Commit ac66c5bb authored Nov 20, 2020 by Saravana Kannan Committed by Greg Kroah-Hartman Dec 09, 2020

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>

parent 7b337cb3

drivers/base/core.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -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