Merge tag 'driver-core-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here is a small set of driver core updates and additions for 6.6-rc1.

  Included in here are:

   - stable kernel documentation updates

   - class structure const work from Ivan on various subsystems

   - kernfs tweaks

   - driver core tests!

   - kobject sanity cleanups

   - kobject structure reordering to save space

   - driver core error code handling fixups

   - other minor driver core cleanups

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

* tag 'driver-core-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (32 commits)
  driver core: Call in reversed order in device_platform_notify_remove()
  driver core: Return proper error code when dev_set_name() fails
  kobject: Remove redundant checks for whether ktype is NULL
  kobject: Add sanity check for kset->kobj.ktype in kset_register()
  drivers: base: test: Add missing MODULE_* macros to root device tests
  drivers: base: test: Add missing MODULE_* macros for platform devices tests
  drivers: base: Free devm resources when unregistering a device
  drivers: base: Add basic devm tests for platform devices
  drivers: base: Add basic devm tests for root devices
  kernfs: fix missing kernfs_iattr_rwsem locking
  docs: stable-kernel-rules: mention that regressions must be prevented
  docs: stable-kernel-rules: fine-tune various details
  docs: stable-kernel-rules: make the examples for option 1 a proper list
  docs: stable-kernel-rules: move text around to improve flow
  docs: stable-kernel-rules: improve structure by changing headlines
  base/node: Remove duplicated include
  kernfs: attach uuid for every kernfs and report it in fsid
  kernfs: add stub helper for kernfs_generic_poll()
  x86/resctrl: make pseudo_lock_class a static const structure
  x86/MSR: make msr_class a static const structure
  ...

25 files changed, 523 insertions, 127 deletions

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 704ba73e1459..b7d7f410c256 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -2306,12 +2306,12 @@ static void device_platform_notify(struct device *dev)
 
 static void device_platform_notify_remove(struct device *dev)
 {
-	acpi_device_notify_remove(dev);
+	if (platform_notify_remove)
+		platform_notify_remove(dev);
 
 	software_node_notify_remove(dev);
 
-	if (platform_notify_remove)
-		platform_notify_remove(dev);
+	acpi_device_notify_remove(dev);
 }
 
 /**
@@ -3528,18 +3528,17 @@ int device_add(struct device *dev)
 	 * the name, and force the use of dev_name()
 	 */
 	if (dev->init_name) {
-		dev_set_name(dev, "%s", dev->init_name);
+		error = dev_set_name(dev, "%s", dev->init_name);
 		dev->init_name = NULL;
 	}
 
+	if (dev_name(dev))
+		error = 0;
 	/* subsystems can specify simple device enumeration */
-	if (!dev_name(dev) && dev->bus && dev->bus->dev_name)
-		dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
-
-	if (!dev_name(dev)) {
-		error = -EINVAL;
+	else if (dev->bus && dev->bus->dev_name)
+		error = dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
+	if (error)
 		goto name_error;
-	}
 
 	pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
 
@@ -3815,6 +3814,17 @@ void device_del(struct device *dev)
 	device_platform_notify_remove(dev);
 	device_links_purge(dev);
 
+	/*
+	 * If a device does not have a driver attached, we need to clean
+	 * up any managed resources. We do this in device_release(), but
+	 * it's never called (and we leak the device) if a managed
+	 * resource holds a reference to the device. So release all
+	 * managed resources here, like we do in driver_detach(). We
+	 * still need to do so again in device_release() in case someone
+	 * adds a new resource after this point, though.
+	 */
+	devres_release_all(dev);
+
 	bus_notify(dev, BUS_NOTIFY_REMOVED_DEVICE);
 	kobject_uevent(&dev->kobj, KOBJ_REMOVE);
 	glue_dir = get_glue_dir(dev);
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 43dab03958f1..9ea22e165acd 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -19,6 +19,7 @@
 #include <linux/cpufeature.h>
 #include <linux/tick.h>
 #include <linux/pm_qos.h>
+#include <linux/delay.h>
 #include <linux/sched/isolation.h>
 
 #include "base.h"
@@ -50,12 +51,30 @@ static int cpu_subsys_online(struct device *dev)
 	int cpuid = dev->id;
 	int from_nid, to_nid;
 	int ret;
+	int retries = 0;
 
 	from_nid = cpu_to_node(cpuid);
 	if (from_nid == NUMA_NO_NODE)
 		return -ENODEV;
 
+retry:
 	ret = cpu_device_up(dev);
+
+	/*
+	 * If -EBUSY is returned, it is likely that hotplug is temporarily
+	 * disabled when cpu_hotplug_disable() was called. This condition is
+	 * transient. So we retry after waiting for an exponentially
+	 * increasing delay up to a total of at least 620ms as some PCI
+	 * device initialization can take quite a while.
+	 */
+	if (ret == -EBUSY) {
+		retries++;
+		if (retries > 5)
+			return ret;
+		msleep(10 * (1 << retries));
+		goto retry;
+	}
+
 	/*
 	 * When hot adding memory to memoryless node and enabling a cpu
 	 * on the node, node number of the cpu may internally change.
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 878aa7646b37..a528cec24264 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -693,6 +693,8 @@ re_probe:
 
 		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;
diff --git a/drivers/base/node.c b/drivers/base/node.c
index 8e871ba9162f..493d533f8375 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -20,7 +20,6 @@
 #include <linux/pm_runtime.h>
 #include <linux/swap.h>
 #include <linux/slab.h>
-#include <linux/hugetlb.h>
 
 static struct bus_type node_subsys = {
 	.name = "node",
diff --git a/drivers/base/test/.kunitconfig b/drivers/base/test/.kunitconfig
new file mode 100644
index 000000000000..473923f0998b
--- /dev/null
+++ b/drivers/base/test/.kunitconfig
@@ -0,0 +1,2 @@
+CONFIG_KUNIT=y
+CONFIG_DM_KUNIT_TEST=y
diff --git a/drivers/base/test/Kconfig b/drivers/base/test/Kconfig
index 610a1ba7a467..9d42051f8f8e 100644
--- a/drivers/base/test/Kconfig
+++ b/drivers/base/test/Kconfig
@@ -9,6 +9,10 @@ config TEST_ASYNC_DRIVER_PROBE
 
 	  If unsure say N.
 
