Merge tag 'driver-core-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here is the large set of driver core changes for 6.4-rc1.

  Once again, a busy development cycle, with lots of changes happening
  in the driver core in the quest to be able to move "struct bus" and
  "struct class" into read-only memory, a task now complete with these
  changes.

  This will make the future rust interactions with the driver core more
  "provably correct" as well as providing more obvious lifetime rules
  for all busses and classes in the kernel.

  The changes required for this did touch many individual classes and
  busses as many callbacks were changed to take const * parameters
  instead. All of these changes have been submitted to the various
  subsystem maintainers, giving them plenty of time to review, and most
  of them actually did so.

  Other than those changes, included in here are a small set of other
  things:

   - kobject logging improvements

   - cacheinfo improvements and updates

   - obligatory fw_devlink updates and fixes

   - documentation updates

   - device property cleanups and const * changes

   - firwmare loader dependency fixes.

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

* tag 'driver-core-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (120 commits)
  device property: make device_property functions take const device *
  driver core: update comments in device_rename()
  driver core: Don't require dynamic_debug for initcall_debug probe timing
  firmware_loader: rework crypto dependencies
  firmware_loader: Strip off \n from customized path
  zram: fix up permission for the hot_add sysfs file
  cacheinfo: Add use_arch[|_cache]_info field/function
  arch_topology: Remove early cacheinfo error message if -ENOENT
  cacheinfo: Check cache properties are present in DT
  cacheinfo: Check sib_leaf in cache_leaves_are_shared()
  cacheinfo: Allow early level detection when DT/ACPI info is missing/broken
  cacheinfo: Add arm64 early level initializer implementation
  cacheinfo: Add arch specific early level initializer
  tty: make tty_class a static const structure
  driver core: class: remove struct class_interface * from callbacks
  driver core: class: mark the struct class in struct class_interface constant
  driver core: class: make class_register() take a const *
  driver core: class: mark class_release() as taking a const *
  driver core: remove incorrect comment for device_create*
  MIPS: vpe-cmp: remove module owner pointer from struct class usage.
  ...

27 files changed, 158 insertions, 59 deletions

diff --git a/arch/arm/include/asm/dma-iommu.h b/arch/arm/include/asm/dma-iommu.h
index fe9ef6f79e9c..82ec1ccf1fee 100644
--- a/arch/arm/include/asm/dma-iommu.h
+++ b/arch/arm/include/asm/dma-iommu.h
@@ -24,7 +24,7 @@ struct dma_iommu_mapping {
 };
 
 struct dma_iommu_mapping *
-arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, u64 size);
+arm_iommu_create_mapping(const struct bus_type *bus, dma_addr_t base, u64 size);
 
 void arm_iommu_release_mapping(struct dma_iommu_mapping *mapping);
 
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 8bc01071474a..b4a33358d2e9 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1543,7 +1543,7 @@ static const struct dma_map_ops iommu_ops = {
  * arm_iommu_attach_device function.
  */
 struct dma_iommu_mapping *
-arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, u64 size)
+arm_iommu_create_mapping(const struct bus_type *bus, dma_addr_t base, u64 size)
 {
 	unsigned int bits = size >> PAGE_SHIFT;
 	unsigned int bitmap_size = BITS_TO_LONGS(bits) * sizeof(long);
diff --git a/arch/arm64/kernel/cacheinfo.c b/arch/arm64/kernel/cacheinfo.c
index c307f69e9b55..d9c9218fa1fd 100644
--- a/arch/arm64/kernel/cacheinfo.c
+++ b/arch/arm64/kernel/cacheinfo.c
@@ -38,11 +38,9 @@ static void ci_leaf_init(struct cacheinfo *this_leaf,
 	this_leaf->type = type;
 }
 
-int init_cache_level(unsigned int cpu)
+static void detect_cache_level(unsigned int *level_p, unsigned int *leaves_p)
 {
 	unsigned int ctype, level, leaves;
-	int fw_level, ret;
-	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 
 	for (level = 1, leaves = 0; level <= MAX_CACHE_LEVEL; level++) {
 		ctype = get_cache_type(level);
@@ -54,6 +52,27 @@ int init_cache_level(unsigned int cpu)
 		leaves += (ctype == CACHE_TYPE_SEPARATE) ? 2 : 1;
 	}
 
