Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 1438 insertions, 0 deletions

diff --git a/drivers/base/dd.c b/drivers/base/dd.c
new file mode 100644
index 000000000..f6525a7ee
--- /dev/null
+++ b/drivers/base/dd.c
@@ -0,0 +1,1438 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * drivers/base/dd.c - The core device/driver interactions.
+ *
+ * This file contains the (sometimes tricky) code that controls the
+ * interactions between devices and drivers, which primarily includes
+ * driver binding and unbinding.
+ *
+ * All of this code used to exist in drivers/base/bus.c, but was
+ * relocated to here in the name of compartmentalization (since it wasn't
+ * strictly code just for the 'struct bus_type'.
+ *
+ * Copyright (c) 2002-5 Patrick Mochel
+ * Copyright (c) 2002-3 Open Source Development Labs
+ * Copyright (c) 2007-2009 Greg Kroah-Hartman <gregkh@suse.de>
+ * Copyright (c) 2007-2009 Novell Inc.
+ */
+
+#include <linux/debugfs.h>
+#include <linux/device.h>
+#include <linux/delay.h>
+#include <linux/dma-map-ops.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kthread.h>
+#include <linux/wait.h>
+#include <linux/async.h>
+#include <linux/pm_domain.h>
+#include <linux/pm_runtime.h>
+#include <linux/pinctrl/devinfo.h>
+#include <linux/slab.h>
+
+#include "base.h"
+#include "power/power.h"
+
+/*
+ * Deferred Probe infrastructure.
+ *
+ * Sometimes driver probe order matters, but the kernel doesn't always have
+ * dependency information which means some drivers will get probed before a
+ * resource it depends on is available.  For example, an SDHCI driver may
+ * first need a GPIO line from an i2c GPIO controller before it can be
+ * initialized.  If a required resource is not available yet, a driver can
+ * request probing to be deferred by returning -EPROBE_DEFER from its probe hook
+ *
+ * Deferred probe maintains two lists of devices, a pending list and an active
+ * list.  A driver returning -EPROBE_DEFER causes the device to be added to the
+ * pending list.  A successful driver probe will trigger moving all devices
+ * from the pending to the active list so that the workqueue will eventually
+ * retry them.
+ *
+ * The deferred_probe_mutex must be held any time the deferred_probe_*_list
+ * of the (struct device*)->p->deferred_probe pointers are manipulated
+ */
+static DEFINE_MUTEX(deferred_probe_mutex);
+static LIST_HEAD(deferred_probe_pending_list);
+static LIST_HEAD(deferred_probe_active_list);
+static atomic_t deferred_trigger_count = ATOMIC_INIT(0);
+static bool initcalls_done;
+
+/* Save the async probe drivers' name from kernel cmdline */
+#define ASYNC_DRV_NAMES_MAX_LEN	256
+static char async_probe_drv_names[ASYNC_DRV_NAMES_MAX_LEN];
+static bool async_probe_default;
+
+/*
+ * In some cases, like suspend to RAM or hibernation, It might be reasonable
+ * to prohibit probing of devices as it could be unsafe.
+ * Once defer_all_probes is true all drivers probes will be forcibly deferred.
+ */
+static bool defer_all_probes;
+
+static void __device_set_deferred_probe_reason(const struct device *dev, char *reason)
+{
+	kfree(dev->p->deferred_probe_reason);
+	dev->p->deferred_probe_reason = reason;
+}
+
+/*
+ * deferred_probe_work_func() - Retry probing devices in the active list.
+ */
+static void deferred_probe_work_func(struct work_struct *work)
+{
+	struct device *dev;
+	struct device_private *private;
+	/*
+	 * This block processes every device in the deferred 'active' list.
+	 * Each device is removed from the active list and passed to
+	 * bus_probe_device() to re-attempt the probe.  The loop continues
+	 * until every device in the active list is removed and retried.
+	 *
+	 * Note: Once the device is removed from the list and the mutex is
+	 * released, it is possible for the device get freed by another thread
+	 * and cause a illegal pointer dereference.  This code uses
+	 * get/put_device() to ensure the device structure cannot disappear
+	 * from under our feet.
+	 */
+	mutex_lock(&deferred_probe_mutex);
+	while (!list_empty(&deferred_probe_active_list)) {
+		private = list_first_entry(&deferred_probe_active_list,
+					typeof(*dev->p), deferred_probe);
+		dev = private->device;
+		list_del_init(&private->deferred_probe);
+
+		get_device(dev);
+
+		__device_set_deferred_probe_reason(dev, NULL);
+
+		/*
+		 * Drop the mutex while probing each device; the probe path may
+		 * manipulate the deferred list
+		 */
+		mutex_unlock(&deferred_probe_mutex);
+
+		/*
+		 * Force the device to the end of the dpm_list since
+		 * the PM code assumes that the order we add things to
+		 * the list is a good order for suspend but deferred
+		 * probe makes that very unsafe.
+		 */
+		device_pm_move_to_tail(dev);
+
+		dev_dbg(dev, "Retrying from deferred list\n");
+		bus_probe_device(dev);
+		mutex_lock(&deferred_probe_mutex);
+
+		put_device(dev);
+	}
+	mutex_unlock(&deferred_probe_mutex);
+}
+static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func);
+
+void driver_deferred_probe_add(struct device *dev)
+{
+	if (!dev_can_match(dev))
+		return;
+
+	mutex_lock(&deferred_probe_mutex);
+	if (list_empty(&dev->p->deferred_probe)) {
+		dev_dbg(dev, "Added to deferred list\n");
+		list_add_tail(&dev->p->deferred_probe, &deferred_probe_pending_list);
+	}
+	mutex_unlock(&deferred_probe_mutex);
+}
+
+void driver_deferred_probe_del(struct device *dev)
+{
+	mutex_lock(&deferred_probe_mutex);
+	if (!list_empty(&dev->p->deferred_probe)) {
+		dev_dbg(dev, "Removed from deferred list\n");
+		list_del_init(&dev->p->deferred_probe);
+		__device_set_deferred_probe_reason(dev, NULL);
+	}
+	mutex_unlock(&deferred_probe_mutex);
+}
+
+static bool driver_deferred_probe_enable;
+/**
+ * driver_deferred_probe_trigger() - Kick off re-probing deferred devices
+ *
+ * This functions moves all devices from the pending list to the active
+ * list and schedules the deferred probe workqueue to process them.  It
+ * should be called anytime a driver is successfully bound to a device.
