}
 EXPORT_SYMBOL_GPL(spi_unregister_master);
 
+static int __spi_master_match(struct device *dev, void *data)
+{
+       struct spi_master *m;
+       u16 *bus_num = data;
+
+       m = container_of(dev, struct spi_master, dev);
+       return m->bus_num == *bus_num;
+}
+
 /**
  * spi_busnum_to_master - look up master associated with bus_num
  * @bus_num: the master's bus number
 {
        struct device           *dev;
        struct spi_master       *master = NULL;
-       struct spi_master       *m;
-
-       down(&spi_master_class.sem);
-       list_for_each_entry(dev, &spi_master_class.children, node) {
-               m = container_of(dev, struct spi_master, dev);
-               if (m->bus_num == bus_num) {
-                       master = spi_master_get(m);
-                       break;
-               }
-       }
-       up(&spi_master_class.sem);
+
+       dev = class_find_device(&spi_master_class, &bus_num,
+                               __spi_master_match);
+       if (dev)
+               master = container_of(dev, struct spi_master, dev);
+       /* reference got in class_find_device */
        return master;
 }
 EXPORT_SYMBOL_GPL(spi_busnum_to_master);