+	*level_p = level;
+	*leaves_p = leaves;
+}
+
+int early_cache_level(unsigned int cpu)
+{
+	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
+
+	detect_cache_level(&this_cpu_ci->num_levels, &this_cpu_ci->num_leaves);
+
+	return 0;
+}
+
+int init_cache_level(unsigned int cpu)
+{
+	unsigned int level, leaves;
+	int fw_level, ret;
+	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
+
+	detect_cache_level(&level, &leaves);
+
 	if (acpi_disabled) {
 		fw_level = of_find_last_cache_level(cpu);
 	} else {
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 1bdad599e769..2f9911256503 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1497,10 +1497,18 @@ static const DEVICE_ATTR_RO(aarch32_el0);
 
 static int __init aarch32_el0_sysfs_init(void)
 {
+	struct device *dev_root;
+	int ret = 0;
+
 	if (!allow_mismatched_32bit_el0)
 		return 0;
 
-	return device_create_file(cpu_subsys.dev_root, &dev_attr_aarch32_el0);
+	dev_root = bus_get_dev_root(&cpu_subsys);
+	if (dev_root) {
+		ret = device_create_file(dev_root, &dev_attr_aarch32_el0);
+		put_device(dev_root);
+	}
+	return ret;
 }
 device_initcall(aarch32_el0_sysfs_init);
 
diff --git a/arch/mips/kernel/mips-mt.c b/arch/mips/kernel/mips-mt.c
index dc023a979803..f88b7919f11f 100644
--- a/arch/mips/kernel/mips-mt.c
+++ b/arch/mips/kernel/mips-mt.c
@@ -234,7 +234,7 @@ static int __init mips_mt_init(void)
 {
 	struct class *mtc;
 
-	mtc = class_create(THIS_MODULE, "mt");
+	mtc = class_create("mt");
 	if (IS_ERR(mtc))
 		return PTR_ERR(mtc);
 
diff --git a/arch/mips/kernel/vpe-cmp.c b/arch/mips/kernel/vpe-cmp.c
index 92140edb3ce3..4ef7f49a4c6d 100644
--- a/arch/mips/kernel/vpe-cmp.c
+++ b/arch/mips/kernel/vpe-cmp.c
@@ -79,7 +79,6 @@ static void vpe_device_release(struct device *cd)
 
 static struct class vpe_class = {
 	.name = "vpe",
-	.owner = THIS_MODULE,
 	.dev_release = vpe_device_release,
 	.dev_groups = vpe_groups,
 };
diff --git a/arch/mips/kernel/vpe-mt.c b/arch/mips/kernel/vpe-mt.c
index 223d6274f2e5..667bc75f6420 100644
--- a/arch/mips/kernel/vpe-mt.c
+++ b/arch/mips/kernel/vpe-mt.c
@@ -316,7 +316,6 @@ static void vpe_device_release(struct device *cd)
 
 static struct class vpe_class = {
 	.name = "vpe",
-	.owner = THIS_MODULE,
 	.dev_release = vpe_device_release,
 	.dev_groups = vpe_groups,
 };
diff --git a/arch/mips/sibyte/common/sb_tbprof.c b/arch/mips/sibyte/common/sb_tbprof.c
index bc47681e825a..ac376dfb4e7c 100644
--- a/arch/mips/sibyte/common/sb_tbprof.c
+++ b/arch/mips/sibyte/common/sb_tbprof.c
@@ -550,7 +550,7 @@ static int __init sbprof_tb_init(void)
 		return -EIO;
 	}
 
-	tbc = class_create(THIS_MODULE, "sb_tracebuffer");
+	tbc = class_create("sb_tracebuffer");
 	if (IS_ERR(tbc)) {
 		err = PTR_ERR(tbc);
 		goto out_chrdev;
diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c
index ef9a61718940..0f39a6b84132 100644
--- a/arch/powerpc/kernel/sysfs.c
+++ b/arch/powerpc/kernel/sysfs.c
@@ -217,13 +217,18 @@ static DEVICE_ATTR(dscr_default, 0600,
 static void __init sysfs_create_dscr_default(void)
 {
 	if (cpu_has_feature(CPU_FTR_DSCR)) {
+		struct device *dev_root;
 		int cpu;
 
 		dscr_default = spr_default_dscr;
 		for_each_possible_cpu(cpu)
 			paca_ptrs[cpu]->dscr_default = dscr_default;
 
