driver core: Use device's fwnode to check if it is waiting for suppliers

To check if a device is still waiting for its supplier devices to be
added, we used to check if the devices is in a global
waiting_for_suppliers list. Since the global list will be deleted in
subsequent patches, this patch stops using this check.

Instead, this patch uses a more device specific check. It checks if the
device's fwnode has any fwnode links that haven't been converted to
device links yet.
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201121020232.908850-14-saravanak@google.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/base/core.c

@@ -51,6 +51,7 @@ static DEFINE_MUTEX(wfs_lock);
 static LIST_HEAD(deferred_sync);
 static unsigned int defer_sync_state_count = 1;
 static DEFINE_MUTEX(fwnode_link_lock);
+static bool fw_devlink_is_permissive(void);
 
 /**
  * fwnode_link_add - Create a link between two fwnode_handles.
@@ -995,13 +996,13 @@ int device_links_check_suppliers(struct device *dev)
 	 * Device waiting for supplier to become available is not allowed to
 	 * probe.
 	 */
-	mutex_lock(&wfs_lock);
-	if (!list_empty(&dev->links.needs_suppliers) &&
-	    dev->links.need_for_probe) {
-		mutex_unlock(&wfs_lock);
+	mutex_lock(&fwnode_link_lock);
+	if (dev->fwnode && !list_empty(&dev->fwnode->suppliers) &&
+	    !fw_devlink_is_permissive()) {
+		mutex_unlock(&fwnode_link_lock);
 		return -EPROBE_DEFER;
 	}
-	mutex_unlock(&wfs_lock);
+	mutex_unlock(&fwnode_link_lock);
 
 	device_links_write_lock();
 
@@ -1167,8 +1168,7 @@ static ssize_t waiting_for_supplier_show(struct device *dev,
 	bool val;
 
 	device_lock(dev);
-	val = !list_empty(&dev->links.needs_suppliers)
-	      && dev->links.need_for_probe;
+	val = !list_empty(&dev->fwnode->suppliers);
 	device_unlock(dev);
 	return sysfs_emit(buf, "%u\n", val);
 }
@@ -2200,7 +2200,7 @@ static int device_add_attrs(struct device *dev)
 			goto err_remove_dev_groups;
 	}
 
-	if (fw_devlink_flags && !fw_devlink_is_permissive()) {
+	if (fw_devlink_flags && !fw_devlink_is_permissive() && dev->fwnode) {
 		error = device_create_file(dev, &dev_attr_waiting_for_supplier);
 		if (error)
 			goto err_remove_dev_online;