From: Bob Moore <[EMAIL PROTECTED]>

Enhanced the implementation of the interpreters'
serialized mode (boot with "acpi_serialize" to set
acpi_glb_all_methods_serialized flag.)
When this mode is specified, instead of creating a serialization
semaphore per control method, the interpreter lock is
simply no longer released before a blocking operation
during control method execution. This effectively makes
the AML Interpreter single-threaded. The overhead of a
semaphore per-method is eliminated.

Signed-off-by: Alexey Starikovskiy <[EMAIL PROTECTED]>
Signed-off-by: Len Brown <[EMAIL PROTECTED]>
---
 drivers/acpi/events/evregion.c    |   15 ++----
 drivers/acpi/events/evxface.c     |    6 +--
 drivers/acpi/executer/excreate.c  |    5 +--
 drivers/acpi/executer/exsystem.c  |   30 +++--------
 drivers/acpi/executer/exutils.c   |  108 +++++++++++++++++++++++++++++-------
 drivers/acpi/namespace/nseval.c   |   11 +---
 drivers/acpi/namespace/nsinit.c   |    7 +--
 drivers/acpi/namespace/nsxfeval.c |   11 ++---
 include/acpi/acinterp.h           |    6 ++-
 9 files changed, 114 insertions(+), 85 deletions(-)

diff --git a/drivers/acpi/events/evregion.c b/drivers/acpi/events/evregion.c
index 21caae0..ef45971 100644
--- a/drivers/acpi/events/evregion.c
+++ b/drivers/acpi/events/evregion.c
@@ -291,7 +291,6 @@ acpi_ev_address_space_dispatch(union acpi_operand_object 
*region_obj,
                               u32 bit_width, acpi_integer * value)
 {
        acpi_status status;
-       acpi_status status2;
        acpi_adr_space_handler handler;
        acpi_adr_space_setup region_setup;
        union acpi_operand_object *handler_desc;
@@ -345,7 +344,7 @@ acpi_ev_address_space_dispatch(union acpi_operand_object 
*region_obj,
                 * setup will potentially execute control methods
                 * (e.g., _REG method for this region)
                 */
-               acpi_ex_exit_interpreter();
+               acpi_ex_relinquish_interpreter();
 
                status = region_setup(region_obj, ACPI_REGION_ACTIVATE,
                                      handler_desc->address_space.context,
@@ -353,10 +352,7 @@ acpi_ev_address_space_dispatch(union acpi_operand_object 
*region_obj,
 
                /* Re-enter the interpreter */
 
-               status2 = acpi_ex_enter_interpreter();
-               if (ACPI_FAILURE(status2)) {
-                       return_ACPI_STATUS(status2);
-               }
+               acpi_ex_reacquire_interpreter();
 
                /* Check for failure of the Region Setup */
 
@@ -409,7 +405,7 @@ acpi_ev_address_space_dispatch(union acpi_operand_object 
*region_obj,
                 * exit the interpreter because the handler *might* block -- we 
don't
                 * know what it will do, so we can't hold the lock on the 
intepreter.
                 */
-               acpi_ex_exit_interpreter();
+               acpi_ex_relinquish_interpreter();
        }
 
        /* Call the handler */
@@ -430,10 +426,7 @@ acpi_ev_address_space_dispatch(union acpi_operand_object 
*region_obj,
                 * We just returned from a non-default handler, we must 
re-enter the
                 * interpreter
                 */
-               status2 = acpi_ex_enter_interpreter();
-               if (ACPI_FAILURE(status2)) {
-                       return_ACPI_STATUS(status2);
-               }
+               acpi_ex_reacquire_interpreter();
        }
 
        return_ACPI_STATUS(status);
diff --git a/drivers/acpi/events/evxface.c b/drivers/acpi/events/evxface.c
index 923fd2b..a2af48e 100644
--- a/drivers/acpi/events/evxface.c
+++ b/drivers/acpi/events/evxface.c
@@ -768,11 +768,9 @@ acpi_status acpi_acquire_global_lock(u16 timeout, u32 * 
handle)
                return (AE_BAD_PARAMETER);
        }
 
-       status = acpi_ex_enter_interpreter();
-       if (ACPI_FAILURE(status)) {
-               return (status);
-       }
+       /* Must lock interpreter to prevent race conditions */
 
