Driver core patches for 4.10-rc1

Here's the new driver core patches for 4.10-rc1.
 
 Big thing here is the nice addition of "functional dependencies" to the
 driver core.  The idea has been talked about for a very long time, great
 job to Rafael for stepping up and implementing it. It's been tested for
 longer than the 4.9-rc1 date, we held off on merging it earlier in order
 to feel more comfortable about it.
 
 Other than that, it's just a handful of small other patches, some good
 cleanups to the mess that is the firmware class code, and we have a test
 driver for the deferred probe logic.
 
 All of these have been in linux-next for a while with no reported
 issues.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here's the new driver core patches for 4.10-rc1.

  Big thing here is the nice addition of "functional dependencies" to
  the driver core. The idea has been talked about for a very long time,
  great job to Rafael for stepping up and implementing it. It's been
  tested for longer than the 4.9-rc1 date, we held off on merging it
  earlier in order to feel more comfortable about it.

  Other than that, it's just a handful of small other patches, some good
  cleanups to the mess that is the firmware class code, and we have a
  test driver for the deferred probe logic.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'driver-core-4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (30 commits)
  firmware: Correct handling of fw_state_wait() return value
  driver core: Silence device links sphinx warning
  firmware: remove warning at documentation generation time
  drivers: base: dma-mapping: Fix typo in dmam_alloc_non_coherent comments
  driver core: test_async: fix up typo found by 0-day
  firmware: move fw_state_is_done() into UHM section
  firmware: do not use fw_lock for fw_state protection
  firmware: drop bit ops in favor of simple state machine
  firmware: refactor loading status
  firmware: fix usermode helper fallback loading
  driver core: firmware_class: convert to use class_groups
  driver core: devcoredump: convert to use class_groups
  driver core: class: add class_groups support
  kernfs: Declare two local data structures static
  driver-core: fix platform_no_drv_owner.cocci warnings
  drivers/base/memory.c: Remove unused 'first_page' variable
  driver core: add CLASS_ATTR_WO()
  drivers: base: cacheinfo: support DT overrides for cache properties
  drivers: base: cacheinfo: add pr_fmt logging
  drivers: base: cacheinfo: fix boot error message when acpi is enabled
  ...

Documentation/ABI/testing/sysfs-devices-deferred_probe

@@ -0,0 +1,12 @@
+What:		/sys/devices/.../deferred_probe
+Date:		August 2016
+Contact:	Ben Hutchings <ben.hutchings@codethink.co.uk>
+Description:
+		The /sys/devices/.../deferred_probe attribute is
+		present for all devices.  If a driver detects during
+		probing a device that a related device is not yet
+		ready, it may defer probing of the first device.  The
+		kernel will retry probing the first device after any
+		other device is successfully probed.  This attribute
+		reads as 1 if probing of this device is currently
+		deferred, or 0 otherwise.

arch/x86/kernel/cpu/intel_cacheinfo.c

@@ -934,6 +934,8 @@ static int __populate_cache_leaves(unsigned int cpu)
 		ci_leaf_init(this_leaf++, &id4_regs);
 		__cache_cpumap_setup(cpu, idx, &id4_regs);
 	}
+	this_cpu_ci->cpu_map_populated = true;
+
 	return 0;
 }
 

drivers/base/Kconfig

@@ -224,6 +224,8 @@ config DEBUG_TEST_DRIVER_REMOVE
 	  unusable. You should say N here unless you are explicitly looking to
 	  test this functionality.
 
+source "drivers/base/test/Kconfig"
+
 config SYS_HYPERVISOR
 	bool
 	default n

drivers/base/Makefile

@@ -24,5 +24,7 @@ obj-$(CONFIG_PINCTRL) += pinctrl.o
 obj-$(CONFIG_DEV_COREDUMP) += devcoredump.o
 obj-$(CONFIG_GENERIC_MSI_IRQ_DOMAIN) += platform-msi.o
 
+obj-y			+= test/
+
 ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG
 

drivers/base/base.h

@@ -107,6 +107,9 @@ extern void bus_remove_device(struct device *dev);
 
 extern int bus_add_driver(struct device_driver *drv);
 extern void bus_remove_driver(struct device_driver *drv);
+extern void device_release_driver_internal(struct device *dev,
+					   struct device_driver *drv,
+					   struct device *parent);
 
 extern void driver_detach(struct device_driver *drv);
 extern int driver_probe_device(struct device_driver *drv, struct device *dev);
@@ -138,6 +141,8 @@ extern void device_unblock_probing(void);
 extern struct kset *devices_kset;
 extern void devices_kset_move_last(struct device *dev);
 
+extern struct device_attribute dev_attr_deferred_probe;
+
 #if defined(CONFIG_MODULES) && defined(CONFIG_SYSFS)
 extern void module_add_driver(struct module *mod, struct device_driver *drv);
 extern void module_remove_driver(struct device_driver *drv);
@@ -152,3 +157,13 @@ extern int devtmpfs_init(void);
 #else
 static inline int devtmpfs_init(void) { return 0; }
 #endif
+
+/* Device links support */
+extern int device_links_read_lock(void);
+extern void device_links_read_unlock(int idx);
+extern int device_links_check_suppliers(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);
+extern bool device_links_busy(struct device *dev);
+extern void device_links_unbind_consumers(struct device *dev);

drivers/base/cacheinfo.c

@@ -16,6 +16,9 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/acpi.h>
 #include <linux/bitops.h>
 #include <linux/cacheinfo.h>
 #include <linux/compiler.h>
@@ -85,7 +88,120 @@ static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
 {
 	return sib_leaf->of_node == this_leaf->of_node;
 }
+
+/* OF properties to query for a given cache type */
+struct cache_type_info {
+	const char *size_prop;
+	const char *line_size_props[2];
+	const char *nr_sets_prop;
+};
+
+static const struct cache_type_info cache_type_info[] = {
+	{
+		.size_prop       = "cache-size",
+		.line_size_props = { "cache-line-size",
+				     "cache-block-size", },
+		.nr_sets_prop    = "cache-sets",
+	}, {
+		.size_prop       = "i-cache-size",
+		.line_size_props = { "i-cache-line-size",
+				     "i-cache-block-size", },
+		.nr_sets_prop    = "i-cache-sets",
+	}, {
+		.size_prop       = "d-cache-size",
+		.line_size_props = { "d-cache-line-size",
+				     "d-cache-block-size", },
+		.nr_sets_prop    = "d-cache-sets",
+	},
+};
+
+static inline int get_cacheinfo_idx(enum cache_type type)
+{
+	if (type == CACHE_TYPE_UNIFIED)
+		return 0;
+	return type;
+}
+
+static void cache_size(struct cacheinfo *this_leaf)
+{
+	const char *propname;
+	const __be32 *cache_size;
+	int ct_idx;
+
+	ct_idx = get_cacheinfo_idx(this_leaf->type);
+	propname = cache_type_info[ct_idx].size_prop;
+
+	cache_size = of_get_property(this_leaf->of_node, propname, NULL);
+	if (cache_size)
+		this_leaf->size = of_read_number(cache_size, 1);
+}
+
+/* not cache_line_size() because that's a macro in include/linux/cache.h */
+static void cache_get_line_size(struct cacheinfo *this_leaf)
+{
+	const __be32 *line_size;
+	int i, lim, ct_idx;
+
+	ct_idx = get_cacheinfo_idx(this_leaf->type);
+	lim = ARRAY_SIZE(cache_type_info[ct_idx].line_size_props);
+
+	for (i = 0; i < lim; i++) {
+		const char *propname;
+
+		propname = cache_type_info[ct_idx].line_size_props[i];
+		line_size = of_get_property(this_leaf->of_node, propname, NULL);
+		if (line_size)
+			break;
+	}
+
+	if (line_size)
+		this_leaf->coherency_line_size = of_read_number(line_size, 1);
+}
+
+static void cache_nr_sets(struct cacheinfo *this_leaf)
+{
+	const char *propname;
+	const __be32 *nr_sets;
+	int ct_idx;
+
+	ct_idx = get_cacheinfo_idx(this_leaf->type);
+	propname = cache_type_info[ct_idx].nr_sets_prop;
+
+	nr_sets = of_get_property(this_leaf->of_node, propname, NULL);
+	if (nr_sets)
+		this_leaf->number_of_sets = of_read_number(nr_sets, 1);
+}
+
+static void cache_associativity(struct cacheinfo *this_leaf)
+{
+	unsigned int line_size = this_leaf->coherency_line_size;
+	unsigned int nr_sets = this_leaf->number_of_sets;
+	unsigned int size = this_leaf->size;
+
+	/*
+	 * If the cache is fully associative, there is no need to
+	 * check the other properties.
+	 */
+	if (!(nr_sets == 1) && (nr_sets > 0 && size > 0 && line_size > 0))
+		this_leaf->ways_of_associativity = (size / nr_sets) / line_size;
+}
+
+static void cache_of_override_properties(unsigned int cpu)
+{
+	int index;
+	struct cacheinfo *this_leaf;
+	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
+
+	for (index = 0; index < cache_leaves(cpu); index++) {
+		this_leaf = this_cpu_ci->info_list + index;
+		cache_size(this_leaf);
+		cache_get_line_size(this_leaf);
+		cache_nr_sets(this_leaf);
+		cache_associativity(this_leaf);
+	}
+}
 #else
+static void cache_of_override_properties(unsigned int cpu) { }
 static inline int cache_setup_of_node(unsigned int cpu) { return 0; }
 static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
 					   struct cacheinfo *sib_leaf)
@@ -104,9 +220,16 @@ static int cache_shared_cpu_map_setup(unsigned int cpu)
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 	struct cacheinfo *this_leaf, *sib_leaf;
 	unsigned int index;
-	int ret;
+	int ret = 0;
 
-	ret = cache_setup_of_node(cpu);
+	if (this_cpu_ci->cpu_map_populated)
+		return 0;
+
+	if (of_have_populated_dt())
+		ret = cache_setup_of_node(cpu);
+	else if (!acpi_disabled)
+		/* No cache property/hierarchy support yet in ACPI */
+		ret = -ENOTSUPP;
 	if (ret)
 		return ret;
 
@@ -161,6 +284,12 @@ static void cache_shared_cpu_map_remove(unsigned int cpu)
 	}
 }
 
