// SPDX-License-Identifier: GPL-2.0/* * drivers/base/core.c - core driver model code (device registration, etc) * * Copyright (c) 2002-3 Patrick Mochel * Copyright (c) 2002-3 Open Source Development Labs * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de> * Copyright (c) 2006 Novell, Inc. */ #include <linux/acpi.h>#include <linux/cpufreq.h>#include <linux/device.h>#include <linux/err.h>#include <linux/fwnode.h>#include <linux/init.h>#include <linux/module.h>#include <linux/slab.h>#include <linux/string.h>#include <linux/kdev_t.h>#include <linux/notifier.h>#include <linux/of.h>#include <linux/of_device.h>#include <linux/genhd.h>#include <linux/mutex.h>#include <linux/pm_runtime.h>#include <linux/netdevice.h>#include <linux/sched/signal.h>#include <linux/sysfs.h> #include "base.h"#include "power/power.h" #ifdef CONFIG_SYSFS_DEPRECATED#ifdef CONFIG_SYSFS_DEPRECATED_V2long sysfs_deprecated = 1;#elselong sysfs_deprecated = 0;#endifstatic int __init sysfs_deprecated_setup(char *arg){ return kstrtol(arg, 10, &sysfs_deprecated);}early_param("sysfs.deprecated", sysfs_deprecated_setup);#endif /* Device links support. */ #ifdef CONFIG_SRCUstatic DEFINE_MUTEX(device_links_lock);DEFINE_STATIC_SRCU(device_links_srcu); static inline void device_links_write_lock(void){ mutex_lock(&device_links_lock);} static inline void device_links_write_unlock(void){ mutex_unlock(&device_links_lock);} int device_links_read_lock(void){ return srcu_read_lock(&device_links_srcu);} void device_links_read_unlock(int idx){ srcu_read_unlock(&device_links_srcu, idx);} int device_links_read_lock_held(void){ return srcu_read_lock_held(&device_links_srcu);}#else /* !CONFIG_SRCU */static DECLARE_RWSEM(device_links_lock); static inline void device_links_write_lock(void){ down_write(&device_links_lock);} static inline void device_links_write_unlock(void){ up_write(&device_links_lock);} int device_links_read_lock(void){ down_read(&device_links_lock); return 0;} void device_links_read_unlock(int not_used){ up_read(&device_links_lock);} #ifdef CONFIG_DEBUG_LOCK_ALLOCint device_links_read_lock_held(void){ return lockdep_is_held(&device_links_lock);}#endif#endif /* !CONFIG_SRCU */ /** * device_is_dependent - Check if one device depends on another one * @dev: Device to check dependencies for. * @target: Device to check against. * * Check if @target depends on @dev or any device dependent on it (its child or * its consumer etc). Return 1 if that is the case or 0 otherwise. */static int device_is_dependent(struct device *dev, void *target){ struct device_link *link; int ret; if (dev == target) return 1; ret = device_for_each_child(dev, target, device_is_dependent); if (ret) return ret; list_for_each_entry(link, &dev->links.consumers, s_node) { if (link->consumer == target) return 1; ret = device_is_dependent(link->consumer, target); if (ret) break; } return ret;} static void device_link_init_status(struct device_link *link, struct device *consumer, struct device *supplier){ switch (supplier->links.status) { case DL_DEV_PROBING: switch (consumer->links.status) { case DL_DEV_PROBING: /* * A consumer driver can create a link to a supplier * that has not completed its probing yet as long as it * knows that the supplier is already functional (for * example, it has just acquired some resources from the * supplier). */ link->status = DL_STATE_CONSUMER_PROBE; break; default: link->status = DL_STATE_DORMANT; break; } break; case DL_DEV_DRIVER_BOUND: switch (consumer->links.status) { case DL_DEV_PROBING: link->status = DL_STATE_CONSUMER_PROBE; break; case DL_DEV_DRIVER_BOUND: link->status = DL_STATE_ACTIVE; break; default: link->status = DL_STATE_AVAILABLE; break; } break; case DL_DEV_UNBINDING: link->status = DL_STATE_SUPPLIER_UNBIND; break; default: link->status = DL_STATE_DORMANT; break; }} static int device_reorder_to_tail(struct device *dev, void *not_used){ struct device_link *link; /* * Devices that have not been registered yet will be put to the ends * of the lists during the registration, so skip them here. */ if (device_is_registered(dev)) devices_kset_move_last(dev); if (device_pm_initialized(dev)) device_pm_move_last(dev); device_for_each_child(dev, NULL, device_reorder_to_tail); list_for_each_entry(link, &dev->links.consumers, s_node) device_reorder_to_tail(link->consumer, NULL); return 0;} /** * device_pm_move_to_tail - Move set of devices to the end of device lists * @dev: Device to move * * This is a device_reorder_to_tail() wrapper taking the requisite locks. * * It moves the @dev along with all of its children and all of its consumers * to the ends of the device_kset and dpm_list, recursively. */void device_pm_move_to_tail(struct device *dev){ int idx; idx = device_links_read_lock(); device_pm_lock(); device_reorder_to_tail(dev, NULL); device_pm_unlock(); device_links_read_unlock(idx);} #define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \ DL_FLAG_AUTOREMOVE_SUPPLIER | \ DL_FLAG_AUTOPROBE_CONSUMER) #define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \ DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE) /** * device_link_add - Create a link between two devices. * @consumer: Consumer end of the link. * @supplier: Supplier end of the link. * @flags: Link flags. * * The caller is responsible for the proper synchronization of the link creation * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the * runtime PM framework to take the link into account. Second, if the * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will * be forced into the active metastate and reference-counted upon the creation * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be * ignored. * * If DL_FLAG_STATELESS is set in @flags, the caller of this function is * expected to release the link returned by it directly with the help of either * device_link_del() or device_link_remove(). * * If that flag is not set, however, the caller of this function is handing the * management of the link over to the driver core entirely and its return value * can only be used to check whether or not the link is present. In that case, * the DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER device link * flags can be used to indicate to the driver core when the link can be safely * deleted. Namely, setting one of them in @flags indicates to the driver core * that the link is not going to be used (by the given caller of this function) * after unbinding the consumer or supplier driver, respectively, from its * device, so the link can be deleted at that point. If none of them is set, * the link will be maintained until one of the devices pointed to by it (either * the consumer or the supplier) is unregistered. * * Also, if DL_FLAG_STATELESS, DL_FLAG_AUTOREMOVE_CONSUMER and * DL_FLAG_AUTOREMOVE_SUPPLIER are not set in @flags (that is, a persistent * managed device link is being added), the DL_FLAG_AUTOPROBE_CONSUMER flag can * be used to request the driver core to automaticall probe for a consmer * driver after successfully binding a driver to the supplier device. * * The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER, * DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at * the same time is invalid and will cause NULL to be returned upfront. * However, if a device link between the given @consumer and @supplier pair * exists already when this function is called for them, the existing link will * be returned regardless of its current type and status (the link's flags may * be modified then). The caller of this function is then expected to treat * the link as though it has just been created, so (in particular) if * DL_FLAG_STATELESS was passed in @flags, the link needs to be released * explicitly when not needed any more (as stated above). * * A side effect of the link creation is re-ordering of dpm_list and the * devices_kset list by moving the consumer device and all devices depending * on it to the ends of these lists (that does not happen to devices