+       acpi_ex_enter_interpreter();
        status = acpi_ev_acquire_global_lock(timeout);
        acpi_ex_exit_interpreter();
 
diff --git a/drivers/acpi/executer/excreate.c b/drivers/acpi/executer/excreate.c
index a4d29b2..c665aa7 100644
--- a/drivers/acpi/executer/excreate.c
+++ b/drivers/acpi/executer/excreate.c
@@ -583,10 +583,7 @@ acpi_ex_create_method(u8 * aml_start,
         * Get the sync_level. If method is serialized, a mutex will be
         * created for this method when it is parsed.
         */
-       if (acpi_gbl_all_methods_serialized) {
-               obj_desc->method.sync_level = 0;
-               obj_desc->method.method_flags |= AML_METHOD_SERIALIZED;
-       } else if (method_flags & AML_METHOD_SERIALIZED) {
+       if (method_flags & AML_METHOD_SERIALIZED) {
                /*
                 * ACPI 1.0: sync_level = 0
                 * ACPI 2.0: sync_level = sync_level in method declaration
diff --git a/drivers/acpi/executer/exsystem.c b/drivers/acpi/executer/exsystem.c
index 3b9736a..7e5aeb1 100644
--- a/drivers/acpi/executer/exsystem.c
+++ b/drivers/acpi/executer/exsystem.c
@@ -66,7 +66,6 @@ ACPI_MODULE_NAME("exsystem")
 acpi_status acpi_ex_system_wait_semaphore(acpi_semaphore semaphore, u16 
timeout)
 {
        acpi_status status;
-       acpi_status status2;
 
        ACPI_FUNCTION_TRACE(ex_system_wait_semaphore);
 
@@ -79,7 +78,7 @@ acpi_status acpi_ex_system_wait_semaphore(acpi_semaphore 
semaphore, u16 timeout)
 
                /* We must wait, so unlock the interpreter */
 
-               acpi_ex_exit_interpreter();
+               acpi_ex_relinquish_interpreter();
 
                status = acpi_os_wait_semaphore(semaphore, 1, timeout);
 
@@ -89,13 +88,7 @@ acpi_status acpi_ex_system_wait_semaphore(acpi_semaphore 
semaphore, u16 timeout)
 
                /* Reacquire the interpreter */
 
-               status2 = acpi_ex_enter_interpreter();
-               if (ACPI_FAILURE(status2)) {
-
-                       /* Report fatal error, could not acquire interpreter */
-
-                       return_ACPI_STATUS(status2);
-               }
+               acpi_ex_reacquire_interpreter();
        }
 
        return_ACPI_STATUS(status);
@@ -119,7 +112,6 @@ acpi_status acpi_ex_system_wait_semaphore(acpi_semaphore 
semaphore, u16 timeout)
 acpi_status acpi_ex_system_wait_mutex(acpi_mutex mutex, u16 timeout)
 {
        acpi_status status;
-       acpi_status status2;
 
        ACPI_FUNCTION_TRACE(ex_system_wait_mutex);
 
@@ -132,7 +124,7 @@ acpi_status acpi_ex_system_wait_mutex(acpi_mutex mutex, u16 
timeout)
 
                /* We must wait, so unlock the interpreter */
 
-               acpi_ex_exit_interpreter();
+               acpi_ex_relinquish_interpreter();
 
                status = acpi_os_acquire_mutex(mutex, timeout);
 
@@ -142,13 +134,7 @@ acpi_status acpi_ex_system_wait_mutex(acpi_mutex mutex, 
u16 timeout)
 
                /* Reacquire the interpreter */
 
-               status2 = acpi_ex_enter_interpreter();
-               if (ACPI_FAILURE(status2)) {
-
-                       /* Report fatal error, could not acquire interpreter */
-
-                       return_ACPI_STATUS(status2);
-               }
+               acpi_ex_reacquire_interpreter();
        }
 
        return_ACPI_STATUS(status);
@@ -209,20 +195,18 @@ acpi_status acpi_ex_system_do_stall(u32 how_long)
 
 acpi_status acpi_ex_system_do_suspend(acpi_integer how_long)
 {
-       acpi_status status;
-
        ACPI_FUNCTION_ENTRY();
 
        /* Since this thread will sleep, we must release the interpreter */
 
-       acpi_ex_exit_interpreter();
+       acpi_ex_relinquish_interpreter();
 
        acpi_os_sleep(how_long);
 
        /* And now we must get the interpreter again */
 
-       status = acpi_ex_enter_interpreter();
-       return (status);
+       acpi_ex_reacquire_interpreter();
+       return (AE_OK);
 }
 
 
/*******************************************************************************
diff --git a/drivers/acpi/executer/exutils.c b/drivers/acpi/executer/exutils.c
index 982c8b6..72adcf4 100644
--- a/drivers/acpi/executer/exutils.c
+++ b/drivers/acpi/executer/exutils.c
@@ -76,46 +76,72 @@ static u32 acpi_ex_digits_needed(acpi_integer value, u32 
base);
  *
  * PARAMETERS:  None
  *
- * RETURN:      Status
+ * RETURN:      None
  *
- * DESCRIPTION: Enter the interpreter execution region.  Failure to enter
- *              the interpreter region is a fatal system error
+ * DESCRIPTION: Enter the interpreter execution region. Failure to enter
+ *              the interpreter region is a fatal system error. Used in
+ *              conjunction with exit_interpreter.
  *
  
