platform/x86: wmi: introduce helper to generate method names

Instead of "manually" constructing the ACPI method name and
hard-coding sizes in WMI functions, introduce a helper method
which generates the method name for an arbitrary WMI block.

Furthermore, save the appropriate buffer size into a macro.

Signed-off-by: Barnabás Pőcze <pobrn@protonmail.com>
Link: https://lore.kernel.org/r/20210904175450.156801-28-pobrn@protonmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
index 5746fb9..2bad1ff 100644 (file)
--- a/drivers/platform/x86/wmi.c
+++ b/drivers/platform/x86/wmi.c
@@ -195,6 +195,22 @@ static acpi_status wmi_method_enable(struct wmi_block *wblock, bool enable)
        return status;
 }
 
+#define WMI_ACPI_METHOD_NAME_SIZE 5
+
+static inline void get_acpi_method_name(const struct wmi_block *wblock,
+                                       const char method,
+                                       char buffer[static WMI_ACPI_METHOD_NAME_SIZE])
+{
+       static_assert(ARRAY_SIZE(wblock->gblock.object_id) == 2);
+       static_assert(WMI_ACPI_METHOD_NAME_SIZE >= 5);
+
+       buffer[0] = 'W';
+       buffer[1] = method;
+       buffer[2] = wblock->gblock.object_id[0];
+       buffer[3] = wblock->gblock.object_id[1];
+       buffer[4] = '\0';
+}
+
 /*
  * Exported WMI functions
  */
@@ -257,7 +273,7 @@ acpi_status wmidev_evaluate_method(struct wmi_device *wdev, u8 instance, u32 met
        acpi_handle handle;
        struct acpi_object_list input;
        union acpi_object params[3];
-       char method[5] = "WM";
+       char method[WMI_ACPI_METHOD_NAME_SIZE];
 
        wblock = container_of(wdev, struct wmi_block, dev);
        block = &wblock->gblock;
@@ -288,7 +304,7 @@ acpi_status wmidev_evaluate_method(struct wmi_device *wdev, u8 instance, u32 met
                params[2].buffer.pointer = in->pointer;
        }
 
-       strncat(method, block->object_id, 2);
+       get_acpi_method_name(wblock, 'M', method);
 
        return acpi_evaluate_object(handle, method, &input, out);
 }
@@ -302,8 +318,8 @@ static acpi_status __query_block(struct wmi_block *wblock, u8 instance,
        acpi_status status, wc_status = AE_ERROR;
        struct acpi_object_list input;
        union acpi_object wq_params[1];
-       char method[5];
-       char wc_method[5] = "WC";
+       char wc_method[WMI_ACPI_METHOD_NAME_SIZE];
+       char method[WMI_ACPI_METHOD_NAME_SIZE];
 
        if (!out)
                return AE_BAD_PARAMETER;
@@ -331,7 +347,7 @@ static acpi_status __query_block(struct wmi_block *wblock, u8 instance,
         * enable collection.
         */
        if (block->flags & ACPI_WMI_EXPENSIVE) {
-               strncat(wc_method, block->object_id, 2);
+               get_acpi_method_name(wblock, 'C', wc_method);
 
                /*
                 * Some GUIDs break the specification by declaring themselves
@@ -341,9 +357,7 @@ static acpi_status __query_block(struct wmi_block *wblock, u8 instance,
                wc_status = acpi_execute_simple_method(handle, wc_method, 1);
        }
 
-       strcpy(method, "WQ");
-       strncat(method, block->object_id, 2);
-
+       get_acpi_method_name(wblock, 'Q', method);
        status = acpi_evaluate_object(handle, method, &input, out);
 
        /*
@@ -415,7 +429,7 @@ acpi_status wmi_set_block(const char *guid_string, u8 instance,
        acpi_handle handle;
        struct acpi_object_list input;
        union acpi_object params[2];
-       char method[5] = "WS";
+       char method[WMI_ACPI_METHOD_NAME_SIZE];
 
        if (!guid_string || !in)
                return AE_BAD_DATA;
@@ -446,7 +460,7 @@ acpi_status wmi_set_block(const char *guid_string, u8 instance,
        params[1].buffer.length = in->length;
        params[1].buffer.pointer = in->pointer;
 
-       strncat(method, block->object_id, 2);
+       get_acpi_method_name(wblock, 'S', method);
 
        return acpi_evaluate_object(handle, method, &input, NULL);
 }
@@ -1040,7 +1054,7 @@ static int wmi_create_device(struct device *wmi_bus_dev,
                             struct acpi_device *device)
 {
        struct acpi_device_info *info;
-       char method[5];
+       char method[WMI_ACPI_METHOD_NAME_SIZE];
        int result;
 
        if (wblock->gblock.flags & ACPI_WMI_EVENT) {
@@ -1059,8 +1073,7 @@ static int wmi_create_device(struct device *wmi_bus_dev,
         * required per the WMI documentation. If it is not present,
         * we ignore this data block.
         */
-       strcpy(method, "WQ");
-       strncat(method, wblock->gblock.object_id, 2);
+       get_acpi_method_name(wblock, 'Q', method);
        result = get_subobj_info(device->handle, method, &info);
 
        if (result) {
@@ -1087,8 +1100,7 @@ static int wmi_create_device(struct device *wmi_bus_dev,
 
        kfree(info);
 
-       strcpy(method, "WS");
-       strncat(method, wblock->gblock.object_id, 2);
+       get_acpi_method_name(wblock, 'S', method);
        result = get_subobj_info(device->handle, method, NULL);
 
        if (result == 0)