+ *
+ * Note, there is a race condition in multi-threaded probe. In the case where
+ * more than one device is probing at the same time, it is possible for one
+ * probe to complete successfully while another is about to defer. If the second
+ * depends on the first, then it will get put on the pending list after the
+ * trigger event has already occurred and will be stuck there.
+ *
+ * The atomic 'deferred_trigger_count' is used to determine if a successful
+ * trigger has occurred in the midst of probing a driver. If the trigger count
+ * changes in the midst of a probe, then deferred processing should be triggered
+ * again.
+ */
+void driver_deferred_probe_trigger(void)
+{
+	if (!driver_deferred_probe_enable)
+		return;
+
+	/*
+	 * A successful probe means that all the devices in the pending list
+	 * should be triggered to be reprobed.  Move all the deferred devices
+	 * into the active list so they can be retried by the workqueue
+	 */
+	mutex_lock(&deferred_probe_mutex);
+	atomic_inc(&deferred_trigger_count);
+	list_splice_tail_init(&deferred_probe_pending_list,
+			      &deferred_probe_active_list);
+	mutex_unlock(&deferred_probe_mutex);
+
+	/*
+	 * Kick the re-probe thread.  It may already be scheduled, but it is
+	 * safe to kick it again.
+	 */
+	queue_work(system_dfl_wq, &deferred_probe_work);
+}
+
+/**
+ * device_block_probing() - Block/defer device's probes
+ *
+ *	It will disable probing of devices and defer their probes instead.
+ */
+void device_block_probing(void)
+{
+	defer_all_probes = true;
+	/* sync with probes to avoid races. */
+	wait_for_device_probe();
+}
+
+/**
+ * device_unblock_probing() - Unblock/enable device's probes
+ *
+ *	It will restore normal behavior and trigger re-probing of deferred
+ * devices.
+ */
+void device_unblock_probing(void)
+{
+	defer_all_probes = false;
+	driver_deferred_probe_trigger();
+}
+
+/**
+ * device_set_deferred_probe_reason() - Set defer probe reason message for device
+ * @dev: the pointer to the struct device
+ * @vaf: the pointer to va_format structure with message
+ */
+void device_set_deferred_probe_reason(const struct device *dev, struct va_format *vaf)
+{
+	const char *drv = dev_driver_string(dev);
+	char *reason;
+
+	mutex_lock(&deferred_probe_mutex);
+
+	reason = kasprintf(GFP_KERNEL, "%s: %pV", drv, vaf);
+	__device_set_deferred_probe_reason(dev, reason);
+
+	mutex_unlock(&deferred_probe_mutex);
+}
+
+/*
+ * deferred_devs_show() - Show the devices in the deferred probe pending list.
+ */
+static int deferred_devs_show(struct seq_file *s, void *data)
+{
+	struct device_private *curr;
+
+	mutex_lock(&deferred_probe_mutex);
+
+	list_for_each_entry(curr, &deferred_probe_pending_list, deferred_probe)
+		seq_printf(s, "%s\t%s", dev_name(curr->device),
+			   curr->deferred_probe_reason ?: "\n");
+
+	mutex_unlock(&deferred_probe_mutex);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(deferred_devs);
+
+static int driver_deferred_probe_timeout = CONFIG_DRIVER_DEFERRED_PROBE_TIMEOUT;
+
+static int __init deferred_probe_timeout_setup(char *str)
+{
+	int timeout;
+
+	if (!kstrtoint(str, 10, &timeout))
+		driver_deferred_probe_timeout = timeout;
+	return 1;
+}
+__setup("deferred_probe_timeout=", deferred_probe_timeout_setup);
+
+/**
+ * driver_deferred_probe_check_state() - Check deferred probe state
+ * @dev: device to check
+ *
+ * Return:
+ * * -ENODEV if initcalls have completed and modules are disabled.
+ * * -ETIMEDOUT if the deferred probe timeout was set and has expired
+ *   and modules are enabled.
+ * * -EPROBE_DEFER in other cases.
+ *
+ * Drivers or subsystems can opt-in to calling this function instead of directly
+ * returning -EPROBE_DEFER.
+ */
+int driver_deferred_probe_check_state(struct device *dev)
+{
+	if (!IS_ENABLED(CONFIG_MODULES) && initcalls_done) {
+		dev_warn(dev, "ignoring dependency for device, assuming no driver\n");
+		return -ENODEV;
+	}
+
+	if (!driver_deferred_probe_timeout && initcalls_done) {
+		dev_warn(dev, "deferred probe timeout, ignoring dependency\n");
+		return -ETIMEDOUT;
+	}
+
+	return -EPROBE_DEFER;
+}
+EXPORT_SYMBOL_GPL(driver_deferred_probe_check_state);
+
+static void deferred_probe_timeout_work_func(struct work_struct *work)
+{
+	struct device_private *p;
+
+	fw_devlink_drivers_done();
+
+	driver_deferred_probe_timeout = 0;
+	driver_deferred_probe_trigger();
+	flush_work(&deferred_probe_work);
+
+	mutex_lock(&deferred_probe_mutex);
+	list_for_each_entry(p, &deferred_probe_pending_list, deferred_probe)
+		dev_warn(p->device, "deferred probe pending: %s", p->deferred_probe_reason ?: "(reason unknown)\n");
+	mutex_unlock(&deferred_probe_mutex);
+
+	fw_devlink_probing_done();
+}
+static DECLARE_DELAYED_WORK(deferred_probe_timeout_work, deferred_probe_timeout_work_func);
+
+void deferred_probe_extend_timeout(void)
+{
+	/*
+	 * If the work hasn't been queued yet or if the work expired, don't
+	 * start a new one.
