| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Rafael J. Wysocki | 2764 | 19.60% | 22 | 6.65% |
| Kay Sievers | 1705 | 12.09% | 31 | 9.37% |
| Greg Kroah-Hartman | 1685 | 11.95% | 46 | 13.90% |
| Saravana Kannan | 1568 | 11.12% | 20 | 6.04% |
| Cornelia Huck | 644 | 4.57% | 13 | 3.93% |
| Patrick Mochel | 602 | 4.27% | 24 | 7.25% |
| Dmitry Torokhov | 580 | 4.11% | 9 | 2.72% |
| Christian Brauner | 371 | 2.63% | 2 | 0.60% |
| Joe Perches | 368 | 2.61% | 6 | 1.81% |
| Dan J Williams | 334 | 2.37% | 3 | 0.91% |
| Eric W. Biedermann | 306 | 2.17% | 3 | 0.91% |
| Mark McLoughlin | 280 | 1.99% | 1 | 0.30% |
| Grygorii Strashko | 219 | 1.55% | 1 | 0.30% |
| Heikki Krogerus | 202 | 1.43% | 4 | 1.21% |
| Suzuki K. Poulose | 170 | 1.21% | 6 | 1.81% |
| Andy Shevchenko | 168 | 1.19% | 2 | 0.60% |
| Ming Lei | 151 | 1.07% | 2 | 0.60% |
| Alan Stern | 120 | 0.85% | 7 | 2.11% |
| Tejun Heo | 118 | 0.84% | 7 | 2.11% |
| Borislav Petkov | 114 | 0.81% | 2 | 0.60% |
| Benjamin Herrenschmidt | 94 | 0.67% | 4 | 1.21% |
| Guenter Roeck | 94 | 0.67% | 1 | 0.30% |
| Linus Torvalds | 81 | 0.57% | 1 | 0.30% |
| Hugh Daschbach | 80 | 0.57% | 1 | 0.30% |
| Lukas Wunner | 77 | 0.55% | 4 | 1.21% |
| pascal paillet | 71 | 0.50% | 1 | 0.30% |
| Sergey Klyaus | 56 | 0.40% | 1 | 0.30% |
| David Graham White | 55 | 0.39% | 1 | 0.30% |
| Andi Kleen | 55 | 0.39% | 1 | 0.30% |
| Tetsuo Handa | 54 | 0.38% | 1 | 0.30% |
| Stephen Rothwell | 48 | 0.34% | 1 | 0.30% |
| Johan Hovold | 46 | 0.33% | 1 | 0.30% |
| Yinghai Lu | 45 | 0.32% | 1 | 0.30% |
| Felipe Balbi | 44 | 0.31% | 1 | 0.30% |
| James Bottomley | 38 | 0.27% | 2 | 0.60% |
| Feng Kan | 37 | 0.26% | 1 | 0.30% |
| Joel A Fernandes | 33 | 0.23% | 1 | 0.30% |
| Al Viro | 32 | 0.23% | 2 | 0.60% |
| Josh Zimmerman | 31 | 0.22% | 1 | 0.30% |
| Mathieu Malaterre | 30 | 0.21% | 1 | 0.30% |
| Ben Hutchings | 30 | 0.21% | 1 | 0.30% |
| Kaitao cheng | 29 | 0.21% | 1 | 0.30% |
| Joerg Roedel | 22 | 0.16% | 1 | 0.30% |
| Vivek Gautam | 21 | 0.15% | 2 | 0.60% |
| Wagner Ferenc | 21 | 0.15% | 1 | 0.30% |
| Peter Rajnoha | 20 | 0.14% | 2 | 0.60% |
| Song Muchun | 19 | 0.13% | 1 | 0.30% |
| Grant C. Likely | 19 | 0.13% | 2 | 0.60% |
| Andrew Morton | 18 | 0.13% | 1 | 0.30% |
| Randy Dunlap | 17 | 0.12% | 3 | 0.91% |
| Dave Young | 14 | 0.10% | 1 | 0.30% |
| Yang Ruirui | 14 | 0.10% | 2 | 0.60% |
| Mika Westerberg | 13 | 0.09% | 1 | 0.30% |
| Jiang Liu | 13 | 0.09% | 1 | 0.30% |
| Jean Delvare | 13 | 0.09% | 2 | 0.60% |
| Alexander Duyck | 12 | 0.09% | 1 | 0.30% |
| Christoph Hellwig | 12 | 0.09% | 2 | 0.60% |
| Liu ShuoX | 10 | 0.07% | 1 | 0.30% |
| Thomas Gleixner | 9 | 0.06% | 2 | 0.60% |
| Zhen Lei | 9 | 0.06% | 1 | 0.30% |
| Peter Zijlstra | 8 | 0.06% | 1 | 0.30% |
| Matthew Wilcox | 8 | 0.06% | 2 | 0.60% |
| Rasmus Villemoes | 8 | 0.06% | 1 | 0.30% |
| Irenge Jules Bashizi | 8 | 0.06% | 2 | 0.60% |
| Lars-Peter Clausen | 8 | 0.06% | 1 | 0.30% |
| Harvey Harrison | 7 | 0.05% | 1 | 0.30% |
| Jesper Juhl | 7 | 0.05% | 1 | 0.30% |
| Peter Chen | 7 | 0.05% | 1 | 0.30% |
| David Herrmann | 6 | 0.04% | 1 | 0.30% |
| Lei Ming | 6 | 0.04% | 1 | 0.30% |
| Jim Cromie | 6 | 0.04% | 1 | 0.30% |
| Liu Ping Fan | 6 | 0.04% | 1 | 0.30% |
| Johannes Berg | 6 | 0.04% | 2 | 0.60% |
| Yijing Wang | 6 | 0.04% | 1 | 0.30% |
| Benson Leung | 5 | 0.04% | 1 | 0.30% |
| Brian Walsh | 5 | 0.04% | 1 | 0.30% |
| LongX Zhang | 5 | 0.04% | 1 | 0.30% |
| Hannes Reinecke | 4 | 0.03% | 1 | 0.30% |
| Jeffy Chen | 4 | 0.03% | 1 | 0.30% |
| Wei Yang | 4 | 0.03% | 1 | 0.30% |
| Phil Carmody | 4 | 0.03% | 2 | 0.60% |
| Alexander Nyberg | 4 | 0.03% | 1 | 0.30% |
| Yani Ioannou | 4 | 0.03% | 1 | 0.30% |
| Gimcuan Hui | 3 | 0.02% | 1 | 0.30% |
| Deepak Saxena | 3 | 0.02% | 1 | 0.30% |
| Arjan van de Ven | 3 | 0.02% | 1 | 0.30% |
| Rob Herring | 3 | 0.02% | 1 | 0.30% |
| Michal Suchanek | 3 | 0.02% | 1 | 0.30% |
| Ingo Molnar | 3 | 0.02% | 1 | 0.30% |
| Robert P. J. Day | 3 | 0.02% | 1 | 0.30% |
| Emese Revfy | 2 | 0.01% | 2 | 0.60% |
| Jani Nikula | 2 | 0.01% | 1 | 0.30% |
| Stephen Hemminger | 2 | 0.01% | 1 | 0.30% |
| Rabin Vincent | 2 | 0.01% | 1 | 0.30% |
| Ethan Zhao | 2 | 0.01% | 1 | 0.30% |
| Dave Jones | 2 | 0.01% | 1 | 0.30% |
| David Brownell | 2 | 0.01% | 1 | 0.30% |
| Jerome Brunet | 2 | 0.01% | 1 | 0.30% |