+static void cache_override_properties(unsigned int cpu)
+{
+	if (of_have_populated_dt())
+		return cache_of_override_properties(cpu);
+}
+
 static void free_cache_attributes(unsigned int cpu)
 {
 	if (!per_cpu_cacheinfo(cpu))
@@ -203,10 +332,11 @@ static int detect_cache_attributes(unsigned int cpu)
 	 */
 	ret = cache_shared_cpu_map_setup(cpu);
 	if (ret) {
-		pr_warn("Unable to detect cache hierarchy from DT for CPU %d\n",
+		pr_warn("Unable to detect cache hierarchy for CPU %d\n", cpu);
-			cpu);
 		goto free_ci;
 	}
+
+	cache_override_properties(cpu);
 	return 0;
 
 free_ci:

drivers/base/class.c

@@ -163,6 +163,18 @@ static void klist_class_dev_put(struct klist_node *n)
 	put_device(dev);
 }
 
+static int class_add_groups(struct class *cls,
+			    const struct attribute_group **groups)
+{
+	return sysfs_create_groups(&cls->p->subsys.kobj, groups);
+}
+
+static void class_remove_groups(struct class *cls,
+				const struct attribute_group **groups)
+{
+	return sysfs_remove_groups(&cls->p->subsys.kobj, groups);
+}
+
 int __class_register(struct class *cls, struct lock_class_key *key)
 {
 	struct subsys_private *cp;
@@ -203,6 +215,8 @@ int __class_register(struct class *cls, struct lock_class_key *key)
 		kfree(cp);
 		return error;
 	}
+	error = class_add_groups(class_get(cls), cls->class_groups);
+	class_put(cls);
 	error = add_class_attrs(class_get(cls));
 	class_put(cls);
 	return error;
@@ -213,6 +227,7 @@ void class_unregister(struct class *cls)
 {
 	pr_debug("device class '%s': unregistering\n", cls->name);
 	remove_class_attrs(cls);
+	class_remove_groups(cls, cls->class_groups);
 	kset_unregister(&cls->p->subsys);
 }
 

drivers/base/core.c

@@ -44,6 +44,572 @@ static int __init sysfs_deprecated_setup(char *arg)
 early_param("sysfs.deprecated", sysfs_deprecated_setup);
 #endif
 
+/* Device links support. */
+
+#ifdef CONFIG_SRCU
+static DEFINE_MUTEX(device_links_lock);
+DEFINE_STATIC_SRCU(device_links_srcu);
+
+static inline void device_links_write_lock(void)
+{
+	mutex_lock(&device_links_lock);
+}
+
+static inline void device_links_write_unlock(void)
+{
+	mutex_unlock(&device_links_lock);
+}
+
+int device_links_read_lock(void)
+{
+	return srcu_read_lock(&device_links_srcu);
+}
+
+void device_links_read_unlock(int idx)
+{
+	srcu_read_unlock(&device_links_srcu, idx);
+}
+#else /* !CONFIG_SRCU */
+static DECLARE_RWSEM(device_links_lock);
+
+static inline void device_links_write_lock(void)
+{
+	down_write(&device_links_lock);
+}
+
+static inline void device_links_write_unlock(void)
+{
+	up_write(&device_links_lock);
+}
+
+int device_links_read_lock(void)
+{
+	down_read(&device_links_lock);
+	return 0;
+}
+
+void device_links_read_unlock(int not_used)
+{
+	up_read(&device_links_lock);
+}
+#endif /* !CONFIG_SRCU */
+
+/**
+ * device_is_dependent - Check if one device depends on another one
+ * @dev: Device to check dependencies for.
+ * @target: Device to check against.
+ *
+ * Check if @target depends on @dev or any device dependent on it (its child or
+ * its consumer etc).  Return 1 if that is the case or 0 otherwise.
+ */
+static int device_is_dependent(struct device *dev, void *target)
+{
+	struct device_link *link;
+	int ret;
+
+	if (WARN_ON(dev == target))
+		return 1;
+
+	ret = device_for_each_child(dev, target, device_is_dependent);
+	if (ret)
+		return ret;
+
+	list_for_each_entry(link, &dev->links.consumers, s_node) {
+		if (WARN_ON(link->consumer == target))
+			return 1;
+
+		ret = device_is_dependent(link->consumer, target);
+		if (ret)
+			break;
+	}
+	return ret;
+}
+
+static int device_reorder_to_tail(struct device *dev, void *not_used)
+{
+	struct device_link *link;
+
+	/*
+	 * Devices that have not been registered yet will be put to the ends
+	 * of the lists during the registration, so skip them here.
+	 */
+	if (device_is_registered(dev))
+		devices_kset_move_last(dev);
+
+	if (device_pm_initialized(dev))
+		device_pm_move_last(dev);
+
+	device_for_each_child(dev, NULL, device_reorder_to_tail);
+	list_for_each_entry(link, &dev->links.consumers, s_node)
+		device_reorder_to_tail(link->consumer, NULL);
+
+	return 0;
+}
+
+/**
+ * device_link_add - Create a link between two devices.
+ * @consumer: Consumer end of the link.
+ * @supplier: Supplier end of the link.
+ * @flags: Link flags.
+ *
+ * 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
+ * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will
+ * be forced into the active metastate and reference-counted upon the creation
+ * of the link.  If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
+ * ignored.
+ *
+ * If the DL_FLAG_AUTOREMOVE is set, the link will be removed automatically
+ * when the consumer device driver unbinds from it.  The combination of both
+ * DL_FLAG_AUTOREMOVE and DL_FLAG_STATELESS set is invalid and will cause NULL
+ * to be returned.
+ *
+ * A side effect of the link creation is re-ordering of dpm_list and the
+ * devices_kset list by moving the consumer device and all devices depending
+ * on it to the ends of these lists (that does not happen to devices that have
+ * not been registered when this function is called).
+ *
+ * The supplier device is required to be registered when this function is called
+ * and NULL will be returned if that is not the case.  The consumer device need
+ * not be registered, however.
+ */
+struct device_link *device_link_add(struct device *consumer,
+				    struct device *supplier, u32 flags)
+{
+	struct device_link *link;
+
+	if (!consumer || !supplier ||
+	    ((flags & DL_FLAG_STATELESS) && (flags & DL_FLAG_AUTOREMOVE)))
+		return NULL;
+
+	device_links_write_lock();
+	device_pm_lock();
+
+	/*
+	 * If the supplier has not been fully registered yet or there is a
+	 * reverse dependency between the consumer and the supplier already in
+	 * the graph, return NULL.
+	 */
+	if (!device_pm_initialized(supplier)
+	    || device_is_dependent(consumer, supplier)) {
+		link = NULL;
+		goto out;
+	}
+
+	list_for_each_entry(link, &supplier->links.consumers, s_node)
+		if (link->consumer == consumer)
+			goto out;
+
+	link = kzalloc(sizeof(*link), GFP_KERNEL);
+	if (!link)
+		goto out;
+
+	if (flags & DL_FLAG_PM_RUNTIME) {
+		if (flags & DL_FLAG_RPM_ACTIVE) {
+			if (pm_runtime_get_sync(supplier) < 0) {
+				pm_runtime_put_noidle(supplier);
+				kfree(link);
+				link = NULL;
+				goto out;
+			}
+			link->rpm_active = true;
+		}
+		pm_runtime_new_link(consumer);
+	}
+	get_device(supplier);
+	link->supplier = supplier;
+	INIT_LIST_HEAD(&link->s_node);
+	get_device(consumer);
+	link->consumer = consumer;
+	INIT_LIST_HEAD(&link->c_node);
+	link->flags = flags;
+
+	/* Determine the initial link state. */
+	if (flags & DL_FLAG_STATELESS) {
+		link->status = DL_STATE_NONE;
+	} else {
+		switch (supplier->links.status) {
+		case DL_DEV_DRIVER_BOUND:
+			switch (consumer->links.status) {
+			case DL_DEV_PROBING:
+				/*
+				 * Balance the decrementation of the supplier's
+				 * runtime PM usage counter after consumer probe
+				 * in driver_probe_device().
+				 */
+				if (flags & DL_FLAG_PM_RUNTIME)
+					pm_runtime_get_sync(supplier);
+
+				link->status = DL_STATE_CONSUMER_PROBE;
+				break;
+			case DL_DEV_DRIVER_BOUND:
+				link->status = DL_STATE_ACTIVE;
+				break;
+			default:
+				link->status = DL_STATE_AVAILABLE;
+				break;
+			}
+			break;
+		case DL_DEV_UNBINDING:
+			link->status = DL_STATE_SUPPLIER_UNBIND;
+			break;
+		default:
+			link->status = DL_STATE_DORMANT;
+			break;
+		}
+	}
+
+	/*
+	 * Move the consumer and all of the devices depending on it to the end
+	 * of dpm_list and the devices_kset list.
+	 *
+	 * It is necessary to hold dpm_list locked throughout all that or else
+	 * we may end up suspending with a wrong ordering of it.
+	 */
+	device_reorder_to_tail(consumer, NULL);
+
+	list_add_tail_rcu(&link->s_node, &supplier->links.consumers);
+	list_add_tail_rcu(&link->c_node, &consumer->links.suppliers);
+
+	dev_info(consumer, "Linked as a consumer to %s\n", dev_name(supplier));
+
+ out:
+	device_pm_unlock();
+	device_links_write_unlock();
+	return link;
+}
+EXPORT_SYMBOL_GPL(device_link_add);
+
+static void device_link_free(struct device_link *link)
+{
+	put_device(link->consumer);
+	put_device(link->supplier);
+	kfree(link);
+}
+
+#ifdef CONFIG_SRCU
+static void __device_link_free_srcu(struct rcu_head *rhead)
+{
+	device_link_free(container_of(rhead, struct device_link, rcu_head));
+}
+
+static void __device_link_del(struct device_link *link)
+{
+	dev_info(link->consumer, "Dropping the link to %s\n",
+		 dev_name(link->supplier));
+
+	if (link->flags & DL_FLAG_PM_RUNTIME)
+		pm_runtime_drop_link(link->consumer);
+
+	list_del_rcu(&link->s_node);
+	list_del_rcu(&link->c_node);
+	call_srcu(&device_links_srcu, &link->rcu_head, __device_link_free_srcu);
+}
+#else /* !CONFIG_SRCU */
+static void __device_link_del(struct device_link *link)
+{
+	dev_info(link->consumer, "Dropping the link to %s\n",
+		 dev_name(link->supplier));
+
+	list_del(&link->s_node);
+	list_del(&link->c_node);
+	device_link_free(link);
+}
+#endif /* !CONFIG_SRCU */
+
+/**
+ * device_link_del - Delete a link between two devices.
+ * @link: Device link to delete.
+ *
+ * The caller must ensure proper synchronization of this function with runtime
+ * PM.
+ */
+void device_link_del(struct device_link *link)
+{
+	device_links_write_lock();
+	device_pm_lock();
+	__device_link_del(link);
+	device_pm_unlock();
+	device_links_write_unlock();
+}
+EXPORT_SYMBOL_GPL(device_link_del);
+
+static void device_links_missing_supplier(struct device *dev)
+{
+	struct device_link *link;
+
+	list_for_each_entry(link, &dev->links.suppliers, c_node)
+		if (link->status == DL_STATE_CONSUMER_PROBE)
+			WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
+}
+
+/**
+ * device_links_check_suppliers - Check presence of supplier drivers.
+ * @dev: Consumer device.
+ *
+ * Check links from this device to any suppliers.  Walk the list of the device's
+ * links to suppliers and see if all of them are available.  If not, simply
+ * return -EPROBE_DEFER.
+ *
+ * We need to guarantee that the supplier will not go away after the check has
+ * been positive here.  It only can go away in __device_release_driver() and
+ * that function  checks the device's links to consumers.  This means we need to
+ * mark the link as "consumer probe in progress" to make the supplier removal
+ * wait for us to complete (or bad things may happen).
+ *
+ * Links with the DL_FLAG_STATELESS flag set are ignored.
+ */
+int device_links_check_suppliers(struct device *dev)
+{
+	struct device_link *link;
+	int ret = 0;
+
+	device_links_write_lock();
+
+	list_for_each_entry(link, &dev->links.suppliers, c_node) {
+		if (link->flags & DL_FLAG_STATELESS)
+			continue;
+
+		if (link->status != DL_STATE_AVAILABLE) {
+			device_links_missing_supplier(dev);
+			ret = -EPROBE_DEFER;
+			break;
+		}
+		WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
+	}
+	dev->links.status = DL_DEV_PROBING;
+
+	device_links_write_unlock();
+	return ret;
+}
+
+/**
+ * device_links_driver_bound - Update device links after probing its driver.
+ * @dev: Device to update the links for.
+ *
+ * The probe has been successful, so update links from this device to any
+ * consumers by changing their status to "available".
+ *
+ * Also change the status of @dev's links to suppliers to "active".
+ *
+ * Links with the DL_FLAG_STATELESS flag set are ignored.
+ */
+void device_links_driver_bound(struct device *dev)
+{
+	struct device_link *link;
+
+	device_links_write_lock();
+
+	list_for_each_entry(link, &dev->links.consumers, s_node) {
+		if (link->flags & DL_FLAG_STATELESS)
+			continue;
+
+		WARN_ON(link->status != DL_STATE_DORMANT);
+		WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
+	}
+
+	list_for_each_entry(link, &dev->links.suppliers, c_node) {
+		if (link->flags & DL_FLAG_STATELESS)
+			continue;
+
+		WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
+		WRITE_ONCE(link->status, DL_STATE_ACTIVE);
+	}
+
+	dev->links.status = DL_DEV_DRIVER_BOUND;
+
+	device_links_write_unlock();
+}
+
+/**
+ * __device_links_no_driver - Update links of a device without a driver.
+ * @dev: Device without a drvier.
+ *
+ * Delete all non-persistent links from this device to any suppliers.
+ *
+ * Persistent links stay around, but their status is changed to "available",
+ * unless they already are in the "supplier unbind in progress" state in which
+ * case they need not be updated.
+ *
+ * Links with the DL_FLAG_STATELESS flag set are ignored.
+ */
+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_STATELESS)
+			continue;
+
+		if (link->flags & DL_FLAG_AUTOREMOVE)
+			__device_link_del(link);
+		else if (link->status != DL_STATE_SUPPLIER_UNBIND)
+			WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
+	}
+
+	dev->links.status = DL_DEV_NO_DRIVER;
+}
+
+void device_links_no_driver(struct device *dev)
+{
+	device_links_write_lock();
+	__device_links_no_driver(dev);
+	device_links_write_unlock();
+}
+
+/**
+ * device_links_driver_cleanup - Update links after driver removal.
+ * @dev: Device whose driver has just gone away.
+ *
+ * Update links to consumers for @dev by changing their status to "dormant" and
+ * invoke %__device_links_no_driver() to update links to suppliers for it as
+ * appropriate.
+ *
+ * Links with the DL_FLAG_STATELESS flag set are ignored.
+ */
+void device_links_driver_cleanup(struct device *dev)
+{
+	struct device_link *link;
+
+	device_links_write_lock();
+
+	list_for_each_entry(link, &dev->links.consumers, s_node) {
+		if (link->flags & DL_FLAG_STATELESS)
+			continue;
+
+		WARN_ON(link->flags & DL_FLAG_AUTOREMOVE);
+		WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
+		WRITE_ONCE(link->status, DL_STATE_DORMANT);
+	}
+
+	__device_links_no_driver(dev);
+
+	device_links_write_unlock();
+}
+
+/**
+ * device_links_busy - Check if there are any busy links to consumers.
+ * @dev: Device to check.
+ *
+ * Check each consumer of the device and return 'true' if its link's status
+ * is one of "consumer probe" or "active" (meaning that the given consumer is
+ * probing right now or its driver is present).  Otherwise, change the link
+ * state to "supplier unbind" to prevent the consumer from being probed
+ * successfully going forward.
+ *
+ * Return 'false' if there are no probing or active consumers.
+ *
+ * Links with the DL_FLAG_STATELESS flag set are ignored.
+ */
+bool device_links_busy(struct device *dev)
+{
+	struct device_link *link;
+	bool ret = false;
+
+	device_links_write_lock();
+
+	list_for_each_entry(link, &dev->links.consumers, s_node) {
+		if (link->flags & DL_FLAG_STATELESS)
+			continue;
+
+		if (link->status == DL_STATE_CONSUMER_PROBE
+		    || link->status == DL_STATE_ACTIVE) {
+			ret = true;
+			break;
+		}
+		WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
+	}
+
+	dev->links.status = DL_DEV_UNBINDING;
+
+	device_links_write_unlock();
+	return ret;
+}
+
+/**
+ * device_links_unbind_consumers - Force unbind consumers of the given device.
+ * @dev: Device to unbind the consumers of.
+ *
+ * Walk the list of links to consumers for @dev and if any of them is in the
+ * "consumer probe" state, wait for all device probes in progress to complete
+ * and start over.
+ *
+ * If that's not the case, change the status of the link to "supplier unbind"
+ * and check if the link was in the "active" state.  If so, force the consumer
+ * driver to unbind and start over (the consumer will not re-probe as we have
+ * changed the state of the link already).
+ *
+ * Links with the DL_FLAG_STATELESS flag set are ignored.
+ */
+void device_links_unbind_consumers(struct device *dev)
+{
+	struct device_link *link;
+
+ start:
+	device_links_write_lock();
+
+	list_for_each_entry(link, &dev->links.consumers, s_node) {
+		enum device_link_state status;
+
+		if (link->flags & DL_FLAG_STATELESS)
+			continue;
+
+		status = link->status;
+		if (status == DL_STATE_CONSUMER_PROBE) {
+			device_links_write_unlock();
+
+			wait_for_device_probe();
+			goto start;
+		}
+		WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
+		if (status == DL_STATE_ACTIVE) {
+			struct device *consumer = link->consumer;
+
+			get_device(consumer);
+
+			device_links_write_unlock();
+
+			device_release_driver_internal(consumer, NULL,
+						       consumer->parent);
+			put_device(consumer);
+			goto start;
+		}
+	}
+
+	device_links_write_unlock();
+}
+
+/**
+ * device_links_purge - Delete existing links to other devices.
+ * @dev: Target device.
+ */
+static void device_links_purge(struct device *dev)
+{
+	struct device_link *link, *ln;
+
+	/*
+	 * Delete all of the remaining links from this device to any other
+	 * devices (either consumers or suppliers).
+	 */
+	device_links_write_lock();
+
+	list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
+		WARN_ON(link->status == DL_STATE_ACTIVE);
+		__device_link_del(link);
+	}
+
+	list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
+		WARN_ON(link->status != DL_STATE_DORMANT &&
+			link->status != DL_STATE_NONE);
+		__device_link_del(link);
+	}
+
+	device_links_write_unlock();
+}
+
+/* Device links support end. */
+
 int (*platform_notify)(struct device *dev) = NULL;
 int (*platform_notify_remove)(struct device *dev) = NULL;
 static struct kobject *dev_kobj;
@@ -494,8 +1060,14 @@ static int device_add_attrs(struct device *dev)
 			goto err_remove_dev_groups;
 	}
 