+	 */
+	if (delayed_work_pending(&deferred_probe_timeout_work) &&
+	    mod_delayed_work(system_percpu_wq, &deferred_probe_timeout_work,
+			     secs_to_jiffies(driver_deferred_probe_timeout)))
+		pr_debug("Extended deferred probe timeout by %d secs\n",
+					driver_deferred_probe_timeout);
+}
+
+/**
+ * deferred_probe_initcall() - Enable probing of deferred devices
+ *
+ * We don't want to get in the way when the bulk of drivers are getting probed.
+ * Instead, this initcall makes sure that deferred probing is delayed until
+ * late_initcall time.
+ */
+static int deferred_probe_initcall(void)
+{
+	debugfs_create_file("devices_deferred", 0444, NULL, NULL,
+			    &deferred_devs_fops);
+
+	driver_deferred_probe_enable = true;
+	driver_deferred_probe_trigger();
+	/* Sort as many dependencies as possible before exiting initcalls */
+	flush_work(&deferred_probe_work);
+	initcalls_done = true;
+
+	if (!IS_ENABLED(CONFIG_MODULES))
+		fw_devlink_drivers_done();
+
+	/*
+	 * Trigger deferred probe again, this time we won't defer anything
+	 * that is optional
+	 */
+	driver_deferred_probe_trigger();
+	flush_work(&deferred_probe_work);
+
+	if (driver_deferred_probe_timeout > 0) {
+		schedule_delayed_work(&deferred_probe_timeout_work,
+			driver_deferred_probe_timeout * HZ);
+	}
+
+	if (!IS_ENABLED(CONFIG_MODULES))
+		fw_devlink_probing_done();
+
+	return 0;
+}
+late_initcall(deferred_probe_initcall);
+
+static void __exit deferred_probe_exit(void)
+{
+	debugfs_lookup_and_remove("devices_deferred", NULL);
+}
+__exitcall(deferred_probe_exit);
+
+int __device_set_driver_override(struct device *dev, const char *s, size_t len)
+{
+	const char *new = NULL, *old;
+
+	if (!s)
+		return -EINVAL;
+
+	/*
+	 * The stored value will be used in sysfs show callback (sysfs_emit()),
+	 * which has a length limit of PAGE_SIZE and adds a trailing newline.
+	 * Thus we can store one character less to avoid truncation during sysfs
+	 * show.
+	 */
+	if (len >= (PAGE_SIZE - 1))
+		return -EINVAL;
+
+	/*
+	 * Compute the real length of the string in case userspace sends us a
+	 * bunch of \0 characters like python likes to do.
+	 */
+	len = strlen(s);
+
+	/* Handle trailing newline */
+	if (len) {
+		char *cp;
+
+		cp = strnchr(s, len, '\n');
+		if (cp)
+			len = cp - s;
+	}
+
+	/*
+	 * If empty string or "\n" passed, new remains NULL, clearing
+	 * the driver_override.name.
+	 */
+	if (len) {
+		new = kstrndup(s, len, GFP_KERNEL);
+		if (!new)
+			return -ENOMEM;
+	}
+
+	scoped_guard(spinlock, &dev->driver_override.lock) {
+		old = dev->driver_override.name;
+		dev->driver_override.name = new;
+	}
+
+	kfree(old);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(__device_set_driver_override);
+
+/**
+ * device_is_bound() - Check if device is bound to a driver
+ * @dev: device to check
+ *
+ * Returns true if passed device has already finished probing successfully
+ * against a driver.
+ *
+ * This function must be called with the device lock held.
+ */
+bool device_is_bound(struct device *dev)
+{
+	return dev->p && klist_node_attached(&dev->p->knode_driver);
+}
+EXPORT_SYMBOL_GPL(device_is_bound);
+
+static void driver_bound(struct device *dev)
+{
+	if (device_is_bound(dev)) {
+		dev_warn(dev, "%s: device already bound\n", __func__);
+		return;
+	}
+
+	dev_dbg(dev, "driver: '%s': %s: bound to device\n", dev->driver->name,
+		__func__);
+
+	klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices);
+	device_links_driver_bound(dev);
+
+	device_pm_check_callbacks(dev);
+
+	/*
+	 * Make sure the device is no longer in one of the deferred lists and
+	 * kick off retrying all pending devices
+	 */
+	driver_deferred_probe_del(dev);
+	driver_deferred_probe_trigger();
+
+	bus_notify(dev, BUS_NOTIFY_BOUND_DRIVER);
+	kobject_uevent(&dev->kobj, KOBJ_BIND);
+}
+
+static ssize_t coredump_store(struct device *dev, struct device_attribute *attr,
+			    const char *buf, size_t count)
+{
+	device_lock(dev);
+	dev->driver->coredump(dev);
+	device_unlock(dev);
+
+	return count;
+}
+static DEVICE_ATTR_WO(coredump);
+
+static int driver_sysfs_add(struct device *dev)
+{
+	int ret;
+
+	bus_notify(dev, BUS_NOTIFY_BIND_DRIVER);
+
+	ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj,
+				kobject_name(&dev->kobj));
+	if (ret)
+		goto fail;
+
+	ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj,
+				"driver");
+	if (ret)
+		goto rm_dev;
+
+	if (!IS_ENABLED(CONFIG_DEV_COREDUMP) || !dev->driver->coredump)
+		return 0;
+
+	ret = device_create_file(dev, &dev_attr_coredump);
+	if (!ret)
+		return 0;
+
+	sysfs_remove_link(&dev->kobj, "driver");
+
+rm_dev:
+	sysfs_remove_link(&dev->driver->p->kobj,
+			  kobject_name(&dev->kobj));
+
+fail:
+	return ret;
+}
+
+static void driver_sysfs_remove(struct device *dev)
+{
+	struct device_driver *drv = dev->driver;
+
+	if (drv) {
+		if (drv->coredump)
+			device_remove_file(dev, &dev_attr_coredump);
+		sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj));
+		sysfs_remove_link(&dev->kobj, "driver");
+	}
+}
+
+/**
+ * device_bind_driver - bind a driver to one device.