| Catalin Marinas | 2 | 0.01% | 1 | 0.30% |
| Sergey Senozhatsky | 2 | 0.01% | 1 | 0.30% |
| Mauro Carvalho Chehab | 1 | 0.01% | 1 | 0.30% |
| Jingoo Han | 1 | 0.01% | 1 | 0.30% |
| Wolfram Sang | 1 | 0.01% | 1 | 0.30% |
| Timur Tabi | 1 | 0.01% | 1 | 0.30% |
| Christoph Egger | 1 | 0.01% | 1 | 0.30% |
| Stefan Weil | 1 | 0.01% | 1 | 0.30% |
| Mark Rutland | 1 | 0.01% | 1 | 0.30% |
| Shaokun Zhang | 1 | 0.01% | 1 | 0.30% |
| Frank A. Uepping | 1 | 0.01% | 1 | 0.30% |
| Stefan Achatz | 1 | 0.01% | 1 | 0.30% |
| Peter Korsgaard | 1 | 0.01% | 1 | 0.30% |
| Jianpeng Ma | 1 | 0.01% | 1 | 0.30% |
| David S. Miller | 1 | 0.01% | 1 | 0.30% |
| Yan Hong | 1 | 0.01% | 1 | 0.30% |
| Josh Triplett | 1 | 0.01% | 1 | 0.30% |
| Adrian Bunk | 1 | 0.01% | 1 | 0.30% |
| Roland Dreier | 1 | 0.01% | 1 | 0.30% |
| Hanjun Guo | 1 | 0.01% | 1 | 0.30% |
| Total | 14100 | 331 |
// 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. */ static LIST_HEAD(wait_for_suppliers); static DEFINE_MUTEX(wfs_lock); static LIST_HEAD(deferred_sync); static unsigned int defer_sync_state_count = 1; static unsigned int defer_fw_devlink_count; static LIST_HEAD(deferred_fw_devlink); static DEFINE_MUTEX(defer_fw_devlink_lock); static bool fw_devlink_is_permissive(void); #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) __acquires(&device_links_srcu) { return srcu_read_lock(&device_links_srcu); } void device_links_read_unlock(int idx) __releases(&device_links_srcu) { 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->flags == (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED)) continue; 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) { if (link->flags == (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED)) continue; 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 | \ DL_FLAG_SYNC_STATE_ONLY) #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_SYNC_STATE_ONLY && flags != DL_FLAG_SYNC_STATE_ONLY) || (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 (non-SYNC_STATE_ONLY) dependency between the consumer and * the supplier already in the graph, return NULL. If the link is a * SYNC_STATE_ONLY link, we don't check for reverse dependencies * because it only affects sync_state() callbacks. */ if (!device_pm_initialized(supplier) || (!(flags & DL_FLAG_SYNC_STATE_ONLY) && 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) { kref_get(&link->kref); if (link->flags & DL_FLAG_SYNC_STATE_ONLY && !(link->flags & DL_FLAG_STATELESS)) { link->flags |= DL_FLAG_STATELESS; goto reorder; } else { link->flags |= DL_FLAG_STATELESS; 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); } if (link->flags & DL_FLAG_SYNC_STATE_ONLY && !(flags & DL_FLAG_SYNC_STATE_ONLY)) { link->flags &= ~DL_FLAG_SYNC_STATE_ONLY; goto reorder; } 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); list_add_tail_rcu(&link->s_node, &supplier->links.consumers); list_add_tail_rcu(&link->c_node, &consumer->links.suppliers); if (flags & DL_FLAG_SYNC_STATE_ONLY) { dev_dbg(consumer, "Linked as a sync state only consumer to %s\n", dev_name(supplier)); goto out; } reorder: /* * 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); 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); /** * device_link_wait_for_supplier - Add device to wait_for_suppliers list * @consumer: Consumer device * * Marks the @consumer device as waiting for suppliers to become available by * adding it to the wait_for_suppliers list. The consumer device will never be * probed until it's removed from the wait_for_suppliers list. * * The caller is responsible for adding the links to the supplier devices once * they are available and removing the @consumer device from the * wait_for_suppliers list once links to all the suppliers have been created. * * This function is NOT meant to be called from the probe function of the * consumer but rather from code that creates/adds the consumer device. */ static void device_link_wait_for_supplier(struct device *consumer, bool need_for_probe) { mutex_lock(&wfs_lock); list_add_tail(&consumer->links.needs_suppliers, &wait_for_suppliers); consumer->links.need_for_probe = need_for_probe; mutex_unlock(&wfs_lock); } static void device_link_wait_for_mandatory_supplier(struct device *consumer) { device_link_wait_for_supplier(consumer, true); } static void device_link_wait_for_optional_supplier(struct device *consumer) { device_link_wait_for_supplier(consumer, false); } /** * device_link_add_missing_supplier_links - Add links from consumer devices to * supplier devices, leaving any * consumer with inactive suppliers on * the wait_for_suppliers list * * Loops through all consumers waiting on suppliers and tries to add all their * supplier links. If that succeeds, the consumer device is removed from * wait_for_suppliers list. Otherwise, they are left in the wait_for_suppliers * list. Devices left on the wait_for_suppliers list will not be probed. * * The fwnode add_links callback is expected to return 0 if it has found and * added all the supplier links for the consumer device. It should return an * error if it isn't able to do so. * * The caller of device_link_wait_for_supplier() is expected to call this once * it's aware of potential suppliers becoming available. */ static void device_link_add_missing_supplier_links(void) { struct device *dev, *tmp; mutex_lock(&wfs_lock); list_for_each_entry_safe(dev, tmp, &wait_for_suppliers, links.needs_suppliers) { int ret = fwnode_call_int_op(dev->fwnode, add_links, dev); if (!ret) list_del_init(&dev->links.needs_suppliers); else if (ret != -ENODEV || fw_devlink_is_permissive()) dev->links.need_for_probe = false; } mutex_unlock(&wfs_lock); } 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(); device_pm_lock(); device_link_put_kref(link); device_pm_unlock(); device_links_write_unlock(); } EXPORT_SYMBOL_GPL(device_link_del); /** * device_link_remove - Delete a stateless link between two devices. * @consumer: Consumer end of the link. * @supplier: Supplier end of the link. * * The caller must ensure proper synchronization of this function with runtime * PM. */ void device_link_remove(void *consumer, struct device *supplier) { struct device_link *link; if (WARN_ON(consumer == supplier)) return; device_links_write_lock(); device_pm_lock(); list_for_each_entry(link, &supplier->links.consumers, s_node) { if (link->consumer == consumer) { device_link_put_kref(link); break; } } device_pm_unlock(); device_links_write_unlock(); } EXPORT_SYMBOL_GPL(device_link_remove); static void device_links_missing_supplier(struct device *dev) { struct device_link *link; list_for_each_entry(link, &dev->links.suppliers, c_node) { if (link->status != DL_STATE_CONSUMER_PROBE) continue; if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) { WRITE_ONCE(link->status, DL_STATE_AVAILABLE); } else { WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY)); WRITE_ONCE(link->status, DL_STATE_DORMANT); } } } /** * device_links_check_suppliers - Check presence of supplier drivers. * @dev: Consumer device. * * Check links from this device to any suppliers. Walk the list of the device's * links to suppliers and see if all of them are available. If not, simply * return -EPROBE_DEFER. * * We need to guarantee that the supplier will not go away after the check has * been positive here. It only can go away in __device_release_driver() and * that function checks the device's links to consumers. This means we need to * mark the link as "consumer probe in progress" to make the supplier removal * wait for us to complete (or bad things may happen). * * Links without the DL_FLAG_MANAGED flag set are ignored. */ int device_links_check_suppliers(struct device *dev) { struct device_link *link; int ret = 0; /* * Device waiting for supplier to become available is not allowed to * probe. */ mutex_lock(&wfs_lock); if (!list_empty(&dev->links.needs_suppliers) && dev->links.need_for_probe) { mutex_unlock(&wfs_lock); return -EPROBE_DEFER; } mutex_unlock(&wfs_lock); device_links_write_lock(); list_for_each_entry(link, &dev->links.suppliers, c_node) { if (!(link->flags & DL_FLAG_MANAGED)) continue; if (link->status != DL_STATE_AVAILABLE && !(link->flags & DL_FLAG_SYNC_STATE_ONLY)) { device_links_missing_supplier(dev); ret = -EPROBE_DEFER; break; } WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE); } dev->links.status = DL_DEV_PROBING; device_links_write_unlock(); return ret; } /** * __device_links_queue_sync_state - Queue a device for sync_state() callback * @dev: Device to call sync_state() on * @list: List head to queue the @dev on * * Queues a device for a sync_state() callback when the device links write lock * isn't held. This allows the sync_state() execution flow to use device links * APIs. The caller must ensure this function is called with * device_links_write_lock() held. * * This function does a get_device() to make sure the device is not freed while * on this list. * * So the caller must also ensure that device_links_flush_sync_list() is called * as soon as the caller releases device_links_write_lock(). This is necessary * to make sure the sync_state() is called in a timely fashion and the * put_device() is called on this device. */ static void __device_links_queue_sync_state(struct device *dev, struct list_head *list) { struct device_link *link; if (!dev_has_sync_state(dev)) return; if (dev->state_synced) return; list_for_each_entry(link, &dev->links.consumers, s_node) { if (!(link->flags & DL_FLAG_MANAGED)) continue; if (link->status != DL_STATE_ACTIVE) return; } /* * Set the flag here to avoid adding the same device to a list more * than once. This can happen if new consumers get added to the device * and probed before the list is flushed. */ dev->state_synced = true; if (WARN_ON(!list_empty(&dev->links.defer_hook))) return; get_device(dev); list_add_tail(&dev->links.defer_hook, list); } /** * device_links_flush_sync_list - Call sync_state() on a list of devices * @list: List of devices to call sync_state() on * @dont_lock_dev: Device for which lock is already held by the caller * * Calls sync_state() on all the devices that have been queued for it. This * function is used in conjunction with __device_links_queue_sync_state(). The * @dont_lock_dev parameter is useful when this function is called from a * context where a device lock is already held. */ static void device_links_flush_sync_list(struct list_head *list, struct device *dont_lock_dev) { struct device *dev, *tmp; list_for_each_entry_safe(dev, tmp, list, links.defer_hook) { list_del_init(&dev->links.defer_hook); if (dev != dont_lock_dev) device_lock(dev); if (dev->bus->sync_state) dev->bus->sync_state(dev); else if (dev->driver && dev->driver->sync_state) dev->driver->sync_state(dev); if (dev != dont_lock_dev) device_unlock(dev); put_device(dev); } } void device_links_supplier_sync_state_pause(void) { device_links_write_lock(); defer_sync_state_count++; device_links_write_unlock(); } void device_links_supplier_sync_state_resume(void) { struct device *dev, *tmp; LIST_HEAD(sync_list); device_links_write_lock(); if (!defer_sync_state_count) { WARN(true, "Unmatched sync_state pause/resume!"); goto out; } defer_sync_state_count--; if (defer_sync_state_count) goto out; list_for_each_entry_safe(dev, tmp, &deferred_sync, links.defer_hook) { /* * Delete from deferred_sync list before queuing it to * sync_list because defer_hook is used for both lists. */ list_del_init(&dev->links.defer_hook); __device_links_queue_sync_state(dev, &sync_list); } out: device_links_write_unlock(); device_links_flush_sync_list(&sync_list, NULL); } static int sync_state_resume_initcall(void) { device_links_supplier_sync_state_resume(); return 0; } late_initcall(sync_state_resume_initcall); static void __device_links_supplier_defer_sync(struct device *sup) { if (list_empty(&sup->links.defer_hook) && dev_has_sync_state(sup)) list_add_tail(&sup->links.defer_hook, &deferred_sync); } static void device_link_drop_managed(struct device_link *link) { link->flags &= ~DL_FLAG_MANAGED; WRITE_ONCE(link->status, DL_STATE_NONE); kref_put(&link->kref, __device_link_del); } /** * device_links_driver_bound - Update device links after probing its driver. * @dev: Device to update the links for. * * The probe has been successful, so update links from this device to any * consumers by changing their status to "available". * * Also change the status of @dev's links to suppliers to "active". * * Links without the DL_FLAG_MANAGED flag set are ignored. */ void device_links_driver_bound(struct device *dev) { struct device_link *link, *ln; LIST_HEAD(sync_list); /* * If a device probes successfully, it's expected to have created all * the device links it needs to or make new device links as it needs * them. So, it no longer needs to wait on any suppliers. */ mutex_lock(&wfs_lock); list_del_init(&dev->links.needs_suppliers); mutex_unlock(&wfs_lock); device_links_write_lock(); list_for_each_entry(link, &dev->links.consumers, s_node) { if (!