From 7b884b7f24b42fa25e92ed724ad82f137610afaf Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Sat, 25 Mar 2023 20:42:34 +0100 Subject: [PATCH] driver core: class.c: convert to only use class_to_subsys Now that class_to_subsys() can be used to get access to the internal class private pointer, convert the remaining few places in class.c that were accessing the pointer directly to use class_to_subsys() instead. By doing this, the need for class_get() and class_put() goes away as no one actually tries to increment the class structures anymore, only the internal dynamic one. Cc: "Rafael J. Wysocki" Link: https://lore.kernel.org/r/20230325194234.46588-2-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman --- drivers/base/class.c | 113 +++++++++++++++++++++++++++------------------------ 1 file changed, 61 insertions(+), 52 deletions(-) diff --git a/drivers/base/class.c b/drivers/base/class.c index c53d6f9..1f12bd5 100644 --- a/drivers/base/class.c +++ b/drivers/base/class.c @@ -66,24 +66,6 @@ done: return sp; } -static const struct class *class_get(const struct class *class) -{ - struct subsys_private *sp = class_to_subsys(class); - - if (sp) - return class; - return NULL; -} - -static void class_put(const struct class *class) -{ - struct subsys_private *sp = class_to_subsys(class); - - /* two puts are required as the call to bus_to_subsys incremented it again */ - subsys_put(sp); - subsys_put(sp); -} - static ssize_t class_attr_show(struct kobject *kobj, struct attribute *attr, char *buf) { @@ -148,13 +130,15 @@ static const struct kobj_type class_ktype = { int class_create_file_ns(const struct class *cls, const struct class_attribute *attr, const void *ns) { + struct subsys_private *sp = class_to_subsys(cls); int error; - if (cls) - error = sysfs_create_file_ns(&cls->p->subsys.kobj, - &attr->attr, ns); - else - error = -EINVAL; + if (!sp) + return -EINVAL; + + error = sysfs_create_file_ns(&sp->subsys.kobj, &attr->attr, ns); + subsys_put(sp); + return error; } EXPORT_SYMBOL_GPL(class_create_file_ns); @@ -162,8 +146,13 @@ EXPORT_SYMBOL_GPL(class_create_file_ns); void class_remove_file_ns(const struct class *cls, const struct class_attribute *attr, const void *ns) { - if (cls) - sysfs_remove_file_ns(&cls->p->subsys.kobj, &attr->attr, ns); + struct subsys_private *sp = class_to_subsys(cls); + + if (!sp) + return; + + sysfs_remove_file_ns(&sp->subsys.kobj, &attr->attr, ns); + subsys_put(sp); } EXPORT_SYMBOL_GPL(class_remove_file_ns); @@ -187,18 +176,6 @@ static void klist_class_dev_put(struct klist_node *n) put_device(dev); } -static int class_add_groups(const struct class *cls, - const struct attribute_group **groups) -{ - return sysfs_create_groups(&cls->p->subsys.kobj, groups); -} - -static void class_remove_groups(const struct class *cls, - const struct attribute_group **groups) -{ - return sysfs_remove_groups(&cls->p->subsys.kobj, groups); -} - int class_register(struct class *cls) { struct subsys_private *cp; @@ -235,8 +212,7 @@ int class_register(struct class *cls) if (error) goto err_out; - error = class_add_groups(class_get(cls), cls->class_groups); - class_put(cls); + error = sysfs_create_groups(&cp->subsys.kobj, cls->class_groups); if (error) { kobject_del(&cp->subsys.kobj); kfree_const(cp->subsys.kobj.name); @@ -253,9 +229,16 @@ EXPORT_SYMBOL_GPL(class_register); void class_unregister(const struct class *cls) { + struct subsys_private *sp = class_to_subsys(cls); + + if (!sp) + return; + pr_debug("device class '%s': unregistering\n", cls->name); - class_remove_groups(cls, cls->class_groups); - kset_unregister(&cls->p->subsys); + + sysfs_remove_groups(&sp->subsys.kobj, cls->class_groups); + kset_unregister(&sp->subsys); + subsys_put(sp); } EXPORT_SYMBOL_GPL(class_unregister); @@ -334,11 +317,15 @@ EXPORT_SYMBOL_GPL(class_destroy); void class_dev_iter_init(struct class_dev_iter *iter, const struct class *class, const