1 files changed, 212 insertions, 148 deletions

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 529af59e25ff..40de2f51a1b1 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -287,7 +287,7 @@ static bool device_is_ancestor(struct device *dev, struct device *target)
 #define DL_MARKER_FLAGS		(DL_FLAG_INFERRED | \
 				 DL_FLAG_CYCLE | \
 				 DL_FLAG_MANAGED)
-static inline bool device_link_flag_is_sync_state_only(u32 flags)
+bool device_link_flag_is_sync_state_only(u32 flags)
 {
 	return (flags & ~DL_MARKER_FLAGS) == DL_FLAG_SYNC_STATE_ONLY;
 }
@@ -460,9 +460,9 @@ static ssize_t auto_remove_on_show(struct device *dev,
 	struct device_link *link = to_devlink(dev);
 	const char *output;
 
-	if (link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
+	if (device_link_test(link, DL_FLAG_AUTOREMOVE_SUPPLIER))
 		output = "supplier unbind";
-	else if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER)
+	else if (device_link_test(link, DL_FLAG_AUTOREMOVE_CONSUMER))
 		output = "consumer unbind";
 	else
 		output = "never";
@@ -476,7 +476,7 @@ static ssize_t runtime_pm_show(struct device *dev,
 {
 	struct device_link *link = to_devlink(dev);
 
-	return sysfs_emit(buf, "%d\n", !!(link->flags & DL_FLAG_PM_RUNTIME));
+	return sysfs_emit(buf, "%d\n", device_link_test(link, DL_FLAG_PM_RUNTIME));
 }
 static DEVICE_ATTR_RO(runtime_pm);
 
@@ -485,8 +485,7 @@ static ssize_t sync_state_only_show(struct device *dev,
 {
 	struct device_link *link = to_devlink(dev);
 
-	return sysfs_emit(buf, "%d\n",
-			  !!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
+	return sysfs_emit(buf, "%d\n", device_link_test(link, DL_FLAG_SYNC_STATE_ONLY));
 }
 static DEVICE_ATTR_RO(sync_state_only);
 
@@ -552,7 +551,7 @@ void device_link_wait_removal(void)
 }
 EXPORT_SYMBOL_GPL(device_link_wait_removal);
 
-static struct class devlink_class = {
+static const struct class devlink_class = {
 	.name = "devlink",
 	.dev_groups = devlink_groups,
 	.dev_release = devlink_dev_release,
@@ -792,12 +791,12 @@ struct device_link *device_link_add(struct device *consumer,
 		if (link->consumer != consumer)
 			continue;
 
-		if (link->flags & DL_FLAG_INFERRED &&
+		if (device_link_test(link, DL_FLAG_INFERRED) &&
 		    !(flags & DL_FLAG_INFERRED))
 			link->flags &= ~DL_FLAG_INFERRED;
 
 		if (flags & DL_FLAG_PM_RUNTIME) {
-			if (!(link->flags & DL_FLAG_PM_RUNTIME)) {
+			if (!device_link_test(link, DL_FLAG_PM_RUNTIME)) {
 				pm_runtime_new_link(consumer);
 				link->flags |= DL_FLAG_PM_RUNTIME;
 			}
@@ -807,8 +806,8 @@ struct device_link *device_link_add(struct device *consumer,
 
 		if (flags & DL_FLAG_STATELESS) {
 			kref_get(&link->kref);
-			if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
-			    !(link->flags & DL_FLAG_STATELESS)) {
+			if (device_link_test(link, DL_FLAG_SYNC_STATE_ONLY) &&
+			    !device_link_test(link, DL_FLAG_STATELESS)) {
 				link->flags |= DL_FLAG_STATELESS;
 				goto reorder;
 			} else {
@@ -823,7 +822,7 @@ struct device_link *device_link_add(struct device *consumer,
 		 * update the existing link to stay around longer.
 		 */
 		if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) {
-			if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
+			if (device_link_test(link, DL_FLAG_AUTOREMOVE_CONSUMER)) {
 				link->flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
 				link->flags |= DL_FLAG_AUTOREMOVE_SUPPLIER;
 			}
@@ -831,12 +830,12 @@ struct device_link *device_link_add(struct device *consumer,
 			link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER |
 					 DL_FLAG_AUTOREMOVE_SUPPLIER);
 		}
-		if (!(link->flags & DL_FLAG_MANAGED)) {
+		if (!device_link_test(link, DL_FLAG_MANAGED)) {
 			kref_get(&link->kref);
 			link->flags |= DL_FLAG_MANAGED;
 			device_link_init_status(link, consumer, supplier);
 		}
-		if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
+		if (device_link_test(link, DL_FLAG_SYNC_STATE_ONLY) &&
 		    !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
 			link->flags &= ~DL_FLAG_SYNC_STATE_ONLY;
 			goto reorder;
@@ -940,7 +939,7 @@ static void __device_link_del(struct kref *kref)
 
