i2c: Sanity checks on adapter registration

Make sure I2C adapters being registered have the required struct
fields set. If they don't, problems will happen later.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

drivers/i2c/i2c-core.c

@@ -848,6 +848,18 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
 		goto out_list;
 	}
 
+	/* Sanity checks */
+	if (unlikely(adap->name[0] == '\0')) {
+		pr_err("i2c-core: Attempt to register an adapter with "
+		       "no name!\n");
+		return -EINVAL;
+	}
+	if (unlikely(!adap->algo)) {
+		pr_err("i2c-core: Attempt to register adapter '%s' with "
+		       "no algo!\n", adap->name);
+		return -EINVAL;
+	}
+
 	rt_mutex_init(&adap->bus_lock);
 	mutex_init(&adap->userspace_clients_lock);
 	INIT_LIST_HEAD(&adap->userspace_clients);