+config DM_KUNIT_TEST
+	tristate "KUnit Tests for the device model" if !KUNIT_ALL_TESTS
+	depends on KUNIT
+
 config DRIVER_PE_KUNIT_TEST
 	bool "KUnit Tests for property entry API" if !KUNIT_ALL_TESTS
 	depends on KUNIT=y
diff --git a/drivers/base/test/Makefile b/drivers/base/test/Makefile
index 7f76fee6f989..e321dfc7e922 100644
--- a/drivers/base/test/Makefile
+++ b/drivers/base/test/Makefile
@@ -1,5 +1,8 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_TEST_ASYNC_DRIVER_PROBE)	+= test_async_driver_probe.o
 
+obj-$(CONFIG_DM_KUNIT_TEST)	+= root-device-test.o
+obj-$(CONFIG_DM_KUNIT_TEST)	+= platform-device-test.o
+
 obj-$(CONFIG_DRIVER_PE_KUNIT_TEST) += property-entry-test.o
 CFLAGS_property-entry-test.o += $(DISABLE_STRUCTLEAK_PLUGIN)
diff --git a/drivers/base/test/platform-device-test.c b/drivers/base/test/platform-device-test.c
new file mode 100644
index 000000000000..ea05b8785743
--- /dev/null
+++ b/drivers/base/test/platform-device-test.c
@@ -0,0 +1,224 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <kunit/resource.h>
+
+#include <linux/device.h>
+#include <linux/platform_device.h>
+
+#define DEVICE_NAME "test"
+
+struct test_priv {
+	bool probe_done;
+	bool release_done;
+	wait_queue_head_t probe_wq;
+	wait_queue_head_t release_wq;
+	struct device *dev;
+};
+
+static int platform_device_devm_init(struct kunit *test)
+{
+	struct test_priv *priv;
+
+	priv = kunit_kzalloc(test, sizeof(*priv), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv);
+	init_waitqueue_head(&priv->probe_wq);
+	init_waitqueue_head(&priv->release_wq);
+
+	test->priv = priv;
+
+	return 0;
+}
+
+static void devm_device_action(void *ptr)
+{
+	struct test_priv *priv = ptr;
+
+	priv->release_done = true;
+	wake_up_interruptible(&priv->release_wq);
+}
+
+static void devm_put_device_action(void *ptr)
+{
+	struct test_priv *priv = ptr;
+
+	put_device(priv->dev);
+	priv->release_done = true;
+	wake_up_interruptible(&priv->release_wq);
+}
+
+#define RELEASE_TIMEOUT_MS	100
+
+/*
+ * Tests that a platform bus, non-probed device will run its
+ * device-managed actions when unregistered.
+ */
+static void platform_device_devm_register_unregister_test(struct kunit *test)
+{
+	struct platform_device *pdev;
+	struct test_priv *priv = test->priv;
+	int ret;
+
+	pdev = platform_device_alloc(DEVICE_NAME, PLATFORM_DEVID_NONE);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pdev);
+
+	ret = platform_device_add(pdev);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	priv->dev = &pdev->dev;
+
+	ret = devm_add_action_or_reset(priv->dev, devm_device_action, priv);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	platform_device_unregister(pdev);
+
+	ret = wait_event_interruptible_timeout(priv->release_wq, priv->release_done,
+					       msecs_to_jiffies(RELEASE_TIMEOUT_MS));
+	KUNIT_EXPECT_GT(test, ret, 0);
+}
+
+/*
+ * Tests that a platform bus, non-probed device will run its
+ * device-managed actions when unregistered, even if someone still holds
+ * a reference to it.
+ */
+static void platform_device_devm_register_get_unregister_with_devm_test(struct kunit *test)
+{
+	struct platform_device *pdev;
+	struct test_priv *priv = test->priv;
+	int ret;
+
+	pdev = platform_device_alloc(DEVICE_NAME, PLATFORM_DEVID_NONE);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pdev);
+
+	ret = platform_device_add(pdev);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	priv->dev = &pdev->dev;
+
+	get_device(priv->dev);
+
+	ret = devm_add_action_or_reset(priv->dev, devm_put_device_action, priv);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	platform_device_unregister(pdev);
+
+	ret = wait_event_interruptible_timeout(priv->release_wq, priv->release_done,
+					       msecs_to_jiffies(RELEASE_TIMEOUT_MS));
+	KUNIT_EXPECT_GT(test, ret, 0);
+}
+
+static int fake_probe(struct platform_device *pdev)
+{
+	struct test_priv *priv = platform_get_drvdata(pdev);
+
+	priv->probe_done = true;
+	wake_up_interruptible(&priv->probe_wq);
+
+	return 0;
+}
+
+static struct platform_driver fake_driver = {
+	.probe	= fake_probe,
+	.driver = {
+		.name = DEVICE_NAME,
+	},
+};
+
+/*
+ * Tests that a platform bus, probed device will run its device-managed
+ * actions when unregistered.
+ */
+static void probed_platform_device_devm_register_unregister_test(struct kunit *test)
+{
+	struct platform_device *pdev;
+	struct test_priv *priv = test->priv;
+	int ret;
+
+	ret = platform_driver_register(&fake_driver);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	pdev = platform_device_alloc(DEVICE_NAME, PLATFORM_DEVID_NONE);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pdev);
+
+	priv->dev = &pdev->dev;
+	platform_set_drvdata(pdev, priv);
+
+	ret = platform_device_add(pdev);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	ret = wait_event_interruptible_timeout(priv->probe_wq, priv->probe_done,
+					       msecs_to_jiffies(RELEASE_TIMEOUT_MS));
+	KUNIT_ASSERT_GT(test, ret, 0);
+
+	ret = devm_add_action_or_reset(priv->dev, devm_device_action, priv);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	platform_device_unregister(pdev);
+
+	ret = wait_event_interruptible_timeout(priv->release_wq, priv->release_done,
+					       msecs_to_jiffies(RELEASE_TIMEOUT_MS));
+	KUNIT_EXPECT_GT(test, ret, 0);
+
+	platform_driver_unregister(&fake_driver);
+}
+
+/*
+ * Tests that a platform bus, probed device will run its device-managed
+ * actions when unregistered, even if someone still holds a reference to