(link->flags & DL_FLAG_MANAGED)) continue; /* * Links created during consumer probe may be in the "consumer * probe" state to start with if the supplier is still probing * when they are created and they may become "active" if the * consumer probe returns first. Skip them here. */ if (link->status == DL_STATE_CONSUMER_PROBE || link->status == DL_STATE_ACTIVE) continue; WARN_ON(link->status != DL_STATE_DORMANT); WRITE_ONCE(link->status, DL_STATE_AVAILABLE); if (link->flags & DL_FLAG_AUTOPROBE_CONSUMER) driver_deferred_probe_add(link->consumer); } if (defer_sync_state_count) __device_links_supplier_defer_sync(dev); else __device_links_queue_sync_state(dev, &sync_list); list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) { struct device *supplier; if (!(link->flags & DL_FLAG_MANAGED)) continue; supplier = link->supplier; if (link->flags & DL_FLAG_SYNC_STATE_ONLY) { /* * When DL_FLAG_SYNC_STATE_ONLY is set, it means no * other DL_MANAGED_LINK_FLAGS have been set. So, it's * save to drop the managed link completely. */ device_link_drop_managed(link); } else { WARN_ON(link->status != DL_STATE_CONSUMER_PROBE); WRITE_ONCE(link->status, DL_STATE_ACTIVE); } /* * This needs to be done even for the deleted * DL_FLAG_SYNC_STATE_ONLY device link in case it was the last * device link that was preventing the supplier from getting a * sync_state() call. */ if (defer_sync_state_count) __device_links_supplier_defer_sync(supplier); else __device_links_queue_sync_state(supplier, &sync_list); } dev->links.status = DL_DEV_DRIVER_BOUND; device_links_write_unlock(); device_links_flush_sync_list(&sync_list, dev); } /** * __device_links_no_driver - Update links of a device without a driver. * @dev: Device without a drvier. * * Delete all non-persistent links from this device to any suppliers. * * Persistent links stay around, but their status is changed to "available", * unless they already are in the "supplier unbind in progress" state in which * case they need not be updated. * * Links without the DL_FLAG_MANAGED flag set are ignored. */ static void __device_links_no_driver(struct device *dev) { struct device_link *link, *ln; list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) { if (!(link->flags & DL_FLAG_MANAGED)) continue; if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) { device_link_drop_managed(link); continue; } if (link->status != DL_STATE_CONSUMER_PROBE && link->status != DL_STATE_ACTIVE) continue; if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) { WRITE_ONCE(link->status, DL_STATE_AVAILABLE); } else { WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY)); WRITE_ONCE(link->status, DL_STATE_DORMANT); } } dev->links.status = DL_DEV_NO_DRIVER; } /** * device_links_no_driver - Update links after failing driver probe. * @dev: Device whose driver has just failed to probe. * * Clean up leftover links to consumers for @dev and invoke * %__device_links_no_driver() to update links to suppliers for it as * appropriate. * * Links without the DL_FLAG_MANAGED flag set are ignored. */ void device_links_no_driver(struct device *dev) { struct device_link *link; device_links_write_lock(); list_for_each_entry(link, &dev->links.consumers, s_node) { if (!(link->flags & DL_FLAG_MANAGED)) continue; /* * The probe has failed, so if the status of the link is * "consumer probe" or "active", it must have been added by * a probing consumer while this device was still probing. * Change its state to "dormant", as it represents a valid * relationship, but it is not functionally meaningful. */ if (link->status == DL_STATE_CONSUMER_PROBE || link->status == DL_STATE_ACTIVE) WRITE_ONCE(link->status, DL_STATE_DORMANT); } __device_links_no_driver(dev); device_links_write_unlock(); } /** * device_links_driver_cleanup - Update links after driver removal. * @dev: Device whose driver has just gone away. * * Update links to consumers for @dev by changing their status to "dormant" and * invoke %__device_links_no_driver() to update links to suppliers for it as * appropriate. * * Links without the DL_FLAG_MANAGED flag set are ignored. */ void device_links_driver_cleanup(struct device *dev) { struct device_link *link, *ln; device_links_write_lock(); list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) { if (!