 static void device_link_put_kref(struct device_link *link)
 {
-	if (link->flags & DL_FLAG_STATELESS)
+	if (device_link_test(link, DL_FLAG_STATELESS))
 		kref_put(&link->kref, __device_link_del);
 	else if (!device_is_registered(link->consumer))
 		__device_link_del(&link->kref);
@@ -1004,7 +1003,7 @@ static void device_links_missing_supplier(struct device *dev)
 		if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
 			WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
 		} else {
-			WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
+			WARN_ON(!device_link_test(link, DL_FLAG_SYNC_STATE_ONLY));
 			WRITE_ONCE(link->status, DL_STATE_DORMANT);
 		}
 	}
@@ -1072,14 +1071,14 @@ int device_links_check_suppliers(struct device *dev)
 	device_links_write_lock();
 
 	list_for_each_entry(link, &dev->links.suppliers, c_node) {
-		if (!(link->flags & DL_FLAG_MANAGED))
+		if (!device_link_test(link, DL_FLAG_MANAGED))
 			continue;
 
 		if (link->status != DL_STATE_AVAILABLE &&
-		    !(link->flags & DL_FLAG_SYNC_STATE_ONLY)) {
+		    !device_link_test(link, DL_FLAG_SYNC_STATE_ONLY)) {
 
 			if (dev_is_best_effort(dev) &&
-			    link->flags & DL_FLAG_INFERRED &&
+			    device_link_test(link, DL_FLAG_INFERRED) &&
 			    !link->supplier->can_match) {
 				ret = -EAGAIN;
 				continue;
@@ -1128,7 +1127,7 @@ static void __device_links_queue_sync_state(struct device *dev,
 		return;
 
 	list_for_each_entry(link, &dev->links.consumers, s_node) {
-		if (!(link->flags & DL_FLAG_MANAGED))
+		if (!device_link_test(link, DL_FLAG_MANAGED))
 			continue;
 		if (link->status != DL_STATE_ACTIVE)
 			return;
@@ -1268,7 +1267,7 @@ void device_links_force_bind(struct device *dev)
 	device_links_write_lock();
 
 	list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
-		if (!(link->flags & DL_FLAG_MANAGED))
+		if (!device_link_test(link, DL_FLAG_MANAGED))
 			continue;
 
 		if (link->status != DL_STATE_AVAILABLE) {
@@ -1329,7 +1328,7 @@ void device_links_driver_bound(struct device *dev)
 	device_links_write_lock();
 
 	list_for_each_entry(link, &dev->links.consumers, s_node) {
-		if (!(link->flags & DL_FLAG_MANAGED))
+		if (!device_link_test(link, DL_FLAG_MANAGED))
 			continue;
 
 		/*
@@ -1345,7 +1344,7 @@ void device_links_driver_bound(struct device *dev)
 		WARN_ON(link->status != DL_STATE_DORMANT);
 		WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
 
-		if (link->flags & DL_FLAG_AUTOPROBE_CONSUMER)
+		if (device_link_test(link, DL_FLAG_AUTOPROBE_CONSUMER))
 			driver_deferred_probe_add(link->consumer);
 	}
 
@@ -1357,11 +1356,11 @@ void device_links_driver_bound(struct device *dev)
 	list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
 		struct device *supplier;
 
