WMI: Cater for multiple events with same GUID

WMI data blocks can contain WMI events with the same GUID but with
different notifiy_ids, for example volume up/down hotkeys.
This patch enables a single event handler to be registered and
unregistered against all events with same GUID but different
notify_ids.  Since an event handler is passed the notify_id of
an event it can can differentiate between the different events.

The patch also ensures we only register and unregister a device per
unique GUID.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>

diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
index aecd9a9..b8e5383 100644 (file)
--- a/drivers/platform/x86/wmi.c
+++ b/drivers/platform/x86/wmi.c
@@ -549,21 +549,34 @@ acpi_status wmi_install_notify_handler(const char *guid,
 wmi_notify_handler handler, void *data)
 {
        struct wmi_block *block;
-       acpi_status status;
+       acpi_status status = AE_NOT_EXIST;
+       char tmp[16], guid_input[16];
+       struct list_head *p;
 
        if (!guid || !handler)
                return AE_BAD_PARAMETER;
 
-       if (!find_guid(guid, &block))
-               return AE_NOT_EXIST;
+       wmi_parse_guid(guid, tmp);
+       wmi_swap_bytes(tmp, guid_input);
 
-       if (block->handler && block->handler != wmi_notify_debug)
-               return AE_ALREADY_ACQUIRED;
+       list_for_each(p, &wmi_block_list) {
+               acpi_status wmi_status;
+               block = list_entry(p, struct wmi_block, list);
 
-       block->handler = handler;
-       block->handler_data = data;
+               if (memcmp(block->gblock.guid, guid_input, 16) == 0) {
+                       if (block->handler &&
+                           block->handler != wmi_notify_debug)
+                               return AE_ALREADY_ACQUIRED;
 
-       status = wmi_method_enable(block, 1);
+                       block->handler = handler;
+                       block->handler_data = data;
+
+                       wmi_status = wmi_method_enable(block, 1);
+                       if ((wmi_status != AE_OK) ||
+                           ((wmi_status == AE_OK) && (status == AE_NOT_EXIST)))
+                               status = wmi_status;
+               }
+       }
 
        return status;
 }
@@ -577,24 +590,40 @@ EXPORT_SYMBOL_GPL(wmi_install_notify_handler);
 acpi_status wmi_remove_notify_handler(const char *guid)
 {
        struct wmi_block *block;
-       acpi_status status = AE_OK;
+       acpi_status status = AE_NOT_EXIST;
+       char tmp[16], guid_input[16];
+       struct list_head *p;
 
        if (!guid)
                return AE_BAD_PARAMETER;
 
-       if (!find_guid(guid, &block))
-               return AE_NOT_EXIST;
+       wmi_parse_guid(guid, tmp);
+       wmi_swap_bytes(tmp, guid_input);
 
-       if (!block->handler || block->handler == wmi_notify_debug)
-               return AE_NULL_ENTRY;
+       list_for_each(p, &wmi_block_list) {
+               acpi_status wmi_status;
+               block = list_entry(p, struct wmi_block, list);
 
-       if (debug_event) {
-               block->handler = wmi_notify_debug;
-       } else {
-               status = wmi_method_enable(block, 0);
-               block->handler = NULL;
-               block->handler_data = NULL;
+               if (memcmp(block->gblock.guid, guid_input, 16) == 0) {
+                       if (!block->handler ||
+                           block->handler == wmi_notify_debug)
+                               return AE_NULL_ENTRY;
+
+                       if (debug_event) {
+                               block->handler = wmi_notify_debug;
+                               status = AE_OK;
+                       } else {
+                               wmi_status = wmi_method_enable(block, 0);
+                               block->handler = NULL;
+                               block->handler_data = NULL;
+                               if ((wmi_status != AE_OK) ||
+                                   ((wmi_status == AE_OK) &&
+                                    (status == AE_NOT_EXIST)))
+                                       status = wmi_status;
+                       }
+               }
        }
+
        return status;
 }
 EXPORT_SYMBOL_GPL(wmi_remove_notify_handler);
@@ -705,22 +734,11 @@ static struct class wmi_class = {
        .dev_attrs = wmi_dev_attrs,
 };
 