+	error = device_create_file(dev, &dev_attr_deferred_probe);
+	if (error)
+		goto err_remove_online;
+
 	return 0;
 
+ err_remove_online:
+	device_remove_file(dev, &dev_attr_online);
  err_remove_dev_groups:
 	device_remove_groups(dev, dev->groups);
  err_remove_type_groups:
@@ -513,6 +1085,7 @@ static void device_remove_attrs(struct device *dev)
 	struct class *class = dev->class;
 	const struct device_type *type = dev->type;
 
+	device_remove_file(dev, &dev_attr_deferred_probe);
 	device_remove_file(dev, &dev_attr_online);
 	device_remove_groups(dev, dev->groups);
 
@@ -711,6 +1284,9 @@ void device_initialize(struct device *dev)
 #ifdef CONFIG_GENERIC_MSI_IRQ
 	INIT_LIST_HEAD(&dev->msi_list);
 #endif
+	INIT_LIST_HEAD(&dev->links.consumers);
+	INIT_LIST_HEAD(&dev->links.suppliers);
+	dev->links.status = DL_DEV_NO_DRIVER;
 }
 EXPORT_SYMBOL_GPL(device_initialize);
 
@@ -1258,6 +1834,8 @@ void device_del(struct device *dev)
 	if (dev->bus)
 		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
 					     BUS_NOTIFY_DEL_DEVICE, dev);
+
+	device_links_purge(dev);
 	dpm_sysfs_remove(dev);
 	if (parent)
 		klist_del(&dev->p->knode_parent);

drivers/base/dd.c

@@ -53,6 +53,19 @@ static LIST_HEAD(deferred_probe_pending_list);
 static LIST_HEAD(deferred_probe_active_list);
 static atomic_t deferred_trigger_count = ATOMIC_INIT(0);
 
+static ssize_t deferred_probe_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	bool value;
+
+	mutex_lock(&deferred_probe_mutex);
+	value = !list_empty(&dev->p->deferred_probe);
+	mutex_unlock(&deferred_probe_mutex);
+
+	return sprintf(buf, "%d\n", value);
+}
+DEVICE_ATTR_RO(deferred_probe);
+
 /*
  * In some cases, like suspend to RAM or hibernation, It might be reasonable
  * to prohibit probing of devices as it could be unsafe.
@@ -244,6 +257,7 @@ static void driver_bound(struct device *dev)
 		 __func__, dev_name(dev));
 
 	klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices);
+	device_links_driver_bound(dev);
 
 	device_pm_check_callbacks(dev);
 