-		if (!(link->flags & DL_FLAG_MANAGED))
+		if (!device_link_test(link, DL_FLAG_MANAGED))
 			continue;
 
 		supplier = link->supplier;
-		if (link->flags & DL_FLAG_SYNC_STATE_ONLY) {
+		if (device_link_test(link, DL_FLAG_SYNC_STATE_ONLY)) {
 			/*
 			 * When DL_FLAG_SYNC_STATE_ONLY is set, it means no
 			 * other DL_MANAGED_LINK_FLAGS have been set. So, it's
@@ -1369,7 +1368,7 @@ void device_links_driver_bound(struct device *dev)
 			 */
 			device_link_drop_managed(link);
 		} else if (dev_is_best_effort(dev) &&
-			   link->flags & DL_FLAG_INFERRED &&
+			   device_link_test(link, DL_FLAG_INFERRED) &&
 			   link->status != DL_STATE_CONSUMER_PROBE &&
 			   !link->supplier->can_match) {
 			/*
@@ -1421,10 +1420,10 @@ static void __device_links_no_driver(struct device *dev)
 	struct device_link *link, *ln;
 
 	list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
-		if (!(link->flags & DL_FLAG_MANAGED))
+		if (!device_link_test(link, DL_FLAG_MANAGED))
 			continue;
 
-		if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
+		if (device_link_test(link, DL_FLAG_AUTOREMOVE_CONSUMER)) {
 			device_link_drop_managed(link);
 			continue;
 		}
@@ -1436,7 +1435,7 @@ static void __device_links_no_driver(struct device *dev)
 		if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
 			WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
 		} else {
-			WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
+			WARN_ON(!device_link_test(link, DL_FLAG_SYNC_STATE_ONLY));
 			WRITE_ONCE(link->status, DL_STATE_DORMANT);
 		}
 	}
@@ -1461,7 +1460,7 @@ void device_links_no_driver(struct device *dev)
 	device_links_write_lock();
 
 	list_for_each_entry(link, &dev->links.consumers, s_node) {
-		if (!(link->flags & DL_FLAG_MANAGED))
+		if (!device_link_test(link, DL_FLAG_MANAGED))
 			continue;
 
 		/*
@@ -1498,10 +1497,10 @@ void device_links_driver_cleanup(struct device *dev)
 	device_links_write_lock();
 
 	list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) {
-		if (!(link->flags & DL_FLAG_MANAGED))
+		if (!device_link_test(link, DL_FLAG_MANAGED))
 			continue;
 
-		WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER);
+		WARN_ON(device_link_test(link, DL_FLAG_AUTOREMOVE_CONSUMER));
 		WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
 
 		/*
@@ -1510,7 +1509,7 @@ void device_links_driver_cleanup(struct device *dev)
 		 * has moved to DL_STATE_SUPPLIER_UNBIND.
 		 */
 		if (link->status == DL_STATE_SUPPLIER_UNBIND &&
-		    link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
+		    device_link_test(link, DL_FLAG_AUTOREMOVE_SUPPLIER))
 			device_link_drop_managed(link);
 
 		WRITE_ONCE(link->status, DL_STATE_DORMANT);
@@ -1544,7 +1543,7 @@ bool device_links_busy(struct device *dev)
 	device_links_write_lock();
 
 	list_for_each_entry(link, &dev->links.consumers, s_node) {
-		if (!(link->flags & DL_FLAG_MANAGED))
+		if (!device_link_test(link, DL_FLAG_MANAGED))
 			continue;
 
 		if (link->status == DL_STATE_CONSUMER_PROBE
@@ -1586,8 +1585,8 @@ void device_links_unbind_consumers(struct device *dev)
 	list_for_each_entry(link, &dev->links.consumers, s_node) {
 		enum device_link_state status;
 
-		if (!(link->flags & DL_FLAG_MANAGED) ||
-		    link->flags & DL_FLAG_SYNC_STATE_ONLY)
+		if (!device_link_test(link, DL_FLAG_MANAGED) ||
+		    device_link_test(link, DL_FLAG_SYNC_STATE_ONLY))
 			continue;
 
 		status = link->status;
@@ -1743,7 +1742,7 @@ static void fw_devlink_parse_fwtree(struct fwnode_handle *fwnode)
 
 static void fw_devlink_relax_link(struct device_link *link)
 {
-	if (!(link->flags & DL_FLAG_INFERRED))
+	if (!device_link_test(link, DL_FLAG_INFERRED))
 		return;
 
 	if (device_link_flag_is_sync_state_only(link->flags))
@@ -1779,13 +1778,13 @@ static int fw_devlink_dev_sync_state(struct device *dev, void *data)
 	struct device_link *link = to_devlink(dev);
 	struct device *sup = link->supplier;
 