******************************************************************************/
 
-acpi_status acpi_ex_enter_interpreter(void)
+void acpi_ex_enter_interpreter(void)
 {
        acpi_status status;
 
-       ACPI_FUNCTION_TRACE(ex_enter_interpreter);
+       ACPI_FUNCTION_TRACE(ex_reacquire_interpreter);
 
        status = acpi_ut_acquire_mutex(ACPI_MTX_INTERPRETER);
        if (ACPI_FAILURE(status)) {
-               ACPI_ERROR((AE_INFO, "Could not acquire interpreter mutex"));
+               ACPI_ERROR((AE_INFO,
+                           "Could not acquire AML Interpreter mutex"));
        }
 
-       return_ACPI_STATUS(status);
+       return_VOID;
 }
 
 
/*******************************************************************************
  *
- * FUNCTION:    acpi_ex_exit_interpreter
+ * FUNCTION:    acpi_ex_reacquire_interpreter
  *
  * PARAMETERS:  None
  *
  * RETURN:      None
  *
- * DESCRIPTION: Exit the interpreter execution region
+ * DESCRIPTION: Reacquire the interpreter execution region from within the
+ *              interpreter code. Failure to enter the interpreter region is a
+ *              fatal system error. Used in  conjuction with
+ *              relinquish_interpreter
+ *
+ 
******************************************************************************/
+
+void acpi_ex_reacquire_interpreter(void)
+{
+
+       ACPI_FUNCTION_TRACE(ex_reacquire_interpreter);
+
+       /*
+        * If the global serialized flag is set, do not release the interpreter,
+        * since it was not actually released by acpi_ex_relinquish_interpreter.
+        * This forces the interpreter to be single threaded.
+        */
+       if (!acpi_gbl_all_methods_serialized) {
+               acpi_ex_enter_interpreter();
+       }
+
+       return_VOID;
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ex_exit_interpreter
+ *
+ * PARAMETERS:  None
+ *
+ * RETURN:      None
  *
- * Cases where the interpreter is unlocked:
- *      1) Completion of the execution of a control method
- *      2) Method blocked on a Sleep() AML opcode
- *      3) Method blocked on an Acquire() AML opcode
- *      4) Method blocked on a Wait() AML opcode
- *      5) Method blocked to acquire the global lock
- *      6) Method blocked to execute a serialized control method that is
- *          already executing
- *      7) About to invoke a user-installed opregion handler
+ * DESCRIPTION: Exit the interpreter execution region. This is the top level
+ *              routine used to exit the interpreter when all processing has
+ *              been completed.
  *
  
******************************************************************************/
 
@@ -127,7 +153,47 @@ void acpi_ex_exit_interpreter(void)
 
        status = acpi_ut_release_mutex(ACPI_MTX_INTERPRETER);
        if (ACPI_FAILURE(status)) {
-               ACPI_ERROR((AE_INFO, "Could not release interpreter mutex"));
+               ACPI_ERROR((AE_INFO,
+                           "Could not release AML Interpreter mutex"));
+       }
+
+       return_VOID;
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ex_relinquish_interpreter
+ *
+ * PARAMETERS:  None
+ *
+ * RETURN:      None
+ *
+ * DESCRIPTION: Exit the interpreter execution region, from within the
+ *              interpreter - before attempting an operation that will possibly
+ *              block the running thread.
+ *
+ * Cases where the interpreter is unlocked internally
+ *      1) Method to be blocked on a Sleep() AML opcode
+ *      2) Method to be blocked on an Acquire() AML opcode
+ *      3) Method to be blocked on a Wait() AML opcode
+ *      4) Method to be blocked to acquire the global lock
+ *      5) Method to be blocked waiting to execute a serialized control method
+ *          that is currently executing
+ *      6) About to invoke a user-installed opregion handler
+ *
+ 
******************************************************************************/
+
+void acpi_ex_relinquish_interpreter(void)
+{
+
+       ACPI_FUNCTION_TRACE(ex_relinquish_interpreter);
+
+       /*
+        * If the global serialized flag is set, do not release the interpreter.
+        * This forces the interpreter to be single threaded.
+        */
+       if (!acpi_gbl_all_methods_serialized) {
+               acpi_ex_exit_interpreter();
        }
 
        return_VOID;
@@ -141,8 +207,8 @@ void acpi_ex_exit_interpreter(void)
  *
  * RETURN:      none
  *
- * DESCRIPTION: Truncate a number to 32-bits if the currently executing method
- *              belongs to a 32-bit ACPI table.
+ * DESCRIPTION: Truncate an ACPI Integer to 32 bits if the execution mode is
+ *              32-bit, as determined by the revision of the DSDT.
  *
  