+ * @dev: device.
+ *
+ * Allow manual attachment of a driver to a device.
+ * Caller must have already set @dev->driver.
+ *
+ * Note that this does not modify the bus reference count.
+ * Please verify that is accounted for before calling this.
+ * (It is ok to call with no other effort from a driver's probe() method.)
+ *
+ * This function must be called with the device lock held.
+ *
+ * Callers should prefer to use device_driver_attach() instead.
+ */
+int device_bind_driver(struct device *dev)
+{
+	int ret;
+
+	ret = driver_sysfs_add(dev);
+	if (!ret) {
+		device_links_force_bind(dev);
+		driver_bound(dev);
+	}
+	else
+		bus_notify(dev, BUS_NOTIFY_DRIVER_NOT_BOUND);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(device_bind_driver);
+
+static atomic_t probe_count = ATOMIC_INIT(0);
+static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
+
+static ssize_t state_synced_store(struct device *dev,
+				  struct device_attribute *attr,
+				  const char *buf, size_t count)
+{
+	int ret = 0;
+
+	if (strcmp("1", buf))
+		return -EINVAL;
+
+	device_lock(dev);
+	if (!dev_test_and_set_state_synced(dev))
+		dev_sync_state(dev);
+	else
+		ret = -EINVAL;
+	device_unlock(dev);
+
+	return ret ? ret : count;
+}
+
+static ssize_t state_synced_show(struct device *dev,
+				 struct device_attribute *attr, char *buf)
+{
+	bool val;
+
+	device_lock(dev);
+	val = dev_state_synced(dev);
+	device_unlock(dev);
+
+	return sysfs_emit(buf, "%u\n", val);
+}
+static DEVICE_ATTR_RW(state_synced);
+
+static void device_unbind_cleanup(struct device *dev)
+{
+	if (dev->driver->p_cb.post_unbind_rust)
+		dev->driver->p_cb.post_unbind_rust(dev);
+	devres_release_all(dev);
+	arch_teardown_dma_ops(dev);
+	kfree(dev->dma_range_map);
+	dev->dma_range_map = NULL;
+	device_set_driver(dev, NULL);
+	dev_set_drvdata(dev, NULL);
+	dev_pm_domain_detach(dev, dev->power.detach_power_off);
+	if (dev->pm_domain && dev->pm_domain->dismiss)
+		dev->pm_domain->dismiss(dev);
+	pm_runtime_reinit(dev);
+	dev_pm_set_driver_flags(dev, 0);
+}
+
+static void device_remove(struct device *dev)
+{
+	device_remove_file(dev, &dev_attr_state_synced);
+	device_remove_groups(dev, dev->driver->dev_groups);
+
+	if (dev->bus && dev->bus->remove)
+		dev->bus->remove(dev);
+	else if (dev->driver->remove)
+		dev->driver->remove(dev);
+}
+
+static int call_driver_probe(struct device *dev, const struct device_driver *drv)
+{
+	int ret = 0;
+
+	if (dev->bus->probe)
+		ret = dev->bus->probe(dev);
+	else if (drv->probe)
+		ret = drv->probe(dev);
+
+	switch (ret) {
+	case 0:
+		break;
+	case -EPROBE_DEFER:
+		/* Driver requested deferred probing */
+		dev_dbg(dev, "Driver %s requests probe deferral\n", drv->name);
+		break;
+	case -ENODEV:
+	case -ENXIO:
+		dev_dbg(dev, "probe with driver %s rejects match %d\n",
+			drv->name, ret);
+		break;
+	default:
+		/* driver matched but the probe failed */
+		dev_err(dev, "probe with driver %s failed with error %d\n",
+			drv->name, ret);
+		break;
+	}
+
+	return ret;
+}
+
+static int really_probe(struct device *dev, const struct device_driver *drv)
+{
+	bool test_remove = IS_ENABLED(CONFIG_DEBUG_TEST_DRIVER_REMOVE) &&
+			   !drv->suppress_bind_attrs;
+	int ret, link_ret;
+
+	if (defer_all_probes) {
+		/*
+		 * Value of defer_all_probes can be set only by
+		 * device_block_probing() which, in turn, will call
+		 * wait_for_device_probe() right after that to avoid any races.
+		 */
+		dev_dbg(dev, "Driver %s force probe deferral\n", drv->name);
+		return -EPROBE_DEFER;
+	}
+
+	link_ret = device_links_check_suppliers(dev);
+	if (link_ret == -EPROBE_DEFER)
+		return link_ret;
+
+	dev_dbg(dev, "bus: '%s': %s: probing driver %s with device\n",
+		drv->bus->name, __func__, drv->name);
+	if (!list_empty(&dev->devres_head)) {
+		dev_crit(dev, "Resources present before probing\n");
+		ret = -EBUSY;
+		goto done;
+	}
+
+re_probe:
+	device_set_driver(dev, drv);
+
+	/* If using pinctrl, bind pins now before probing */
+	ret = pinctrl_bind_pins(dev);
+	if (ret)
+		goto pinctrl_bind_failed;
+
+	if (dev->bus->dma_configure) {
+		ret = dev->bus->dma_configure(dev);
+		if (ret)
+			goto pinctrl_bind_failed;
+	}
+
+	ret = driver_sysfs_add(dev);
+	if (ret) {
+		dev_err(dev, "%s: driver_sysfs_add failed\n", __func__);
+		goto sysfs_failed;
+	}
+
+	if (dev->pm_domain && dev->pm_domain->activate) {
+		ret = dev->pm_domain->activate(dev);
+		if (ret)
+			goto probe_failed;
+	}
+
+	ret = call_driver_probe(dev, drv);
+	if (ret) {
+		/*
+		 * If fw_devlink_best_effort is active (denoted by -EAGAIN), the
+		 * device might actually probe properly once some of its missing
+		 * suppliers have probed. So, treat this as if the driver
+		 * returned -EPROBE_DEFER.