-	if (!(link->flags & DL_FLAG_MANAGED) ||
+	if (!device_link_test(link, DL_FLAG_MANAGED) ||
 	    link->status == DL_STATE_ACTIVE || sup->state_synced ||
 	    !dev_has_sync_state(sup))
 		return 0;
 
 	if (fw_devlink_sync_state == FW_DEVLINK_SYNC_STATE_STRICT) {
-		dev_warn(sup, "sync_state() pending due to %s\n",
+		dev_info(sup, "sync_state() pending due to %s\n",
 			 dev_name(link->consumer));
 		return 0;
 	}
@@ -1881,8 +1880,6 @@ static void fw_devlink_unblock_consumers(struct device *dev)
 	device_links_write_unlock();
 }
 
-#define get_dev_from_fwnode(fwnode)	get_device((fwnode)->dev)
-
 static bool fwnode_init_without_drv(struct fwnode_handle *fwnode)
 {
 	struct device *dev;
@@ -1971,7 +1968,7 @@ static struct device *fwnode_get_next_parent_dev(const struct fwnode_handle *fwn
 
 /**
  * __fw_devlink_relax_cycles - Relax and mark dependency cycles.
- * @con: Potential consumer device.
+ * @con_handle: Potential consumer device fwnode.
  * @sup_handle: Potential supplier's fwnode.
  *
  * Needs to be called with fwnode_lock and device link lock held.
@@ -1989,10 +1986,10 @@ static struct device *fwnode_get_next_parent_dev(const struct fwnode_handle *fwn
  *
  * Return true if one or more cycles were found. Otherwise, return false.
  */
-static bool __fw_devlink_relax_cycles(struct device *con,
+static bool __fw_devlink_relax_cycles(struct fwnode_handle *con_handle,
 				 struct fwnode_handle *sup_handle)
 {
-	struct device *sup_dev = NULL, *par_dev = NULL;
+	struct device *sup_dev = NULL, *par_dev = NULL, *con_dev = NULL;
 	struct fwnode_link *link;
 	struct device_link *dev_link;
 	bool ret = false;
@@ -2009,22 +2006,22 @@ static bool __fw_devlink_relax_cycles(struct device *con,
 
 	sup_handle->flags |= FWNODE_FLAG_VISITED;
 
-	sup_dev = get_dev_from_fwnode(sup_handle);
-
 	/* Termination condition. */
-	if (sup_dev == con) {
+	if (sup_handle == con_handle) {
 		pr_debug("----- cycle: start -----\n");
 		ret = true;
 		goto out;
 	}
 
+	sup_dev = get_dev_from_fwnode(sup_handle);
+	con_dev = get_dev_from_fwnode(con_handle);
 	/*
 	 * If sup_dev is bound to a driver and @con hasn't started binding to a
 	 * driver, sup_dev can't be a consumer of @con. So, no need to check
 	 * further.
 	 */
 	if (sup_dev && sup_dev->links.status ==  DL_DEV_DRIVER_BOUND &&
-	    con->links.status == DL_DEV_NO_DRIVER) {
+	    con_dev && con_dev->links.status == DL_DEV_NO_DRIVER) {
 		ret = false;
 		goto out;
 	}
@@ -2033,7 +2030,7 @@ static bool __fw_devlink_relax_cycles(struct device *con,
 		if (link->flags & FWLINK_FLAG_IGNORE)
 			continue;
 
-		if (__fw_devlink_relax_cycles(con, link->supplier)) {
+		if (__fw_devlink_relax_cycles(con_handle, link->supplier)) {
 			__fwnode_link_cycle(link);
 			ret = true;
 		}
@@ -2048,7 +2045,7 @@ static bool __fw_devlink_relax_cycles(struct device *con,
 	else
 		par_dev = fwnode_get_next_parent_dev(sup_handle);
 