@@ -338,6 +352,10 @@ static int really_probe(struct device *dev, struct device_driver *drv)
 		return ret;
 	}
 
+	ret = device_links_check_suppliers(dev);
+	if (ret)
+		return ret;
+
 	atomic_inc(&probe_count);
 	pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
 		 drv->bus->name, __func__, drv->name, dev_name(dev));
@@ -416,6 +434,7 @@ probe_failed:
 		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
 					     BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
 pinctrl_bind_failed:
+	device_links_no_driver(dev);
 	devres_release_all(dev);
 	driver_sysfs_remove(dev);
 	dev->driver = NULL;
@@ -508,6 +527,7 @@ int driver_probe_device(struct device_driver *drv, struct device *dev)
 	pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
 		 drv->bus->name, __func__, dev_name(dev), drv->name);
 
+	pm_runtime_get_suppliers(dev);
 	if (dev->parent)
 		pm_runtime_get_sync(dev->parent);
 
@@ -518,6 +538,7 @@ int driver_probe_device(struct device_driver *drv, struct device *dev)
 	if (dev->parent)
 		pm_runtime_put(dev->parent);
 
+	pm_runtime_put_suppliers(dev);
 	return ret;
 }
 
@@ -772,7 +793,7 @@ EXPORT_SYMBOL_GPL(driver_attach);
  * __device_release_driver() must be called with @dev lock held.
  * When called for a USB interface, @dev->parent lock must be held as well.
  */
-static void __device_release_driver(struct device *dev)
+static void __device_release_driver(struct device *dev, struct device *parent)
 {
 	struct device_driver *drv;
 
@@ -781,7 +802,27 @@ static void __device_release_driver(struct device *dev)
 		if (driver_allows_async_probing(drv))
 			async_synchronize_full();
 
+		while (device_links_busy(dev)) {
+			device_unlock(dev);
+			if (parent)
+				device_unlock(parent);
+
+			device_links_unbind_consumers(dev);
+			if (parent)
+				device_lock(parent);
+
+			device_lock(dev);
+			/*
+			 * A concurrent invocation of the same function might
+			 * have released the driver successfully while this one
+			 * was waiting, so check for that.
+			 */
+			if (dev->driver != drv)
+				return;
+		}
+
 		pm_runtime_get_sync(dev);
+		pm_runtime_clean_up_links(dev);
 
 		driver_sysfs_remove(dev);
 
@@ -796,6 +837,8 @@ static void __device_release_driver(struct device *dev)
 			dev->bus->remove(dev);
 		else if (drv->remove)
 			drv->remove(dev);
+
+		device_links_driver_cleanup(dev);
 		devres_release_all(dev);
 		dev->driver = NULL;
 		dev_set_drvdata(dev, NULL);
@@ -812,12 +855,32 @@ static void __device_release_driver(struct device *dev)
 	}
 }
 
+void device_release_driver_internal(struct device *dev,
+				    struct device_driver *drv,
+				    struct device *parent)
+{
+	if (parent)
+		device_lock(parent);
+
+	device_lock(dev);
+	if (!drv || drv == dev->driver)
+		__device_release_driver(dev, parent);
+
+	device_unlock(dev);
+	if (parent)
+		device_unlock(parent);
+}
+
 /**
  * device_release_driver - manually detach device from driver.
  * @dev: device.
  *
  * Manually detach device from driver.
  * When called for a USB interface, @dev->parent lock must be held.
+ *
+ * If this function is to be called with @dev->parent lock held, ensure that
+ * the device's consumers are unbound in advance or that their locks can be
+ * acquired under the @dev->parent lock.
  */
 void device_release_driver(struct device *dev)
 {
@@ -826,9 +889,7 @@ void device_release_driver(struct device *dev)
 	 * within their ->remove callback for the same device, they
 	 * will deadlock right here.
 	 */
-	device_lock(dev);
+	device_release_driver_internal(dev, NULL, NULL);
-	__device_release_driver(dev);
-	device_unlock(dev);
 }
 EXPORT_SYMBOL_GPL(device_release_driver);
 
@@ -853,15 +914,7 @@ void driver_detach(struct device_driver *drv)
 		dev = dev_prv->device;
 		get_device(dev);
 		spin_unlock(&drv->p->klist_devices.k_lock);
-
+		device_release_driver_internal(dev, drv, dev->parent);
-		if (dev->parent)	/* Needed for USB */
-			device_lock(dev->parent);
-		device_lock(dev);
-		if (dev->driver == drv)
-			__device_release_driver(dev);
-		device_unlock(dev);
-		if (dev->parent)
-			device_unlock(dev->parent);
 		put_device(dev);
 	}
 }

drivers/base/devcoredump.c

@@ -160,18 +160,20 @@ static ssize_t disabled_store(struct class *class, struct class_attribute *attr,
 
 	return count;
 }
+static CLASS_ATTR_RW(disabled);
 
-static struct class_attribute devcd_class_attrs[] = {
+static struct attribute *devcd_class_attrs[] = {
-	__ATTR_RW(disabled),
+	&class_attr_disabled.attr,
-	__ATTR_NULL
+	NULL,
 };
+ATTRIBUTE_GROUPS(devcd_class);
 
 static struct class devcd_class = {
 	.name		= "devcoredump",
 	.owner		= THIS_MODULE,
 	.dev_release	= devcd_dev_release,
 	.dev_groups	= devcd_dev_groups,
-	.class_attrs	= devcd_class_attrs,
+	.class_groups	= devcd_class_groups,
 };
 
 static ssize_t devcd_readv(char *buffer, loff_t offset, size_t count,

drivers/base/dma-mapping.c

@@ -108,13 +108,13 @@ void dmam_free_coherent(struct device *dev, size_t size, void *vaddr,
 EXPORT_SYMBOL(dmam_free_coherent);
 
 /**
- * dmam_alloc_non_coherent - Managed dma_alloc_non_coherent()
+ * dmam_alloc_non_coherent - Managed dma_alloc_noncoherent()
  * @dev: Device to allocate non_coherent memory for
  * @size: Size of allocation
  * @dma_handle: Out argument for allocated DMA handle
  * @gfp: Allocation flags
  *
- * Managed dma_alloc_non_coherent().  Memory allocated using this
+ * Managed dma_alloc_noncoherent().  Memory allocated using this
  * function will be automatically released on driver detach.
  *
  * RETURNS:

drivers/base/firmware_class.c

@@ -30,6 +30,7 @@
 #include <linux/syscore_ops.h>
 #include <linux/reboot.h>
 #include <linux/security.h>
+#include <linux/swait.h>
 
 #include <generated/utsrelease.h>
 
@@ -91,10 +92,11 @@ static inline bool fw_is_builtin_firmware(const struct firmware *fw)
 }
 #endif
 
-enum {
+enum fw_status {
+	FW_STATUS_UNKNOWN,
 	FW_STATUS_LOADING,
 	FW_STATUS_DONE,
-	FW_STATUS_ABORT,
+	FW_STATUS_ABORTED,
 };
 
 static int loading_timeout = 60;	/* In seconds */
@@ -104,6 +106,82 @@ static inline long firmware_loading_timeout(void)
 	return loading_timeout > 0 ? loading_timeout * HZ : MAX_JIFFY_OFFSET;
 }
 
+/*
+ * Concurrent request_firmware() for the same firmware need to be
+ * serialized.  struct fw_state is simple state machine which hold the
+ * state of the firmware loading.
+ */
+struct fw_state {
+	struct swait_queue_head wq;
+	enum fw_status status;
+};
+
+static void fw_state_init(struct fw_state *fw_st)
+{
+	init_swait_queue_head(&fw_st->wq);
+	fw_st->status = FW_STATUS_UNKNOWN;
+}
+
+static inline bool __fw_state_is_done(enum fw_status status)
+{
+	return status == FW_STATUS_DONE || status == FW_STATUS_ABORTED;
+}
+
+static int __fw_state_wait_common(struct fw_state *fw_st, long timeout)
+{
+	long ret;
+
+	ret = swait_event_interruptible_timeout(fw_st->wq,
+				__fw_state_is_done(READ_ONCE(fw_st->status)),
+				timeout);
+	if (ret != 0 && fw_st->status == FW_STATUS_ABORTED)
+		return -ENOENT;
+	if (!ret)
+		return -ETIMEDOUT;
+
+	return ret < 0 ? ret : 0;
+}
+
+static void __fw_state_set(struct fw_state *fw_st,
+			   enum fw_status status)
+{
+	WRITE_ONCE(fw_st->status, status);
+
+	if (status == FW_STATUS_DONE || status == FW_STATUS_ABORTED)
+		swake_up(&fw_st->wq);
+}
+
+#define fw_state_start(fw_st)					\
+	__fw_state_set(fw_st, FW_STATUS_LOADING)
+#define fw_state_done(fw_st)					\
+	__fw_state_set(fw_st, FW_STATUS_DONE)
+#define fw_state_wait(fw_st)					\
+	__fw_state_wait_common(fw_st, MAX_SCHEDULE_TIMEOUT)
+
+#ifndef CONFIG_FW_LOADER_USER_HELPER
+
+#define fw_state_is_aborted(fw_st)	false
+
+#else /* CONFIG_FW_LOADER_USER_HELPER */
+
+static int __fw_state_check(struct fw_state *fw_st, enum fw_status status)
+{
+	return fw_st->status == status;
+}
+
+#define fw_state_aborted(fw_st)					\
+	__fw_state_set(fw_st, FW_STATUS_ABORTED)
+#define fw_state_is_done(fw_st)					\
+	__fw_state_check(fw_st, FW_STATUS_DONE)
+#define fw_state_is_loading(fw_st)				\
+	__fw_state_check(fw_st, FW_STATUS_LOADING)
+#define fw_state_is_aborted(fw_st)				\
+	__fw_state_check(fw_st, FW_STATUS_ABORTED)
+#define fw_state_wait_timeout(fw_st, timeout)			\
+	__fw_state_wait_common(fw_st, timeout)
+
+#endif /* CONFIG_FW_LOADER_USER_HELPER */
+
 /* firmware behavior options */
 #define FW_OPT_UEVENT	(1U << 0)
 #define FW_OPT_NOWAIT	(1U << 1)
@@ -145,9 +223,8 @@ struct firmware_cache {
 struct firmware_buf {
 	struct kref ref;
 	struct list_head list;
-	struct completion completion;
 	struct firmware_cache *fwc;
-	unsigned long status;
+	struct fw_state fw_st;
 	void *data;
 	size_t size;
 	size_t allocated_size;
@@ -205,7 +282,7 @@ static struct firmware_buf *__allocate_fw_buf(const char *fw_name,
 	buf->fwc = fwc;
 	buf->data = dbuf;
 	buf->allocated_size = size;
-	init_completion(&buf->completion);
+	fw_state_init(&buf->fw_st);
 #ifdef CONFIG_FW_LOADER_USER_HELPER
 	INIT_LIST_HEAD(&buf->pending_list);
 #endif
@@ -305,15 +382,6 @@ static const char * const fw_path[] = {
 module_param_string(path, fw_path_para, sizeof(fw_path_para), 0644);
 MODULE_PARM_DESC(path, "customized firmware image search path with a higher priority than default path");
 