+ * it.
+ */
+static void probed_platform_device_devm_register_get_unregister_with_devm_test(struct kunit *test)
+{
+	struct platform_device *pdev;
+	struct test_priv *priv = test->priv;
+	int ret;
+
+	ret = platform_driver_register(&fake_driver);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	pdev = platform_device_alloc(DEVICE_NAME, PLATFORM_DEVID_NONE);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pdev);
+
+	priv->dev = &pdev->dev;
+	platform_set_drvdata(pdev, priv);
+
+	ret = platform_device_add(pdev);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	ret = wait_event_interruptible_timeout(priv->probe_wq, priv->probe_done,
+					       msecs_to_jiffies(RELEASE_TIMEOUT_MS));
+	KUNIT_ASSERT_GT(test, ret, 0);
+
+	get_device(priv->dev);
+
+	ret = devm_add_action_or_reset(priv->dev, devm_put_device_action, priv);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	platform_device_unregister(pdev);
+
+	ret = wait_event_interruptible_timeout(priv->release_wq, priv->release_done,
+					       msecs_to_jiffies(RELEASE_TIMEOUT_MS));
+	KUNIT_EXPECT_GT(test, ret, 0);
+
+	platform_driver_unregister(&fake_driver);
+}
+
+static struct kunit_case platform_device_devm_tests[] = {
+	KUNIT_CASE(platform_device_devm_register_unregister_test),
+	KUNIT_CASE(platform_device_devm_register_get_unregister_with_devm_test),
+	KUNIT_CASE(probed_platform_device_devm_register_unregister_test),
+	KUNIT_CASE(probed_platform_device_devm_register_get_unregister_with_devm_test),
+	{}
+};
+
+static struct kunit_suite platform_device_devm_test_suite = {
+	.name = "platform-device-devm",
+	.init = platform_device_devm_init,
+	.test_cases = platform_device_devm_tests,
+};
+
+kunit_test_suite(platform_device_devm_test_suite);
+
+MODULE_DESCRIPTION("Test module for platform devices");
+MODULE_AUTHOR("Maxime Ripard <mripard@kernel.org>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/base/test/root-device-test.c b/drivers/base/test/root-device-test.c
new file mode 100644
index 000000000000..9aea23c9123e
--- /dev/null
+++ b/drivers/base/test/root-device-test.c
@@ -0,0 +1,112 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright 2023 Maxime Ripard <mripard@kernel.org>
+
+#include <kunit/resource.h>
+
+#include <linux/device.h>
+
+#define DEVICE_NAME "test"
+
+struct test_priv {
+	bool probe_done;
+	bool release_done;
+	wait_queue_head_t release_wq;
+	struct device *dev;
+};
+
+static int root_device_devm_init(struct kunit *test)
+{
+	struct test_priv *priv;
+
+	priv = kunit_kzalloc(test, sizeof(*priv), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv);
+	init_waitqueue_head(&priv->release_wq);
+
+	test->priv = priv;
+
+	return 0;
+}
+
+static void devm_device_action(void *ptr)
+{
+	struct test_priv *priv = ptr;
+
+	priv->release_done = true;
+	wake_up_interruptible(&priv->release_wq);
+}
+
+#define RELEASE_TIMEOUT_MS	100
+
+/*
+ * Tests that a bus-less, non-probed device will run its device-managed
+ * actions when unregistered.
+ */
+static void root_device_devm_register_unregister_test(struct kunit *test)
+{
+	struct test_priv *priv = test->priv;
+	int ret;
+
+	priv->dev = root_device_register(DEVICE_NAME);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->dev);
+
+	ret = devm_add_action_or_reset(priv->dev, devm_device_action, priv);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	root_device_unregister(priv->dev);
+
+	ret = wait_event_interruptible_timeout(priv->release_wq, priv->release_done,
+					       msecs_to_jiffies(RELEASE_TIMEOUT_MS));
+	KUNIT_EXPECT_GT(test, ret, 0);
+}
+
+static void devm_put_device_action(void *ptr)
+{
+	struct test_priv *priv = ptr;
+
+	put_device(priv->dev);
+	priv->release_done = true;
+	wake_up_interruptible(&priv->release_wq);
+}
+
+/*
+ * Tests that a bus-less, non-probed device will run its device-managed
+ * actions when unregistered, even if someone still holds a reference to
+ * it.
+ */
+static void root_device_devm_register_get_unregister_with_devm_test(struct kunit *test)
+{
+	struct test_priv *priv = test->priv;
+	int ret;
+
+	priv->dev = root_device_register(DEVICE_NAME);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->dev);
+
+	get_device(priv->dev);
+
+	ret = devm_add_action_or_reset(priv->dev, devm_put_device_action, priv);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	root_device_unregister(priv->dev);
+
+	ret = wait_event_interruptible_timeout(priv->release_wq, priv->release_done,
+					       msecs_to_jiffies(RELEASE_TIMEOUT_MS));
+	KUNIT_EXPECT_GT(test, ret, 0);
+}
+
+static struct kunit_case root_device_devm_tests[] = {
+	KUNIT_CASE(root_device_devm_register_unregister_test),
+	KUNIT_CASE(root_device_devm_register_get_unregister_with_devm_test),
+	{}
+};
+
+static struct kunit_suite root_device_devm_test_suite = {
+	.name = "root-device-devm",
+	.init = root_device_devm_init,
+	.test_cases = root_device_devm_tests,
+};
+
+kunit_test_suite(root_device_devm_test_suite);
+
+MODULE_DESCRIPTION("Test module for root devices");
+MODULE_AUTHOR("Maxime Ripard <mripard@kernel.org>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/base/test/test_async_driver_probe.c b/drivers/base/test/test_async_driver_probe.c
index 929410d0dd6f..3465800baa6c 100644
--- a/drivers/base/test/test_async_driver_probe.c
+++ b/drivers/base/test/test_async_driver_probe.c
@@ -84,7 +84,7 @@ test_platform_device_register_node(char *name, int id, int nid)
 