-	if (par_dev && __fw_devlink_relax_cycles(con, par_dev->fwnode)) {
+	if (par_dev && __fw_devlink_relax_cycles(con_handle, par_dev->fwnode)) {
 		pr_debug("%pfwf: cycle: child of %pfwf\n", sup_handle,
 			 par_dev->fwnode);
 		ret = true;
@@ -2063,10 +2060,10 @@ static bool __fw_devlink_relax_cycles(struct device *con,
 		 * such due to a cycle.
 		 */
 		if (device_link_flag_is_sync_state_only(dev_link->flags) &&
-		    !(dev_link->flags & DL_FLAG_CYCLE))
+		    !device_link_test(dev_link, DL_FLAG_CYCLE))
 			continue;
 
-		if (__fw_devlink_relax_cycles(con,
+		if (__fw_devlink_relax_cycles(con_handle,
 					      dev_link->supplier->fwnode)) {
 			pr_debug("%pfwf: cycle: depends on %pfwf\n", sup_handle,
 				 dev_link->supplier->fwnode);
@@ -2079,6 +2076,7 @@ static bool __fw_devlink_relax_cycles(struct device *con,
 out:
 	sup_handle->flags &= ~FWNODE_FLAG_VISITED;
 	put_device(sup_dev);
+	put_device(con_dev);
 	put_device(par_dev);
 	return ret;
 }
@@ -2114,11 +2112,6 @@ static int fw_devlink_create_devlink(struct device *con,
 	if (link->flags & FWLINK_FLAG_IGNORE)
 		return 0;
 
-	if (con->fwnode == link->consumer)
-		flags = fw_devlink_get_flags(link->flags);
-	else
-		flags = FW_DEVLINK_FLAGS_PERMISSIVE;
-
 	/*
 	 * In some cases, a device P might also be a supplier to its child node
 	 * C. However, this would defer the probe of C until the probe of P
@@ -2139,25 +2132,23 @@ static int fw_devlink_create_devlink(struct device *con,
 		return -EINVAL;
 
 	/*
-	 * SYNC_STATE_ONLY device links don't block probing and supports cycles.
-	 * So, one might expect that cycle detection isn't necessary for them.
-	 * However, if the device link was marked as SYNC_STATE_ONLY because
-	 * it's part of a cycle, then we still need to do cycle detection. This
-	 * is because the consumer and supplier might be part of multiple cycles
-	 * and we need to detect all those cycles.
+	 * Don't try to optimize by not calling the cycle detection logic under
+	 * certain conditions. There's always some corner case that won't get
+	 * detected.
 	 */
-	if (!device_link_flag_is_sync_state_only(flags) ||
-	    flags & DL_FLAG_CYCLE) {
-		device_links_write_lock();
-		if (__fw_devlink_relax_cycles(con, sup_handle)) {
-			__fwnode_link_cycle(link);
-			flags = fw_devlink_get_flags(link->flags);
-			pr_debug("----- cycle: end -----\n");
-			dev_info(con, "Fixed dependency cycle(s) with %pfwf\n",
-				 sup_handle);
-		}
-		device_links_write_unlock();
+	device_links_write_lock();
+	if (__fw_devlink_relax_cycles(link->consumer, sup_handle)) {
+		__fwnode_link_cycle(link);
+		pr_debug("----- cycle: end -----\n");
+		pr_info("%pfwf: Fixed dependency cycle(s) with %pfwf\n",
+			link->consumer, sup_handle);
 	}
+	device_links_write_unlock();
+
+	if (con->fwnode == link->consumer)
+		flags = fw_devlink_get_flags(link->flags);
+	else
+		flags = FW_DEVLINK_FLAGS_PERMISSIVE;
 
 	if (sup_handle->flags & FWNODE_FLAG_NOT_DEVICE)
 		sup_dev = fwnode_get_next_parent_dev(sup_handle);
@@ -2180,8 +2171,8 @@ static int fw_devlink_create_devlink(struct device *con,
 		}
 
 		if (con != sup_dev && !device_link_add(con, sup_dev, flags)) {
-			dev_err(con, "Failed to create device link (0x%x) with %s\n",
-				flags, dev_name(sup_dev));
+			dev_err(con, "Failed to create device link (0x%x) with supplier %s for %pfwf\n",
+				flags, dev_name(sup_dev), link->consumer);
 			ret = -EINVAL;
 		}
 
@@ -2630,6 +2621,35 @@ static const char *dev_uevent_name(const struct kobject *kobj)
 	return NULL;
 }
 