-static void fw_finish_direct_load(struct device *device,
-				  struct firmware_buf *buf)
-{
-	mutex_lock(&fw_lock);
-	set_bit(FW_STATUS_DONE, &buf->status);
-	complete_all(&buf->completion);
-	mutex_unlock(&fw_lock);
-}
-
 static int
 fw_get_filesystem_firmware(struct device *device, struct firmware_buf *buf)
 {
@@ -360,7 +428,7 @@ fw_get_filesystem_firmware(struct device *device, struct firmware_buf *buf)
 		}
 		dev_dbg(device, "direct-loading %s\n", buf->fw_id);
 		buf->size = size;
-		fw_finish_direct_load(device, buf);
+		fw_state_done(&buf->fw_st);
 		break;
 	}
 	__putname(path);
@@ -478,12 +546,11 @@ static void __fw_load_abort(struct firmware_buf *buf)
 	 * There is a small window in which user can write to 'loading'
 	 * between loading done and disappearance of 'loading'
 	 */
-	if (test_bit(FW_STATUS_DONE, &buf->status))
+	if (fw_state_is_done(&buf->fw_st))
 		return;
 
 	list_del_init(&buf->pending_list);
-	set_bit(FW_STATUS_ABORT, &buf->status);
+	fw_state_aborted(&buf->fw_st);
-	complete_all(&buf->completion);
 }
 
 static void fw_load_abort(struct firmware_priv *fw_priv)
@@ -496,9 +563,6 @@ static void fw_load_abort(struct firmware_priv *fw_priv)
 	fw_priv->buf = NULL;
 }
 
-#define is_fw_load_aborted(buf)	\
-	test_bit(FW_STATUS_ABORT, &(buf)->status)
-
 static LIST_HEAD(pending_fw_head);
 
 /* reboot notifier for avoid deadlock with usermode_lock */
@@ -546,11 +610,13 @@ static ssize_t timeout_store(struct class *class, struct class_attribute *attr,
 
 	return count;
 }
+static CLASS_ATTR_RW(timeout);
 
-static struct class_attribute firmware_class_attrs[] = {
+static struct attribute *firmware_class_attrs[] = {
-	__ATTR_RW(timeout),
+	&class_attr_timeout.attr,
-	__ATTR_NULL
+	NULL,
 };
+ATTRIBUTE_GROUPS(firmware_class);
 
 static void fw_dev_release(struct device *dev)
 {
@@ -585,7 +651,7 @@ static int firmware_uevent(struct device *dev, struct kobj_uevent_env *env)
 
 static struct class firmware_class = {
 	.name		= "firmware",
-	.class_attrs	= firmware_class_attrs,
+	.class_groups	= firmware_class_groups,
 	.dev_uevent	= firmware_uevent,
 	.dev_release	= fw_dev_release,
 };
@@ -598,7 +664,7 @@ static ssize_t firmware_loading_show(struct device *dev,
 
 	mutex_lock(&fw_lock);
 	if (fw_priv->buf)
-		loading = test_bit(FW_STATUS_LOADING, &fw_priv->buf->status);
+		loading = fw_state_is_loading(&fw_priv->buf->fw_st);
 	mutex_unlock(&fw_lock);
 
 	return sprintf(buf, "%d\n", loading);
@@ -653,23 +719,20 @@ static ssize_t firmware_loading_store(struct device *dev,
 	switch (loading) {
 	case 1:
 		/* discarding any previous partial load */
-		if (!test_bit(FW_STATUS_DONE, &fw_buf->status)) {
+		if (!fw_state_is_done(&fw_buf->fw_st)) {
 			for (i = 0; i < fw_buf->nr_pages; i++)
 				__free_page(fw_buf->pages[i]);
 			vfree(fw_buf->pages);
 			fw_buf->pages = NULL;
 			fw_buf->page_array_size = 0;
 			fw_buf->nr_pages = 0;
-			set_bit(FW_STATUS_LOADING, &fw_buf->status);
+			fw_state_start(&fw_buf->fw_st);
 		}
 		break;
 	case 0:
-		if (test_bit(FW_STATUS_LOADING, &fw_buf->status)) {
+		if (fw_state_is_loading(&fw_buf->fw_st)) {
 			int rc;
 
-			set_bit(FW_STATUS_DONE, &fw_buf->status);
-			clear_bit(FW_STATUS_LOADING, &fw_buf->status);
-
 			/*
 			 * Several loading requests may be pending on
 			 * one same firmware buf, so let all requests
@@ -691,10 +754,11 @@ static ssize_t firmware_loading_store(struct device *dev,
 			 */
 			list_del_init(&fw_buf->pending_list);
 			if (rc) {
-				set_bit(FW_STATUS_ABORT, &fw_buf->status);
+				fw_state_aborted(&fw_buf->fw_st);
 				written = rc;
+			} else {
+				fw_state_done(&fw_buf->fw_st);
 			}
-			complete_all(&fw_buf->completion);
 			break;
 		}
 		/* fallthrough */
@@ -755,7 +819,7 @@ static ssize_t firmware_data_read(struct file *filp, struct kobject *kobj,
 
 	mutex_lock(&fw_lock);
 	buf = fw_priv->buf;
-	if (!buf || test_bit(FW_STATUS_DONE, &buf->status)) {
+	if (!buf || fw_state_is_done(&buf->fw_st)) {
 		ret_count = -ENODEV;
 		goto out;
 	}
@@ -842,7 +906,7 @@ static ssize_t firmware_data_write(struct file *filp, struct kobject *kobj,
 
 	mutex_lock(&fw_lock);
 	buf = fw_priv->buf;
-	if (!buf || test_bit(FW_STATUS_DONE, &buf->status)) {
+	if (!buf || fw_state_is_done(&buf->fw_st)) {
 		retval = -ENODEV;
 		goto out;
 	}
@@ -955,17 +1019,14 @@ static int _request_firmware_load(struct firmware_priv *fw_priv,
 		timeout = MAX_JIFFY_OFFSET;
 	}
 
-	retval = wait_for_completion_interruptible_timeout(&buf->completion,
+	retval = fw_state_wait_timeout(&buf->fw_st, timeout);
-			timeout);
+	if (retval < 0) {
-	if (retval == -ERESTARTSYS || !retval) {
 		mutex_lock(&fw_lock);
 		fw_load_abort(fw_priv);
 		mutex_unlock(&fw_lock);
-	} else if (retval > 0) {
-		retval = 0;
 	}
 
-	if (is_fw_load_aborted(buf))
+	if (fw_state_is_aborted(&buf->fw_st))
 		retval = -EAGAIN;
 	else if (buf->is_paged_buf && !buf->data)
 		retval = -ENOMEM;
@@ -1015,35 +1076,12 @@ fw_load_from_user_helper(struct firmware *firmware, const char *name,
 	return -ENOENT;
 }
 
-/* No abort during direct loading */
-#define is_fw_load_aborted(buf) false
-
 #ifdef CONFIG_PM_SLEEP
 static inline void kill_requests_without_uevent(void) { }
 #endif
 
 #endif /* CONFIG_FW_LOADER_USER_HELPER */
 
-
-/* wait until the shared firmware_buf becomes ready (or error) */
-static int sync_cached_firmware_buf(struct firmware_buf *buf)
-{
-	int ret = 0;
-
-	mutex_lock(&fw_lock);
-	while (!test_bit(FW_STATUS_DONE, &buf->status)) {
-		if (is_fw_load_aborted(buf)) {
-			ret = -ENOENT;
-			break;
-		}
-		mutex_unlock(&fw_lock);
-		ret = wait_for_completion_interruptible(&buf->completion);
-		mutex_lock(&fw_lock);
-	}
-	mutex_unlock(&fw_lock);
-	return ret;
-}
-
 /* prepare firmware and firmware_buf structs;
  * return 0 if a firmware is already assigned, 1 if need to load one,
  * or a negative error code
@@ -1077,7 +1115,7 @@ _request_firmware_prepare(struct firmware **firmware_p, const char *name,
 	firmware->priv = buf;
 
 	if (ret > 0) {
-		ret = sync_cached_firmware_buf(buf);
+		ret = fw_state_wait(&buf->fw_st);
 		if (!ret) {
 			fw_set_page_data(buf, firmware);
 			return 0; /* assigned */
@@ -1095,7 +1133,7 @@ static int assign_firmware_buf(struct firmware *fw, struct device *device,
 	struct firmware_buf *buf = fw->priv;
 
 	mutex_lock(&fw_lock);
-	if (!buf->size || is_fw_load_aborted(buf)) {
+	if (!buf->size || fw_state_is_aborted(&buf->fw_st)) {
 		mutex_unlock(&fw_lock);
 		return -ENOENT;
 	}
@@ -1345,9 +1383,9 @@ static void request_firmware_work_func(struct work_struct *work)
  *
  *	Asynchronous variant of request_firmware() for user contexts:
  *		- sleep for as small periods as possible since it may
- *		increase kernel boot time of built-in device drivers
+ *		  increase kernel boot time of built-in device drivers
- *		requesting firmware in their ->probe() methods, if
+ *		  requesting firmware in their ->probe() methods, if
- *		@gfp is GFP_KERNEL.
+ *		  @gfp is GFP_KERNEL.
  *
  *		- can't sleep at all if @gfp is GFP_ATOMIC.
  **/

drivers/base/memory.c

@@ -226,11 +226,9 @@ memory_block_action(unsigned long phys_index, unsigned long action, int online_t
 {
 	unsigned long start_pfn;
 	unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
-	struct page *first_page;
 	int ret;
 
 	start_pfn = section_nr_to_pfn(phys_index);
-	first_page = pfn_to_page(start_pfn);
 
 	switch (action) {
 	case MEM_ONLINE:

drivers/base/power/main.c

@@ -131,6 +131,7 @@ void device_pm_add(struct device *dev)
 		dev_warn(dev, "parent %s should not be sleeping\n",
 			dev_name(dev->parent));
 	list_add_tail(&dev->power.entry, &dpm_list);
+	dev->power.in_dpm_list = true;
 	mutex_unlock(&dpm_list_mtx);
 }
 