-		device_create_file(cpu_subsys.dev_root, &dev_attr_dscr_default);
+		dev_root = bus_get_dev_root(&cpu_subsys);
+		if (dev_root) {
+			device_create_file(dev_root, &dev_attr_dscr_default);
+			put_device(dev_root);
+		}
 	}
 }
 #endif /* CONFIG_PPC64 */
@@ -746,7 +751,12 @@ static DEVICE_ATTR(svm, 0444, show_svm, NULL);
 
 static void __init create_svm_file(void)
 {
-	device_create_file(cpu_subsys.dev_root, &dev_attr_svm);
+	struct device *dev_root = bus_get_dev_root(&cpu_subsys);
+
+	if (dev_root) {
+		device_create_file(dev_root, &dev_attr_svm);
+		put_device(dev_root);
+	}
 }
 #else
 static void __init create_svm_file(void)
diff --git a/arch/powerpc/platforms/book3s/vas-api.c b/arch/powerpc/platforms/book3s/vas-api.c
index 36c21648d19a..77ea9335fd04 100644
--- a/arch/powerpc/platforms/book3s/vas-api.c
+++ b/arch/powerpc/platforms/book3s/vas-api.c
@@ -581,7 +581,7 @@ int vas_register_coproc_api(struct module *mod, enum vas_cop_type cop_type,
 	pr_devel("%s device allocated, dev [%i,%i]\n", name,
 			MAJOR(coproc_device.devt), MINOR(coproc_device.devt));
 
-	coproc_device.class = class_create(mod, name);
+	coproc_device.class = class_create(name);
 	if (IS_ERR(coproc_device.class)) {
 		rc = PTR_ERR(coproc_device.class);
 		pr_err("Unable to create %s class %d\n", name, rc);
diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c
index 841cb7f31f4f..6dfe8d611164 100644
--- a/arch/powerpc/platforms/powernv/idle.c
+++ b/arch/powerpc/platforms/powernv/idle.c
@@ -1464,14 +1464,19 @@ static int __init pnv_init_idle_states(void)
 			power7_fastsleep_workaround_entry = false;
 			power7_fastsleep_workaround_exit = false;
 		} else {
+			struct device *dev_root;
 			/*
 			 * OPAL_PM_SLEEP_ENABLED_ER1 is set. It indicates that
 			 * workaround is needed to use fastsleep. Provide sysfs
 			 * control to choose how this workaround has to be
 			 * applied.
 			 */
-			device_create_file(cpu_subsys.dev_root,
-				&dev_attr_fastsleep_workaround_applyonce);
+			dev_root = bus_get_dev_root(&cpu_subsys);
+			if (dev_root) {
+				device_create_file(dev_root,
+						   &dev_attr_fastsleep_workaround_applyonce);
+				put_device(dev_root);
+			}
 		}
 
 		update_subcore_sibling_mask();
diff --git a/arch/powerpc/platforms/powernv/subcore.c b/arch/powerpc/platforms/powernv/subcore.c
index 7e98b00ea2e8..428532a69762 100644
--- a/arch/powerpc/platforms/powernv/subcore.c
+++ b/arch/powerpc/platforms/powernv/subcore.c
@@ -415,7 +415,9 @@ static DEVICE_ATTR(subcores_per_core, 0644,
 
 static int subcore_init(void)
 {
+	struct device *dev_root;
 	unsigned pvr_ver;
+	int rc = 0;
 
 	pvr_ver = PVR_VER(mfspr(SPRN_PVR));
 
@@ -435,7 +437,11 @@ static int subcore_init(void)
 
 	set_subcores_per_core(1);
 
-	return device_create_file(cpu_subsys.dev_root,
-				  &dev_attr_subcores_per_core);
+	dev_root = bus_get_dev_root(&cpu_subsys);
+	if (dev_root) {
+		rc = device_create_file(dev_root, &dev_attr_subcores_per_core);
+		put_device(dev_root);
+	}
+	return rc;
 }
 machine_device_initcall(powernv, subcore_init);
diff --git a/arch/powerpc/platforms/pseries/dlpar.c b/arch/powerpc/platforms/pseries/dlpar.c
index 75ffdbcd2865..719c97a155ed 100644
--- a/arch/powerpc/platforms/pseries/dlpar.c
+++ b/arch/powerpc/platforms/pseries/dlpar.c
@@ -512,7 +512,7 @@ static int dlpar_parse_id_type(char **cmd, struct pseries_hp_errorlog *hp_elog)
 	return 0;
 }
 
-static ssize_t dlpar_store(struct class *class, struct class_attribute *attr,
+static ssize_t dlpar_store(const struct class *class, const struct class_attribute *attr,
 			   const char *buf, size_t count)
 {
 	struct pseries_hp_errorlog hp_elog;
@@ -551,7 +551,7 @@ dlpar_store_out:
 	return rc ? rc : count;
 }
 
-static ssize_t dlpar_show(struct class *class, struct class_attribute *attr,
+static ssize_t dlpar_show(const struct class *class, const struct class_attribute *attr,
 			  char *buf)
 {
 	return sprintf(buf, "%s\n", "memory,cpu");
diff --git a/arch/powerpc/platforms/pseries/ibmebus.c b/arch/powerpc/platforms/pseries/ibmebus.c
index bb9c18682783..44703f13985b 100644
--- a/arch/powerpc/platforms/pseries/ibmebus.c
+++ b/arch/powerpc/platforms/pseries/ibmebus.c
@@ -267,7 +267,7 @@ static char *ibmebus_chomp(const char *in, size_t count)
 	return out;
 }
 
-static ssize_t probe_store(struct bus_type *bus, const char *buf, size_t count)
+static ssize_t probe_store(const struct bus_type *bus, const char *buf, size_t count)
 {
 	struct device_node *dn = NULL;
 	struct device *dev;
@@ -305,7 +305,7 @@ out:
 }
 static BUS_ATTR_WO(probe);
 
-static ssize_t remove_store(struct bus_type *bus, const char *buf, size_t count)
+static ssize_t remove_store(const struct bus_type *bus, const char *buf, size_t count)
 {
 	struct device *dev;
 	char *path;
diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
index 643d309d1bd0..6b25642adfa0 100644
--- a/arch/powerpc/platforms/pseries/mobility.c
+++ b/arch/powerpc/platforms/pseries/mobility.c
@@ -787,8 +787,8 @@ int rtas_syscall_dispatch_ibm_suspend_me(u64 handle)
 	return pseries_migrate_partition(handle);
 }
 
-static ssize_t migration_store(struct class *class,
-			       struct class_attribute *attr, const char *buf,
+static ssize_t migration_store(const struct class *class,
+			       const struct class_attribute *attr, const char *buf,
 			       size_t count)
 {
 	u64 streamid;
diff --git a/arch/powerpc/platforms/pseries/pseries_energy.c b/arch/powerpc/platforms/pseries/pseries_energy.c
index 09e98d301db0..2c661b798235 100644
--- a/arch/powerpc/platforms/pseries/pseries_energy.c
+++ b/arch/powerpc/platforms/pseries/pseries_energy.c
@@ -300,20 +300,22 @@ static struct device_attribute attr_percpu_deactivate_hint =
 static int __init pseries_energy_init(void)
 {
 	int cpu, err;
-	struct device *cpu_dev;
+	struct device *cpu_dev, *dev_root;
 
 	if (!firmware_has_feature(FW_FEATURE_BEST_ENERGY))
 		return 0; /* H_BEST_ENERGY hcall not supported */
 
 	/* Create the sysfs files */
-	err = device_create_file(cpu_subsys.dev_root,
-				&attr_cpu_activate_hint_list);
-	if (!err)
-		err = device_create_file(cpu_subsys.dev_root,
-				&attr_cpu_deactivate_hint_list);
+	dev_root = bus_get_dev_root(&cpu_subsys);
+	if (dev_root) {
+		err = device_create_file(dev_root, &attr_cpu_activate_hint_list);
+		if (!err)
+			err = device_create_file(dev_root, &attr_cpu_deactivate_hint_list);
+		put_device(dev_root);
+		if (err)
+			return err;
+	}
 
