ACPICA: Re-implement interpreters' "serialized mode"

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

3 files changed, 8 insertions, 21 deletions

diff --git a/drivers/acpi/namespace/nseval.c b/drivers/acpi/namespace/nseval.c
index 4b0a4a8c984..71566161ac8 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 aec8488c001..0d3a42bf2f1 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 dca6799ac67..6a0a46eda9a 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: