1 files changed, 370 insertions, 253 deletions

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 9828da9b933c..2fde698430df 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -9,28 +9,29 @@
  */
 
 #include <linux/acpi.h>
+#include <linux/blkdev.h>
+#include <linux/cleanup.h>
 #include <linux/cpufreq.h>
 #include <linux/device.h>
+#include <linux/dma-map-ops.h> /* for dma_default_coherent */
 #include <linux/err.h>
 #include <linux/fwnode.h>
 #include <linux/init.h>
+#include <linux/kdev_t.h>
 #include <linux/kstrtox.h>
 #include <linux/module.h>
-#include <linux/slab.h>
-#include <linux/kdev_t.h>
+#include <linux/mutex.h>
+#include <linux/netdevice.h>
 #include <linux/notifier.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
-#include <linux/blkdev.h>
-#include <linux/mutex.h>
 #include <linux/pm_runtime.h>
-#include <linux/netdevice.h>
-#include <linux/sched/signal.h>
 #include <linux/sched/mm.h>
+#include <linux/sched/signal.h>
+#include <linux/slab.h>
 #include <linux/string_helpers.h>
 #include <linux/swiotlb.h>
 #include <linux/sysfs.h>
-#include <linux/dma-map-ops.h> /* for dma_default_coherent */
 
 #include "base.h"
 #include "physical_location.h"
@@ -44,6 +45,7 @@ static bool fw_devlink_is_permissive(void);
 static void __fw_devlink_link_to_consumers(struct device *dev);
 static bool fw_devlink_drv_reg_done;
 static bool fw_devlink_best_effort;
+static struct workqueue_struct *device_link_wq;
 
 /**
  * __fwnode_link_add - Create a link between two fwnode_handles.
@@ -92,14 +94,12 @@ static int __fwnode_link_add(struct fwnode_handle *con,
 	return 0;
 }
 
-int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup)
+int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup,
+		    u8 flags)
 {
-	int ret;
+	guard(mutex)(&fwnode_link_lock);
 
-	mutex_lock(&fwnode_link_lock);
-	ret = __fwnode_link_add(con, sup, 0);
-	mutex_unlock(&fwnode_link_lock);
-	return ret;
+	return __fwnode_link_add(con, sup, flags);
 }
 
 /**
@@ -140,10 +140,10 @@ static void fwnode_links_purge_suppliers(struct fwnode_handle *fwnode)
 {
 	struct fwnode_link *link, *tmp;
 
-	mutex_lock(&fwnode_link_lock);
+	guard(mutex)(&fwnode_link_lock);
+
 	list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook)
 		__fwnode_link_del(link);
-	mutex_unlock(&fwnode_link_lock);
 }
 
 /**
@@ -156,10 +156,10 @@ static void fwnode_links_purge_consumers(struct fwnode_handle *fwnode)
 {
 	struct fwnode_link *link, *tmp;
 
-	mutex_lock(&fwnode_link_lock);
+	guard(mutex)(&fwnode_link_lock);
+
 	list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook)
 		__fwnode_link_del(link);
-	mutex_unlock(&fwnode_link_lock);
 }
 
 /**
@@ -532,13 +532,27 @@ static void devlink_dev_release(struct device *dev)
 	/*
 	 * It may take a while to complete this work because of the SRCU
 	 * synchronization in device_link_release_fn() and if the consumer or
-	 * supplier devices get deleted when it runs, so put it into the "long"
-	 * workqueue.
+	 * supplier devices get deleted when it runs, so put it into the
+	 * dedicated workqueue.
 	 */
-	queue_work(system_long_wq, &link->rm_work);
+	queue_work(device_link_wq, &link->rm_work);
 }
 
-static struct class devlink_class = {
+/**
+ * device_link_wait_removal - Wait for ongoing devlink removal jobs to terminate
+ */
+void device_link_wait_removal(void)
+{
+	/*
+	 * devlink removal jobs are queued in the dedicated work queue.
+	 * To be sure that all removal jobs are terminated, ensure that any
+	 * scheduled work has run to completion.
+	 */
+	flush_workqueue(device_link_wq);
+}
+EXPORT_SYMBOL_GPL(device_link_wait_removal);
+
+static const struct class devlink_class = {
 	.name = "devlink",
 	.dev_groups = devlink_groups,
 	.dev_release = devlink_dev_release,
@@ -546,20 +560,11 @@ static struct class devlink_class = {
 
 static int devlink_add_symlinks(struct device *dev)
 {
+	char *buf_con __free(kfree) = NULL, *buf_sup __free(kfree) = NULL;
 	int ret;
-	size_t len;
 	struct device_link *link = to_devlink(dev);
 	struct device *sup = link->supplier;
 	struct device *con = link->consumer;
-	char *buf;
-
-	len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
-		  strlen(dev_bus_name(con)) + strlen(dev_name(con)));
-	len += strlen(":");
-	len += strlen("supplier:") + 1;
-	buf = kzalloc(len, GFP_KERNEL);
-	if (!buf)
-		return -ENOMEM;
 
 	ret = sysfs_create_link(&link->link_dev.kobj, &sup->kobj, "supplier");
 	if (ret)
@@ -569,58 +574,64 @@ static int devlink_add_symlinks(struct device *dev)
 	if (ret)
 		goto err_con;
 
-	snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
-	ret = sysfs_create_link(&sup->kobj, &link->link_dev.kobj, buf);
+	buf_con = kasprintf(GFP_KERNEL, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
+	if (!buf_con) {
+		ret = -ENOMEM;
+		goto err_con_dev;
+	}
+
+	ret = sysfs_create_link(&sup->kobj, &link->link_dev.kobj, buf_con);
 	if (ret)
 		goto err_con_dev;
 
-	snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
-	ret = sysfs_create_link(&con->kobj, &link->link_dev.kobj, buf);
+	buf_sup = kasprintf(GFP_KERNEL, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
+	if (!buf_sup) {
+		ret = -ENOMEM;
+		goto err_sup_dev;
+	}
+
+	ret = sysfs_create_link(&con->kobj, &link->link_dev.kobj, buf_sup);
 	if (ret)
 		goto err_sup_dev;
 
 	goto out;
 
 err_sup_dev:
-	snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
-	sysfs_remove_link(&sup->kobj, buf);
+	sysfs_remove_link(&sup->kobj, buf_con);
 err_con_dev:
 	sysfs_remove_link(&link->link_dev.kobj, "consumer");
 err_con:
 	sysfs_remove_link(&link->link_dev.kobj, "supplier");
 out:
-	kfree(buf);
 	return ret;
 }
 
 static void devlink_remove_symlinks(struct device *dev)
 {
+	char *buf_con __free(kfree) = NULL, *buf_sup __free(kfree) = NULL;
 	struct device_link *link = to_devlink(dev);
-	size_t len;
 	struct device *sup = link->supplier;
 	struct device *con = link->consumer;
-	char *buf;
 
 	sysfs_remove_link(&link->link_dev.kobj, "consumer");
 	sysfs_remove_link(&link->link_dev.kobj, "supplier");
 
-	len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
-		  strlen(dev_bus_name(con)) + strlen(dev_name(con)));
-	len += strlen(":");
-	len += strlen("supplier:") + 1;
-	buf = kzalloc(len, GFP_KERNEL);
-	if (!buf) {
-		WARN(1, "Unable to properly free device link symlinks!\n");
-		return;
-	}
-
 	if (device_is_registered(con)) {
-		snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
-		sysfs_remove_link(&con->kobj, buf);
+		buf_sup = kasprintf(GFP_KERNEL, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
+		if (!buf_sup)
+			goto out;
+		sysfs_remove_link(&con->kobj, buf_sup);
 	}
-	snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
-	sysfs_remove_link(&sup->kobj, buf);
-	kfree(buf);
+
+	buf_con = kasprintf(GFP_KERNEL, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
+	if (!buf_con)
+		goto out;
+	sysfs_remove_link(&sup->kobj, buf_con);
+
+	return;
+
+out:
+	WARN(1, "Unable to properly free device link symlinks!\n");
 }
 
 static struct class_interface devlink_class_intf = {
@@ -661,6 +672,9 @@ postcore_initcall(devlink_class_init);
  * @supplier: Supplier end of the link.
  * @flags: Link flags.
  *
+ * Return: On success, a device_link struct will be returned.
+ *         On error or invalid flag settings, NULL will be returned.
+ *
  * The caller is responsible for the proper synchronization of the link creation
  * with runtime PM.  First, setting the DL_FLAG_PM_RUNTIME flag will cause the
  * runtime PM framework to take the link into account.  Second, if the
@@ -1011,7 +1025,8 @@ static struct fwnode_handle *fwnode_links_check_suppliers(
 		return NULL;
 
 	list_for_each_entry(link, &fwnode->suppliers, c_hook)
-		if (!(link->flags & FWLINK_FLAG_CYCLE))
+		if (!(link->flags &
+		      (FWLINK_FLAG_CYCLE | FWLINK_FLAG_IGNORE)))
 			return link->supplier;
 
 	return NULL;
@@ -1043,20 +1058,16 @@ int device_links_check_suppliers(struct device *dev)
 	 * Device waiting for supplier to become available is not allowed to
 	 * probe.
 	 */
-	mutex_lock(&fwnode_link_lock);
-	sup_fw = fwnode_links_check_suppliers(dev->fwnode);
-	if (sup_fw) {
-		if (!dev_is_best_effort(dev)) {
-			fwnode_ret = -EPROBE_DEFER;
-			dev_err_probe(dev, -EPROBE_DEFER,
-				    "wait for supplier %pfwf\n", sup_fw);
-		} else {
-			fwnode_ret = -EAGAIN;
+	scoped_guard(mutex, &fwnode_link_lock) {
+		sup_fw = fwnode_links_check_suppliers(dev->fwnode);
+		if (sup_fw) {
+			if (dev_is_best_effort(dev))
+				fwnode_ret = -EAGAIN;
+			else
+				return dev_err_probe(dev, -EPROBE_DEFER,
+						     "wait for supplier %pfwf\n", sup_fw);
 		}
 	}
-	mutex_unlock(&fwnode_link_lock);
-	if (fwnode_ret == -EPROBE_DEFER)
-		return fwnode_ret;
 
 	device_links_write_lock();
 
@@ -1075,10 +1086,8 @@ int device_links_check_suppliers(struct device *dev)
 			}
 
 			device_links_missing_supplier(dev);
-			dev_err_probe(dev, -EPROBE_DEFER,
-				      "supplier %s not ready\n",
-				      dev_name(link->supplier));
-			ret = -EPROBE_DEFER;
+			ret = dev_err_probe(dev, -EPROBE_DEFER,
+					    "supplier %s not ready\n", dev_name(link->supplier));
 			break;
 		}
 		WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
@@ -1231,9 +1240,8 @@ static ssize_t waiting_for_supplier_show(struct device *dev,
 	bool val;
 
 	device_lock(dev);
-	mutex_lock(&fwnode_link_lock);
-	val = !!fwnode_links_check_suppliers(dev->fwnode);
-	mutex_unlock(&fwnode_link_lock);
+	scoped_guard(mutex, &fwnode_link_lock)
+		val = !!fwnode_links_check_suppliers(dev->fwnode);
 	device_unlock(dev);
 	return sysfs_emit(buf, "%u\n", val);
 }
@@ -1306,13 +1314,15 @@ void device_links_driver_bound(struct device *dev)
 	 */
 	if (dev->fwnode && dev->fwnode->dev == dev) {
 		struct fwnode_handle *child;
+
 		fwnode_links_purge_suppliers(dev->fwnode);
-		mutex_lock(&fwnode_link_lock);
+
+		guard(mutex)(&fwnode_link_lock);
+
 		fwnode_for_each_available_child_node(dev->fwnode, child)
 			__fw_devlink_pickup_dangling_consumers(child,
 							       dev->fwnode);
 		__fw_devlink_link_to_consumers(dev);
-		mutex_unlock(&fwnode_link_lock);
 	}
 	device_remove_file(dev, &dev_attr_waiting_for_supplier);
 
@@ -1871,6 +1881,7 @@ 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)
 {
@@ -1902,8 +1913,65 @@ static bool fwnode_ancestor_init_without_drv(struct fwnode_handle *fwnode)
 }
 
 /**
+ * fwnode_is_ancestor_of - Test if @ancestor is ancestor of @child
+ * @ancestor: Firmware which is tested for being an ancestor
+ * @child: Firmware which is tested for being the child
+ *
+ * A node is considered an ancestor of itself too.
+ *
+ * Return: true if @ancestor is an ancestor of @child. Otherwise, returns false.
+ */
+static bool fwnode_is_ancestor_of(const struct fwnode_handle *ancestor,
+				  const struct fwnode_handle *child)
+{
+	struct fwnode_handle *parent;
+
+	if (IS_ERR_OR_NULL(ancestor))
+		return false;
+
+	if (child == ancestor)
+		return true;
+
+	fwnode_for_each_parent_node(child, parent) {
+		if (parent == ancestor) {
+			fwnode_handle_put(parent);
+			return true;
+		}
+	}
+	return false;
+}
+
+/**
+ * fwnode_get_next_parent_dev - Find device of closest ancestor fwnode
+ * @fwnode: firmware node
+ *
+ * Given a firmware node (@fwnode), this function finds its closest ancestor
+ * firmware node that has a corresponding struct device and returns that struct
+ * device.
+ *
+ * The caller is responsible for calling put_device() on the returned device
+ * pointer.
+ *
+ * Return: a pointer to the device of the @fwnode's closest ancestor.
+ */
+static struct device *fwnode_get_next_parent_dev(const struct fwnode_handle *fwnode)
+{
+	struct fwnode_handle *parent;
+	struct device *dev;
+
+	fwnode_for_each_parent_node(fwnode, parent) {
+		dev = get_dev_from_fwnode(parent);
+		if (dev) {
+			fwnode_handle_put(parent);
+			return dev;
+		}
+	}
+	return NULL;
+}
+
+/**
  * __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.
@@ -1921,10 +1989,10 @@ static bool fwnode_ancestor_init_without_drv(struct fwnode_handle *fwnode)
  *
  * 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;
@@ -1941,28 +2009,31 @@ 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;
 	}
 
 	list_for_each_entry(link, &sup_handle->suppliers, c_hook) {
-		if (__fw_devlink_relax_cycles(con, link->supplier)) {
+		if (link->flags & FWLINK_FLAG_IGNORE)
+			continue;
+
+		if (__fw_devlink_relax_cycles(con_handle, link->supplier)) {
 			__fwnode_link_cycle(link);
 			ret = true;
 		}
@@ -1977,7 +2048,7 @@ 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;
@@ -1995,7 +2066,7 @@ static bool __fw_devlink_relax_cycles(struct device *con,
 		    !(dev_link->flags & 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);
@@ -2008,6 +2079,7 @@ 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;
 }
@@ -2040,10 +2112,8 @@ static int fw_devlink_create_devlink(struct device *con,
 	int ret = 0;
 	u32 flags;
 
-	if (con->fwnode == link->consumer)
-		flags = fw_devlink_get_flags(link->flags);
-	else
-		flags = FW_DEVLINK_FLAGS_PERMISSIVE;
+	if (link->flags & FWLINK_FLAG_IGNORE)
+		return 0;
 
 	/*
 	 * In some cases, a device P might also be a supplier to its child node
@@ -2065,25 +2135,23 @@ 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);
@@ -2106,8 +2174,8 @@ 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;
 		}
 