+		 */
+		if (link_ret == -EAGAIN)
+			ret = -EPROBE_DEFER;
+
+		/*
+		 * Return probe errors as positive values so that the callers
+		 * can distinguish them from other errors.
+		 */
+		ret = -ret;
+		goto probe_failed;
+	}
+
+	ret = device_add_groups(dev, drv->dev_groups);
+	if (ret) {
+		dev_err(dev, "device_add_groups() failed\n");
+		goto dev_groups_failed;
+	}
+
+	if (dev_has_sync_state(dev)) {
+		ret = device_create_file(dev, &dev_attr_state_synced);
+		if (ret) {
+			dev_err(dev, "state_synced sysfs add failed\n");
+			goto dev_sysfs_state_synced_failed;
+		}
+	}
+
+	if (test_remove) {
+		test_remove = false;
+
+		device_remove(dev);
+		driver_sysfs_remove(dev);
+		if (dev->bus && dev->bus->dma_cleanup)
+			dev->bus->dma_cleanup(dev);
+		device_unbind_cleanup(dev);
+
+		goto re_probe;
+	}
+
+	pinctrl_init_done(dev);
+
+	if (dev->pm_domain && dev->pm_domain->sync)
+		dev->pm_domain->sync(dev);
+
+	driver_bound(dev);
+	dev_dbg(dev, "bus: '%s': %s: bound device to driver %s\n",
+		drv->bus->name, __func__, drv->name);
+	goto done;
+
+dev_sysfs_state_synced_failed:
+dev_groups_failed:
+	device_remove(dev);
+probe_failed:
+	driver_sysfs_remove(dev);
+sysfs_failed:
+	bus_notify(dev, BUS_NOTIFY_DRIVER_NOT_BOUND);
+	if (dev->bus && dev->bus->dma_cleanup)
+		dev->bus->dma_cleanup(dev);
+pinctrl_bind_failed:
+	device_links_no_driver(dev);
+	device_unbind_cleanup(dev);
+done:
+	return ret;
+}
+
+/*
+ * For initcall_debug, show the driver probe time.
+ */
+static int really_probe_debug(struct device *dev, const struct device_driver *drv)
+{
+	ktime_t calltime, rettime;
+	int ret;
+
+	calltime = ktime_get();
+	ret = really_probe(dev, drv);
+	rettime = ktime_get();
+	/*
+	 * Don't change this to pr_debug() because that requires
+	 * CONFIG_DYNAMIC_DEBUG and we want a simple 'initcall_debug' on the
+	 * kernel commandline to print this all the time at the debug level.
+	 */
+	printk(KERN_DEBUG "probe of %s with driver %s returned %d after %lld usecs\n",
+	       dev_name(dev), drv->name, ret, ktime_us_delta(rettime, calltime));
+	return ret;
+}
+
+/**
+ * driver_probe_done
+ * Determine if the probe sequence is finished or not.
+ *
+ * Should somehow figure out how to use a semaphore, not an atomic variable...
+ */
+bool __init driver_probe_done(void)
+{
+	int local_probe_count = atomic_read(&probe_count);
+
+	pr_debug("%s: probe_count = %d\n", __func__, local_probe_count);
+	return !local_probe_count;
+}
+
+/**
+ * wait_for_device_probe
+ * Wait for device probing to be completed.
+ */
+void wait_for_device_probe(void)
+{
+	/* wait for the deferred probe workqueue to finish */
+	flush_work(&deferred_probe_work);
+
+	/* wait for the known devices to complete their probing */
+	wait_event(probe_waitqueue, atomic_read(&probe_count) == 0);
+	async_synchronize_full();
+}
+EXPORT_SYMBOL_GPL(wait_for_device_probe);
+
+static int __driver_probe_device(const struct device_driver *drv, struct device *dev)
+{
+	int ret = 0;
+
+	if (dev->p->dead || !device_is_registered(dev))
+		return -ENODEV;
+	if (dev->driver)
+		return -EBUSY;
+
+	/*
+	 * In device_add(), the "struct device" gets linked into the subsystem's
+	 * list of devices and broadcast to userspace (via uevent) before we're
+	 * quite ready to probe. Those open pathways to driver probe before
+	 * we've finished enough of device_add() to reliably support probe.
+	 * Detect this and tell other pathways to try again later. device_add()
+	 * itself will also try to probe immediately after setting
+	 * "ready_to_probe".
+	 */
+	if (!dev_ready_to_probe(dev))
+		return dev_err_probe(dev, -EPROBE_DEFER, "Device not ready to probe\n");
+
+	/*
+	 * Call dev_set_can_match() after calling dev_ready_to_probe(), so
+	 * driver_deferred_probe_add() won't actually add the device to the
+	 * deferred probe list when dev_ready_to_probe() returns false.
+	 *
+	 * When dev_ready_to_probe() returns false, it means that device_add()
+	 * will do another probe() attempt for us.