@@ -145,6 +146,7 @@ void device_pm_remove(struct device *dev)
 	complete_all(&dev->power.completion);
 	mutex_lock(&dpm_list_mtx);
 	list_del_init(&dev->power.entry);
+	dev->power.in_dpm_list = false;
 	mutex_unlock(&dpm_list_mtx);
 	device_wakeup_disable(dev);
 	pm_runtime_remove(dev);
@@ -244,6 +246,62 @@ static void dpm_wait_for_children(struct device *dev, bool async)
        device_for_each_child(dev, &async, dpm_wait_fn);
 }
 
+static void dpm_wait_for_suppliers(struct device *dev, bool async)
+{
+	struct device_link *link;
+	int idx;
+
+	idx = device_links_read_lock();
+
+	/*
+	 * If the supplier goes away right after we've checked the link to it,
+	 * we'll wait for its completion to change the state, but that's fine,
+	 * because the only things that will block as a result are the SRCU
+	 * callbacks freeing the link objects for the links in the list we're
+	 * walking.
+	 */
+	list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
+		if (READ_ONCE(link->status) != DL_STATE_DORMANT)
+			dpm_wait(link->supplier, async);
+
+	device_links_read_unlock(idx);
+}
+
+static void dpm_wait_for_superior(struct device *dev, bool async)
+{
+	dpm_wait(dev->parent, async);
+	dpm_wait_for_suppliers(dev, async);
+}
+
+static void dpm_wait_for_consumers(struct device *dev, bool async)
+{
+	struct device_link *link;
+	int idx;
+
+	idx = device_links_read_lock();
+
+	/*
+	 * The status of a device link can only be changed from "dormant" by a
+	 * probe, but that cannot happen during system suspend/resume.  In
+	 * theory it can change to "dormant" at that time, but then it is
+	 * reasonable to wait for the target device anyway (eg. if it goes
+	 * away, it's better to wait for it to go away completely and then
+	 * continue instead of trying to continue in parallel with its
+	 * unregistration).
+	 */
+	list_for_each_entry_rcu(link, &dev->links.consumers, s_node)
+		if (READ_ONCE(link->status) != DL_STATE_DORMANT)
+			dpm_wait(link->consumer, async);
+
+	device_links_read_unlock(idx);
+}
+
+static void dpm_wait_for_subordinate(struct device *dev, bool async)
+{
+	dpm_wait_for_children(dev, async);
+	dpm_wait_for_consumers(dev, async);
+}
+
 /**
  * pm_op - Return the PM operation appropriate for given PM event.
  * @ops: PM operations to choose from.
@@ -488,7 +546,7 @@ static int device_resume_noirq(struct device *dev, pm_message_t state, bool asyn
 	if (!dev->power.is_noirq_suspended)
 		goto Out;
 
-	dpm_wait(dev->parent, async);
+	dpm_wait_for_superior(dev, async);
 
 	if (dev->pm_domain) {
 		info = "noirq power domain ";
@@ -618,7 +676,7 @@ static int device_resume_early(struct device *dev, pm_message_t state, bool asyn
 	if (!dev->power.is_late_suspended)
 		goto Out;
 
-	dpm_wait(dev->parent, async);
+	dpm_wait_for_superior(dev, async);
 
 	if (dev->pm_domain) {
 		info = "early power domain ";
@@ -750,7 +808,7 @@ static int device_resume(struct device *dev, pm_message_t state, bool async)
 		goto Complete;
 	}
 
-	dpm_wait(dev->parent, async);
+	dpm_wait_for_superior(dev, async);
 	dpm_watchdog_set(&wd, dev);
 	device_lock(dev);
 
@@ -1027,7 +1085,7 @@ static int __device_suspend_noirq(struct device *dev, pm_message_t state, bool a
 	TRACE_DEVICE(dev);
 	TRACE_SUSPEND(0);
 
-	dpm_wait_for_children(dev, async);
+	dpm_wait_for_subordinate(dev, async);
 
 	if (async_error)
 		goto Complete;
@@ -1174,7 +1232,7 @@ static int __device_suspend_late(struct device *dev, pm_message_t state, bool as
 
 	__pm_runtime_disable(dev, false);
 
-	dpm_wait_for_children(dev, async);
+	dpm_wait_for_subordinate(dev, async);
 
 	if (async_error)
 		goto Complete;
@@ -1342,6 +1400,22 @@ static int legacy_suspend(struct device *dev, pm_message_t state,
 	return error;
 }
 
+static void dpm_clear_suppliers_direct_complete(struct device *dev)
+{
+	struct device_link *link;
+	int idx;
+
+	idx = device_links_read_lock();
+
+	list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) {
+		spin_lock_irq(&link->supplier->power.lock);
+		link->supplier->power.direct_complete = false;
+		spin_unlock_irq(&link->supplier->power.lock);
+	}
+
+	device_links_read_unlock(idx);
+}
+
 /**
  * device_suspend - Execute "suspend" callbacks for given device.
  * @dev: Device to handle.
@@ -1358,7 +1432,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 	TRACE_DEVICE(dev);
 	TRACE_SUSPEND(0);
 
-	dpm_wait_for_children(dev, async);
+	dpm_wait_for_subordinate(dev, async);
 
 	if (async_error)
 		goto Complete;
@@ -1454,6 +1528,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 
 			spin_unlock_irq(&parent->power.lock);
 		}
+		dpm_clear_suppliers_direct_complete(dev);
 	}
 
 	device_unlock(dev);

drivers/base/power/power.h

@@ -144,6 +144,11 @@ extern void device_pm_move_after(struct device *, struct device *);
 extern void device_pm_move_last(struct device *);
 extern void device_pm_check_callbacks(struct device *dev);
 
+static inline bool device_pm_initialized(struct device *dev)
+{
+	return dev->power.in_dpm_list;
+}
+
 #else /* !CONFIG_PM_SLEEP */
 
 static inline void device_pm_sleep_init(struct device *dev) {}
@@ -163,6 +168,11 @@ static inline void device_pm_move_last(struct device *dev) {}
 
 static inline void device_pm_check_callbacks(struct device *dev) {}
 
+static inline bool device_pm_initialized(struct device *dev)
+{
+	return device_is_registered(dev);
+}
+
 #endif /* !CONFIG_PM_SLEEP */
 
 static inline void device_pm_init(struct device *dev)

drivers/base/power/runtime.c

@@ -12,6 +12,8 @@
 #include <linux/pm_runtime.h>
 #include <linux/pm_wakeirq.h>
 #include <trace/events/rpm.h>
+
+#include "../base.h"
 #include "power.h"
 
 typedef int (*pm_callback_t)(struct device *);
@@ -259,6 +261,42 @@ static int rpm_check_suspend_allowed(struct device *dev)
 	return retval;
 }
 
+static int rpm_get_suppliers(struct device *dev)
+{
+	struct device_link *link;
+
+	list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) {
+		int retval;
+
+		if (!(link->flags & DL_FLAG_PM_RUNTIME))
+			continue;
+
+		if (READ_ONCE(link->status) == DL_STATE_SUPPLIER_UNBIND ||
+		    link->rpm_active)
+			continue;
+
+		retval = pm_runtime_get_sync(link->supplier);
+		if (retval < 0) {
+			pm_runtime_put_noidle(link->supplier);
+			return retval;
+		}
+		link->rpm_active = true;
+	}
+	return 0;
+}
+
+static void rpm_put_suppliers(struct device *dev)
+{
+	struct device_link *link;
+
+	list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
+		if (link->rpm_active &&
+		    READ_ONCE(link->status) != DL_STATE_SUPPLIER_UNBIND) {
+			pm_runtime_put(link->supplier);
+			link->rpm_active = false;
+		}
+}
+
 /**
  * __rpm_callback - Run a given runtime PM callback for a given device.
  * @cb: Runtime PM callback to run.
@@ -267,19 +305,57 @@ static int rpm_check_suspend_allowed(struct device *dev)
 static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
 	__releases(&dev->power.lock) __acquires(&dev->power.lock)
 {
-	int retval;
+	int retval, idx;
+	bool use_links = dev->power.links_count > 0;
 
-	if (dev->power.irq_safe)
+	if (dev->power.irq_safe) {
 		spin_unlock(&dev->power.lock);
-	else
+	} else {
 		spin_unlock_irq(&dev->power.lock);
 
+		/*
+		 * Resume suppliers if necessary.
+		 *
+		 * The device's runtime PM status cannot change until this
+		 * routine returns, so it is safe to read the status outside of
+		 * the lock.
+		 */
+		if (use_links && dev->power.runtime_status == RPM_RESUMING) {
+			idx = device_links_read_lock();
+
+			retval = rpm_get_suppliers(dev);
+			if (retval)
+				goto fail;
+
+			device_links_read_unlock(idx);
+		}
+	}
+
 	retval = cb(dev);
 
-	if (dev->power.irq_safe)
+	if (dev->power.irq_safe) {
 		spin_lock(&dev->power.lock);
-	else
+	} else {
+		/*
+		 * If the device is suspending and the callback has returned
+		 * success, drop the usage counters of the suppliers that have
+		 * been reference counted on its resume.
+		 *
+		 * Do that if resume fails too.
+		 */
+		if (use_links
+		    && ((dev->power.runtime_status == RPM_SUSPENDING && !retval)
+		    || (dev->power.runtime_status == RPM_RESUMING && retval))) {
+			idx = device_links_read_lock();
+
+ fail:
+			rpm_put_suppliers(dev);
+
+			device_links_read_unlock(idx);
+		}
+
 		spin_lock_irq(&dev->power.lock);
+	}
 
 	return retval;
 }
@@ -1457,6 +1533,94 @@ void pm_runtime_remove(struct device *dev)
 	pm_runtime_reinit(dev);
 }
 
