platform/x86: think-lmi: Use ACPI object when extracting strings

Move the ACPI buffer handling out of tlmi_extract_output_string()
and instead pass the unpacked ACPI object to prepare for future
changes.

Reviewed-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Link: https://lore.kernel.org/r/20250216193251.866125-3-W_Armin@gmx.de
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

diff --git a/drivers/platform/x86/think-lmi.c b/drivers/platform/x86/think-lmi.c
index 323316ac6783aa343c4c6430040a4af648786880..2c94a4af9a1da66e5969eaf1dd42f1c14cba8e68 100644 (file)
--- a/drivers/platform/x86/think-lmi.c
+++ b/drivers/platform/x86/think-lmi.c
@@ -262,16 +262,11 @@ static int tlmi_simple_call(const char *guid, const char *arg)
        return 0;
 }
 
-/* Extract output string from WMI return buffer */
-static int tlmi_extract_output_string(const struct acpi_buffer *output,
-                                     char **string)
+/* Extract output string from WMI return value */
+static int tlmi_extract_output_string(union acpi_object *obj, char **string)
 {
-       const union acpi_object *obj;
        char *s;
 
-       obj = output->pointer;
-       if (!obj)
-               return -ENOMEM;
        if (obj->type != ACPI_TYPE_STRING || !obj->string.pointer)
                return -EIO;
 
@@ -352,17 +347,21 @@ static int tlmi_opcode_setting(char *setting, const char *value)
 static int tlmi_setting(int item, char **value, const char *guid_string)
 {
        struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
+       union acpi_object *obj;
        acpi_status status;
        int ret;
 
        status = wmi_query_block(guid_string, item, &output);
-       if (ACPI_FAILURE(status)) {
-               kfree(output.pointer);
+       if (ACPI_FAILURE(status))
                return -EIO;
-       }
 
-       ret = tlmi_extract_output_string(&output, value);
-       kfree(output.pointer);
+       obj = output.pointer;
+       if (!obj)
+               return -ENODATA;
+
+       ret = tlmi_extract_output_string(obj, value);
+       kfree(obj);
+
        return ret;
 }
 
@@ -370,19 +369,22 @@ static int tlmi_get_bios_selections(const char *item, char **value)
 {
        const struct acpi_buffer input = { strlen(item), (char *)item };
        struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
+       union acpi_object *obj;
        acpi_status status;
        int ret;
 
        status = wmi_evaluate_method(LENOVO_GET_BIOS_SELECTIONS_GUID,
                                     0, 0, &input, &output);
-
-       if (ACPI_FAILURE(status)) {
-               kfree(output.pointer);
+       if (ACPI_FAILURE(status))
                return -EIO;
-       }
 
-       ret = tlmi_extract_output_string(&output, value);
-       kfree(output.pointer);
+       obj = output.pointer;
+       if (!obj)
+               return -ENODATA;
+
+       ret = tlmi_extract_output_string(obj, value);
+       kfree(obj);
+
        return ret;
 }