Re: [PATCH net-next v4 05/10] drivers: base: Add device_find_in_class_name()

On Wed, Jan 18, 2017 at 1:21 AM, Florian Fainelli [off-list ref] wrote:

Add a helper function to lookup a device reference given a class name.
This is a preliminary patch to remove adhoc code from net/dsa/dsa.c and
make it more generic.

+static int device_class_name_match(struct device *dev, void *class)

And why not const char *class?

+{
+       if (dev->class != NULL && !strcmp(dev->class->name, class))

if (dev->class && ...)

+               return 1;
+
+       return 0;

Perhaps even one line:

return dev->class && ...;

+}
+
+/**
+ * device_find_in_class_name - device iterator for locating a particular device
+ * within the specified class name
+ * @parent: parent struct device
+ * @class_name: Class name to match against
+ *
+ * This function returns 1 if the device (specified by @parent), or one of its child
+ * is in the class whose name is specified by @class_name. Returns 0 otherwise.
+ *
+ * NOTE: you will need to drop the reference with put_device() after use.
+ */
+struct device *device_find_in_class_name(struct device *parent,
+                                        char *class_name)

const char *class_name

+{
+       if (device_class_name_match(parent, class_name)) {
+               get_device(parent);
+               return parent;
+       }
+
+       return device_find_child(parent, class_name, device_class_name_match);
+}
+EXPORT_SYMBOL_GPL(device_find_in_class_name);

+extern struct device *device_find_in_class_name(struct device *parent,
+                                               char *class_name);

Ditto.

-- 
With Best Regards,
Andy Shevchenko