+/*
+ * Try filling "DRIVER=<name>" uevent variable for a device. Because this
+ * function may race with binding and unbinding the device from a driver,
+ * we need to be careful. Binding is generally safe, at worst we miss the
+ * fact that the device is already bound to a driver (but the driver
+ * information that is delivered through uevents is best-effort, it may
+ * become obsolete as soon as it is generated anyways). Unbinding is more
+ * risky as driver pointer is transitioning to NULL, so READ_ONCE() should
+ * be used to make sure we are dealing with the same pointer, and to
+ * ensure that driver structure is not going to disappear from under us
+ * we take bus' drivers klist lock. The assumption that only registered
+ * driver can be bound to a device, and to unregister a driver bus code
+ * will take the same lock.
+ */
+static void dev_driver_uevent(const struct device *dev, struct kobj_uevent_env *env)
+{
+	struct subsys_private *sp = bus_to_subsys(dev->bus);
+
+	if (sp) {
+		scoped_guard(spinlock, &sp->klist_drivers.k_lock) {
+			struct device_driver *drv = READ_ONCE(dev->driver);
+			if (drv)
+				add_uevent_var(env, "DRIVER=%s", drv->name);
+		}
+
+		subsys_put(sp);
+	}
+}
+
 static int dev_uevent(const struct kobject *kobj, struct kobj_uevent_env *env)
 {
 	const struct device *dev = kobj_to_dev(kobj);
@@ -2661,8 +2681,8 @@ static int dev_uevent(const struct kobject *kobj, struct kobj_uevent_env *env)
 	if (dev->type && dev->type->name)
 		add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
 
-	if (dev->driver)
-		add_uevent_var(env, "DRIVER=%s", dev->driver->name);
+	/* Add "DRIVER=%s" variable if the device is bound to a driver */
+	dev_driver_uevent(dev, env);
 
 	/* Add common DT information about the device */
 	of_device_uevent(dev, env);
@@ -2732,11 +2752,8 @@ static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
 	if (!env)
 		return -ENOMEM;
 
-	/* Synchronize with really_probe() */
-	device_lock(dev);
 	/* let the kset specific function add its keys */
 	retval = kset->uevent_ops->uevent(&dev->kobj, env);
-	device_unlock(dev);
 	if (retval)
 		goto out;
 
@@ -3706,7 +3723,7 @@ done:
 	device_pm_remove(dev);
 	dpm_sysfs_remove(dev);
  DPMError:
-	dev->driver = NULL;
+	device_set_driver(dev, NULL);
 	bus_remove_device(dev);
  BusError:
 	device_remove_attrs(dev);
@@ -3977,8 +3994,8 @@ const char *device_get_devnode(const struct device *dev,
 /**
  * device_for_each_child - device child iterator.
  * @parent: parent struct device.
- * @fn: function to be called for each device.
  * @data: data for the callback.
+ * @fn: function to be called for each device.
  *
  * Iterate over @parent's child devices, and call @fn for each,
  * passing it @data.
@@ -3987,7 +4004,7 @@ const char *device_get_devnode(const struct device *dev,
  * other than 0, we break out and return that value.
  */
 int device_for_each_child(struct device *parent, void *data,
-			  int (*fn)(struct device *dev, void *data))
+			  device_iter_t fn)
 {
 	struct klist_iter i;
 	struct device *child;
@@ -4007,8 +4024,8 @@ EXPORT_SYMBOL_GPL(device_for_each_child);
 /**
  * device_for_each_child_reverse - device child iterator in reversed order.
  * @parent: parent struct device.
- * @fn: function to be called for each device.
  * @data: data for the callback.
+ * @fn: function to be called for each device.
  *
  * Iterate over @parent's child devices, and call @fn for each,
  * passing it @data.
@@ -4017,7 +4034,7 @@ EXPORT_SYMBOL_GPL(device_for_each_child);
  * other than 0, we break out and return that value.
  */
 int device_for_each_child_reverse(struct device *parent, void *data,
-				  int (*fn)(struct device *dev, void *data))
+				  device_iter_t fn)
 {
 	struct klist_iter i;
 	struct device *child;
@@ -4038,8 +4055,8 @@ EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
  * device_for_each_child_reverse_from - device child iterator in reversed order.
  * @parent: parent struct device.
  * @from: optional starting point in child list
- * @fn: function to be called for each device.
  * @data: data for the callback.
+ * @fn: function to be called for each device.
  *
  * Iterate over @parent's child devices, starting at @from, and call @fn
  * for each, passing it @data. This helper is identical to
@@ -4050,14 +4067,14 @@ EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
  * device_for_each_child_reverse_from();
  */
 int device_for_each_child_reverse_from(struct device *parent,
-				       struct device *from, const void *data,
-				       int (*fn)(struct device *, const void *))
+				       struct device *from, void *data,
+				       device_iter_t fn)
 {
 	struct klist_iter i;
 	struct device *child;
 	int error = 0;
 
