ACPICA: Optimize buffer allocation procedure
Eliminate duplicate code.
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/utilities/utalloc.c b/drivers/acpi/utilities/utalloc.c
index 7dcb67e..241c535 100644
--- a/drivers/acpi/utilities/utalloc.c
+++ b/drivers/acpi/utilities/utalloc.c
@@ -232,7 +232,7 @@
* RETURN: Status
*
* DESCRIPTION: Validate that the buffer is of the required length or
- * allocate a new buffer. Returned buffer is always zeroed.
+ * allocate a new buffer. Returned buffer is always zeroed.
*
******************************************************************************/
@@ -240,7 +240,7 @@
acpi_ut_initialize_buffer(struct acpi_buffer * buffer,
acpi_size required_length)
{
- acpi_status status = AE_OK;
+ acpi_size input_buffer_length;
/* Parameter validation */
@@ -248,55 +248,58 @@
return (AE_BAD_PARAMETER);
}
- switch (buffer->length) {
+ /*
+ * Buffer->Length is used as both an input and output parameter. Get the
+ * input actual length and set the output required buffer length.
+ */
+ input_buffer_length = buffer->length;
+ buffer->length = required_length;
+
+ /*
+ * The input buffer length contains the actual buffer length, or the type
+ * of buffer to be allocated by this routine.
+ */
+ switch (input_buffer_length) {
case ACPI_NO_BUFFER:
- /* Set the exception and returned the required length */
+ /* Return the exception (and the required buffer length) */
- status = AE_BUFFER_OVERFLOW;
- break;
+ return (AE_BUFFER_OVERFLOW);
case ACPI_ALLOCATE_BUFFER:
/* Allocate a new buffer */
buffer->pointer = acpi_os_allocate(required_length);
- if (!buffer->pointer) {
- return (AE_NO_MEMORY);
- }
-
- /* Clear the buffer */
-
- ACPI_MEMSET(buffer->pointer, 0, required_length);
break;
case ACPI_ALLOCATE_LOCAL_BUFFER:
/* Allocate a new buffer with local interface to allow tracking */
- buffer->pointer = ACPI_ALLOCATE_ZEROED(required_length);
- if (!buffer->pointer) {
- return (AE_NO_MEMORY);
- }
+ buffer->pointer = ACPI_ALLOCATE(required_length);
break;
default:
/* Existing buffer: Validate the size of the buffer */
- if (buffer->length < required_length) {
- status = AE_BUFFER_OVERFLOW;
- break;
+ if (input_buffer_length < required_length) {
+ return (AE_BUFFER_OVERFLOW);
}
-
- /* Clear the buffer */
-
- ACPI_MEMSET(buffer->pointer, 0, required_length);
break;
}
- buffer->length = required_length;
- return (status);
+ /* Validate allocation from above or input buffer pointer */
+
+ if (!buffer->pointer) {
+ return (AE_NO_MEMORY);
+ }
+
+ /* Have a valid buffer, clear it */
+
+ ACPI_MEMSET(buffer->pointer, 0, required_length);
+ return (AE_OK);
}
#ifdef NOT_USED_BY_LINUX