-	if (err)
-		return err;
 	for_each_possible_cpu(cpu) {
 		cpu_dev = get_cpu_device(cpu);
 		err = device_create_file(cpu_dev,
@@ -337,14 +339,18 @@ static int __init pseries_energy_init(void)
 static void __exit pseries_energy_cleanup(void)
 {
 	int cpu;
-	struct device *cpu_dev;
+	struct device *cpu_dev, *dev_root;
 
 	if (!sysfs_entries)
 		return;
 
 	/* Remove the sysfs files */
-	device_remove_file(cpu_subsys.dev_root, &attr_cpu_activate_hint_list);
-	device_remove_file(cpu_subsys.dev_root, &attr_cpu_deactivate_hint_list);
+	dev_root = bus_get_dev_root(&cpu_subsys);
+	if (dev_root) {
+		device_remove_file(dev_root, &attr_cpu_activate_hint_list);
+		device_remove_file(dev_root, &attr_cpu_deactivate_hint_list);
+		put_device(dev_root);
+	}
 
 	for_each_possible_cpu(cpu) {
 		cpu_dev = get_cpu_device(cpu);
diff --git a/arch/powerpc/platforms/pseries/suspend.c b/arch/powerpc/platforms/pseries/suspend.c
index 1b902cbf85c5..5c43435472cc 100644
--- a/arch/powerpc/platforms/pseries/suspend.c
+++ b/arch/powerpc/platforms/pseries/suspend.c
@@ -143,6 +143,7 @@ static const struct platform_suspend_ops pseries_suspend_ops = {
  **/
 static int pseries_suspend_sysfs_register(struct device *dev)
 {
+	struct device *dev_root;
 	int rc;
 
 	if ((rc = subsys_system_register(&suspend_subsys, NULL)))
@@ -151,8 +152,13 @@ static int pseries_suspend_sysfs_register(struct device *dev)
 	dev->id = 0;
 	dev->bus = &suspend_subsys;
 
-	if ((rc = device_create_file(suspend_subsys.dev_root, &dev_attr_hibernate)))
-		goto subsys_unregister;
+	dev_root = bus_get_dev_root(&suspend_subsys);
+	if (dev_root) {
+		rc = device_create_file(dev_root, &dev_attr_hibernate);
+		put_device(dev_root);
+		if (rc)
+			goto subsys_unregister;
+	}
 
 	return 0;
 
diff --git a/arch/powerpc/platforms/pseries/vio.c b/arch/powerpc/platforms/pseries/vio.c
index 770df9351aaa..bf7aff6390be 100644
--- a/arch/powerpc/platforms/pseries/vio.c
+++ b/arch/powerpc/platforms/pseries/vio.c
@@ -1006,7 +1006,7 @@ ATTRIBUTE_GROUPS(vio_cmo_dev);
 /* sysfs bus functions and data structures for CMO */
 
 #define viobus_cmo_rd_attr(name)                                        \
-static ssize_t cmo_bus_##name##_show(struct bus_type *bt, char *buf)    \
+static ssize_t cmo_bus_##name##_show(const struct bus_type *bt, char *buf)    \
 {                                                                       \
 	return sprintf(buf, "%lu\n", vio_cmo.name);                     \
 }                                                                       \
@@ -1015,7 +1015,7 @@ static struct bus_attribute bus_attr_cmo_bus_##name =			\
 
 #define viobus_cmo_pool_rd_attr(name, var)                              \
 static ssize_t                                                          \
-cmo_##name##_##var##_show(struct bus_type *bt, char *buf)               \
+cmo_##name##_##var##_show(const struct bus_type *bt, char *buf)         \
 {                                                                       \
 	return sprintf(buf, "%lu\n", vio_cmo.name.var);                 \
 }                                                                       \
@@ -1030,12 +1030,12 @@ viobus_cmo_pool_rd_attr(reserve, size);
 viobus_cmo_pool_rd_attr(excess, size);
 viobus_cmo_pool_rd_attr(excess, free);
 
-static ssize_t cmo_high_show(struct bus_type *bt, char *buf)
+static ssize_t cmo_high_show(const struct bus_type *bt, char *buf)
 {
 	return sprintf(buf, "%lu\n", vio_cmo.high);
 }
 