-	if (!parent->p)
+	if (!parent || !parent->p)
 		return 0;
 
 	klist_iter_init_node(&parent->p->klist_children, &i,
@@ -4072,8 +4089,8 @@ EXPORT_SYMBOL_GPL(device_for_each_child_reverse_from);
 /**
  * device_find_child - device iterator for locating a particular device.
  * @parent: parent struct device
- * @match: Callback function to check device
  * @data: Data to pass to match function
+ * @match: Callback function to check device
  *
  * This is similar to the device_for_each_child() function above, but it
  * returns a reference to a device that is 'found' for later use, as
@@ -4086,8 +4103,8 @@ EXPORT_SYMBOL_GPL(device_for_each_child_reverse_from);
  *
  * NOTE: you will need to drop the reference with put_device() after use.
  */
-struct device *device_find_child(struct device *parent, void *data,
-				 int (*match)(struct device *dev, void *data))
+struct device *device_find_child(struct device *parent, const void *data,
+				 device_match_t match)
 {
 	struct klist_iter i;
 	struct device *child;
@@ -4096,62 +4113,17 @@ struct device *device_find_child(struct device *parent, void *data,
 		return NULL;
 
 	klist_iter_init(&parent->p->klist_children, &i);
-	while ((child = next_device(&i)))
-		if (match(child, data) && get_device(child))
+	while ((child = next_device(&i))) {
+		if (match(child, data)) {
+			get_device(child);
 			break;
+		}
+	}
 	klist_iter_exit(&i);
 	return child;
 }
 EXPORT_SYMBOL_GPL(device_find_child);
 
-/**
- * device_find_child_by_name - device iterator for locating a child device.
- * @parent: parent struct device
- * @name: name of the child device
- *
- * This is similar to the device_find_child() function above, but it
- * returns a reference to a device that has the name @name.
- *
- * NOTE: you will need to drop the reference with put_device() after use.
- */
-struct device *device_find_child_by_name(struct device *parent,
-					 const char *name)
-{
-	struct klist_iter i;
-	struct device *child;
-
-	if (!parent)
-		return NULL;
-
-	klist_iter_init(&parent->p->klist_children, &i);
-	while ((child = next_device(&i)))
-		if (sysfs_streq(dev_name(child), name) && get_device(child))
-			break;
-	klist_iter_exit(&i);
-	return child;
-}
-EXPORT_SYMBOL_GPL(device_find_child_by_name);
-
-static int match_any(struct device *dev, void *unused)
-{
-	return 1;
-}
-
-/**
- * device_find_any_child - device iterator for locating a child device, if any.
- * @parent: parent struct device
- *
- * This is similar to the device_find_child() function above, but it
- * returns a reference to a child device, if any.
- *
- * NOTE: you will need to drop the reference with put_device() after use.
- */
-struct device *device_find_any_child(struct device *parent)
-{
-	return device_find_child(parent, NULL, match_any);
-}
-EXPORT_SYMBOL_GPL(device_find_any_child);
-
 int __init devices_init(void)
 {
 	devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
@@ -4166,7 +4138,7 @@ int __init devices_init(void)
 	sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
 	if (!sysfs_dev_char_kobj)
 		goto char_kobj_err;
-	device_link_wq = alloc_workqueue("device_link_wq", 0, 0);
+	device_link_wq = alloc_workqueue("device_link_wq", WQ_PERCPU, 0);
 	if (!device_link_wq)
 		goto wq_err;
 
@@ -5223,6 +5195,67 @@ void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
 EXPORT_SYMBOL_GPL(set_secondary_fwnode);
 
