[PATCH] [59/275] i2c: Unregister dummy devices last on adapter removal

[Andi Kleen]

2.6.35-longterm review patch.  If anyone has any objections, please let me know.

------------------
From: Jean Delvare <khali@xxxxxxxxxxxx>

commit 5219bf884b6e2b54e734ca1799b6f0014bb2b4b7 upstream.

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@xxxxxxxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Tested-by: Hans Verkuil <hverkuil@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 drivers/i2c/i2c-core.c |   14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

Index: linux-2.6.35.y/drivers/i2c/i2c-core.c
===================================================================
--- linux-2.6.35.y.orig/drivers/i2c/i2c-core.c	2011-03-29 22:51:46.201540988 -0700
+++ linux-2.6.35.y/drivers/i2c/i2c-core.c	2011-03-29 23:02:59.377316103 -0700
@@ -923,6 +923,14 @@
 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;
@@ -977,8 +985,12 @@
 	i2c_unlock_adapter(adap);
 
 	/* 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,
--
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