-static struct wmi_block *wmi_create_device(const struct guid_block *gblock,
-                                          acpi_handle handle)
+static int wmi_create_device(const struct guid_block *gblock,
+                            struct wmi_block *wblock, acpi_handle handle)
 {
-       struct wmi_block *wblock;
-       int error;
        char guid_string[37];
 
-       wblock = kzalloc(sizeof(struct wmi_block), GFP_KERNEL);
-       if (!wblock) {
-               error = -ENOMEM;
-               goto err_out;
-       }
-
-       wblock->handle = handle;
-       wblock->gblock = *gblock;
-
        wblock->dev.class = &wmi_class;
 
        wmi_gtoa(gblock->guid, guid_string);
@@ -728,17 +746,7 @@ static struct wmi_block *wmi_create_device(const struct guid_block *gblock,
 
        dev_set_drvdata(&wblock->dev, wblock);
 
-       error = device_register(&wblock->dev);
-       if (error)
-               goto err_free;
-
-       list_add_tail(&wblock->list, &wmi_block_list);
-       return wblock;
-
-err_free:
-       kfree(wblock);
-err_out:
-       return ERR_PTR(error);
+       return device_register(&wblock->dev);
 }
 
 static void wmi_free_devices(void)
@@ -747,7 +755,8 @@ static void wmi_free_devices(void)
 
        /* Delete devices for all the GUIDs */
        list_for_each_entry_safe(wblock, next, &wmi_block_list, list)
-               device_unregister(&wblock->dev);
+               if (wblock->dev.class)
+                       device_unregister(&wblock->dev);
 }
 
 static bool guid_already_parsed(const char *guid_string)
@@ -770,7 +779,6 @@ static acpi_status parse_wdg(acpi_handle handle)
        union acpi_object *obj;
        const struct guid_block *gblock;
        struct wmi_block *wblock;
-       char guid_string[37];
        acpi_status status;
        int retval;
        u32 i, total;
@@ -792,28 +800,31 @@ static acpi_status parse_wdg(acpi_handle handle)
        total = obj->buffer.length / sizeof(struct guid_block);
 
        for (i = 0; i < total; i++) {
+               if (debug_dump_wdg)
+                       wmi_dump_wdg(&gblock[i]);
+
+               wblock = kzalloc(sizeof(struct wmi_block), GFP_KERNEL);
+               if (!wblock)
+                       return AE_NO_MEMORY;
+
+               wblock->handle = handle;
+               wblock->gblock = gblock[i];
+
                /*
                  Some WMI devices, like those for nVidia hooks, have a
                  duplicate GUID. It's not clear what we should do in this
-                 case yet, so for now, we'll just ignore the duplicate.
-                 Anyone who wants to add support for that device can come
-                 up with a better workaround for the mess then.
+                 case yet, so for now, we'll just ignore the duplicate
+                 for device creation.
                */
-               if (guid_already_parsed(gblock[i].guid) == true) {
-                       wmi_gtoa(gblock[i].guid, guid_string);
-                       pr_info("Skipping duplicate GUID %s\n", guid_string);
-                       continue;
+               if (!guid_already_parsed(gblock[i].guid)) {
+                       retval = wmi_create_device(&gblock[i], wblock, handle);
+                       if (retval) {
+                               wmi_free_devices();
+                               break;
+                       }
                }
 
-               if (debug_dump_wdg)
-                       wmi_dump_wdg(&gblock[i]);
-
-               wblock = wmi_create_device(&gblock[i], handle);
-               if (IS_ERR(wblock)) {
-                       retval = PTR_ERR(wblock);
-                       wmi_free_devices();
-                       break;
-               }
+               list_add_tail(&wblock->list, &wmi_block_list);
 
                if (debug_event) {
                        wblock->handler = wmi_notify_debug;