driver core: Allow only unprobed consumers for SYNC_STATE_ONLY device links

SYNC_STATE_ONLY device links only affect the behavior of sync_state()
callbacks. Specifically, they prevent sync_state() only callbacks from
being called on a device if one or more of its consumers haven't probed.

So, creating a SYNC_STATE_ONLY device link from an already probed
consumer is useless. So, don't allow creating such device links.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201121020232.908850-10-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Saravana Kannan 2020-11-20 18:02:24 -08:00 committed by Greg Kroah-Hartman
parent 7b337cb3eb
commit ac66c5bbb4

View File

@ -649,6 +649,17 @@ struct device_link *device_link_add(struct device *consumer,
goto out;
}
/*
* SYNC_STATE_ONLY links are useless once a consumer device has probed.
* So, only create it if the consumer hasn't probed yet.
*/
if (flags & DL_FLAG_SYNC_STATE_ONLY &&
consumer->links.status != DL_DEV_NO_DRIVER &&
consumer->links.status != DL_DEV_PROBING) {
link = NULL;
goto out;
}
/*
* DL_FLAG_AUTOREMOVE_SUPPLIER indicates that the link will be needed
* longer than for DL_FLAG_AUTOREMOVE_CONSUMER and setting them both