 	pdev = platform_device_alloc(name, id);
 	if (!pdev)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 	if (nid != NUMA_NO_NODE)
 		set_dev_node(&pdev->dev, nid);
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index ea6b4013bc38..23f6f2eda84c 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -28,8 +28,13 @@
 DEFINE_IDR(dev_nums_idr);
 static DEFINE_MUTEX(idr_lock);
 
-struct class *tpm_class;
-struct class *tpmrm_class;
+const struct class tpm_class = {
+	.name = "tpm",
+	.shutdown_pre = tpm_class_shutdown,
+};
+const struct class tpmrm_class = {
+	.name = "tmprm",
+};
 dev_t tpm_devt;
 
 static int tpm_request_locality(struct tpm_chip *chip)
@@ -336,7 +341,7 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
 
 	device_initialize(&chip->dev);
 
-	chip->dev.class = tpm_class;
+	chip->dev.class = &tpm_class;
 	chip->dev.release = tpm_dev_release;
 	chip->dev.parent = pdev;
 	chip->dev.groups = chip->groups;
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 586ca10b0d72..66b16d26eecc 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -476,18 +476,15 @@ static int __init tpm_init(void)
 {
 	int rc;
 
-	tpm_class = class_create("tpm");
-	if (IS_ERR(tpm_class)) {
+	rc = class_register(&tpm_class);
+	if (rc) {
 		pr_err("couldn't create tpm class\n");
-		return PTR_ERR(tpm_class);
+		return rc;
 	}
 
-	tpm_class->shutdown_pre = tpm_class_shutdown;
-
-	tpmrm_class = class_create("tpmrm");
-	if (IS_ERR(tpmrm_class)) {
+	rc = class_register(&tpmrm_class);
+	if (rc) {
 		pr_err("couldn't create tpmrm class\n");
-		rc = PTR_ERR(tpmrm_class);
 		goto out_destroy_tpm_class;
 	}
 
@@ -508,9 +505,9 @@ static int __init tpm_init(void)
 out_unreg_chrdev:
 	unregister_chrdev_region(tpm_devt, 2 * TPM_NUM_DEVICES);
 out_destroy_tpmrm_class:
-	class_destroy(tpmrm_class);
+	class_unregister(&tpmrm_class);
 out_destroy_tpm_class:
-	class_destroy(tpm_class);
+	class_unregister(&tpm_class);
 
 	return rc;
 }
@@ -518,8 +515,8 @@ out_destroy_tpm_class:
 static void __exit tpm_exit(void)
 {
 	idr_destroy(&dev_nums_idr);
-	class_destroy(tpm_class);
-	class_destroy(tpmrm_class);
+	class_unregister(&tpm_class);
+	class_unregister(&tpmrm_class);
 	unregister_chrdev_region(tpm_devt, 2*TPM_NUM_DEVICES);
 	tpm_dev_common_exit();
 }
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 460bb85dd142..61445f1dc46d 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -230,8 +230,8 @@ enum tpm2_pt_props {
  * compiler warnings about stack frame size. */
 #define TPM_MAX_RNG_DATA	128
 
-extern struct class *tpm_class;
-extern struct class *tpmrm_class;
+extern const struct class tpm_class;
+extern const struct class tpmrm_class;
 extern dev_t tpm_devt;
 extern const struct file_operations tpm_fops;
 extern const struct file_operations tpmrm_fops;
diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
index ffb35f0154c1..363afdd4d1d3 100644
--- a/drivers/char/tpm/tpm2-space.c
+++ b/drivers/char/tpm/tpm2-space.c
@@ -606,7 +606,7 @@ int tpm_devs_add(struct tpm_chip *chip)
 
 	device_initialize(&chip->devs);
 	chip->devs.parent = chip->dev.parent;
-	chip->devs.class = tpmrm_class;
+	chip->devs.class = &tpmrm_class;
 
 	/*
 	 * Get extra reference on main device to hold on behalf of devs.
diff --git a/drivers/hid/hid-roccat-arvo.c b/drivers/hid/hid-roccat-arvo.c
index ea6b79b3aeeb..d55aaabab1ed 100644
--- a/drivers/hid/hid-roccat-arvo.c
+++ b/drivers/hid/hid-roccat-arvo.c
@@ -23,8 +23,6 @@
 #include "hid-roccat-common.h"
 #include "hid-roccat-arvo.h"
 
