[PATCH] i2c: clarify comments about the dev_released completion

[Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>]

There was quite some confusion why this completion is there and if it is
still necessary. Sadly, it is. However, let's improve the comments and
share what we rediscovered.

Signed-off-by: Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>
---
 drivers/i2c/i2c-core.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 39d25a8cb1ad..7a9368750b9a 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1796,11 +1796,15 @@ void i2c_del_adapter(struct i2c_adapter *adap)
 	/* device name is gone after device_unregister */
 	dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
 
-	/* clean up the sysfs representation */
+	/* wait until all references to the device are gone
+	 *
+	 * FIXME: This is old code and should ideally be replaced by an
+	 * alternative which results in decoupling the lifetime of the struct
+	 * device from the i2c_adapter, like spi or netdev do. Any solution
+	 * should be throughly tested with DEBUG_KOBJECT_RELEASE enabled!
+	 */
 	init_completion(&adap->dev_released);
 	device_unregister(&adap->dev);
-
-	/* wait for sysfs to drop all references */
 	wait_for_completion(&adap->dev_released);
 
 	/* free bus id */
-- 
2.1.4