(link->flags & DL_FLAG_MANAGED)) continue; WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER); WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND); /* * autoremove the links between this @dev and its consumer * devices that are not active, i.e. where the link state * has moved to DL_STATE_SUPPLIER_UNBIND. */ if (link->status == DL_STATE_SUPPLIER_UNBIND && link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER) device_link_drop_managed(link); WRITE_ONCE(link->status, DL_STATE_DORMANT); } list_del_init(&dev->links.defer_hook); __device_links_no_driver(dev); device_links_write_unlock(); } /** * device_links_busy - Check if there are any busy links to consumers. * @dev: Device to check. * * Check each consumer of the device and return 'true' if its link's status * is one of "consumer probe" or "active" (meaning that the given consumer is * probing right now or its driver is present). Otherwise, change the link * state to "supplier unbind" to prevent the consumer from being probed * successfully going forward. * * Return 'false' if there are no probing or active consumers. * * Links without the DL_FLAG_MANAGED flag set are ignored. */ bool device_links_busy(struct device *dev) { struct device_link *link; bool ret = false; device_links_write_lock(); list_for_each_entry(link, &dev->links.consumers, s_node) { if (!(link->flags & DL_FLAG_MANAGED)) continue; if (link->status == DL_STATE_CONSUMER_PROBE || link->status == DL_STATE_ACTIVE) { ret = true; break; } WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND); } dev->links.status = DL_DEV_UNBINDING; device_links_write_unlock(); return ret; } /** * device_links_unbind_consumers - Force unbind consumers of the given device. * @dev: Device to unbind the consumers of. * * Walk the list of links to consumers for @dev and if any of them is in the * "consumer probe" state, wait for all device probes in progress to complete * and start over. * * If that's not the case, change the status of the link to "supplier unbind" * and check if the link was in the "active" state. If so, force the consumer * driver to unbind and start over (the consumer will not re-probe as we have * changed the state of the link already). * * Links without the DL_FLAG_MANAGED flag set are ignored. */ void device_links_unbind_consumers(struct device *dev) { struct device_link *link; start: device_links_write_lock(); list_for_each_entry(link, &dev->links.consumers, s_node) { enum device_link_state status; if (!(link->flags & DL_FLAG_MANAGED) || link->flags & DL_FLAG_SYNC_STATE_ONLY) continue; status = link->status; if (status == DL_STATE_CONSUMER_PROBE) { device_links_write_unlock(); wait_for_device_probe(); goto start; } WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND); if (status == DL_STATE_ACTIVE) { struct device *consumer = link->consumer; get_device(consumer); device_links_write_unlock(); device_release_driver_internal(consumer, NULL, consumer->parent); put_device(consumer); goto start; } } device_links_write_unlock(); } /** * device_links_purge - Delete existing links to other devices. * @dev: Target device. */ static void device_links_purge(struct device *dev) { struct device_link *link, *ln; mutex_lock(&wfs_lock); list_del(&dev->links.needs_suppliers); mutex_unlock(&wfs_lock); /* * Delete all of the remaining links from this device to any other * devices (either consumers or suppliers). */ device_links_write_lock(); list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) { WARN_ON(link->status == DL_STATE_ACTIVE); __device_link_del(&link->kref); } list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) { WARN_ON(link->status != DL_STATE_DORMANT && link->status != DL_STATE_NONE); __device_link_del(&link->kref); } device_links_write_unlock(); } static u32 fw_devlink_flags = DL_FLAG_SYNC_STATE_ONLY; static int __init fw_devlink_setup(char *arg) { if (!arg) return -EINVAL; if (strcmp(arg, "off") == 0) { fw_devlink_flags = 0; } else if (strcmp(arg, "permissive") == 0) { fw_devlink_flags = DL_FLAG_SYNC_STATE_ONLY; } else if (strcmp(arg, "on") == 