+	 */
+	dev_set_can_match(dev);
+	dev_dbg(dev, "bus: '%s': %s: matched device with driver %s\n",
+		drv->bus->name, __func__, drv->name);
+
+	pm_runtime_get_suppliers(dev);
+	if (dev->parent)
+		pm_runtime_get_sync(dev->parent);
+
+	pm_runtime_barrier(dev);
+	if (initcall_debug)
+		ret = really_probe_debug(dev, drv);
+	else
+		ret = really_probe(dev, drv);
+	pm_request_idle(dev);
+
+	if (dev->parent)
+		pm_runtime_put(dev->parent);
+
+	pm_runtime_put_suppliers(dev);
+	return ret;
+}
+
+/**
+ * driver_probe_device - attempt to bind device & driver together
+ * @drv: driver to bind a device to
+ * @dev: device to try to bind to the driver
+ *
+ * This function returns -ENODEV if the device is not registered, -EBUSY if it
+ * already has a driver, 0 if the device is bound successfully and a positive
+ * (inverted) error code for failures from the ->probe method.
+ *
+ * This function must be called with @dev lock held.  When called for a
+ * USB interface, @dev->parent lock must be held as well.
+ *
+ * If the device has a parent, runtime-resume the parent before driver probing.
+ */
+static int driver_probe_device(const struct device_driver *drv, struct device *dev)
+{
+	int trigger_count = atomic_read(&deferred_trigger_count);
+	int ret;
+
+	atomic_inc(&probe_count);
+	ret = __driver_probe_device(drv, dev);
+	if (ret == -EPROBE_DEFER || ret == EPROBE_DEFER) {
+		driver_deferred_probe_add(dev);
+
+		/*
+		 * Did a trigger occur while probing? Need to re-trigger if yes
+		 */
+		if (trigger_count != atomic_read(&deferred_trigger_count) &&
+		    !defer_all_probes)
+			driver_deferred_probe_trigger();
+	}
+	atomic_dec(&probe_count);
+	wake_up_all(&probe_waitqueue);
+	return ret;
+}
+
+static inline bool cmdline_requested_async_probing(const char *drv_name)
+{
+	bool async_drv;
+
+	async_drv = parse_option_str(async_probe_drv_names, drv_name);
+
+	return (async_probe_default != async_drv);
+}
+
+/* The option format is "driver_async_probe=drv_name1,drv_name2,..." */
+static int __init save_async_options(char *buf)
+{
+	if (strlen(buf) >= ASYNC_DRV_NAMES_MAX_LEN)
+		pr_warn("Too long list of driver names for 'driver_async_probe'!\n");
+
+	strscpy(async_probe_drv_names, buf, ASYNC_DRV_NAMES_MAX_LEN);
+	async_probe_default = parse_option_str(async_probe_drv_names, "*");
+
+	return 1;
+}
+__setup("driver_async_probe=", save_async_options);
+
+static bool driver_allows_async_probing(const struct device_driver *drv)
+{
+	switch (drv->probe_type) {
+	case PROBE_PREFER_ASYNCHRONOUS:
+		return true;
+
+	case PROBE_FORCE_SYNCHRONOUS:
+		return false;
+
+	default:
+		if (cmdline_requested_async_probing(drv->name))
+			return true;
+
+		if (module_requested_async_probing(drv->owner))
+			return true;
+
+		return false;
+	}
+}
+
+struct device_attach_data {
+	struct device *dev;
+
+	/*
+	 * Indicates whether we are considering asynchronous probing or
+	 * not. Only initial binding after device or driver registration
+	 * (including deferral processing) may be done asynchronously, the
+	 * rest is always synchronous, as we expect it is being done by
+	 * request from userspace.
+	 */
+	bool check_async;
+
+	/*
+	 * Indicates if we are binding synchronous or asynchronous drivers.
+	 * When asynchronous probing is enabled we'll execute 2 passes
+	 * over drivers: first pass doing synchronous probing and second
+	 * doing asynchronous probing (if synchronous did not succeed -
+	 * most likely because there was no driver requiring synchronous
+	 * probing - and we found asynchronous driver during first pass).
+	 * The 2 passes are done because we can't shoot asynchronous
+	 * probe for given device and driver from bus_for_each_drv() since
+	 * driver pointer is not guaranteed to stay valid once
+	 * bus_for_each_drv() iterates to the next driver on the bus.
+	 */
+	bool want_async;
+
+	/*
+	 * We'll set have_async to 'true' if, while scanning for matching
+	 * driver, we'll encounter one that requests asynchronous probing.
+	 */
+	bool have_async;
+};
+
+static int __device_attach_driver(struct device_driver *drv, void *_data)
+{
+	struct device_attach_data *data = _data;
+	struct device *dev = data->dev;
+	bool async_allowed;
+	int ret;
+
+	ret = driver_match_device(drv, dev);
+	if (ret == 0) {
+		/* no match */
+		return 0;
+	} else if (ret == -EPROBE_DEFER) {
+		dev_dbg(dev, "Device match requests probe deferral\n");
+		dev_set_can_match(dev);
+		driver_deferred_probe_add(dev);
+		/*
+		 * Device can't match with a driver right now, so don't attempt
+		 * to match or bind with other drivers on the bus.
+		 */
+		return ret;
+	} else if (ret < 0) {
+		dev_dbg(dev, "Bus failed to match device: %d\n", ret);
+		return ret;
+	} /* ret > 0 means positive match */
+
+	async_allowed = driver_allows_async_probing(drv);
+
+	if (async_allowed)
+		data->have_async = true;
+
+	if (data->check_async && async_allowed != data->want_async)
+		return 0;
+
+	/*
+	 * Ignore errors returned by ->probe so that the next driver can try
+	 * its luck.
