Commit b6f617df authored by Saravana Kannan's avatar Saravana Kannan Committed by Greg Kroah-Hartman
Browse files

driver core: Update device link status properly for device_bind_driver() 

Device link status was not getting updated correctly when
device_bind_driver() is called on a device. This causes a warning[1].
Fix this by updating device links that can be updated and dropping
device links that can't be updated to a sensible state.

[1] - https://lore.kernel.org/lkml/56f7d032-ba5a-a8c7-23de-2969d98c527e@nvidia.com/



Tested-by: default avatarJon Hunter <jonathanh@nvidia.com>
Signed-off-by: default avatarSaravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210302211133.2244281-3-saravanak@google.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent f2db85b6

drivers/base/base.h

+1 −0
Original line number Diff line number Diff line
@@ -185,6 +185,7 @@ extern int device_links_read_lock(void); 
extern void device_links_read_unlock(int idx);

extern int device_links_read_lock_held(void);

extern int device_links_check_suppliers(struct device *dev);

extern void device_links_force_bind(struct device *dev);

extern void device_links_driver_bound(struct device *dev);

extern void device_links_driver_cleanup(struct device *dev);

extern void device_links_no_driver(struct device *dev);

drivers/base/core.c

+35 −0
Original line number Diff line number Diff line
@@ -1153,6 +1153,41 @@ static ssize_t waiting_for_supplier_show(struct device *dev, 
}

static DEVICE_ATTR_RO(waiting_for_supplier);



/**

 * device_links_force_bind - Prepares device to be force bound

 * @dev: Consumer device.

 *

 * device_bind_driver() force binds a device to a driver without calling any

 * driver probe functions. So the consumer really isn't going to wait for any

 * supplier before it's bound to the driver. We still want the device link

 * states to be sensible when this happens.

 *

 * In preparation for device_bind_driver(), this function goes through each

 * supplier device links and checks if the supplier is bound. If it is, then

 * the device link status is set to CONSUMER_PROBE. Otherwise, the device link

 * is dropped. Links without the DL_FLAG_MANAGED flag set are ignored.

 */

void device_links_force_bind(struct device *dev)

{

	struct device_link *link, *ln;



	device_links_write_lock();



	list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {

		if (!(link->flags & DL_FLAG_MANAGED))

			continue;



		if (link->status != DL_STATE_AVAILABLE) {

			device_link_drop_managed(link);

			continue;

		}

		WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);

	}

	dev->links.status = DL_DEV_PROBING;



	device_links_write_unlock();

}



/**

 * device_links_driver_bound - Update device links after probing its driver.

 * @dev: Device to update the links for.

drivers/base/dd.c

+3 −1
Original line number Diff line number Diff line
@@ -459,8 +459,10 @@ int device_bind_driver(struct device *dev) 
	int ret;



	ret = driver_sysfs_add(dev);

	if (!ret)

	if (!ret) {

		device_links_force_bind(dev);

		driver_bound(dev);

	}

	else if (dev->bus)

		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,

					     BUS_NOTIFY_DRIVER_NOT_BOUND, dev);