Merge tag 'driver-core-4.21-rc1' of git://git.kernel.org/pub/scm/linu…

…x/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here is the "big" set of driver core patches for 4.21-rc1.

  It's not really big, just a number of small changes for some reported
  issues, some documentation updates to hopefully make it harder for
  people to abuse the driver model, and some other minor cleanups.

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

* tag 'driver-core-4.21-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  mm, memory_hotplug: update a comment in unregister_memory()
  component: convert to DEFINE_SHOW_ATTRIBUTE
  sysfs: Disable lockdep for driver bind/unbind files
  driver core: Add missing dev->bus->need_parent_lock checks
  kobject: return error code if writing /sys/.../uevent fails
  driver core: Move async_synchronize_full call
  driver core: platform: Respect return code of platform_device_register_full()
  kref/kobject: Improve documentation
  drivers/base/memory.c: Use DEVICE_ATTR_RO and friends
  driver core: Replace simple_strto{l,ul} by kstrtou{l,ul}
  kernfs: Improve kernfs_notify() poll notification latency
  kobject: Fix warnings in lib/kobject_uevent.c
  kobject: drop unnecessary cast "%llu" for u64
  driver core: fix comments for device_block_probing()
  driver core: Replace simple_strtol by kstrtoint

Documentation/kobject.txt

@@ -279,10 +279,14 @@ such a method has a form like::
 One important point cannot be overstated: every kobject must have a
 release() method, and the kobject must persist (in a consistent state)
 until that method is called. If these constraints are not met, the code is
-flawed.  Note that the kernel will warn you if you forget to provide a
+flawed. Note that the kernel will warn you if you forget to provide a
 release() method.  Do not try to get rid of this warning by providing an
-"empty" release function; you will be mocked mercilessly by the kobject
-maintainer if you attempt this.
+"empty" release function.
+
+If all your cleanup function needs to do is call kfree(), then you must
+create a wrapper function which uses container_of() to upcast to the correct
+type (as shown in the example above) and then calls kfree() on the overall
+structure.
 
 Note, the name of the kobject is available in the release function, but it
 must NOT be changed within this callback.  Otherwise there will be a memory

drivers/base/bus.c

@@ -31,6 +31,9 @@ static struct kset *system_kset;
 
 #define to_drv_attr(_attr) container_of(_attr, struct driver_attribute, attr)
 
+#define DRIVER_ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store) \
+	struct driver_attribute driver_attr_##_name =		\
+		__ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store)
 
 static int __must_check bus_rescan_devices_helper(struct device *dev,
 						void *data);
@@ -195,7 +198,7 @@ static ssize_t unbind_store(struct device_driver *drv, const char *buf,
 	bus_put(bus);
 	return err;
 }
-static DRIVER_ATTR_WO(unbind);
+static DRIVER_ATTR_IGNORE_LOCKDEP(unbind, S_IWUSR, NULL, unbind_store);
 
 /*
  * Manually attach a device to a driver.
@@ -231,7 +234,7 @@ static ssize_t bind_store(struct device_driver *drv, const char *buf,
 	bus_put(bus);
 	return err;
 }
-static DRIVER_ATTR_WO(bind);
+static DRIVER_ATTR_IGNORE_LOCKDEP(bind, S_IWUSR, NULL, bind_store);
 
 static ssize_t show_drivers_autoprobe(struct bus_type *bus, char *buf)
 {
@@ -611,8 +614,10 @@ static void remove_probe_files(struct bus_type *bus)
 static ssize_t uevent_store(struct device_driver *drv, const char *buf,
 			    size_t count)
 {
-	kobject_synth_uevent(&drv->p->kobj, buf, count);
-	return count;
+	int rc;
+
+	rc = kobject_synth_uevent(&drv->p->kobj, buf, count);
+	return rc ? rc : count;
 }
 static DRIVER_ATTR_WO(uevent);
 
@@ -828,8 +833,10 @@ static void klist_devices_put(struct klist_node *n)
 static ssize_t bus_uevent_store(struct bus_type *bus,
 				const char *buf, size_t count)
 {
-	kobject_synth_uevent(&bus->p->subsys.kobj, buf, count);
-	return count;
+	int rc;
+
+	rc = kobject_synth_uevent(&bus->p->subsys.kobj, buf, count);
+	return rc ? rc : count;
 }
 static BUS_ATTR(uevent, S_IWUSR, NULL, bus_uevent_store);
 

drivers/base/component.c

@@ -85,17 +85,7 @@ static int component_devices_show(struct seq_file *s, void *data)
 	return 0;
 }
 
