Revert "driver core: Add support for linking devices during device addition"

#endif

/* Device links support. */

static LIST_HEAD(wait_for_suppliers);

static DEFINE_MUTEX(wfs_lock);

#ifdef CONFIG_SRCU

static DEFINE_MUTEX(device_links_lock);

}

EXPORT_SYMBOL_GPL(device_link_add);

/**

 * device_link_wait_for_supplier - Mark device as waiting for supplier

 * @consumer: Consumer device

 *

 * Marks the consumer device as waiting for suppliers to become available. The

 * consumer device will never be probed until it's unmarked as waiting for

 * suppliers. The caller is responsible for adding the link to the supplier

 * once the supplier device is present.

 *

 * This function is NOT meant to be called from the probe function of the

 * consumer but rather from code that creates/adds the consumer device.

 */

static void device_link_wait_for_supplier(struct device *consumer)

{

	mutex_lock(&wfs_lock);

	list_add_tail(&consumer->links.needs_suppliers, &wait_for_suppliers);

	mutex_unlock(&wfs_lock);

}

/**

 * device_link_check_waiting_consumers - Try to unmark waiting consumers

 *

 * Loops through all consumers waiting on suppliers and tries to add all their

 * supplier links. If that succeeds, the consumer device is unmarked as waiting

 * for suppliers. Otherwise, they are left marked as waiting on suppliers,

 *

 * The add_links bus callback is expected to return 0 if it has found and added

 * all the supplier links for the consumer device. It should return an error if

 * it isn't able to do so.

 *

 * The caller of device_link_wait_for_supplier() is expected to call this once

 * it's aware of potential suppliers becoming available.

 */

static void device_link_check_waiting_consumers(void)

{

	struct device *dev, *tmp;

	mutex_lock(&wfs_lock);

	list_for_each_entry_safe(dev, tmp, &wait_for_suppliers,

				 links.needs_suppliers)

		if (!dev->bus->add_links(dev))

			list_del_init(&dev->links.needs_suppliers);

	mutex_unlock(&wfs_lock);

}

static void device_link_free(struct device_link *link)

{

	while (refcount_dec_not_one(&link->rpm_active))

	struct device_link *link;

	int ret = 0;

	/*

	 * If a device is waiting for one or more suppliers (in

	 * wait_for_suppliers list), it is not ready to probe yet. So just

	 * return -EPROBE_DEFER without having to check the links with existing

	 * suppliers.

	 */

	mutex_lock(&wfs_lock);

	if (!list_empty(&dev->links.needs_suppliers)) {

		mutex_unlock(&wfs_lock);

		return -EPROBE_DEFER;

	}

	mutex_unlock(&wfs_lock);

	device_links_write_lock();

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

{

	struct device_link *link, *ln;

	mutex_lock(&wfs_lock);

	list_del(&dev->links.needs_suppliers);

	mutex_unlock(&wfs_lock);

	/*

	 * Delete all of the remaining links from this device to any other

	 * devices (either consumers or suppliers).

#endif

	INIT_LIST_HEAD(&dev->links.consumers);

	INIT_LIST_HEAD(&dev->links.suppliers);

	INIT_LIST_HEAD(&dev->links.needs_suppliers);

	dev->links.status = DL_DEV_NO_DRIVER;

}

EXPORT_SYMBOL_GPL(device_initialize);

					     BUS_NOTIFY_ADD_DEVICE, dev);

	kobject_uevent(&dev->kobj, KOBJ_ADD);

	/*

	 * Check if any of the other devices (consumers) have been waiting for

	 * this device (supplier) to be added so that they can create a device

	 * link to it.

	 *

	 * This needs to happen after device_pm_add() because device_link_add()

	 * requires the supplier be registered before it's called.

	 *

	 * But this also needs to happe before bus_probe_device() to make sure

	 * waiting consumers can link to it before the driver is bound to the

	 * device and the driver sync_state callback is called for this device.

	 */

	device_link_check_waiting_consumers();

	if (dev->bus && dev->bus->add_links && dev->bus->add_links(dev))

		device_link_wait_for_supplier(dev);

	bus_probe_device(dev);

	if (parent)

		klist_add_tail(&dev->p->knode_parent,

 *		-EPROBE_DEFER it will queue the device for deferred probing.

 * @uevent:	Called when a device is added, removed, or a few other things

 *		that generate uevents to add the environment variables.

 * @add_links:	Called, perhaps multiple times per device, after a device is

 *		added to this bus.  The function is expected to create device

 *		links to all the suppliers of the input device that are

 *		available at the time this function is called.  As in, the

 *		function should NOT stop at the first failed device link if

 *		other unlinked supplier devices are present in the system.

 *

 *		Return 0 if device links have been successfully created to all

 *		the suppliers of this device.  Return an error if some of the

 *		suppliers are not yet available and this function needs to be

 *		reattempted in the future.

 * @probe:	Called when a new device or driver add to this bus, and callback

 *		the specific driver's probe to initial the matched device.

 * @remove:	Called when a device removed from this bus.

	int (*match)(struct device *dev, struct device_driver *drv);

	int (*uevent)(struct device *dev, struct kobj_uevent_env *env);

	int (*add_links)(struct device *dev);

	int (*probe)(struct device *dev);

	int (*remove)(struct device *dev);

	void (*shutdown)(struct device *dev);

 * struct dev_links_info - Device data related to device links.

 * @suppliers: List of links to supplier devices.

 * @consumers: List of links to consumer devices.

 * @needs_suppliers: Hook to global list of devices waiting for suppliers.

 * @status: Driver status information.

 */

struct dev_links_info {

	struct list_head suppliers;

	struct list_head consumers;

	struct list_head needs_suppliers;

	enum dl_dev_state status;

};