@@ -2257,16 +2325,14 @@ static void fw_devlink_link_device(struct device *dev)
 
 	fw_devlink_parse_fwtree(fwnode);
 
-	mutex_lock(&fwnode_link_lock);
+	guard(mutex)(&fwnode_link_lock);
+
 	__fw_devlink_link_to_consumers(dev);
 	__fw_devlink_link_to_suppliers(dev, fwnode);
-	mutex_unlock(&fwnode_link_lock);
 }
 
 /* Device links support end. */
 
-int (*platform_notify)(struct device *dev) = NULL;
-int (*platform_notify_remove)(struct device *dev) = NULL;
 static struct kobject *dev_kobj;
 
 /* /sys/dev/char */
@@ -2314,16 +2380,10 @@ static void device_platform_notify(struct device *dev)
 	acpi_device_notify(dev);
 
 	software_node_notify(dev);
-
-	if (platform_notify)
-		platform_notify(dev);
 }
 
 static void device_platform_notify_remove(struct device *dev)
 {
-	if (platform_notify_remove)
-		platform_notify_remove(dev);
-
 	software_node_notify_remove(dev);
 
 	acpi_device_notify_remove(dev);
@@ -2465,6 +2525,15 @@ ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
 }
 EXPORT_SYMBOL_GPL(device_show_bool);
 
+ssize_t device_show_string(struct device *dev,
+			   struct device_attribute *attr, char *buf)
+{
+	struct dev_ext_attribute *ea = to_ext_attr(attr);
+
+	return sysfs_emit(buf, "%s\n", (char *)ea->var);
+}
+EXPORT_SYMBOL_GPL(device_show_string);
+
 /**
  * device_release - free device structure.
  * @kobj: device's kobject.
@@ -2508,7 +2577,7 @@ static const void *device_namespace(const struct kobject *kobj)
 	const struct device *dev = kobj_to_dev(kobj);
 	const void *ns = NULL;
 
-	if (dev->class && dev->class->ns_type)
+	if (dev->class && dev->class->namespace)
 		ns = dev->class->namespace(dev);
 
 	return ns;
@@ -2657,8 +2726,11 @@ 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;
 
@@ -2763,15 +2835,6 @@ static void devm_attr_group_remove(struct device *dev, void *res)
 	sysfs_remove_group(&dev->kobj, group);
 }
 
-static void devm_attr_groups_remove(struct device *dev, void *res)
-{
-	union device_attr_group_devres *devres = res;
-	const struct attribute_group **groups = devres->groups;
-
-	dev_dbg(dev, "%s: removing groups %p\n", __func__, groups);
-	sysfs_remove_groups(&dev->kobj, groups);
-}
-
 /**
  * devm_device_add_group - given a device, create a managed attribute group
  * @dev:	The device to create the group for
@@ -2804,42 +2867,6 @@ int devm_device_add_group(struct device *dev, const struct attribute_group *grp)
 }
 EXPORT_SYMBOL_GPL(devm_device_add_group);
 
-/**
- * devm_device_add_groups - create a bunch of managed attribute groups
- * @dev:	The device to create the group for
- * @groups:	The attribute groups to create, NULL terminated
- *
- * This function creates a bunch of managed attribute groups.  If an error
- * occurs when creating a group, all previously created groups will be
- * removed, unwinding everything back to the original state when this
- * function was called.  It will explicitly warn and error if any of the
- * attribute files being created already exist.
- *
- * Returns 0 on success or error code from sysfs_create_group on failure.
- */
-int devm_device_add_groups(struct device *dev,
-			   const struct attribute_group **groups)
-{
-	union device_attr_group_devres *devres;
-	int error;
-
-	devres = devres_alloc(devm_attr_groups_remove,
-			      sizeof(*devres), GFP_KERNEL);
-	if (!devres)
-		return -ENOMEM;
-
-	error = sysfs_create_groups(&dev->kobj, groups);
-	if (error) {
-		devres_free(devres);
-		return error;
-	}
-
-	devres->groups = groups;
-	devres_add(dev, devres);
-	return 0;
-}
-EXPORT_SYMBOL_GPL(devm_device_add_groups);
-
 static int device_add_attrs(struct device *dev)
 {
 	const struct class *class = dev->class;
@@ -3127,7 +3154,7 @@ void device_initialize(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(device_initialize);
 
