */
 	acpi_mutex os_mutex;	/* Actual OS synchronization object */
 	union acpi_operand_object *prev;	/* Link for list of acquired mutexes */
 	union acpi_operand_object *next;	/* Link for list of acquired mutexes */