******************************************************************************/
 
diff --git a/drivers/acpi/namespace/nseval.c b/drivers/acpi/namespace/nseval.c
index 4b0a4a8..7156616 100644
--- a/drivers/acpi/namespace/nseval.c
+++ b/drivers/acpi/namespace/nseval.c
@@ -154,11 +154,7 @@ acpi_status acpi_ns_evaluate(struct acpi_evaluate_info 
*info)
                 * Execute the method via the interpreter. The interpreter is 
locked
                 * here before calling into the AML parser
                 */
-               status = acpi_ex_enter_interpreter();
-               if (ACPI_FAILURE(status)) {
-                       return_ACPI_STATUS(status);
-               }
-
+               acpi_ex_enter_interpreter();
                status = acpi_ps_execute_method(info);
                acpi_ex_exit_interpreter();
        } else {
@@ -182,10 +178,7 @@ acpi_status acpi_ns_evaluate(struct acpi_evaluate_info 
*info)
                 * resolution, we must lock it because we could access an 
opregion.
                 * The opregion access code assumes that the interpreter is 
locked.
                 */
-               status = acpi_ex_enter_interpreter();
-               if (ACPI_FAILURE(status)) {
-                       return_ACPI_STATUS(status);
-               }
+               acpi_ex_enter_interpreter();
 
                /* Function has a strange interface */
 
diff --git a/drivers/acpi/namespace/nsinit.c b/drivers/acpi/namespace/nsinit.c
index aec8488..0d3a42b 100644
--- a/drivers/acpi/namespace/nsinit.c
+++ b/drivers/acpi/namespace/nsinit.c
@@ -213,7 +213,7 @@ acpi_ns_init_one_object(acpi_handle obj_handle,
                        u32 level, void *context, void **return_value)
 {
        acpi_object_type type;
-       acpi_status status;
+       acpi_status status = AE_OK;
        struct acpi_init_walk_info *info =
            (struct acpi_init_walk_info *)context;
        struct acpi_namespace_node *node =
@@ -267,10 +267,7 @@ acpi_ns_init_one_object(acpi_handle obj_handle,
        /*
         * Must lock the interpreter before executing AML code
         */
-       status = acpi_ex_enter_interpreter();
-       if (ACPI_FAILURE(status)) {
-               return (status);
-       }
+       acpi_ex_enter_interpreter();
 
        /*
         * Each of these types can contain executable AML code within the
diff --git a/drivers/acpi/namespace/nsxfeval.c 
b/drivers/acpi/namespace/nsxfeval.c
index dca6799..6a0a46e 100644
--- a/drivers/acpi/namespace/nsxfeval.c
+++ b/drivers/acpi/namespace/nsxfeval.c
@@ -170,7 +170,6 @@ acpi_evaluate_object(acpi_handle handle,
                     struct acpi_buffer *return_buffer)
 {
        acpi_status status;
-       acpi_status status2;
        struct acpi_evaluate_info *info;
        acpi_size buffer_space_needed;
        u32 i;
@@ -329,14 +328,12 @@ acpi_evaluate_object(acpi_handle handle,
                 * Delete the internal return object. NOTE: Interpreter must be
                 * locked to avoid race condition.
                 */
-               status2 = acpi_ex_enter_interpreter();
-               if (ACPI_SUCCESS(status2)) {
+               acpi_ex_enter_interpreter();
 
-                       /* Remove one reference on the return object (should 
delete it) */
+               /* Remove one reference on the return object (should delete it) 
*/
 
-                       acpi_ut_remove_reference(info->return_object);
-                       acpi_ex_exit_interpreter();
-               }
+               acpi_ut_remove_reference(info->return_object);
+               acpi_ex_exit_interpreter();
        }
 
       cleanup:
diff --git a/include/acpi/acinterp.h b/include/acpi/acinterp.h
index f266b38..8aebe57 100644
--- a/include/acpi/acinterp.h
+++ b/include/acpi/acinterp.h
@@ -445,10 +445,14 @@ acpi_ex_copy_integer_to_buffer_field(union 
acpi_operand_object *source_desc,
 /*
  * exutils - interpreter/scanner utilities
  */
-acpi_status acpi_ex_enter_interpreter(void);
+void acpi_ex_enter_interpreter(void);
 
 void acpi_ex_exit_interpreter(void);
 
+void acpi_ex_reacquire_interpreter(void);
+
+void acpi_ex_relinquish_interpreter(void);
+
 void acpi_ex_truncate_for32bit_table(union acpi_operand_object *obj_desc);
 
 u8 acpi_ex_acquire_global_lock(u32 rule);
-- 
1.5.0.rc3.39.gec804
-
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