-static ssize_t cmo_high_store(struct bus_type *bt, const char *buf,
+static ssize_t cmo_high_store(const struct bus_type *bt, const char *buf,
 			      size_t count)
 {
 	unsigned long flags;
diff --git a/arch/powerpc/sysdev/fsl_mpic_timer_wakeup.c b/arch/powerpc/sysdev/fsl_mpic_timer_wakeup.c
index c2baa283e624..ce6c739c51e5 100644
--- a/arch/powerpc/sysdev/fsl_mpic_timer_wakeup.c
+++ b/arch/powerpc/sysdev/fsl_mpic_timer_wakeup.c
@@ -116,7 +116,8 @@ static struct device_attribute mpic_attributes = __ATTR(timer_wakeup, 0644,
 
 static int __init fsl_wakeup_sys_init(void)
 {
-	int ret;
+	struct device *dev_root;
+	int ret = -EINVAL;
 
 	fsl_wakeup = kzalloc(sizeof(struct fsl_mpic_timer_wakeup), GFP_KERNEL);
 	if (!fsl_wakeup)
@@ -124,16 +125,26 @@ static int __init fsl_wakeup_sys_init(void)
 
 	INIT_WORK(&fsl_wakeup->free_work, fsl_free_resource);
 
-	ret = device_create_file(mpic_subsys.dev_root, &mpic_attributes);
-	if (ret)
-		kfree(fsl_wakeup);
+	dev_root = bus_get_dev_root(&mpic_subsys);
+	if (dev_root) {
+		ret = device_create_file(dev_root, &mpic_attributes);
+		put_device(dev_root);
+		if (ret)
+			kfree(fsl_wakeup);
+	}
 
 	return ret;
 }
 
 static void __exit fsl_wakeup_sys_exit(void)
 {
-	device_remove_file(mpic_subsys.dev_root, &mpic_attributes);
+	struct device *dev_root;
+
+	dev_root = bus_get_dev_root(&mpic_subsys);
+	if (dev_root) {
+		device_remove_file(dev_root, &mpic_attributes);
+		put_device(dev_root);
+	}
 
 	mutex_lock(&sysfs_lock);
 
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index d4888453bbf8..4df797ab8ca2 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -1227,11 +1227,17 @@ static DEVICE_ATTR_WO(rescan);
 
 static int __init s390_smp_init(void)
 {
+	struct device *dev_root;
 	int cpu, rc = 0;
 
-	rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
-	if (rc)
-		return rc;
+	dev_root = bus_get_dev_root(&cpu_subsys);
+	if (dev_root) {
+		rc = device_create_file(dev_root, &dev_attr_rescan);
+		put_device(dev_root);
+		if (rc)
+			return rc;
+	}
+
 	for_each_present_cpu(cpu) {
 		rc = smp_add_present_cpu(cpu);
 		if (rc)
diff --git a/arch/s390/kernel/topology.c b/arch/s390/kernel/topology.c
index c6eecd4a5302..72af753d1bba 100644
--- a/arch/s390/kernel/topology.c
+++ b/arch/s390/kernel/topology.c
@@ -649,12 +649,21 @@ static struct ctl_table topology_dir_table[] = {
 
 static int __init topology_init(void)
 {
+	struct device *dev_root;
+	int rc = 0;
+
 	timer_setup(&topology_timer, topology_timer_fn, TIMER_DEFERRABLE);
 	if (MACHINE_HAS_TOPOLOGY)
 		set_topology_timer();
 	else
 		topology_update_polarization_simple();
 	register_sysctl_table(topology_dir_table);
-	return device_create_file(cpu_subsys.dev_root, &dev_attr_dispatching);
+
+	dev_root = bus_get_dev_root(&cpu_subsys);
+	if (dev_root) {
+		rc = device_create_file(dev_root, &dev_attr_dispatching);
+		put_device(dev_root);
+	}
+	return rc;
 }
 device_initcall(topology_init);
diff --git a/arch/sh/drivers/dma/dma-sysfs.c b/arch/sh/drivers/dma/dma-sysfs.c
index 8ef318150f84..431bc18f0a41 100644
--- a/arch/sh/drivers/dma/dma-sysfs.c
+++ b/arch/sh/drivers/dma/dma-sysfs.c
@@ -45,13 +45,19 @@ static DEVICE_ATTR(devices, S_IRUGO, dma_show_devices, NULL);
 
 static int __init dma_subsys_init(void)
 {
+	struct device *dev_root;
 	int ret;
 
 	ret = subsys_system_register(&dma_subsys, NULL);
 	if (unlikely(ret))
 		return ret;
 
