ACPI: scheduling in atomic via acpi_evaluate_integer ()

Now I know why I had strange "scheduling in atomic" problems:
acpi_evaluate_integer() does malloc(..., irqs_disabled() ? GFP_ATOMIC
: GFP_KERNEL)... which is (of course) broken.

There's no way to reliably tell if we need GFP_ATOMIC or not from
code, this one for example fails to detect spinlocks held.

Fortunately, allocation seems small enough to be done on stack.

Signed-off-by: Pavel Machek <pavel@suse.cz>
Acked-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 4 insertions, 12 deletions

diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c
index e827be36ee8..f844941089b 100644
--- a/drivers/acpi/utils.c
+++ b/drivers/acpi/utils.c
@@ -259,34 +259,26 @@ acpi_evaluate_integer(acpi_handle handle,
                       struct acpi_object_list *arguments, unsigned long long *data)
 {
         acpi_status status = AE_OK;
-        union acpi_object *element;
+        union acpi_object element;
         struct acpi_buffer buffer = { 0, NULL };
 
-
         if (!data)
                 return AE_BAD_PARAMETER;
 
-        element = kzalloc(sizeof(union acpi_object), irqs_disabled() ? GFP_ATOMIC: GFP_KERNEL);
-        if (!element)
-                return AE_NO_MEMORY;
-
         buffer.length = sizeof(union acpi_object);
-        buffer.pointer = element;
+        buffer.pointer = &element;
         status = acpi_evaluate_object(handle, pathname, arguments, &buffer);
         if (ACPI_FAILURE(status)) {
                 acpi_util_eval_error(handle, pathname, status);
-                kfree(element);
                 return status;
         }
 
-        if (element->type != ACPI_TYPE_INTEGER) {
+        if (element.type != ACPI_TYPE_INTEGER) {
                 acpi_util_eval_error(handle, pathname, AE_BAD_DATA);
-                kfree(element);
                 return AE_BAD_DATA;
         }
 
-        *data = element->integer.value;
-        kfree(element);
+        *data = element.integer.value;
 
         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Return value [%llu]\n", *data));