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>

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;
 	}
 

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;
 

include/acpi/actypes.h

@@ -928,22 +928,14 @@ 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 */
 	void *pointer;		/* pointer to 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
  */