-static struct class *arvo_class;
-
 static ssize_t arvo_sysfs_show_mode_key(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
@@ -268,6 +266,11 @@ static const struct attribute_group *arvo_groups[] = {
 	NULL,
 };
 
+static const struct class arvo_class = {
+	.name = "arvo",
+	.dev_groups = arvo_groups,
+};
+
 static int arvo_init_arvo_device_struct(struct usb_device *usb_dev,
 		struct arvo_device *arvo)
 {
@@ -309,7 +312,7 @@ static int arvo_init_specials(struct hid_device *hdev)
 		goto exit_free;
 	}
 
-	retval = roccat_connect(arvo_class, hdev,
+	retval = roccat_connect(&arvo_class, hdev,
 			sizeof(struct arvo_roccat_report));
 	if (retval < 0) {
 		hid_err(hdev, "couldn't init char dev\n");
@@ -433,21 +436,20 @@ static int __init arvo_init(void)
 {
 	int retval;
 
-	arvo_class = class_create("arvo");
-	if (IS_ERR(arvo_class))
-		return PTR_ERR(arvo_class);
-	arvo_class->dev_groups = arvo_groups;
+	retval = class_register(&arvo_class);
+	if (retval)
+		return retval;
 
 	retval = hid_register_driver(&arvo_driver);
 	if (retval)
-		class_destroy(arvo_class);
+		class_unregister(&arvo_class);
 	return retval;
 }
 
 static void __exit arvo_exit(void)
 {
 	hid_unregister_driver(&arvo_driver);
-	class_destroy(arvo_class);
+	class_unregister(&arvo_class);
 }
 
 module_init(arvo_init);
diff --git a/drivers/hid/hid-roccat-isku.c b/drivers/hid/hid-roccat-isku.c
index 3903a2cea00c..458060403397 100644
--- a/drivers/hid/hid-roccat-isku.c
+++ b/drivers/hid/hid-roccat-isku.c
@@ -23,8 +23,6 @@
 #include "hid-roccat-common.h"
 #include "hid-roccat-isku.h"
 
-static struct class *isku_class;
-
 static void isku_profile_activated(struct isku_device *isku, uint new_profile)
 {
 	isku->actual_profile = new_profile;
@@ -248,6 +246,11 @@ static const struct attribute_group *isku_groups[] = {
 	NULL,
 };
 
+static const struct class isku_class = {
+	.name = "isku",
+	.dev_groups = isku_groups,
+};
+
 static int isku_init_isku_device_struct(struct usb_device *usb_dev,
 		struct isku_device *isku)
 {
@@ -289,7 +292,7 @@ static int isku_init_specials(struct hid_device *hdev)
 		goto exit_free;
 	}
 
-	retval = roccat_connect(isku_class, hdev,
+	retval = roccat_connect(&isku_class, hdev,
 			sizeof(struct isku_roccat_report));
 	if (retval < 0) {
 		hid_err(hdev, "couldn't init char dev\n");
@@ -435,21 +438,21 @@ static struct hid_driver isku_driver = {
 static int __init isku_init(void)
 {
 	int retval;
-	isku_class = class_create("isku");
-	if (IS_ERR(isku_class))
-		return PTR_ERR(isku_class);
-	isku_class->dev_groups = isku_groups;
+
+	retval = class_register(&isku_class);
+	if (retval)
+		return retval;
 
 	retval = hid_register_driver(&isku_driver);
 	if (retval)
-		class_destroy(isku_class);
+		class_unregister(&isku_class);
 	return retval;
 }
 
 static void __exit isku_exit(void)
 {
 	hid_unregister_driver(&isku_driver);
-	class_destroy(isku_class);
+	class_unregister(&isku_class);
 }
 
 module_init(isku_init);
diff --git a/drivers/hid/hid-roccat-kone.c b/drivers/hid/hid-roccat-kone.c
index 945ae236fb45..00a1abc7e839 100644
--- a/drivers/hid/hid-roccat-kone.c
+++ b/drivers/hid/hid-roccat-kone.c
@@ -89,9 +89,6 @@ static int kone_send(struct usb_device *usb_dev, uint usb_command,
 	return ((len < 0) ? len : ((len != size) ? -EIO : 0));
 }
 
-/* kone_class is used for creating sysfs attributes via roccat char device */
-static struct class *kone_class;
-
 static void kone_set_settings_checksum(struct kone_settings *settings)
 {
 	uint16_t checksum = 0;
@@ -657,6 +654,12 @@ static const struct attribute_group *kone_groups[] = {
 	NULL,
 };
 
+/* kone_class is used for creating sysfs attributes via roccat char device */
+static const struct class kone_class = {
+	.name = "kone",
+	.dev_groups = kone_groups,
+};
+
 static int kone_init_kone_device_struct(struct usb_device *usb_dev,
 		struct kone_device *kone)
 {
@@ -712,8 +715,8 @@ static int kone_init_specials(struct hid_device *hdev)
 			goto exit_free;
 		}
 
-		retval = roccat_connect(kone_class, hdev,
-				sizeof(struct kone_roccat_report));
+		retval = roccat_connect(&kone_class, hdev,
+					sizeof(struct kone_roccat_report));
 		if (retval < 0) {
 			hid_err(hdev, "couldn't init char dev\n");
 			/* be tolerant about not getting chrdev */
@@ -890,21 +893,20 @@ static int __init kone_init(void)
 	int retval;
 