-static int component_devices_open(struct inode *inode, struct file *file)
-{
-	return single_open(file, component_devices_show, inode->i_private);
-}
-
-static const struct file_operations component_devices_fops = {
-	.open = component_devices_open,
-	.read = seq_read,
-	.llseek = seq_lseek,
-	.release = single_release,
-};
+DEFINE_SHOW_ATTRIBUTE(component_devices);
 
 static int __init component_debug_init(void)
 {

drivers/base/core.c

@@ -815,10 +815,12 @@ ssize_t device_store_ulong(struct device *dev,
 			   const char *buf, size_t size)
 {
 	struct dev_ext_attribute *ea = to_ext_attr(attr);
-	char *end;
-	unsigned long new = simple_strtoul(buf, &end, 0);
-	if (end == buf)
-		return -EINVAL;
+	int ret;
+	unsigned long new;
+
+	ret = kstrtoul(buf, 0, &new);
+	if (ret)
+		return ret;
 	*(unsigned long *)(ea->var) = new;
 	/* Always return full write size even if we didn't consume all */
 	return size;
@@ -839,9 +841,14 @@ ssize_t device_store_int(struct device *dev,
 			 const char *buf, size_t size)
 {
 	struct dev_ext_attribute *ea = to_ext_attr(attr);
-	char *end;
-	long new = simple_strtol(buf, &end, 0);
-	if (end == buf || new > INT_MAX || new < INT_MIN)
+	int ret;
+	long new;
+
+	ret = kstrtol(buf, 0, &new);
+	if (ret)
+		return ret;
+
+	if (new > INT_MAX || new < INT_MIN)
 		return -EINVAL;
 	*(int *)(ea->var) = new;
 	/* Always return full write size even if we didn't consume all */
@@ -911,8 +918,7 @@ static void device_release(struct kobject *kobj)
 	else if (dev->class && dev->class->dev_release)
 		dev->class->dev_release(dev);
 	else
-		WARN(1, KERN_ERR "Device '%s' does not have a release() "
-			"function, it is broken and must be fixed.\n",
+		WARN(1, KERN_ERR "Device '%s' does not have a release() function, it is broken and must be fixed. See Documentation/kobject.txt.\n",
 			dev_name(dev));
 	kfree(p);
 }
@@ -1088,8 +1094,14 @@ static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
 static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
 			    const char *buf, size_t count)
 {
-	if (kobject_synth_uevent(&dev->kobj, buf, count))
+	int rc;
+
+	rc = kobject_synth_uevent(&dev->kobj, buf, count);
+
+	if (rc) {
 		dev_err(dev, "uevent: failed to send synthetic uevent\n");
+		return rc;
+	}
 
 	return count;
 }

drivers/base/dd.c

@@ -179,7 +179,7 @@ static void driver_deferred_probe_trigger(void)
 }
 
 /**
- * device_block_probing() - Block/defere device's probes
+ * device_block_probing() - Block/defer device's probes
  *
  *	It will disable probing of devices and defer their probes instead.
  */
@@ -223,7 +223,10 @@ DEFINE_SHOW_ATTRIBUTE(deferred_devs);
 static int deferred_probe_timeout = -1;
 static int __init deferred_probe_timeout_setup(char *str)
 {
-	deferred_probe_timeout = simple_strtol(str, NULL, 10);
+	int timeout;
+
+	if (!kstrtoint(str, 10, &timeout))
+		deferred_probe_timeout = timeout;
 	return 1;
 }
 __setup("deferred_probe_timeout=", deferred_probe_timeout_setup);
@@ -453,7 +456,7 @@ static int really_probe(struct device *dev, struct device_driver *drv)
 	if (defer_all_probes) {
 		/*
 		 * Value of defer_all_probes can be set only by
-		 * device_defer_all_probes_enable() which, in turn, will call
+		 * 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);
@@ -928,16 +931,13 @@ static void __device_release_driver(struct device *dev, struct device *parent)
 
 	drv = dev->driver;
 	if (drv) {
-		if (driver_allows_async_probing(drv))
-			async_synchronize_full();
-
 		while (device_links_busy(dev)) {
 			device_unlock(dev);
-			if (parent)
+			if (parent && dev->bus->need_parent_lock)
 				device_unlock(parent);
 
 			device_links_unbind_consumers(dev);
-			if (parent)
+			if (parent && dev->bus->need_parent_lock)
 				device_lock(parent);
 
 			device_lock(dev);
@@ -1036,6 +1036,9 @@ void driver_detach(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)) {