that have * not been registered when this function is called). * * The supplier device is required to be registered when this function is called * and NULL will be returned if that is not the case. The consumer device need * not be registered, however. */struct device_link *device_link_add(struct device *consumer, struct device *supplier, u32 flags){ struct device_link *link; if (!consumer || !supplier || flags & ~DL_ADD_VALID_FLAGS || (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) || (flags & DL_FLAG_AUTOPROBE_CONSUMER && flags & (DL_FLAG_AUTOREMOVE_CONSUMER | DL_FLAG_AUTOREMOVE_SUPPLIER))) return NULL; if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) { if (pm_runtime_get_sync(supplier) < 0) { pm_runtime_put_noidle(supplier); return NULL; } } if (!(flags & DL_FLAG_STATELESS)) flags |= DL_FLAG_MANAGED; device_links_write_lock(); device_pm_lock(); /* * If the supplier has not been fully registered yet or there is a * reverse dependency between the consumer and the supplier already in * the graph, return NULL. */ if (!device_pm_initialized(supplier) || device_is_dependent(consumer, supplier)) { link = NULL; goto out; } /* * DL_FLAG_AUTOREMOVE_SUPPLIER indicates that the link will be needed * longer than for DL_FLAG_AUTOREMOVE_CONSUMER and setting them both * together doesn't make sense, so prefer DL_FLAG_AUTOREMOVE_SUPPLIER. */ if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER; list_for_each_entry(link, &supplier->links.consumers, s_node) { if (link->consumer != consumer) continue; if (flags & DL_FLAG_PM_RUNTIME) { if (!(link->flags & DL_FLAG_PM_RUNTIME)) { pm_runtime_new_link(consumer); link->flags |= DL_FLAG_PM_RUNTIME; } if (flags & DL_FLAG_RPM_ACTIVE) refcount_inc(&link->rpm_active); } if (flags & DL_FLAG_STATELESS) { link->flags |= DL_FLAG_STATELESS; kref_get(&link->kref); goto out; } /* * If the life time of the link following from the new flags is * longer than indicated by the flags of the existing link, * update the existing link to stay around longer. */ if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) { if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) { link->flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER; link->flags |= DL_FLAG_AUTOREMOVE_SUPPLIER; } } else if (!(flags & DL_FLAG_AUTOREMOVE_CONSUMER)) { link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER | DL_FLAG_AUTOREMOVE_SUPPLIER); } if (!(link->flags & DL_FLAG_MANAGED)) { kref_get(&link->kref); link->flags |= DL_FLAG_MANAGED; device_link_init_status(link, consumer, supplier); } goto out; } link = kzalloc(sizeof(*link), GFP_KERNEL); if (!link) goto out; refcount_set(&link->rpm_active, 1); if (flags & DL_FLAG_PM_RUNTIME) { if (flags & DL_FLAG_RPM_ACTIVE) refcount_inc(&link->rpm_active); pm_runtime_new_link(consumer); } get_device(supplier); link->supplier = supplier; INIT_LIST_HEAD(&link->s_node); get_device(consumer); link->consumer = consumer; INIT_LIST_HEAD(&link->c_node); link->flags = flags; kref_init(&link->kref); /* Determine the initial link state. */ if (flags & DL_FLAG_STATELESS) link->status = DL_STATE_NONE; else device_link_init_status(link, consumer, supplier); /* * Some callers expect the link creation during consumer driver probe to * resume the supplier even without DL_FLAG_RPM_ACTIVE. */ if (link->status == DL_STATE_CONSUMER_PROBE && flags & DL_FLAG_PM_RUNTIME) pm_runtime_resume(supplier); /* * Move the consumer and all of the devices depending on it to the end * of dpm_list and the devices_kset list. * * It is necessary to hold dpm_list locked throughout all that or else * we may end up suspending with a wrong ordering of it. */ device_reorder_to_tail(consumer, NULL); list_add_tail_rcu(&link->s_node, &supplier->links.consumers); list_add_tail_rcu(&link->c_node, &consumer->links.suppliers); dev_dbg(consumer, "Linked as a consumer to %s\n", dev_name(supplier)); out: device_pm_unlock(); device_links_write_unlock(); if ((flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) && !link) pm_runtime_put(supplier); return