 	/* class name has to be same as driver name */
-	kone_class = class_create("kone");
-	if (IS_ERR(kone_class))
-		return PTR_ERR(kone_class);
-	kone_class->dev_groups = kone_groups;
+	retval = class_register(&kone_class);
+	if (retval)
+		return retval;
 
 	retval = hid_register_driver(&kone_driver);
 	if (retval)
-		class_destroy(kone_class);
+		class_unregister(&kone_class);
 	return retval;
 }
 
 static void __exit kone_exit(void)
 {
 	hid_unregister_driver(&kone_driver);
-	class_destroy(kone_class);
+	class_unregister(&kone_class);
 }
 
 module_init(kone_init);
diff --git a/drivers/hid/hid-roccat-koneplus.c b/drivers/hid/hid-roccat-koneplus.c
index 97b83b6f53dd..22b895436a7c 100644
--- a/drivers/hid/hid-roccat-koneplus.c
+++ b/drivers/hid/hid-roccat-koneplus.c
@@ -26,8 +26,6 @@
 
 static uint profile_numbers[5] = {0, 1, 2, 3, 4};
 
-static struct class *koneplus_class;
-
 static void koneplus_profile_activated(struct koneplus_device *koneplus,
 		uint new_profile)
 {
@@ -356,6 +354,11 @@ static const struct attribute_group *koneplus_groups[] = {
 	NULL,
 };
 
+static const struct class koneplus_class = {
+	.name = "koneplus",
+	.dev_groups = koneplus_groups,
+};
+
 static int koneplus_init_koneplus_device_struct(struct usb_device *usb_dev,
 		struct koneplus_device *koneplus)
 {
@@ -394,8 +397,8 @@ static int koneplus_init_specials(struct hid_device *hdev)
 			goto exit_free;
 		}
 
-		retval = roccat_connect(koneplus_class, hdev,
-				sizeof(struct koneplus_roccat_report));
+		retval = roccat_connect(&koneplus_class, hdev,
+					sizeof(struct koneplus_roccat_report));
 		if (retval < 0) {
 			hid_err(hdev, "couldn't init char dev\n");
 		} else {
@@ -549,21 +552,20 @@ static int __init koneplus_init(void)
 	int retval;
 
 	/* class name has to be same as driver name */
-	koneplus_class = class_create("koneplus");
-	if (IS_ERR(koneplus_class))
-		return PTR_ERR(koneplus_class);
-	koneplus_class->dev_groups = koneplus_groups;
+	retval = class_register(&koneplus_class);
+	if (retval)
+		return retval;
 
 	retval = hid_register_driver(&koneplus_driver);
 	if (retval)
-		class_destroy(koneplus_class);
+		class_unregister(&koneplus_class);
 	return retval;
 }
 
 static void __exit koneplus_exit(void)
 {
 	hid_unregister_driver(&koneplus_driver);
-	class_destroy(koneplus_class);
+	class_unregister(&koneplus_class);
 }
 
 module_init(koneplus_init);
diff --git a/drivers/hid/hid-roccat-konepure.c b/drivers/hid/hid-roccat-konepure.c
index a297756f2410..beca8aef8bbb 100644
--- a/drivers/hid/hid-roccat-konepure.c
+++ b/drivers/hid/hid-roccat-konepure.c
@@ -36,8 +36,6 @@ struct konepure_mouse_report_button {
 	uint8_t unknown[2];
 } __packed;
 
-static struct class *konepure_class;
-
 ROCCAT_COMMON2_BIN_ATTRIBUTE_W(control, 0x04, 0x03);
 ROCCAT_COMMON2_BIN_ATTRIBUTE_RW(actual_profile, 0x05, 0x03);
 ROCCAT_COMMON2_BIN_ATTRIBUTE_RW(profile_settings, 0x06, 0x1f);
@@ -72,6 +70,11 @@ static const struct attribute_group *konepure_groups[] = {
 	NULL,
 };
 
+static const struct class konepure_class = {
+	.name = "konepure",
+	.dev_groups = konepure_groups,
+};
+
 static int konepure_init_specials(struct hid_device *hdev)
 {
 	struct usb_interface *intf = to_usb_interface(hdev->dev.parent);
@@ -98,8 +101,8 @@ static int konepure_init_specials(struct hid_device *hdev)
 		goto exit_free;
 	}
 
-	retval = roccat_connect(konepure_class, hdev,
-			sizeof(struct konepure_mouse_report_button));
+	retval = roccat_connect(&konepure_class, hdev,
+				sizeof(struct konepure_mouse_report_button));
 	if (retval < 0) {
 		hid_err(hdev, "couldn't init char dev\n");
 	} else {
@@ -207,21 +210,20 @@ static int __init konepure_init(void)
 {
 	int retval;
 
-	konepure_class = class_create("konepure");
-	if (IS_ERR(konepure_class))
-		return PTR_ERR(konepure_class);
-	konepure_class->dev_groups = konepure_groups;
+	retval = class_register(&konepure_class);
+	if (retval)
+		return retval;
 
 	retval = hid_register_driver(&konepure_driver);
 	if (retval)
-		class_destroy(konepure_class);
+		class_unregister(&konepure_class);
 	return retval;
 }
 
 static void __exit konepure_exit(void)
 {
 	hid_unregister_driver(&konepure_driver);
-	class_destroy(konepure_class);
+	class_unregister(&konepure_class);
 }
 
 module_init(konepure_init);
diff --git a/drivers/hid/hid-roccat-kovaplus.c b/drivers/hid/hid-roccat-kovaplus.c
index 1a1d96e11683..86af538c10d6 100644
--- a/drivers/hid/hid-roccat-kovaplus.c
+++ b/drivers/hid/hid-roccat-kovaplus.c
@@ -24,8 +24,6 @@
 
 static uint profile_numbers[5] = {0, 1, 2, 3, 4};
 
-static struct class *kovaplus_class;
-
 static uint kovaplus_convert_event_cpi(uint value)
 {
 	return (value == 7 ? 4 : (value == 4 ? 3 : value));
@@ -409,6 +407,11 @@ static const struct attribute_group *kovaplus_groups[] = {
 	NULL,
 };
 