+/**
+ * pm_runtime_clean_up_links - Prepare links to consumers for driver removal.
+ * @dev: Device whose driver is going to be removed.
+ *
+ * Check links from this device to any consumers and if any of them have active
+ * runtime PM references to the device, drop the usage counter of the device
+ * (once per link).
+ *
+ * Links with the DL_FLAG_STATELESS flag set are ignored.
+ *
+ * Since the device is guaranteed to be runtime-active at the point this is
+ * called, nothing else needs to be done here.
+ *
+ * Moreover, this is called after device_links_busy() has returned 'false', so
+ * the status of each link is guaranteed to be DL_STATE_SUPPLIER_UNBIND and
+ * therefore rpm_active can't be manipulated concurrently.
+ */
+void pm_runtime_clean_up_links(struct device *dev)
+{
+	struct device_link *link;
+	int idx;
+
+	idx = device_links_read_lock();
+
+	list_for_each_entry_rcu(link, &dev->links.consumers, s_node) {
+		if (link->flags & DL_FLAG_STATELESS)
+			continue;
+
+		if (link->rpm_active) {
+			pm_runtime_put_noidle(dev);
+			link->rpm_active = false;
+		}
+	}
+
+	device_links_read_unlock(idx);
+}
+
+/**
+ * pm_runtime_get_suppliers - Resume and reference-count supplier devices.
+ * @dev: Consumer device.
+ */
+void pm_runtime_get_suppliers(struct device *dev)
+{
+	struct device_link *link;
+	int idx;
+
+	idx = device_links_read_lock();
+
+	list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
+		if (link->flags & DL_FLAG_PM_RUNTIME)
+			pm_runtime_get_sync(link->supplier);
+
+	device_links_read_unlock(idx);
+}
+
+/**
+ * pm_runtime_put_suppliers - Drop references to supplier devices.
+ * @dev: Consumer device.
+ */
+void pm_runtime_put_suppliers(struct device *dev)
+{
+	struct device_link *link;
+	int idx;
+
+	idx = device_links_read_lock();
+
+	list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
+		if (link->flags & DL_FLAG_PM_RUNTIME)
+			pm_runtime_put(link->supplier);
+
+	device_links_read_unlock(idx);
+}
+
+void pm_runtime_new_link(struct device *dev)
+{
+	spin_lock_irq(&dev->power.lock);
+	dev->power.links_count++;
+	spin_unlock_irq(&dev->power.lock);
+}
+
+void pm_runtime_drop_link(struct device *dev)
+{
+	spin_lock_irq(&dev->power.lock);
+	WARN_ON(dev->power.links_count == 0);
+	dev->power.links_count--;
+	spin_unlock_irq(&dev->power.lock);
+}
+
 /**
  * pm_runtime_force_suspend - Force a device into suspend state if needed.
  * @dev: Device to suspend.

drivers/base/test/Kconfig

@@ -0,0 +1,9 @@
+config TEST_ASYNC_DRIVER_PROBE
+	tristate "Build kernel module to test asynchronous driver probing"
+	depends on m
+	help
+	  Enabling this option produces a kernel module that allows
+	  testing asynchronous driver probing by the device core.
+	  The module name will be test_async_driver_probe.ko
+
+	  If unsure say N.

drivers/base/test/Makefile

@@ -0,0 +1 @@
+obj-$(CONFIG_TEST_ASYNC_DRIVER_PROBE)	+= test_async_driver_probe.o

drivers/base/test/test_async_driver_probe.c

@@ -0,0 +1,169 @@
+/*
+ * Copyright (C) 2014 Google, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/hrtimer.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/time.h>
+
+#define TEST_PROBE_DELAY	(5 * 1000)	/* 5 sec */
+#define TEST_PROBE_THRESHOLD	(TEST_PROBE_DELAY / 2)
+
+static int test_probe(struct platform_device *pdev)
+{
+	dev_info(&pdev->dev, "sleeping for %d msecs in probe\n",
+		 TEST_PROBE_DELAY);
+	msleep(TEST_PROBE_DELAY);
+	dev_info(&pdev->dev, "done sleeping\n");
+
+	return 0;
+}
+
+static struct platform_driver async_driver = {
+	.driver = {
+		.name = "test_async_driver",
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+	},
+	.probe = test_probe,
+};
+
+static struct platform_driver sync_driver = {
+	.driver = {
+		.name = "test_sync_driver",
+		.probe_type = PROBE_FORCE_SYNCHRONOUS,
+	},
+	.probe = test_probe,
+};
+
+static struct platform_device *async_dev_1, *async_dev_2;
+static struct platform_device *sync_dev_1;
+
+static int __init test_async_probe_init(void)
+{
+	ktime_t calltime, delta;
+	unsigned long long duration;
+	int error;
+
+	pr_info("registering first asynchronous device...\n");
+
+	async_dev_1 = platform_device_register_simple("test_async_driver", 1,
+						      NULL, 0);
+	if (IS_ERR(async_dev_1)) {
+		error = PTR_ERR(async_dev_1);
+		pr_err("failed to create async_dev_1: %d", error);
+		return error;
+	}
+
+	pr_info("registering asynchronous driver...\n");
+	calltime = ktime_get();
+	error = platform_driver_register(&async_driver);
+	if (error) {
+		pr_err("Failed to register async_driver: %d\n", error);
+		goto err_unregister_async_dev_1;
+	}
+
+	delta = ktime_sub(ktime_get(), calltime);
+	duration = (unsigned long long) ktime_to_ms(delta);
+	pr_info("registration took %lld msecs\n", duration);
+	if (duration > TEST_PROBE_THRESHOLD) {
+		pr_err("test failed: probe took too long\n");
+		error = -ETIMEDOUT;
+		goto err_unregister_async_driver;
+	}
+
+	pr_info("registering second asynchronous device...\n");
+	calltime = ktime_get();
+	async_dev_2 = platform_device_register_simple("test_async_driver", 2,
+						      NULL, 0);
+	if (IS_ERR(async_dev_2)) {
+		error = PTR_ERR(async_dev_2);
+		pr_err("failed to create async_dev_2: %d", error);
+		goto err_unregister_async_driver;
+	}
+
+	delta = ktime_sub(ktime_get(), calltime);
+	duration = (unsigned long long) ktime_to_ms(delta);
+	pr_info("registration took %lld msecs\n", duration);
+	if (duration > TEST_PROBE_THRESHOLD) {
+		pr_err("test failed: probe took too long\n");
+		error = -ETIMEDOUT;
+		goto err_unregister_async_dev_2;
+	}
+
+	pr_info("registering synchronous driver...\n");
+
+	error = platform_driver_register(&sync_driver);
+	if (error) {
+		pr_err("Failed to register async_driver: %d\n", error);
+		goto err_unregister_async_dev_2;
+	}
+
+	pr_info("registering synchronous device...\n");
+	calltime = ktime_get();
+	sync_dev_1 = platform_device_register_simple("test_sync_driver", 1,
+						     NULL, 0);
+	if (IS_ERR(sync_dev_1)) {
+		error = PTR_ERR(sync_dev_1);
+		pr_err("failed to create sync_dev_1: %d", error);
+		goto err_unregister_sync_driver;
+	}
+
+	delta = ktime_sub(ktime_get(), calltime);
+	duration = (unsigned long long) ktime_to_ms(delta);
+	pr_info("registration took %lld msecs\n", duration);
+	if (duration < TEST_PROBE_THRESHOLD) {
+		pr_err("test failed: probe was too quick\n");
+		error = -ETIMEDOUT;
+		goto err_unregister_sync_dev_1;
+	}
+
+	pr_info("completed successfully");
+
+	return 0;
+
+err_unregister_sync_dev_1:
+	platform_device_unregister(sync_dev_1);
+
+err_unregister_sync_driver:
+	platform_driver_unregister(&sync_driver);
+
+err_unregister_async_dev_2:
+	platform_device_unregister(async_dev_2);
+
+err_unregister_async_driver:
+	platform_driver_unregister(&async_driver);
+
+err_unregister_async_dev_1:
+	platform_device_unregister(async_dev_1);
+
+	return error;
+}
+module_init(test_async_probe_init);
+
+static void __exit test_async_probe_exit(void)
+{
+	platform_driver_unregister(&async_driver);
+	platform_driver_unregister(&sync_driver);
+	platform_device_unregister(async_dev_1);
+	platform_device_unregister(async_dev_2);
+	platform_device_unregister(sync_dev_1);
+}
+module_exit(test_async_probe_exit);
+
+MODULE_DESCRIPTION("Test module for asynchronous driver probing");
+MODULE_AUTHOR("Dmitry Torokhov <dtor@chromium.org>");
+MODULE_LICENSE("GPL");

fs/kernfs/inode.c

@@ -335,7 +335,7 @@ static int kernfs_xattr_set(const struct xattr_handler *handler,
 	return simple_xattr_set(&attrs->xattrs, name, value, size, flags);
 }
 
-const struct xattr_handler kernfs_trusted_xattr_handler = {
+static const struct xattr_handler kernfs_trusted_xattr_handler = {
 	.prefix = XATTR_TRUSTED_PREFIX,
 	.get = kernfs_xattr_get,
 	.set = kernfs_xattr_set,
@@ -372,7 +372,7 @@ static int kernfs_security_xattr_set(const struct xattr_handler *handler,
 	return error;
 }
 
-const struct xattr_handler kernfs_security_xattr_handler = {
+static const struct xattr_handler kernfs_security_xattr_handler = {
 	.prefix = XATTR_SECURITY_PREFIX,
 	.get = kernfs_xattr_get,
 	.set = kernfs_security_xattr_set,

include/linux/cacheinfo.h

@@ -71,6 +71,7 @@ struct cpu_cacheinfo {
 	struct cacheinfo *info_list;
 	unsigned int num_levels;
 	unsigned int num_leaves;
+	bool cpu_map_populated;
 };
 
 /*

include/linux/debugfs.h

@@ -63,6 +63,21 @@ debugfs_real_fops(const struct file *filp)
 	return filp->f_path.dentry->d_fsdata;
 }
 
+#define DEFINE_DEBUGFS_ATTRIBUTE(__fops, __get, __set, __fmt)		\
+static int __fops ## _open(struct inode *inode, struct file *file)	\
+{									\
+	__simple_attr_check_format(__fmt, 0ull);			\
+	return simple_attr_open(inode, file, __get, __set, __fmt);	\
+}									\
+static const struct file_operations __fops = {				\
+	.owner	 = THIS_MODULE,						\
+	.open	 = __fops ## _open,					\
+	.release = simple_attr_release,					\
+	.read	 = debugfs_attr_read,					\
+	.write	 = debugfs_attr_write,					\
+	.llseek  = generic_file_llseek,					\
+}
+
 #if defined(CONFIG_DEBUG_FS)
 
 struct dentry *debugfs_create_file(const char *name, umode_t mode,
@@ -100,21 +115,6 @@ ssize_t debugfs_attr_read(struct file *file, char __user *buf,
 ssize_t debugfs_attr_write(struct file *file, const char __user *buf,
 			size_t len, loff_t *ppos);
 