link;}EXPORT_SYMBOL_GPL(device_link_add); static void device_link_free(struct device_link *link){ while (refcount_dec_not_one(&link->rpm_active)) pm_runtime_put(link->supplier); put_device(link->consumer); put_device(link->supplier); kfree(link);} #ifdef CONFIG_SRCUstatic void __device_link_free_srcu(struct rcu_head *rhead){ device_link_free(container_of(rhead, struct device_link, rcu_head));} static void __device_link_del(struct kref *kref){ struct device_link *link = container_of(kref, struct device_link, kref); dev_dbg(link->consumer, "Dropping the link to %s\n", dev_name(link->supplier)); if (link->flags & DL_FLAG_PM_RUNTIME) pm_runtime_drop_link(link->consumer); list_del_rcu(&link->s_node); list_del_rcu(&link->c_node); call_srcu(&device_links_srcu, &link->rcu_head, __device_link_free_srcu);}#else /* !CONFIG_SRCU */static void __device_link_del(struct kref *kref){ struct device_link *link = container_of(kref, struct device_link, kref); dev_info(link->consumer, "Dropping the link to %s\n", dev_name(link->supplier)); if (link->flags & DL_FLAG_PM_RUNTIME) pm_runtime_drop_link(link->consumer); list_del(&link->s_node); list_del(&link->c_node); device_link_free(link);}#endif /* !CONFIG_SRCU */ static void device_link_put_kref(struct device_link *link){ if (link->flags & DL_FLAG_STATELESS) kref_put(&link->kref, __device_link_del); else WARN(1, "Unable to drop a managed device link reference\n");} /** * device_link_del - Delete a stateless link between two devices. * @link: Device link to delete. * * The caller must ensure proper synchronization of this function with runtime * PM. If the link was added multiple times, it needs to be deleted as often. * Care is required for hotplugged devices: Their links are purged on removal * and calling device_link_del() is then no longer allowed. */void device_link_del(struct device_link *link){ device_links_write_lock();Lines 1–500 of 3491. Load more
// SPDX-License-Identifier: GPL-2.0 /* * drivers/base/core.c - core driver model code (device registration, etc) * * Copyright (c) 2002-3 Patrick Mochel * Copyright (c) 2002-3 Open Source Development Labs * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de> * Copyright (c) 2006 Novell, Inc. */ #include <linux/acpi.h> #include <linux/cpufreq.h> #include <linux/device.h> #include <linux/err.h> #include <linux/fwnode.h> #include <linux/init.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/string.h> #include <linux/kdev_t.h> #include <linux/notifier.h> #include <linux/of.h> #include <linux/of_device.h> #include <linux/genhd.h> #include <linux/mutex.h> #include <linux/pm_runtime.h> #include <linux/netdevice.h> #include <linux/sched/signal.h> #include <linux/sysfs.h> #include "base.h" #include "power/power.h" #ifdef CONFIG_SYSFS_DEPRECATED #ifdef CONFIG_SYSFS_DEPRECATED_V2 long sysfs_deprecated = 1; #else long sysfs_deprecated = 0; #endif static int __init sysfs_deprecated_setup(char *arg) { return kstrtol(arg, 10, &sysfs_deprecated); } early_param("sysfs.deprecated", sysfs_deprecated_setup); #endif /* Device links support. */ #ifdef CONFIG_SRCU static DEFINE_MUTEX(device_links_lock); DEFINE_STATIC_SRCU(device_links_srcu); static inline void device_links_write_lock(void) { mutex_lock(&device_links_lock); } static inline void device_links_write_unlock(void) { mutex_unlock(&device_links_lock); } int device_links_read_lock(void) { return srcu_read_lock(&device_links_srcu); } void device_links_read_unlock(int idx) { srcu_read_unlock(&device_links_srcu, idx); } int device_links_read_lock_held(void) { return srcu_read_lock_held(&device_links_srcu); } #else /* !CONFIG_SRCU */ static DECLARE_RWSEM(device_links_lock); static inline void device_links_write_lock(void) { down_write(&device_links_lock); } static inline void device_links_write_unlock(void) { up_write(&device_links_lock); } int device_links_read_lock(void) { down_read(&device_links_lock); return 0; } void