i2c: Unregister dummy devices last on adapter removal

Remove real devices first and dummy devices last. This gives device
driver which instantiated dummy devices themselves a chance to clean
them up before we do.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Tested-by: Hans Verkuil <hverkuil@xs4all.nl>
Cc: stable@kernel.org

1 files changed, 13 insertions, 1 deletions

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index c7db6980e3a..b916675605b 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1021,6 +1021,14 @@ static int i2c_do_del_adapter(struct i2c_driver *driver,
 static int __unregister_client(struct device *dev, void *dummy)
 {
         struct i2c_client *client = i2c_verify_client(dev);
+        if (client && strcmp(client->name, "dummy"))
+                i2c_unregister_device(client);
+        return 0;
+}
+
+static int __unregister_dummy(struct device *dev, void *dummy)
+{
+        struct i2c_client *client = i2c_verify_client(dev);
         if (client)
                 i2c_unregister_device(client);
         return 0;
@@ -1075,8 +1083,12 @@ int i2c_del_adapter(struct i2c_adapter *adap)
         mutex_unlock(&adap->userspace_clients_lock);
 
         /* Detach any active clients. This can't fail, thus we do not
-           checking the returned value. */
+         * check the returned value. This is a two-pass process, because
+         * we can't remove the dummy devices during the first pass: they
+         * could have been instantiated by real devices wishing to clean
+         * them up properly, so we give them a chance to do that first. */
         res = device_for_each_child(&adap->dev, NULL, __unregister_client);
+        res = device_for_each_child(&adap->dev, NULL, __unregister_dummy);
 
 #ifdef CONFIG_I2C_COMPAT
         class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,