-#define DEFINE_DEBUGFS_ATTRIBUTE(__fops, __get, __set, __fmt)		\
-static int __fops ## _open(struct inode *inode, struct file *file)	\
-{									\
-	__simple_attr_check_format(__fmt, 0ull);			\
-	return simple_attr_open(inode, file, __get, __set, __fmt);	\
-}									\
-static const struct file_operations __fops = {				\
-	.owner	 = THIS_MODULE,					\
-	.open	 = __fops ## _open,					\
-	.release = simple_attr_release,				\
-	.read	 = debugfs_attr_read,					\
-	.write	 = debugfs_attr_write,					\
-	.llseek  = generic_file_llseek,				\
-}
-
 struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
                 struct dentry *new_dir, const char *new_name);
 
@@ -234,8 +234,18 @@ static inline void debugfs_use_file_finish(int srcu_idx)
 	__releases(&debugfs_srcu)
 { }
 
-#define DEFINE_DEBUGFS_ATTRIBUTE(__fops, __get, __set, __fmt)	\
+static inline ssize_t debugfs_attr_read(struct file *file, char __user *buf,
-	static const struct file_operations __fops = { 0 }
+					size_t len, loff_t *ppos)
+{
+	return -ENODEV;
+}
+
+static inline ssize_t debugfs_attr_write(struct file *file,
+					const char __user *buf,
+					size_t len, loff_t *ppos)
+{
+	return -ENODEV;
+}
 
 static inline struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
                 struct dentry *new_dir, char *new_name)

include/linux/device.h

@@ -362,6 +362,7 @@ int subsys_virtual_register(struct bus_type *subsys,
  * @name:	Name of the class.
  * @owner:	The module owner.
  * @class_attrs: Default attributes of this class.
+ * @class_groups: Default attributes of this class.
  * @dev_groups:	Default attributes of the devices that belong to the class.
  * @dev_kobj:	The kobject that represents this class and links it into the hierarchy.
  * @dev_uevent:	Called when a device is added, removed from this class, or a
@@ -390,6 +391,7 @@ struct class {
 	struct module		*owner;
 
 	struct class_attribute		*class_attrs;
+	const struct attribute_group	**class_groups;
 	const struct attribute_group	**dev_groups;
 	struct kobject			*dev_kobj;
 
@@ -465,6 +467,8 @@ struct class_attribute {
 	struct class_attribute class_attr_##_name = __ATTR_RW(_name)
 #define CLASS_ATTR_RO(_name) \
 	struct class_attribute class_attr_##_name = __ATTR_RO(_name)
+#define CLASS_ATTR_WO(_name) \
+	struct class_attribute class_attr_##_name = __ATTR_WO(_name)
 
 extern int __must_check class_create_file_ns(struct class *class,
 					     const struct class_attribute *attr,
@@ -726,6 +730,87 @@ struct device_dma_parameters {
 	unsigned long segment_boundary_mask;
 };
 
+/**
+ * enum device_link_state - Device link states.
+ * @DL_STATE_NONE: The presence of the drivers is not being tracked.
+ * @DL_STATE_DORMANT: None of the supplier/consumer drivers is present.
+ * @DL_STATE_AVAILABLE: The supplier driver is present, but the consumer is not.
+ * @DL_STATE_CONSUMER_PROBE: The consumer is probing (supplier driver present).
+ * @DL_STATE_ACTIVE: Both the supplier and consumer drivers are present.
+ * @DL_STATE_SUPPLIER_UNBIND: The supplier driver is unbinding.
+ */
+enum device_link_state {
+	DL_STATE_NONE = -1,
+	DL_STATE_DORMANT = 0,
+	DL_STATE_AVAILABLE,
+	DL_STATE_CONSUMER_PROBE,
+	DL_STATE_ACTIVE,
+	DL_STATE_SUPPLIER_UNBIND,
+};
+
+/*
+ * Device link flags.
+ *
+ * STATELESS: The core won't track the presence of supplier/consumer drivers.
+ * AUTOREMOVE: Remove this link automatically on consumer driver unbind.
+ * PM_RUNTIME: If set, the runtime PM framework will use this link.
+ * RPM_ACTIVE: Run pm_runtime_get_sync() on the supplier during link creation.
+ */
+#define DL_FLAG_STATELESS	BIT(0)
+#define DL_FLAG_AUTOREMOVE	BIT(1)
+#define DL_FLAG_PM_RUNTIME	BIT(2)
+#define DL_FLAG_RPM_ACTIVE	BIT(3)
+
+/**
+ * struct device_link - Device link representation.
+ * @supplier: The device on the supplier end of the link.
+ * @s_node: Hook to the supplier device's list of links to consumers.
+ * @consumer: The device on the consumer end of the link.
+ * @c_node: Hook to the consumer device's list of links to suppliers.
+ * @status: The state of the link (with respect to the presence of drivers).
+ * @flags: Link flags.
+ * @rpm_active: Whether or not the consumer device is runtime-PM-active.
+ * @rcu_head: An RCU head to use for deferred execution of SRCU callbacks.
+ */
+struct device_link {
+	struct device *supplier;
+	struct list_head s_node;
+	struct device *consumer;
+	struct list_head c_node;
+	enum device_link_state status;
+	u32 flags;
+	bool rpm_active;
+#ifdef CONFIG_SRCU
+	struct rcu_head rcu_head;
+#endif
+};
+
+/**
+ * enum dl_dev_state - Device driver presence tracking information.
+ * @DL_DEV_NO_DRIVER: There is no driver attached to the device.
+ * @DL_DEV_PROBING: A driver is probing.
+ * @DL_DEV_DRIVER_BOUND: The driver has been bound to the device.
+ * @DL_DEV_UNBINDING: The driver is unbinding from the device.
+ */
+enum dl_dev_state {
+	DL_DEV_NO_DRIVER = 0,
+	DL_DEV_PROBING,
+	DL_DEV_DRIVER_BOUND,
+	DL_DEV_UNBINDING,
+};
+
+/**
+ * struct dev_links_info - Device data related to device links.
+ * @suppliers: List of links to supplier devices.
+ * @consumers: List of links to consumer devices.
+ * @status: Driver status information.
+ */
+struct dev_links_info {
+	struct list_head suppliers;
+	struct list_head consumers;
+	enum dl_dev_state status;
+};
+
 /**
  * struct device - The basic device structure
  * @parent:	The device's "parent" device, the device to which it is attached.
@@ -751,6 +836,7 @@ struct device_dma_parameters {
  * 		on.  This shrinks the "Board Support Packages" (BSPs) and
  * 		minimizes board-specific #ifdefs in drivers.
  * @driver_data: Private pointer for driver specific info.
+ * @links:	Links to suppliers and consumers of this device.
  * @power:	For device power management.
  * 		See Documentation/power/admin-guide/devices.rst for details.
  * @pm_domain:	Provide callbacks that are executed during system suspend,
@@ -818,6 +904,7 @@ struct device {
 					   core doesn't touch it */
 	void		*driver_data;	/* Driver data, set and get with
 					   dev_set/get_drvdata */
+	struct dev_links_info	links;
 	struct dev_pm_info	power;
 	struct dev_pm_domain	*pm_domain;
 
@@ -1135,6 +1222,10 @@ extern void device_shutdown(void);
 /* debugging and troubleshooting/diagnostic helpers. */
 extern const char *dev_driver_string(const struct device *dev);
 
+/* Device links interface. */
+struct device_link *device_link_add(struct device *consumer,
+				    struct device *supplier, u32 flags);
+void device_link_del(struct device_link *link);
 
 #ifdef CONFIG_PRINTK
 

include/linux/pm.h

@@ -559,6 +559,7 @@ struct dev_pm_info {
 	pm_message_t		power_state;
 	unsigned int		can_wakeup:1;
 	unsigned int		async_suspend:1;
+	bool			in_dpm_list:1;	/* Owned by the PM core */
 	bool			is_prepared:1;	/* Owned by the PM core */
 	bool			is_suspended:1;	/* Ditto */
 	bool			is_noirq_suspended:1;
@@ -596,6 +597,7 @@ struct dev_pm_info {
 	unsigned int		use_autosuspend:1;
 	unsigned int		timer_autosuspends:1;
 	unsigned int		memalloc_noio:1;
+	unsigned int		links_count;
 	enum rpm_request	request;
 	enum rpm_status		runtime_status;
 	int			runtime_error;

include/linux/pm_runtime.h

@@ -55,6 +55,11 @@ extern unsigned long pm_runtime_autosuspend_expiration(struct device *dev);
 extern void pm_runtime_update_max_time_suspended(struct device *dev,
 						 s64 delta_ns);
 extern void pm_runtime_set_memalloc_noio(struct device *dev, bool enable);
+extern void pm_runtime_clean_up_links(struct device *dev);
+extern void pm_runtime_get_suppliers(struct device *dev);
+extern void pm_runtime_put_suppliers(struct device *dev);
+extern void pm_runtime_new_link(struct device *dev);
+extern void pm_runtime_drop_link(struct device *dev);
 
 static inline void pm_suspend_ignore_children(struct device *dev, bool enable)
 {
@@ -179,6 +184,11 @@ static inline unsigned long pm_runtime_autosuspend_expiration(
 				struct device *dev) { return 0; }
 static inline void pm_runtime_set_memalloc_noio(struct device *dev,
 						bool enable){}
+static inline void pm_runtime_clean_up_links(struct device *dev) {}
+static inline void pm_runtime_get_suppliers(struct device *dev) {}
+static inline void pm_runtime_put_suppliers(struct device *dev) {}
+static inline void pm_runtime_new_link(struct device *dev) {}
+static inline void pm_runtime_drop_link(struct device *dev) {}
 
 #endif /* !CONFIG_PM */
 

lib/kobject_uevent.c

@@ -56,7 +56,7 @@ static const char *kobject_actions[] = {
  * kobject_action_type - translate action string to numeric type
  *
  * @buf: buffer containing the action string, newline is ignored
- * @len: length of buffer
+ * @count: length of buffer
  * @type: pointer to the location to store the action type
  *
  * Returns 0 if the action string was recognized.
@@ -154,8 +154,8 @@ static void cleanup_uevent_env(struct subprocess_info *info)
 /**
  * kobject_uevent_env - send an uevent with environmental data
  *
- * @action: action that is happening
  * @kobj: struct kobject that the action is happening to
+ * @action: action that is happening
  * @envp_ext: pointer to environmental data
  *
  * Returns 0 if kobject_uevent_env() is completed with success or the
@@ -363,8 +363,8 @@ EXPORT_SYMBOL_GPL(kobject_uevent_env);
 /**
  * kobject_uevent - notify userspace by sending an uevent
  *
- * @action: action that is happening
  * @kobj: struct kobject that the action is happening to
+ * @action: action that is happening
  *
  * Returns 0 if kobject_uevent() is completed with success or the
  * corresponding error when it fails.