+static const struct class kovaplus_class = {
+	.name = "kovaplus",
+	.dev_groups = kovaplus_groups,
+};
+
 static int kovaplus_init_kovaplus_device_struct(struct usb_device *usb_dev,
 		struct kovaplus_device *kovaplus)
 {
@@ -463,8 +466,8 @@ static int kovaplus_init_specials(struct hid_device *hdev)
 			goto exit_free;
 		}
 
-		retval = roccat_connect(kovaplus_class, hdev,
-				sizeof(struct kovaplus_roccat_report));
+		retval = roccat_connect(&kovaplus_class, hdev,
+					sizeof(struct kovaplus_roccat_report));
 		if (retval < 0) {
 			hid_err(hdev, "couldn't init char dev\n");
 		} else {
@@ -638,21 +641,20 @@ static int __init kovaplus_init(void)
 {
 	int retval;
 
-	kovaplus_class = class_create("kovaplus");
-	if (IS_ERR(kovaplus_class))
-		return PTR_ERR(kovaplus_class);
-	kovaplus_class->dev_groups = kovaplus_groups;
+	retval = class_register(&kovaplus_class);
+	if (retval)
+		return retval;
 
 	retval = hid_register_driver(&kovaplus_driver);
 	if (retval)
-		class_destroy(kovaplus_class);
+		class_unregister(&kovaplus_class);
 	return retval;
 }
 
 static void __exit kovaplus_exit(void)
 {
 	hid_unregister_driver(&kovaplus_driver);
-	class_destroy(kovaplus_class);
+	class_unregister(&kovaplus_class);
 }
 
 module_init(kovaplus_init);
diff --git a/drivers/hid/hid-roccat-pyra.c b/drivers/hid/hid-roccat-pyra.c
index 15528c3b013c..5663b9cd9c69 100644
--- a/drivers/hid/hid-roccat-pyra.c
+++ b/drivers/hid/hid-roccat-pyra.c
@@ -26,9 +26,6 @@
 
 static uint profile_numbers[5] = {0, 1, 2, 3, 4};
 
-/* pyra_class is used for creating sysfs attributes via roccat char device */
-static struct class *pyra_class;
-
 static void profile_activated(struct pyra_device *pyra,
 		unsigned int new_profile)
 {
@@ -366,6 +363,12 @@ static const struct attribute_group *pyra_groups[] = {
 	NULL,
 };
 
+/* pyra_class is used for creating sysfs attributes via roccat char device */
+static const struct class pyra_class = {
+	.name = "pyra",
+	.dev_groups = pyra_groups,
+};
+
 static int pyra_init_pyra_device_struct(struct usb_device *usb_dev,
 		struct pyra_device *pyra)
 {
@@ -413,7 +416,7 @@ static int pyra_init_specials(struct hid_device *hdev)
 			goto exit_free;
 		}
 
-		retval = roccat_connect(pyra_class, hdev,
+		retval = roccat_connect(&pyra_class, hdev,
 				sizeof(struct pyra_roccat_report));
 		if (retval < 0) {
 			hid_err(hdev, "couldn't init char dev\n");
@@ -585,21 +588,20 @@ static int __init pyra_init(void)
 	int retval;
 
 	/* class name has to be same as driver name */
-	pyra_class = class_create("pyra");
-	if (IS_ERR(pyra_class))
-		return PTR_ERR(pyra_class);
-	pyra_class->dev_groups = pyra_groups;
+	retval = class_register(&pyra_class);
+	if (retval)
+		return retval;
 
 	retval = hid_register_driver(&pyra_driver);
 	if (retval)
-		class_destroy(pyra_class);
+		class_unregister(&pyra_class);
 	return retval;
 }
 
 static void __exit pyra_exit(void)
 {
 	hid_unregister_driver(&pyra_driver);
-	class_destroy(pyra_class);
+	class_unregister(&pyra_class);
 }
 
 module_init(pyra_init);
diff --git a/drivers/hid/hid-roccat-ryos.c b/drivers/hid/hid-roccat-ryos.c
index 0eb17a3b925d..57714a4525e2 100644
--- a/drivers/hid/hid-roccat-ryos.c
+++ b/drivers/hid/hid-roccat-ryos.c
@@ -28,8 +28,6 @@ struct ryos_report_special {
 	uint8_t data[4];
 } __packed;
 
-static struct class *ryos_class;
-
 ROCCAT_COMMON2_BIN_ATTRIBUTE_W(control, 0x04, 0x03);
 ROCCAT_COMMON2_BIN_ATTRIBUTE_RW(profile, 0x05, 0x03);
 ROCCAT_COMMON2_BIN_ATTRIBUTE_RW(keys_primary, 0x06, 0x7d);
@@ -80,6 +78,11 @@ static const struct attribute_group *ryos_groups[] = {
 	NULL,
 };
 
+static const struct class ryos_class = {
+	.name = "ryos",
+	.dev_groups = ryos_groups,
+};
+
 static int ryos_init_specials(struct hid_device *hdev)
 {
 	struct usb_interface *intf = to_usb_interface(hdev->dev.parent);
@@ -106,7 +109,7 @@ static int ryos_init_specials(struct hid_device *hdev)
 		goto exit_free;
 	}
 
-	retval = roccat_connect(ryos_class, hdev,
+	retval = roccat_connect(&ryos_class, hdev,
 			sizeof(struct ryos_report_special));
 	if (retval < 0) {
 		hid_err(hdev, "couldn't init char dev\n");
@@ -216,21 +219,20 @@ static int __init ryos_init(void)
 {
 	int retval;
 