+	 */
+	ret = driver_probe_device(drv, dev);
+	if (ret < 0)
+		return ret;
+	return ret == 0;
+}
+
+static void __device_attach_async_helper(void *_dev, async_cookie_t cookie)
+{
+	struct device *dev = _dev;
+	struct device_attach_data data = {
+		.dev		= dev,
+		.check_async	= true,
+		.want_async	= true,
+	};
+
+	device_lock(dev);
+
+	/*
+	 * Check if device has already been removed or claimed. This may
+	 * happen with driver loading, device discovery/registration,
+	 * and deferred probe processing happens all at once with
+	 * multiple threads.
+	 */
+	if (dev->p->dead || dev->driver)
+		goto out_unlock;
+
+	if (dev->parent)
+		pm_runtime_get_sync(dev->parent);
+
+	bus_for_each_drv(dev->bus, NULL, &data, __device_attach_driver);
+	dev_dbg(dev, "async probe completed\n");
+
+	pm_request_idle(dev);
+
+	if (dev->parent)
+		pm_runtime_put(dev->parent);
+out_unlock:
+	device_unlock(dev);
+
+	put_device(dev);
+}
+
+static int __device_attach(struct device *dev, bool allow_async)
+{
+	int ret = 0;
+	bool async = false;
+
+	device_lock(dev);
+	if (dev->p->dead) {
+		goto out_unlock;
+	} else if (dev->driver) {
+		if (device_is_bound(dev)) {
+			ret = 1;
+			goto out_unlock;
+		}
+		ret = device_bind_driver(dev);
+		if (ret == 0)
+			ret = 1;
+		else {
+			device_set_driver(dev, NULL);
+			ret = 0;
+		}
+	} else {
+		struct device_attach_data data = {
+			.dev = dev,
+			.check_async = allow_async,
+			.want_async = false,
+		};
+
+		if (dev->parent)
+			pm_runtime_get_sync(dev->parent);
+
+		ret = bus_for_each_drv(dev->bus, NULL, &data,
+					__device_attach_driver);
+		if (!ret && allow_async && data.have_async) {
+			/*
+			 * If we could not find appropriate driver
+			 * synchronously and we are allowed to do
+			 * async probes and there are drivers that
+			 * want to probe asynchronously, we'll
+			 * try them.
+			 */
+			dev_dbg(dev, "scheduling asynchronous probe\n");
+			get_device(dev);
+			async = true;
+		} else {
+			pm_request_idle(dev);
+		}
+
+		if (dev->parent)
+			pm_runtime_put(dev->parent);
+	}
+out_unlock:
+	device_unlock(dev);
+	if (async)
+		async_schedule_dev(__device_attach_async_helper, dev);
+	return ret;
+}
+
+/**
+ * device_attach - try to attach device to a driver.
+ * @dev: device.
+ *
+ * Walk the list of drivers that the bus has and call
+ * driver_probe_device() for each pair. If a compatible
+ * pair is found, break out and return.
+ *
+ * Returns 1 if the device was bound to a driver;
+ * 0 if no matching driver was found;
+ * -ENODEV if the device is not registered.
+ *
+ * When called for a USB interface, @dev->parent lock must be held.
+ */
+int device_attach(struct device *dev)
+{
+	return __device_attach(dev, false);
+}
+EXPORT_SYMBOL_GPL(device_attach);
+
+void device_initial_probe(struct device *dev)
+{
+	struct subsys_private *sp = bus_to_subsys(dev->bus);
+
+	if (!sp)
+		return;
+
+	if (sp->drivers_autoprobe)
+		__device_attach(dev, true);
+
+	subsys_put(sp);
+}
+
+/*
+ * __device_driver_lock - acquire locks needed to manipulate dev->drv
+ * @dev: Device we will update driver info for
+ * @parent: Parent device. Needed if the bus requires parent lock
+ *
+ * This function will take the required locks for manipulating dev->drv.
+ * Normally this will just be the @dev lock, but when called for a USB
+ * interface, @parent lock will be held as well.
+ */
+static void __device_driver_lock(struct device *dev, struct device *parent)
+{
+	if (parent && dev->bus->need_parent_lock)
+		device_lock(parent);
+	device_lock(dev);
+}
+
+/*
+ * __device_driver_unlock - release locks needed to manipulate dev->drv
+ * @dev: Device we will update driver info for
+ * @parent: Parent device. Needed if the bus requires parent lock
+ *
+ * This function will release the required locks for manipulating dev->drv.
+ * Normally this will just be the @dev lock, but when called for a
+ * USB interface, @parent lock will be released as well.
+ */
+static void __device_driver_unlock(struct device *dev, struct device *parent)
+{
+	device_unlock(dev);
+	if (parent && dev->bus->need_parent_lock)
+		device_unlock(parent);
+}
+
+/**
+ * device_driver_attach - attach a specific driver to a specific device
+ * @drv: Driver to attach
+ * @dev: Device to attach it to
+ *
+ * Manually attach driver to a device. Will acquire both @dev lock and
+ * @dev->parent lock if needed. Returns 0 on success, -ERR on failure.
+ */
+int device_driver_attach(const struct device_driver *drv, struct device *dev)
+{
+	int ret;
+
+	__device_driver_lock(dev, dev->parent);
+	ret = __driver_probe_device(drv, dev);
+	__device_driver_unlock(dev, dev->parent);
+
+	/* also return probe errors as normal negative errnos */
+	if (ret > 0)
+		ret = -ret;
+	if (ret == -EPROBE_DEFER)
+		return -EAGAIN;
+	return ret;
+}
+EXPORT_SYMBOL_GPL(device_driver_attach);
+
+static void __driver_attach_async_helper(void *_dev, async_cookie_t cookie)
+{
+	struct device *dev = _dev;
+	const struct device_driver *drv;
+	int ret;
+
+	__device_driver_lock(dev, dev->parent);
+	drv = dev->p->async_driver;
+	dev->p->async_driver = NULL;
+	ret = driver_probe_device(drv, dev);
+	__device_driver_unlock(dev, dev->parent);
+
+	dev_dbg(dev, "driver %s async attach completed: %d\n", drv->name, ret);
+
+	put_device(dev);
+}
+
+static int __driver_attach(struct device *dev, void *data)
+{
+	const struct device_driver *drv = data;
+	bool async = false;
+	int ret;
+
+	/*
+	 * Lock device and try to bind to it. We drop the error
+	 * here and always return 0, because we need to keep trying
+	 * to bind to devices and some drivers will return an error
+	 * simply if it didn't support the device.