device_links_read_unlock(int not_used) { up_read(&device_links_lock); } #ifdef CONFIG_DEBUG_LOCK_ALLOC int device_links_read_lock_held(void) { return lockdep_is_held(&device_links_lock); } #endif #endif /* !CONFIG_SRCU */ /** * device_is_dependent - Check if one device depends on another one * @dev: Device to check dependencies for. * @target: Device to check against. * * Check if @target depends on @dev or any device dependent on it (its child or * its consumer etc). Return 1 if that is the case or 0 otherwise. */ static int device_is_dependent(struct device *dev, void *target) { struct device_link *link; int ret; if (dev == target) return 1; ret = device_for_each_child(dev, target, device_is_dependent); if (ret) return ret; list_for_each_entry(link, &dev->links.consumers, s_node) { if (link->consumer == target) return 1; ret = device_is_dependent(link->consumer, target); if (ret) break; } return ret; } static void device_link_init_status(struct device_link *link, struct device *consumer, struct device *supplier) { switch (supplier->links.status) { case DL_DEV_PROBING: switch (consumer->links.status) { case DL_DEV_PROBING: /* * A consumer driver can create a link to a supplier * that has not completed its probing yet as long as it * knows that the supplier is already functional (for * example, it has just acquired some resources from the * supplier). */ link->status = DL_STATE_CONSUMER_PROBE; break; default: link->status = DL_STATE_DORMANT; break; } break; case DL_DEV_DRIVER_BOUND: switch (consumer->links.status) { case DL_DEV_PROBING: link->status = DL_STATE_CONSUMER_PROBE; break; case DL_DEV_DRIVER_BOUND: link->status = DL_STATE_ACTIVE; break; default: link->status = DL_STATE_AVAILABLE; break; } break; case DL_DEV_UNBINDING: link->status = DL_STATE_SUPPLIER_UNBIND; break; default: link->status = DL_STATE_DORMANT; break; } } static int device_reorder_to_tail(struct device *dev, void *not_used) { struct device_link *link; /* * Devices that have not been registered yet will be put to the ends * of the lists during the registration, so skip them here. */ if (device_is_registered(dev)) devices_kset_move_last(dev); if (device_pm_initialized(dev)) device_pm_move_last(dev); device_for_each_child(dev, NULL, device_reorder_to_tail); list_for_each_entry(link, &dev->links.consumers, s_node) device_reorder_to_tail(link->consumer, NULL); return 0; } /** * device_pm_move_to_tail - Move set of devices to the end of device lists * @dev: Device to move * * This is a device_reorder_to_tail() wrapper taking the requisite locks. * * It moves the @dev along with all of its children and all of its consumers * to the ends of the device_kset and dpm_list, recursively. */ void device_pm_move_to_tail(struct device *dev) { int idx; idx = device_links_read_lock(); device_pm_lock(); device_reorder_to_tail(dev, NULL); device_pm_unlock(); device_links_read_unlock(idx); } #define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \ DL_FLAG_AUTOREMOVE_SUPPLIER | \ DL_FLAG_AUTOPROBE_CONSUMER) #define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \ DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE) /** * device_link_add - Create a link between two devices. * @consumer: Consumer end of the link. * @supplier: Supplier end of the link. * @flags: Link flags. * * The caller is responsible for the proper synchronization of the link creation * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the * runtime PM framework to take the link into account. Second, if the * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will * be forced into the active metastate and reference-counted upon the creation * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be * ignored. * * If DL_FLAG_STATELESS is set in @flags, the caller of this function is * expected to release the link returned by it directly with the help of either * device_link_del() or device_link_remove(). * * If that flag is not set, however, the caller of this function is handing the * management of the link over to the driver core entirely and its return value * can only be used to check whether or not the link is present. In that case, * the DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER device link * flags can be used to indicate to the driver core when the link can be safely * deleted. Namely, setting one of them in @flags indicates to the driver core * that the link is not going to be used (by the given caller of this function) * after unbinding the consumer or supplier driver, respectively, from its * device, so the link can be deleted at that point. If none of them is set, * the link will be maintained until one of the devices pointed to by it (either * the consumer or the supplier) is unregistered. * * Also, if DL_FLAG_STATELESS, DL_FLAG_AUTOREMOVE_CONSUMER and * DL_FLAG_AUTOREMOVE_SUPPLIER are not set in @flags (that is, a persistent * managed device link is being added), the DL_FLAG_AUTOPROBE_CONSUMER flag can * be used to request the driver core to automaticall probe for a consmer * driver after successfully binding a driver to the supplier device. * * The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER, * DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at * the same time is invalid and will cause NULL to be returned upfront. * However, if a device link between the given @consumer and @supplier pair * exists already when this function is called for them, the existing link will * be returned regardless of its current type and status (the link's flags may * be modified then). The caller of this function is then expected to treat * the link as though it has just been created, so (in particular) if * DL_FLAG_STATELESS was passed in @flags, the link needs to be released * explicitly when not needed any more (as stated above). * * A side effect of the link creation is re-ordering of dpm_list and the * devices_kset list by moving the consumer device and all devices depending * on it to the ends of these lists (that does not happen to devices that have * not been registered when this function is called). * * The supplier device is required to be registered when this function is called * and NULL will be returned if that is not the case. The consumer device need * not be registered, however. */ struct device_link *device_link_add(struct device *consumer, struct device *supplier, u32 flags) { struct device_link *link; if (!consumer || !supplier || flags & ~DL_ADD_VALID_FLAGS || (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) || (flags & DL_FLAG_AUTOPROBE_CONSUMER && flags & (DL_FLAG_AUTOREMOVE_CONSUMER | DL_FLAG_AUTOREMOVE_SUPPLIER))) return NULL; if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) { if (pm_runtime_get_sync(supplier) < 0) { pm_runtime_put_noidle(supplier); return NULL; } } if (!(flags & DL_FLAG_STATELESS)) flags |= DL_FLAG_MANAGED; device_links_write_lock(); device_pm_lock(); /* * If the supplier has not been fully registered yet or there is a * reverse dependency between the consumer and the supplier already in * the graph, return NULL. */ if (!device_pm_initialized(supplier) || device_is_dependent(consumer, supplier)) { link = NULL; goto out; } /* * DL_FLAG_AUTOREMOVE_SUPPLIER indicates that the link will be needed * longer than for DL_FLAG_AUTOREMOVE_CONSUMER and setting them both * together doesn't make sense, so prefer DL_FLAG_AUTOREMOVE_SUPPLIER. */ if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER; list_for_each_entry(link, &supplier->links.consumers, s_node) { if (link->consumer != consumer) continue; if (flags & DL_FLAG_PM_RUNTIME) { if (!(link->flags & DL_FLAG_PM_RUNTIME)) { pm_runtime_new_link(consumer); link->flags |= DL_FLAG_PM_RUNTIME; } if (flags & DL_FLAG_RPM_ACTIVE) refcount_inc(&link->rpm_active); } if (flags & DL_FLAG_STATELESS) { link->flags |= DL_FLAG_STATELESS; kref_get(&link->kref); goto out; } /* * If the life time of the link following from the new flags is * longer than indicated by the flags of the existing link, * update the existing link to stay around longer. */ if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) { if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) { link->flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER; link->flags |= DL_FLAG_AUTOREMOVE_SUPPLIER; } } else if (!