-	return device_create_file(dma_subsys.dev_root, &dev_attr_devices);
+	dev_root = bus_get_dev_root(&dma_subsys);
+	if (dev_root) {
+		ret = device_create_file(dev_root, &dev_attr_devices);
+		put_device(dev_root);
+	}
+	return ret;
 }
 postcore_initcall(dma_subsys_init);
 
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index 7a329e561354..3afcf3de0dd4 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -632,6 +632,7 @@ static const struct attribute_group cpu_root_microcode_group = {
 
 static int __init microcode_init(void)
 {
+	struct device *dev_root;
 	struct cpuinfo_x86 *c = &boot_cpu_data;
 	int error;
 
@@ -652,10 +653,14 @@ static int __init microcode_init(void)
 	if (IS_ERR(microcode_pdev))
 		return PTR_ERR(microcode_pdev);
 
-	error = sysfs_create_group(&cpu_subsys.dev_root->kobj, &cpu_root_microcode_group);
-	if (error) {
-		pr_err("Error creating microcode group!\n");
-		goto out_pdev;
+	dev_root = bus_get_dev_root(&cpu_subsys);
+	if (dev_root) {
+		error = sysfs_create_group(&dev_root->kobj, &cpu_root_microcode_group);
+		put_device(dev_root);
+		if (error) {
+			pr_err("Error creating microcode group!\n");
+			goto out_pdev;
+		}
 	}
 
 	/* Do per-CPU setup */
diff --git a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c b/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
index 524f8ff3e69c..458cb7419502 100644
--- a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
+++ b/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
@@ -1580,7 +1580,7 @@ int rdt_pseudo_lock_init(void)
 
 	pseudo_lock_major = ret;
 
-	pseudo_lock_class = class_create(THIS_MODULE, "pseudo_lock");
+	pseudo_lock_class = class_create("pseudo_lock");
 	if (IS_ERR(pseudo_lock_class)) {
 		ret = PTR_ERR(pseudo_lock_class);
 		unregister_chrdev(pseudo_lock_major, "pseudo_lock");
diff --git a/arch/x86/kernel/cpu/umwait.c b/arch/x86/kernel/cpu/umwait.c
index ec8064c0ae03..2293efd6ffa6 100644
--- a/arch/x86/kernel/cpu/umwait.c
+++ b/arch/x86/kernel/cpu/umwait.c
@@ -232,7 +232,11 @@ static int __init umwait_init(void)
 	 * Add umwait control interface. Ignore failure, so at least the
 	 * default values are set up in case the machine manages to boot.
 	 */
-	dev = cpu_subsys.dev_root;
-	return sysfs_create_group(&dev->kobj, &umwait_attr_group);
+	dev = bus_get_dev_root(&cpu_subsys);
+	if (dev) {
+		ret = sysfs_create_group(&dev->kobj, &umwait_attr_group);
+		put_device(dev);
+	}
+	return ret;
 }
 device_initcall(umwait_init);
diff --git a/arch/x86/kernel/cpuid.c b/arch/x86/kernel/cpuid.c
index 621ba9c0f17a..bdc0d5539b57 100644
--- a/arch/x86/kernel/cpuid.c
+++ b/arch/x86/kernel/cpuid.c
@@ -154,7 +154,7 @@ static int __init cpuid_init(void)
 		       CPUID_MAJOR);
 		return -EBUSY;
 	}
-	cpuid_class = class_create(THIS_MODULE, "cpuid");
+	cpuid_class = class_create("cpuid");
 	if (IS_ERR(cpuid_class)) {
 		err = PTR_ERR(cpuid_class);
 		goto out_chrdev;
diff --git a/arch/x86/kernel/msr.c b/arch/x86/kernel/msr.c
index 708751311786..7bb17d37db01 100644
--- a/arch/x86/kernel/msr.c
+++ b/arch/x86/kernel/msr.c
@@ -263,7 +263,7 @@ static int __init msr_init(void)
 		pr_err("unable to get major %d for msr\n", MSR_MAJOR);
 		return -EBUSY;
 	}
-	msr_class = class_create(THIS_MODULE, "msr");
+	msr_class = class_create("msr");
 	if (IS_ERR(msr_class)) {
 		err = PTR_ERR(msr_class);
 		goto out_chrdev;