struct device *start, const struct device_type *type) { + struct subsys_private *sp = class_to_subsys(class); struct klist_node *start_knode = NULL; + if (!sp) + return; + if (start) start_knode = &start->p->knode_class; - klist_iter_init_node(&class->p->klist_devices, &iter->ki, start_knode); + klist_iter_init_node(&sp->klist_devices, &iter->ki, start_knode); iter->type = type; } EXPORT_SYMBOL_GPL(class_dev_iter_init); @@ -405,13 +392,14 @@ EXPORT_SYMBOL_GPL(class_dev_iter_exit); int class_for_each_device(const struct class *class, const struct device *start, void *data, int (*fn)(struct device *, void *)) { + struct subsys_private *sp = class_to_subsys(class); struct class_dev_iter iter; struct device *dev; int error = 0; if (!class) return -EINVAL; - if (!class->p) { + if (!sp) { WARN(1, "%s called for class '%s' before it was initialized", __func__, class->name); return -EINVAL; @@ -424,6 +412,7 @@ int class_for_each_device(const struct class *class, const struct device *start, break; } class_dev_iter_exit(&iter); + subsys_put(sp); return error; } @@ -453,12 +442,13 @@ struct device *class_find_device(const struct class *class, const struct device const void *data, int (*match)(struct device *, const void *)) { + struct subsys_private *sp = class_to_subsys(class); struct class_dev_iter iter; struct device *dev; if (!class) return NULL; - if (!class->p) { + if (!sp) { WARN(1, "%s called for class '%s' before it was initialized", __func__, class->name); return NULL; @@ -472,6 +462,7 @@ struct device *class_find_device(const struct class *class, const struct device } } class_dev_iter_exit(&iter); + subsys_put(sp); return dev; } @@ -479,6 +470,7 @@ EXPORT_SYMBOL_GPL(class_find_device); int class_interface_register(struct class_interface *class_intf) { + struct subsys_private *sp; const struct class *parent; struct class_dev_iter iter; struct device *dev; @@ -486,19 +478,25 @@ int class_interface_register(struct class_interface *class_intf) if (!class_intf || !class_intf->class) return -ENODEV; - parent = class_get(class_intf->class); - if (!parent) + parent = class_intf->class; + sp = class_to_subsys(parent); + if (!sp) return -EINVAL; - mutex_lock(&parent->p->mutex); - list_add_tail(&class_intf->node, &parent->p->interfaces); + /* + * Reference in sp is now incremented and will be dropped when + * the interface is removed in the call to class_interface_unregister() + */ + + mutex_lock(&sp->mutex); + list_add_tail(&class_intf->node, &sp->interfaces); if (class_intf->add_dev) { class_dev_iter_init(&iter, parent, NULL, NULL); while ((dev = class_dev_iter_next(&iter))) class_intf->add_dev(dev, class_intf); class_dev_iter_exit(&iter); } - mutex_unlock(&parent->p->mutex); + mutex_unlock(&sp->mutex); return 0; } @@ -506,6 +504,7 @@ EXPORT_SYMBOL_GPL(class_interface_register); void class_interface_unregister(struct class_interface *class_intf) { + struct subsys_private *sp; struct class *parent = class_intf->class; struct class_dev_iter iter; struct device *dev; @@ -513,7 +512,11 @@ void class_interface_unregister(struct class_interface *class_intf) if (!parent) return; - mutex_lock(&parent->p->mutex); + sp = class_to_subsys(parent); + if (!sp) + return; + + mutex_lock(&sp->mutex); list_del_init(&class_intf->node); if (class_intf->remove_dev) { class_dev_iter_init(&iter, parent, NULL, NULL); @@ -521,9 +524,15 @@ void class_interface_unregister(struct class_interface *class_intf) class_intf->remove_dev(dev, class_intf); class_dev_iter_exit(&iter); } - mutex_unlock(&parent->p->mutex); + mutex_unlock(&sp->mutex); - class_put(parent); + /* + * Decrement the reference count twice, once for the class_to_subsys() + * call in the start of this function, and the second one from the + * reference increment in class_interface_register() + */ + subsys_put(sp); + subsys_put(sp); } EXPORT_SYMBOL_GPL(class_interface_unregister); -- 2.7.4