(flags & DL_FLAG_AUTOREMOVE_CONSUMER)) { link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER | DL_FLAG_AUTOREMOVE_SUPPLIER); } if (!(link->flags & DL_FLAG_MANAGED)) { kref_get(&link->kref); link->flags |= DL_FLAG_MANAGED; device_link_init_status(link, consumer, supplier); } goto out; } link = kzalloc(sizeof(*link), GFP_KERNEL); if (!link) goto out; refcount_set(&link->rpm_active, 1); if (flags & DL_FLAG_PM_RUNTIME) { if (flags & DL_FLAG_RPM_ACTIVE) refcount_inc(&link->rpm_active); pm_runtime_new_link(consumer); } get_device(supplier); link->supplier = supplier; INIT_LIST_HEAD(&link->s_node); get_device(consumer); link->consumer = consumer; INIT_LIST_HEAD(&link->c_node); link->flags = flags; kref_init(&link->kref); /* Determine the initial link state. */ if (flags & DL_FLAG_STATELESS) link->status = DL_STATE_NONE; else device_link_init_status(link, consumer, supplier); /* * Some callers expect the link creation during consumer driver probe to * resume the supplier even without DL_FLAG_RPM_ACTIVE. */ if (link->status == DL_STATE_CONSUMER_PROBE && flags & DL_FLAG_PM_RUNTIME) pm_runtime_resume(supplier); /* * Move the consumer and all of the devices depending on it to the end * of dpm_list and the devices_kset list. * * It is necessary to hold dpm_list locked throughout all that or else * we may end up suspending with a wrong ordering of it. */ device_reorder_to_tail(consumer, NULL); list_add_tail_rcu(&link->s_node, &supplier->links.consumers); list_add_tail_rcu(&link->c_node, &consumer->links.suppliers); dev_dbg(consumer, "Linked as a consumer to %s\n", dev_name(supplier)); out: device_pm_unlock(); device_links_write_unlock(); if ((flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) && !link) pm_runtime_put(supplier); return link; } EXPORT_SYMBOL_GPL(device_link_add); static void device_link_free(struct device_link *link) { while (refcount_dec_not_one(&link->rpm_active)) pm_runtime_put(link->supplier); put_device(link->consumer); put_device(link->supplier); kfree(link); } #ifdef CONFIG_SRCU static void __device_link_free_srcu(struct rcu_head *rhead) { device_link_free(container_of(rhead, struct device_link, rcu_head)); } static void __device_link_del(struct kref *kref) { struct device_link *link = container_of(kref, struct device_link, kref); dev_dbg(link->consumer, "Dropping the link to %s\n", dev_name(link->supplier)); if (link->flags & DL_FLAG_PM_RUNTIME) pm_runtime_drop_link(link->consumer); list_del_rcu(&link->s_node); list_del_rcu(&link->c_node); call_srcu(&device_links_srcu, &link->rcu_head, __device_link_free_srcu); } #else /* !CONFIG_SRCU */ static void __device_link_del(struct kref *kref) { struct device_link *link = container_of(kref, struct device_link, kref); dev_info(link->consumer, "Dropping the link to %s\n", dev_name(link->supplier)); if (link->flags & DL_FLAG_PM_RUNTIME) pm_runtime_drop_link(link->consumer); list_del(&link->s_node); list_del(&link->c_node); device_link_free(link); } #endif /* !CONFIG_SRCU */ static void device_link_put_kref(struct device_link *link) { if (link->flags & DL_FLAG_STATELESS) kref_put(&link->kref, __device_link_del); else WARN(1, "Unable to drop a managed device link reference\n"); } /** * device_link_del - Delete a stateless link between two devices. * @link: Device link to delete. * * The caller must ensure proper synchronization of this function with runtime * PM. If the link was added multiple times, it needs to be deleted as often. * Care is required for hotplugged devices: Their links are purged on removal * and calling device_link_del() is then no longer allowed. */ void device_link_del(struct device_link *link) { device_links_write_lock();