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.
  ...

1 files changed, 32 insertions, 16 deletions

diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index dd4b82d7510f..84a21084d67d 100644
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -84,7 +84,7 @@ done:
 	return sp;
 }
 
-static struct bus_type *bus_get(struct bus_type *bus)
+static const struct bus_type *bus_get(const struct bus_type *bus)
 {
 	struct subsys_private *sp = bus_to_subsys(bus);
 
@@ -233,7 +233,7 @@ static const struct kset_uevent_ops bus_uevent_ops = {
 static ssize_t unbind_store(struct device_driver *drv, const char *buf,
 			    size_t count)
 {
-	struct bus_type *bus = bus_get(drv->bus);
+	const struct bus_type *bus = bus_get(drv->bus);
 	struct device *dev;
 	int err = -ENODEV;
 
@@ -256,7 +256,7 @@ static DRIVER_ATTR_IGNORE_LOCKDEP(unbind, 0200, NULL, unbind_store);
 static ssize_t bind_store(struct device_driver *drv, const char *buf,
 			  size_t count)
 {
-	struct bus_type *bus = bus_get(drv->bus);
+	const struct bus_type *bus = bus_get(drv->bus);
 	struct device *dev;
 	int err = -ENODEV;
 
@@ -274,7 +274,7 @@ static ssize_t bind_store(struct device_driver *drv, const char *buf,
 }
 static DRIVER_ATTR_IGNORE_LOCKDEP(bind, 0200, NULL, bind_store);
 
-static ssize_t drivers_autoprobe_show(struct bus_type *bus, char *buf)
+static ssize_t drivers_autoprobe_show(const struct bus_type *bus, char *buf)
 {
 	struct subsys_private *sp = bus_to_subsys(bus);
 	int ret;
@@ -287,7 +287,7 @@ static ssize_t drivers_autoprobe_show(struct bus_type *bus, char *buf)
 	return ret;
 }
 
-static ssize_t drivers_autoprobe_store(struct bus_type *bus,
+static ssize_t drivers_autoprobe_store(const struct bus_type *bus,
 				       const char *buf, size_t count)
 {
 	struct subsys_private *sp = bus_to_subsys(bus);
@@ -304,7 +304,7 @@ static ssize_t drivers_autoprobe_store(struct bus_type *bus,
 	return count;
 }
 
-static ssize_t drivers_probe_store(struct bus_type *bus,
+static ssize_t drivers_probe_store(const struct bus_type *bus,
 				   const char *buf, size_t count)
 {
 	struct device *dev;
@@ -769,7 +769,7 @@ static int __must_check bus_rescan_devices_helper(struct device *dev,
  * attached and rescan it against existing drivers to see if it matches
  * any by calling device_attach() for the unbound devices.
  */
-int bus_rescan_devices(struct bus_type *bus)
+int bus_rescan_devices(const struct bus_type *bus)
 {
 	return bus_for_each_dev(bus, NULL, NULL, bus_rescan_devices_helper);
 }
@@ -808,7 +808,7 @@ static void klist_devices_put(struct klist_node *n)
 	put_device(dev);
 }
 
-static ssize_t bus_uevent_store(struct bus_type *bus,
+static ssize_t bus_uevent_store(const struct bus_type *bus,
 				const char *buf, size_t count)
 {
 	struct subsys_private *sp = bus_to_subsys(bus);
@@ -841,7 +841,7 @@ static struct bus_attribute bus_attr_uevent = __ATTR(uevent, 0200, NULL,
  * infrastructure, then register the children subsystems it has:
  * the devices and drivers that belong to the subsystem.
  */
-int bus_register(struct bus_type *bus)
+int bus_register(const struct bus_type *bus)
 {
 	int retval;
 	struct subsys_private *priv;
@@ -935,8 +935,8 @@ void bus_unregister(const struct bus_type *bus)
 		return;
 
 	pr_debug("bus: '%s': unregistering\n", bus->name);
-	if (bus->dev_root)
-		device_unregister(bus->dev_root);
+	if (sp->dev_root)
+		device_unregister(sp->dev_root);
 
 	bus_kobj = &sp->subsys.kobj;
 	sysfs_remove_groups(bus_kobj, bus->bus_groups);
@@ -1198,6 +1198,7 @@ static int subsys_register(struct bus_type *subsys,
 			   const struct attribute_group **groups,
 			   struct kobject *parent_of_root)
 {
+	struct subsys_private *sp;
 	struct device *dev;
 	int err;
 
@@ -1205,6 +1206,12 @@ static int subsys_register(struct bus_type *subsys,
 	if (err < 0)
 		return err;
 
+	sp = bus_to_subsys(subsys);
+	if (!sp) {
+		err = -EINVAL;
+		goto err_sp;
+	}
+
 	dev = kzalloc(sizeof(struct device), GFP_KERNEL);
 	if (!dev) {
 		err = -ENOMEM;
@@ -1223,7 +1230,8 @@ static int subsys_register(struct bus_type *subsys,
 	if (err < 0)
 		goto err_dev_reg;
 
-	subsys->dev_root = dev;
+	sp->dev_root = dev;
+	subsys_put(sp);
 	return 0;
 
 err_dev_reg:
@@ -1232,6 +1240,8 @@ err_dev_reg:
 err_name:
 	kfree(dev);
 err_dev:
+	subsys_put(sp);
+err_sp:
 	bus_unregister(subsys);
 	return err;
 }
@@ -1297,7 +1307,7 @@ EXPORT_SYMBOL_GPL(subsys_virtual_register);
  * from being unregistered or unloaded while the caller is using it.
  * The caller is responsible for preventing this.
  */
-struct device_driver *driver_find(const char *name, struct bus_type *bus)
+struct device_driver *driver_find(const char *name, const struct bus_type *bus)
 {
 	struct subsys_private *sp = bus_to_subsys(bus);
 	struct kobject *k;
@@ -1349,9 +1359,15 @@ bool bus_is_registered(const struct bus_type *bus)
  */
 struct device *bus_get_dev_root(const struct bus_type *bus)
 {
-	if (bus)
-		return get_device(bus->dev_root);
-	return NULL;
+	struct subsys_private *sp = bus_to_subsys(bus);
+	struct device *dev_root;
+
+	if (!sp)
+		return NULL;
+
+	dev_root = get_device(sp->dev_root);
+	subsys_put(sp);
+	return dev_root;
 }
 EXPORT_SYMBOL_GPL(bus_get_dev_root);