ACPICA: Remove unused ACPI_FREE_BUFFER macro. No functional change.

This macro is no longer used by ACPICA and it is not public.
Also update comments related to the use of ACPI_ALLOCATE_BUFFER and
the use of acpi_os_free (kfree is equivalent and prefered in the
kernel) to free the buffer.

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

3 files changed, 22 insertions, 23 deletions

diff --git a/drivers/acpi/acpica/nsxfeval.c b/drivers/acpi/acpica/nsxfeval.c
index e973e311f856..1f0c28ba50df 100644
--- a/drivers/acpi/acpica/nsxfeval.c
+++ b/drivers/acpi/acpica/nsxfeval.c
@@ -84,7 +84,7 @@ acpi_evaluate_object_typed(acpi_handle handle,
                            acpi_object_type return_type)
 {
         acpi_status status;
-        u8 must_free = FALSE;
+        u8 free_buffer_on_error = FALSE;
 
         ACPI_FUNCTION_TRACE(acpi_evaluate_object_typed);
 
@@ -95,14 +95,13 @@ acpi_evaluate_object_typed(acpi_handle handle,
         }
 
         if (return_buffer->length == ACPI_ALLOCATE_BUFFER) {
-                must_free = TRUE;
+                free_buffer_on_error = TRUE;
         }
 
         /* Evaluate the object */
 
-        status =
-            acpi_evaluate_object(handle, pathname, external_params,
-                                 return_buffer);
+        status = acpi_evaluate_object(handle, pathname,
+                                      external_params, return_buffer);
         if (ACPI_FAILURE(status)) {
                 return_ACPI_STATUS(status);
         }
@@ -135,11 +134,15 @@ acpi_evaluate_object_typed(acpi_handle handle,
                                            pointer)->type),
                     acpi_ut_get_type_name(return_type)));
 
-        if (must_free) {
-
-                /* Caller used ACPI_ALLOCATE_BUFFER, free the return buffer */
-
-                ACPI_FREE_BUFFER(*return_buffer);
+        if (free_buffer_on_error) {
+                /*
+                 * Free a buffer created via ACPI_ALLOCATE_BUFFER.
+                 * Note: We use acpi_os_free here because acpi_os_allocate was used
+                 * to allocate the buffer. This purposefully bypasses the
+                 * (optionally enabled) allocation tracking mechanism since we
+                 * only want to track internal allocations.
+                 */
+                acpi_os_free(return_buffer->pointer);
                 return_buffer->pointer = NULL;
         }
 
diff --git a/drivers/acpi/acpica/utalloc.c b/drivers/acpi/acpica/utalloc.c
index 814267f52715..1851762fc5b5 100644
--- a/drivers/acpi/acpica/utalloc.c
+++ b/drivers/acpi/acpica/utalloc.c
@@ -302,9 +302,13 @@ acpi_ut_initialize_buffer(struct acpi_buffer * buffer,
                 return (AE_BUFFER_OVERFLOW);
 
         case ACPI_ALLOCATE_BUFFER:
-
-                /* Allocate a new buffer */
-
+                /*
+                 * Allocate a new buffer. We directectly call acpi_os_allocate here to
+                 * purposefully bypass the (optionally enabled) internal allocation
+                 * tracking mechanism since we only want to track internal
+                 * allocations. Note: The caller should use acpi_os_free to free this
+                 * buffer created via ACPI_ALLOCATE_BUFFER.
+                 */
                 buffer->pointer = acpi_os_allocate(required_length);
                 break;
 
diff --git a/include/acpi/actypes.h b/include/acpi/actypes.h
index 809b1a0fee7f..68a3ada689c9 100644
--- a/include/acpi/actypes.h
+++ b/include/acpi/actypes.h
@@ -928,8 +928,8 @@ struct acpi_object_list {
  * Miscellaneous common Data Structures used by the interfaces
  */
 #define ACPI_NO_BUFFER              0
-#define ACPI_ALLOCATE_BUFFER        (acpi_size) (-1)
-#define ACPI_ALLOCATE_LOCAL_BUFFER  (acpi_size) (-2)
+#define ACPI_ALLOCATE_BUFFER        (acpi_size) (-1)    /* Let ACPICA allocate buffer */
+#define ACPI_ALLOCATE_LOCAL_BUFFER  (acpi_size) (-2)    /* For internal use only (enables tracking) */
 
 struct acpi_buffer {
         acpi_size length;       /* Length in bytes of the buffer */
@@ -937,14 +937,6 @@ struct acpi_buffer {
 };
 
 /*
- * Free a buffer created in an struct acpi_buffer via ACPI_ALLOCATE_BUFFER.
- * Note: We use acpi_os_free here because acpi_os_allocate was used to allocate
- * the buffer. This purposefully bypasses the internal allocation tracking
- * mechanism (if it is enabled).
- */
-#define ACPI_FREE_BUFFER(b)         acpi_os_free((b).pointer)
-
-/*
  * name_type for acpi_get_name
  */
 #define ACPI_FULL_PATHNAME              0