 /**
+ * device_remove_of_node - Remove an of_node from a device
+ * @dev: device whose device tree node is being removed
+ */
+void device_remove_of_node(struct device *dev)
+{
+	dev = get_device(dev);
+	if (!dev)
+		return;
+
+	if (!dev->of_node)
+		goto end;
+
+	if (dev->fwnode == of_fwnode_handle(dev->of_node))
+		dev->fwnode = NULL;
+
+	of_node_put(dev->of_node);
+	dev->of_node = NULL;
+
+end:
+	put_device(dev);
+}
+EXPORT_SYMBOL_GPL(device_remove_of_node);
+
+/**
+ * device_add_of_node - Add an of_node to an existing device
+ * @dev: device whose device tree node is being added
+ * @of_node: of_node to add
+ *
+ * Return: 0 on success or error code on failure.
+ */
+int device_add_of_node(struct device *dev, struct device_node *of_node)
+{
+	int ret;
+
+	if (!of_node)
+		return -EINVAL;
+
+	dev = get_device(dev);
+	if (!dev)
+		return -EINVAL;
+
+	if (dev->of_node) {
+		dev_err(dev, "Cannot replace node %pOF with %pOF\n",
+			dev->of_node, of_node);
+		ret = -EBUSY;
+		goto end;
+	}
+
+	dev->of_node = of_node_get(of_node);
+
+	if (!dev->fwnode)
+		dev->fwnode = of_fwnode_handle(of_node);
+
+	ret = 0;
+end:
+	put_device(dev);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(device_add_of_node);
+
+/**
  * device_set_of_node_from_dev - reuse device-tree node of another device
  * @dev: device whose device-tree node is being set
  * @dev2: device whose device-tree node is being reused
@@ -5245,21 +5278,52 @@ void device_set_node(struct device *dev, struct fwnode_handle *fwnode)
 }
 EXPORT_SYMBOL_GPL(device_set_node);
 
+/**
+ * get_dev_from_fwnode - Obtain a reference count of the struct device the
+ * struct fwnode_handle is associated with.
+ * @fwnode: The pointer to the struct fwnode_handle to obtain the struct device
+ * reference count of.
+ *
+ * This function obtains a reference count of the device the device pointer
+ * embedded in the struct fwnode_handle points to.
+ *
+ * Note that the struct device pointer embedded in struct fwnode_handle does
+ * *not* have a reference count of the struct device itself.
+ *
+ * Hence, it is a UAF (and thus a bug) to call this function if the caller can't
+ * guarantee that the last reference count of the corresponding struct device is
+ * not dropped concurrently.
+ *
+ * This is possible since struct fwnode_handle has its own reference count and
+ * hence can out-live the struct device it is associated with.
+ */
+struct device *get_dev_from_fwnode(struct fwnode_handle *fwnode)
+{
+	return get_device((fwnode)->dev);
+}
+EXPORT_SYMBOL_GPL(get_dev_from_fwnode);
+
 int device_match_name(struct device *dev, const void *name)
 {
 	return sysfs_streq(dev_name(dev), name);
 }
 EXPORT_SYMBOL_GPL(device_match_name);
 
+int device_match_type(struct device *dev, const void *type)
+{
+	return dev->type == type;
+}
+EXPORT_SYMBOL_GPL(device_match_type);
+
 int device_match_of_node(struct device *dev, const void *np)
 {
-	return dev->of_node == np;
+	return np && dev->of_node == np;
 }
 EXPORT_SYMBOL_GPL(device_match_of_node);
 
 int device_match_fwnode(struct device *dev, const void *fwnode)
 {
-	return dev_fwnode(dev) == fwnode;
+	return fwnode && dev_fwnode(dev) == fwnode;
 }
 EXPORT_SYMBOL_GPL(device_match_fwnode);
 
@@ -5271,13 +5335,13 @@ EXPORT_SYMBOL_GPL(device_match_devt);
 
 int device_match_acpi_dev(struct device *dev, const void *adev)
 {
-	return ACPI_COMPANION(dev) == adev;
+	return adev && ACPI_COMPANION(dev) == adev;
 }
 EXPORT_SYMBOL(device_match_acpi_dev);
 
 int device_match_acpi_handle(struct device *dev, const void *handle)
 {
-	return ACPI_HANDLE(dev) == handle;
+	return handle && ACPI_HANDLE(dev) == handle;
 }
 EXPORT_SYMBOL(device_match_acpi_handle);