-	ryos_class = class_create("ryos");
-	if (IS_ERR(ryos_class))
-		return PTR_ERR(ryos_class);
-	ryos_class->dev_groups = ryos_groups;
+	retval = class_register(&ryos_class);
+	if (retval)
+		return retval;
 
 	retval = hid_register_driver(&ryos_driver);
 	if (retval)
-		class_destroy(ryos_class);
+		class_unregister(&ryos_class);
 	return retval;
 }
 
 static void __exit ryos_exit(void)
 {
 	hid_unregister_driver(&ryos_driver);
-	class_destroy(ryos_class);
+	class_unregister(&ryos_class);
 }
 
 module_init(ryos_init);
diff --git a/drivers/hid/hid-roccat-savu.c b/drivers/hid/hid-roccat-savu.c
index 93be7acef673..2baa47a0efc5 100644
--- a/drivers/hid/hid-roccat-savu.c
+++ b/drivers/hid/hid-roccat-savu.c
@@ -22,8 +22,6 @@
 #include "hid-roccat-common.h"
 #include "hid-roccat-savu.h"
 
-static struct class *savu_class;
-
 ROCCAT_COMMON2_BIN_ATTRIBUTE_W(control, 0x4, 0x03);
 ROCCAT_COMMON2_BIN_ATTRIBUTE_RW(profile, 0x5, 0x03);
 ROCCAT_COMMON2_BIN_ATTRIBUTE_RW(general, 0x6, 0x10);
@@ -52,6 +50,11 @@ static const struct attribute_group *savu_groups[] = {
 	NULL,
 };
 
+static const struct class savu_class = {
+	.name = "savu",
+	.dev_groups = savu_groups,
+};
+
 static int savu_init_specials(struct hid_device *hdev)
 {
 	struct usb_interface *intf = to_usb_interface(hdev->dev.parent);
@@ -78,7 +81,7 @@ static int savu_init_specials(struct hid_device *hdev)
 		goto exit_free;
 	}
 
-	retval = roccat_connect(savu_class, hdev,
+	retval = roccat_connect(&savu_class, hdev,
 			sizeof(struct savu_roccat_report));
 	if (retval < 0) {
 		hid_err(hdev, "couldn't init char dev\n");
@@ -204,21 +207,20 @@ static int __init savu_init(void)
 {
 	int retval;
 
-	savu_class = class_create("savu");
-	if (IS_ERR(savu_class))
-		return PTR_ERR(savu_class);
-	savu_class->dev_groups = savu_groups;
+	retval = class_register(&savu_class);
+	if (retval)
+		return retval;
 
 	retval = hid_register_driver(&savu_driver);
 	if (retval)
-		class_destroy(savu_class);
+		class_unregister(&savu_class);
 	return retval;
 }
 
 static void __exit savu_exit(void)
 {
 	hid_unregister_driver(&savu_driver);
-	class_destroy(savu_class);
+	class_unregister(&savu_class);
 }
 
 module_init(savu_init);
diff --git a/drivers/hid/hid-roccat.c b/drivers/hid/hid-roccat.c
index 6da80e442fdd..c7f7562e22e5 100644
--- a/drivers/hid/hid-roccat.c
+++ b/drivers/hid/hid-roccat.c
@@ -295,7 +295,7 @@ EXPORT_SYMBOL_GPL(roccat_report_event);
  * Return value is minor device number in Range [0, ROCCAT_MAX_DEVICES] on
  * success, a negative error code on failure.
  */
-int roccat_connect(struct class *klass, struct hid_device *hid, int report_size)
+int roccat_connect(const struct class *klass, struct hid_device *hid, int report_size)
 {
 	unsigned int minor;
 	struct roccat_device *device;
diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c
index e63c56a0d57f..13c8dd8cd350 100644
--- a/drivers/hid/hidraw.c
+++ b/drivers/hid/hidraw.c
@@ -32,7 +32,9 @@
 
 static int hidraw_major;
 static struct cdev hidraw_cdev;
-static struct class *hidraw_class;
+static const struct class hidraw_class = {
+	.name = "hidraw",
+};
 static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES];
 static DECLARE_RWSEM(minors_rwsem);
 
@@ -329,7 +331,7 @@ static void drop_ref(struct hidraw *hidraw, int exists_bit)
 			hid_hw_close(hidraw->hid);
 			wake_up_interruptible(&hidraw->wait);
 		}
-		device_destroy(hidraw_class,
+		device_destroy(&hidraw_class,
 			       MKDEV(hidraw_major, hidraw->minor));
 	} else {
 		--hidraw->open;
@@ -569,7 +571,7 @@ int hidraw_connect(struct hid_device *hid)
 		goto out;
 	}
 
-	dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
+	dev->dev = device_create(&hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
 				 NULL, "%s%d", "hidraw", minor);
 
 	if (IS_ERR(dev->dev)) {
@@ -623,11 +625,9 @@ int __init hidraw_init(void)
 
 	hidraw_major = MAJOR(dev_id);
 
-	hidraw_class = class_create("hidraw");
-	if (IS_ERR(hidraw_class)) {
-		result = PTR_ERR(hidraw_class);
+	result = class_register(&hidraw_class);
+	if (result)
 		goto error_cdev;
-	}
 
         cdev_init(&hidraw_cdev, &hidraw_ops);
 	result = cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
@@ -639,7 +639,7 @@ out:
 	return result;
 
 error_class:
-	class_destroy(hidraw_class);
+	class_unregister(&hidraw_class);
 error_cdev:
 	unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 	goto out;
@@ -650,7 +650,7 @@ void hidraw_exit(void)
 	dev_t dev_id = MKDEV(hidraw_major, 0);
 
 	cdev_del(&hidraw_cdev);
-	class_destroy(hidraw_class);
+	class_unregister(&hidraw_class);
 	unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 
 }