-struct kobject *virtual_device_parent(struct device *dev)
+struct kobject *virtual_device_parent(void)
 {
 	static struct kobject *virtual_dir = NULL;
 
@@ -3205,7 +3232,7 @@ static struct kobject *get_device_parent(struct device *dev,
 		 * in a "glue" directory to prevent namespace collisions.
 		 */
 		if (parent == NULL)
-			parent_kobj = virtual_device_parent(dev);
+			parent_kobj = virtual_device_parent();
 		else if (parent->class && !dev->class->ns_type) {
 			subsys_put(sp);
 			return &parent->kobj;
@@ -3954,13 +3981,13 @@ 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;
 	int error = 0;
 
-	if (!parent->p)
+	if (!parent || !parent->p)
 		return 0;
 
 	klist_iter_init(&parent->p->klist_children, &i);
@@ -3984,13 +4011,13 @@ 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;
 	int error = 0;
 
-	if (!parent->p)
+	if (!parent || !parent->p)
 		return 0;
 
 	klist_iter_init(&parent->p->klist_children, &i);
@@ -4002,87 +4029,77 @@ int device_for_each_child_reverse(struct device *parent, void *data,
 EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
 
 /**
- * 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
- *
- * 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
- * determined by the @match callback.
+ * 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.
  *
- * The callback should return 0 if the device doesn't match and non-zero
- * if it does.  If the callback returns non-zero and a reference to the
- * current device can be obtained, this function will return to the caller
- * and not iterate over any more devices.
+ * Iterate over @parent's child devices, starting at @from, and call @fn
+ * for each, passing it @data. This helper is identical to
+ * device_for_each_child_reverse() when @from is NULL.
  *
- * NOTE: you will need to drop the reference with put_device() after use.
+ * @fn is checked each iteration. If it returns anything other than 0,
+ * iteration stop and that value is returned to the caller of
+ * device_for_each_child_reverse_from();
  */
-struct device *device_find_child(struct device *parent, void *data,
-				 int (*match)(struct device *dev, void *data))
+int device_for_each_child_reverse_from(struct device *parent,
+				       struct device *from, void *data,
+				       device_iter_t fn)
 {
 	struct klist_iter i;
 	struct device *child;
+	int error = 0;
 
-	if (!parent)
-		return NULL;
+	if (!parent || !parent->p)
+		return 0;
 
-	klist_iter_init(&parent->p->klist_children, &i);
-	while ((child = next_device(&i)))
-		if (match(child, data) && get_device(child))
-			break;
+	klist_iter_init_node(&parent->p->klist_children, &i,
+			     (from ? &from->p->knode_parent : NULL));
+	while ((child = prev_device(&i)) && !error)
+		error = fn(child, data);
 	klist_iter_exit(&i);
-	return child;
+	return error;
 }
-EXPORT_SYMBOL_GPL(device_find_child);
+EXPORT_SYMBOL_GPL(device_for_each_child_reverse_from);
 
 /**
- * device_find_child_by_name - device iterator for locating a child device.
+ * device_find_child - device iterator for locating a particular device.
  * @parent: parent struct device
- * @name: name of the child device
+ * @match: Callback function to check device
+ * @data: Data to pass to match function
+ *
+ * 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
+ * determined by the @match callback.
  *
- * This is similar to the device_find_child() function above, but it
- * returns a reference to a device that has the name @name.
+ * The callback should return 0 if the device doesn't match and non-zero
+ * if it does.  If the callback returns non-zero and a reference to the
+ * current device can be obtained, this function will return to the caller
+ * and not iterate over any more devices.
  *
  * 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 device *device_find_child(struct device *parent, const void *data,
+				 device_match_t match)
 {
 	struct klist_iter i;
 	struct device *child;
 