0) { fw_devlink_flags = DL_FLAG_AUTOPROBE_CONSUMER; } else if (strcmp(arg, "rpm") == 0) { fw_devlink_flags = DL_FLAG_AUTOPROBE_CONSUMER | DL_FLAG_PM_RUNTIME; } return 0; } early_param("fw_devlink", fw_devlink_setup); u32 fw_devlink_get_flags(void) { return fw_devlink_flags; } static bool fw_devlink_is_permissive(void) { return fw_devlink_flags == DL_FLAG_SYNC_STATE_ONLY; } static void fw_devlink_link_device(struct device *dev) { int fw_ret; if (!fw_devlink_flags) return; mutex_lock(&defer_fw_devlink_lock); if (!defer_fw_devlink_count) device_link_add_missing_supplier_links(); /* * The device's fwnode not having add_links() doesn't affect if other * consumers can find this device as a supplier. So, this check is * intentionally placed after device_link_add_missing_supplier_links(). */ if (!fwnode_has_op(dev->fwnode, add_links)) goto out; /* * If fw_devlink is being deferred, assume all devices have mandatory * suppliers they need to link to later. Then, when the fw_devlink is * resumed, all these devices will get a chance to try and link to any * suppliers they have. */ if (!defer_fw_devlink_count) { fw_ret = fwnode_call_int_op(dev->fwnode, add_links, dev); if (fw_ret == -ENODEV && fw_devlink_is_permissive()) fw_ret = -EAGAIN; } else { fw_ret = -ENODEV; /* * defer_hook is not used to add device to deferred_sync list * until device is bound. Since deferred fw devlink also blocks * probing, same list hook can be used for deferred_fw_devlink. */ list_add_tail(&dev->links.defer_hook, &deferred_fw_devlink); } if (fw_ret == -ENODEV) device_link_wait_for_mandatory_supplier(dev); else if (fw_ret) device_link_wait_for_optional_supplier(dev); out: mutex_unlock(&defer_fw_devlink_lock); } /** * fw_devlink_pause - Pause parsing of fwnode to create device links * * Calling this function defers any fwnode parsing to create device links until * fw_devlink_resume() is called. Both these functions are ref counted and the * caller needs to match the calls. * * While fw_devlink is paused: * - Any device that is added won't have its fwnode parsed to create device * links. * - The probe of the device will also be deferred during this period. * - Any devices that were already added, but waiting for suppliers won't be * able to link to newly added devices. * * Once fw_devlink_resume(): * - All the fwnodes that was not parsed will be parsed. * - All the devices that were deferred probing will be reattempted if they * aren't waiting for any more suppliers. * * This pair of functions, is mainly meant to optimize the parsing of fwnodes * when a lot of devices that need to link to each other are added in a short * interval of time. For example, adding all the top level devices in a system. * * For example, if N devices are added and: * - All the consumers are added before their suppliers * - All the suppliers of the N devices are part of the N devices * * Then: * * - With the use of fw_devlink_pause() and fw_devlink_resume(), each device * will only need one parsing of its fwnode because it is guaranteed to find * all the supplier devices already registered and ready to link to. It won't * have to do another pass later to find one or more suppliers it couldn't * find in the first parse of the fwnode. So, we'll only need O(N) fwnode * parses. * * - Without the use of fw_devlink_pause() and fw_devlink_resume(), we would * end up doing O(N^2) parses of fwnodes because every device that's added is * guaranteed to trigger a parse of the fwnode of every device added before * it. This O(N^2) parse is made worse by the fact that when a fwnode of a * device is parsed, all it descendant devices might need to have their * fwnodes parsed too (even if the devices themselves aren't added). */ void fw_devlink_pause(void) { mutex_lock(&defer_fw_devlink_lock); defer_fw_devlink_count++; mutex_unlock(&defer_fw_devlink_lock); } /** fw_devlink_resume - Resume parsing of fwnode to create device links * * This function is used in conjunction with fw_devlink_pause() and is ref * counted. See documentation for fw_devlink_pause() for more details. */ void fw_devlink_resume(void) { struct device *dev, *tmp; LIST_HEAD(probe_list); mutex_lock(&defer_fw_devlink_lock); if (!defer_fw_devlink_count) { WARN(true, "Unmatched fw_devlink pause/resume!"); goto