sony-laptop: fix SNC buffer calls when SN06 returns Integers

SN06 in some cases returns an Integer instead of a buffer. While the
code handling the return value was trying to cope with the difference,
the memcpy call was not making any difference between the two types of
acpi_object union. This regression was introduced in 3.5.
While there also rework the return value logic to improve readability.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=48671
Cc: <stable@vger.kernel.org>
Cc: Fabrizio Narni <shibotto@gmail.com>
Cc: <mus.svz@gmail.com>
Signed-off-by: Mattia Dongili <malattia@linux.it>
Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>

diff --git a/drivers/platform/x86/sony-laptop.c b/drivers/platform/x86/sony-laptop.c
index daaddec68def7e1c7cb11e4fe6d54e4193943c55..b8ad71f7863fa2b0fa9c741e9605ffdfe5a92fcf 100644 (file)
--- a/drivers/platform/x86/sony-laptop.c
+++ b/drivers/platform/x86/sony-laptop.c
@@ -786,28 +786,29 @@ static int sony_nc_int_call(acpi_handle handle, char *name, int *value,
 static int sony_nc_buffer_call(acpi_handle handle, char *name, u64 *value,
                void *buffer, size_t buflen)
 {
+       int ret = 0;
        size_t len = len;
        union acpi_object *object = __call_snc_method(handle, name, value);
 
        if (!object)
                return -EINVAL;
 
-       if (object->type == ACPI_TYPE_BUFFER)
+       if (object->type == ACPI_TYPE_BUFFER) {
                len = MIN(buflen, object->buffer.length);
+               memcpy(buffer, object->buffer.pointer, len);
 
-       else if (object->type == ACPI_TYPE_INTEGER)
+       } else if (object->type == ACPI_TYPE_INTEGER) {
                len = MIN(buflen, sizeof(object->integer.value));
+               memcpy(buffer, &object->integer.value, len);
 
-       else {
+       } else {
                pr_warn("Invalid acpi_object: expected 0x%x got 0x%x\n",
                                ACPI_TYPE_BUFFER, object->type);
-               kfree(object);
-               return -EINVAL;
+               ret = -EINVAL;
        }
 
-       memcpy(buffer, object->buffer.pointer, len);
        kfree(object);
-       return 0;
+       return ret;
 }
 
 struct sony_nc_handles {