-	if (!parent)
+	if (!parent || !parent->p)
 		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))
+	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_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);
+EXPORT_SYMBOL_GPL(device_find_child);
 
 int __init devices_init(void)
 {
@@ -4098,9 +4115,14 @@ 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);
+	if (!device_link_wq)
+		goto wq_err;
 
 	return 0;
 
+ wq_err:
+	kobject_put(sysfs_dev_char_kobj);
  char_kobj_err:
 	kobject_put(sysfs_dev_block_kobj);
  block_kobj_err:
@@ -4467,9 +4489,11 @@ EXPORT_SYMBOL_GPL(device_destroy);
  */
 int device_rename(struct device *dev, const char *new_name)
 {
+	struct subsys_private *sp = NULL;
 	struct kobject *kobj = &dev->kobj;
 	char *old_device_name = NULL;
 	int error;
+	bool is_link_renamed = false;
 
 	dev = get_device(dev);
 	if (!dev)
@@ -4484,7 +4508,7 @@ int device_rename(struct device *dev, const char *new_name)
 	}
 
 	if (dev->class) {
-		struct subsys_private *sp = class_to_subsys(dev->class);
+		sp = class_to_subsys(dev->class);
 
 		if (!sp) {
 			error = -EINVAL;
@@ -4493,16 +4517,19 @@ int device_rename(struct device *dev, const char *new_name)
 
 		error = sysfs_rename_link_ns(&sp->subsys.kobj, kobj, old_device_name,
 					     new_name, kobject_namespace(kobj));
-		subsys_put(sp);
 		if (error)
 			goto out;
+
+		is_link_renamed = true;
 	}
 
 	error = kobject_rename(kobj, new_name);
-	if (error)
-		goto out;
-
 out:
+	if (error && is_link_renamed)
+		sysfs_rename_link_ns(&sp->subsys.kobj, kobj, new_name,
+				     old_device_name, kobject_namespace(kobj));
+	subsys_put(sp);
+
 	put_device(dev);
 
 	kfree(old_device_name);
@@ -4824,7 +4851,7 @@ set_dev_info(const struct device *dev, struct dev_printk_info *dev_info)
 	else
 		return;
 
-	strscpy(dev_info->subsystem, subsys, sizeof(dev_info->subsystem));
+	strscpy(dev_info->subsystem, subsys);
 
 	/*
 	 * Add device identifier DEVICE=:
@@ -4934,6 +4961,49 @@ define_dev_printk_level(_dev_info, KERN_INFO);
 