+	 *
+	 * driver_probe_device() will spit a warning if there
+	 * is an error.
+	 */
+
+	ret = driver_match_device(drv, dev);
+	if (ret == 0) {
+		/* no match */
+		return 0;
+	} else if (ret == -EPROBE_DEFER) {
+		dev_dbg(dev, "Device match requests probe deferral\n");
+		dev_set_can_match(dev);
+		driver_deferred_probe_add(dev);
+		/*
+		 * Driver could not match with device, but may match with
+		 * another device on the bus.
+		 */
+		return 0;
+	} else if (ret < 0) {
+		dev_dbg(dev, "Bus failed to match device: %d\n", ret);
+		/*
+		 * Driver could not match with device, but may match with
+		 * another device on the bus.
+		 */
+		return 0;
+	} /* ret > 0 means positive match */
+
+	if (driver_allows_async_probing(drv)) {
+		/*
+		 * Instead of probing the device synchronously we will
+		 * probe it asynchronously to allow for more parallelism.
+		 *
+		 * We only take the device lock here in order to guarantee
+		 * that the dev->driver and async_driver fields are protected
+		 */
+		dev_dbg(dev, "probing driver %s asynchronously\n", drv->name);
+		device_lock(dev);
+		if (!dev->driver && !dev->p->async_driver) {
+			get_device(dev);
+			dev->p->async_driver = drv;
+			async = true;
+		}
+		device_unlock(dev);
+		if (async)
+			async_schedule_dev(__driver_attach_async_helper, dev);
+		return 0;
+	}
+
+	__device_driver_lock(dev, dev->parent);
+	driver_probe_device(drv, dev);
+	__device_driver_unlock(dev, dev->parent);
+
+	return 0;
+}
+
+/**
+ * driver_attach - try to bind driver to devices.
+ * @drv: driver.
+ *
+ * Walk the list of devices that the bus has on it and try to
+ * match the driver with each one.  If driver_probe_device()
+ * returns 0 and the @dev->driver is set, we've found a
+ * compatible pair.
+ */
+int driver_attach(const struct device_driver *drv)
+{
+	/* The (void *) will be put back to const * in __driver_attach() */
+	return bus_for_each_dev(drv->bus, NULL, (void *)drv, __driver_attach);
+}
+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, struct device *parent)
+{
+	struct device_driver *drv;
+
+	drv = dev->driver;
+	if (drv) {
+		pm_runtime_get_sync(dev);
+
+		while (device_links_busy(dev)) {
+			__device_driver_unlock(dev, parent);
+
+			device_links_unbind_consumers(dev);
+
+			__device_driver_lock(dev, parent);
+			/*
+			 * 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) {
+				pm_runtime_put(dev);
+				return;
+			}
+		}
+
+		driver_sysfs_remove(dev);
+
+		bus_notify(dev, BUS_NOTIFY_UNBIND_DRIVER);
+
+		pm_runtime_put_sync(dev);
+
+		device_remove(dev);
+
+		if (dev->bus && dev->bus->dma_cleanup)
+			dev->bus->dma_cleanup(dev);
+
+		device_unbind_cleanup(dev);
+		device_links_driver_cleanup(dev);
+
+		klist_remove(&dev->p->knode_driver);
+		device_pm_check_callbacks(dev);
+
+		bus_notify(dev, BUS_NOTIFY_UNBOUND_DRIVER);
+		kobject_uevent(&dev->kobj, KOBJ_UNBIND);
+	}
+}
+
+void device_release_driver_internal(struct device *dev,
+				    const struct device_driver *drv,
+				    struct device *parent)
+{
+	__device_driver_lock(dev, parent);
+
+	if (!drv || drv == dev->driver)
+		__device_release_driver(dev, parent);
+
+	__device_driver_unlock(dev, 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)
+{
+	/*
+	 * If anyone calls device_release_driver() recursively from
+	 * within their ->remove callback for the same device, they
+	 * will deadlock right here.
+	 */
+	device_release_driver_internal(dev, NULL, NULL);
+}
+EXPORT_SYMBOL_GPL(device_release_driver);
+
+/**
+ * device_driver_detach - detach driver from a specific device
+ * @dev: device to detach driver from
+ *
+ * Detach driver from device. Will acquire both @dev lock and @dev->parent
+ * lock if needed.
+ */
+void device_driver_detach(struct device *dev)
+{
+	device_release_driver_internal(dev, NULL, dev->parent);
+}
+
+/**
+ * driver_detach - detach driver from all devices it controls.
+ * @drv: driver.
+ */
+void driver_detach(const struct device_driver *drv)
+{
+	struct device_private *dev_prv;
+	struct device *dev;
+
+	if (driver_allows_async_probing(drv))
+		async_synchronize_full();
+
+	for (;;) {
+		spin_lock(&drv->p->klist_devices.k_lock);
+		if (list_empty(&drv->p->klist_devices.k_list)) {
+			spin_unlock(&drv->p->klist_devices.k_lock);
+			break;
+		}
+		dev_prv = list_last_entry(&drv->p->klist_devices.k_list,
+				     struct device_private,
+				     knode_driver.n_node);
+		dev = dev_prv->device;
+		get_device(dev);
+		spin_unlock(&drv->p->klist_devices.k_lock);
+		device_release_driver_internal(dev, drv, dev->parent);
+		put_device(dev);
+	}
+}