 #endif
 
+static void __dev_probe_failed(const struct device *dev, int err, bool fatal,
+			       const char *fmt, va_list vargsp)
+{
+	struct va_format vaf;
+	va_list vargs;
+
+	/*
+	 * On x86_64 and possibly on other architectures, va_list is actually a
+	 * size-1 array containing a structure.  As a result, function parameter
+	 * vargsp decays from T[1] to T*, and &vargsp has type T** rather than
+	 * T(*)[1], which is expected by its assignment to vaf.va below.
+	 *
+	 * One standard way to solve this mess is by creating a copy in a local
+	 * variable of type va_list and then using a pointer to that local copy
+	 * instead, which is the approach employed here.
+	 */
+	va_copy(vargs, vargsp);
+
+	vaf.fmt = fmt;
+	vaf.va = &vargs;
+
+	switch (err) {
+	case -EPROBE_DEFER:
+		device_set_deferred_probe_reason(dev, &vaf);
+		dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
+		break;
+
+	case -ENOMEM:
+		/* Don't print anything on -ENOMEM, there's already enough output */
+		break;
+
+	default:
+		/* Log fatal final failures as errors, otherwise produce warnings */
+		if (fatal)
+			dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
+		else
+			dev_warn(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
+		break;
+	}
+
+	va_end(vargs);
+}
+
 /**
  * dev_err_probe - probe error check and log helper
  * @dev: the pointer to the struct device
@@ -4946,7 +5016,7 @@ define_dev_printk_level(_dev_info, KERN_INFO);
  * -EPROBE_DEFER and propagate error upwards.
  * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
  * checked later by reading devices_deferred debugfs attribute.
- * It replaces code sequence::
+ * It replaces the following code sequence::
  *
  * 	if (err != -EPROBE_DEFER)
  * 		dev_err(dev, ...);
@@ -4958,37 +5028,78 @@ define_dev_printk_level(_dev_info, KERN_INFO);
  *
  * 	return dev_err_probe(dev, err, ...);
  *
- * Using this helper in your probe function is totally fine even if @err is
- * known to never be -EPROBE_DEFER.
+ * Using this helper in your probe function is totally fine even if @err
+ * is known to never be -EPROBE_DEFER.
  * The benefit compared to a normal dev_err() is the standardized format
- * of the error code, it being emitted symbolically (i.e. you get "EAGAIN"
- * instead of "-35") and the fact that the error code is returned which allows
- * more compact error paths.
+ * of the error code, which is emitted symbolically (i.e. you get "EAGAIN"
+ * instead of "-35"), and having the error code returned allows more
+ * compact error paths.
  *
  * Returns @err.
  */
 int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
 {
-	struct va_format vaf;
-	va_list args;
+	va_list vargs;
 
-	va_start(args, fmt);
-	vaf.fmt = fmt;
-	vaf.va = &args;
+	va_start(vargs, fmt);
 
-	if (err != -EPROBE_DEFER) {
-		dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
-	} else {
-		device_set_deferred_probe_reason(dev, &vaf);
-		dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
-	}
+	/* Use dev_err() for logging when err doesn't equal -EPROBE_DEFER */
+	__dev_probe_failed(dev, err, true, fmt, vargs);
 
-	va_end(args);
+	va_end(vargs);
 
 	return err;
 }
 EXPORT_SYMBOL_GPL(dev_err_probe);
 
+/**
+ * dev_warn_probe - probe error check and log helper
+ * @dev: the pointer to the struct device
+ * @err: error value to test
+ * @fmt: printf-style format string
+ * @...: arguments as specified in the format string
+ *
+ * This helper implements common pattern present in probe functions for error
+ * checking: print debug or warning message depending if the error value is
+ * -EPROBE_DEFER and propagate error upwards.
+ * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
+ * checked later by reading devices_deferred debugfs attribute.
+ * It replaces the following code sequence::
+ *
+ * 	if (err != -EPROBE_DEFER)
+ * 		dev_warn(dev, ...);
+ * 	else
+ * 		dev_dbg(dev, ...);
+ * 	return err;
+ *
+ * with::
+ *
+ * 	return dev_warn_probe(dev, err, ...);
+ *
+ * Using this helper in your probe function is totally fine even if @err
+ * is known to never be -EPROBE_DEFER.
+ * The benefit compared to a normal dev_warn() is the standardized format
+ * of the error code, which is emitted symbolically (i.e. you get "EAGAIN"
+ * instead of "-35"), and having the error code returned allows more
+ * compact error paths.
+ *
+ * Returns @err.
+ */
+int dev_warn_probe(const struct device *dev, int err, const char *fmt, ...)
+{
+	va_list vargs;
+
+	va_start(vargs, fmt);
+
+	/* Use dev_warn() for logging when err doesn't equal -EPROBE_DEFER */
+	__dev_probe_failed(dev, err, false, fmt, vargs);
+
+	va_end(vargs);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(dev_warn_probe);
+
 static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
 {
 	return fwnode && !IS_ERR(fwnode->secondary);
@@ -5089,15 +5200,21 @@ int device_match_name(struct device *dev, const void *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);
 
@@ -5109,13 +5226,13 @@ 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);