out; } defer_fw_devlink_count--; if (defer_fw_devlink_count) goto out; device_link_add_missing_supplier_links(); list_splice_tail_init(&deferred_fw_devlink, &probe_list); out: mutex_unlock(&defer_fw_devlink_lock); /* * bus_probe_device() can cause new devices to get added and they'll * try to grab defer_fw_devlink_lock. So, this needs to be done outside * the defer_fw_devlink_lock. */ list_for_each_entry_safe(dev, tmp, &probe_list, links.defer_hook) { list_del_init(&dev->links.defer_hook); bus_probe_device(dev); } } /* Device links support end. */ int (*platform_notify)(struct device *dev) = NULL; int (*platform_notify_remove)(struct device *dev) = NULL; static struct kobject *dev_kobj; struct kobject *sysfs_dev_char_kobj; struct kobject *sysfs_dev_block_kobj; static DEFINE_MUTEX(device_hotplug_lock); void lock_device_hotplug(void) { mutex_lock(&device_hotplug_lock); } void unlock_device_hotplug(void) { mutex_unlock(&device_hotplug_lock); } int lock_device_hotplug_sysfs(void) { if (mutex_trylock(&device_hotplug_lock)) return 0; /* Avoid busy looping (5 ms of sleep should do). */ msleep(5); return restart_syscall(); } #ifdef CONFIG_BLOCK static inline int device_is_not_partition(struct device *dev) { return !(dev->type == &part_type); } #else static inline int device_is_not_partition(struct device *dev) { return 1; } #endif static int device_platform_notify(struct device *dev, enum kobject_action action) { int ret; ret = acpi_platform_notify(dev, action); if (ret) return ret; ret = software_node_notify(dev, action); if (ret) return ret; if (platform_notify && action == KOBJ_ADD) platform_notify(dev); else if (platform_notify_remove && action == KOBJ_REMOVE) platform_notify_remove(dev); return 0; } /** * dev_driver_string - Return a device's driver name, if at all possible * @dev: struct device to get the name of * * Will return the device's driver's name if it is bound to a device. If * the device is not bound to a driver, it will return the name of the bus * it is attached to. If it is not attached to a bus either, an empty * string will be returned. */ const char *dev_driver_string(const struct device *dev) { struct device_driver *drv; /* dev->driver can change to NULL underneath us because of unbinding, * so be careful about accessing it. dev->bus and dev->class should * never change once they are set, so they don't need special care. */ drv = READ_ONCE(dev->driver); return drv ? drv->name : (dev->bus ? dev->bus->name : (dev->class ? dev->class->name : "")); } EXPORT_SYMBOL(dev_driver_string); #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr) static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr, char *buf) { struct device_attribute *dev_attr = to_dev_attr(attr); struct device *dev = kobj_to_dev(kobj); ssize_t ret = -EIO; if (dev_attr->show) ret = dev_attr->show(dev, dev_attr, buf); if (ret >= (ssize_t)PAGE_SIZE) { printk("dev_attr_show: %pS returned bad count\n", dev_attr->show); } return ret; } static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr, const char *buf, size_t count) { struct device_attribute *dev_attr = to_dev_attr(attr); struct device *dev = kobj_to_dev(kobj); ssize_t ret = -EIO; if (dev_attr->store) ret = dev_attr->store(dev, dev_attr, buf, count); return ret; } static const struct sysfs_ops dev_sysfs_ops = { .show = dev_attr_show, .store = dev_attr_store, }; #define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr) ssize_t device_store_ulong(struct device *dev, struct device_attribute *attr, const char *buf, size_t size) { struct dev_ext_attribute *ea = to_ext_attr(attr); int ret; unsigned long new; ret = kstrtoul(buf, 0, &new); if (ret) return ret; *(unsigned long *)(ea->var) = new; /* Always return full write size even if we didn't consume all */ return size; } EXPORT_SYMBOL_GPL(device_store_ulong); ssize_t device_show_ulong(struct device *dev, struct device_attribute *attr, char *buf) { struct dev_ext_attribute *ea = to_ext_attr(attr); return snprintf(buf, PAGE_SIZE, "%lx\n", *(unsigned long *)(ea->var)); } EXPORT_SYMBOL_GPL(device_show_ulong); ssize_t device_store_int(struct device *dev, struct device_attribute *attr, const char *buf, size_t size) { struct dev_ext_attribute *ea = to_ext_attr(attr); int ret; long new; ret = kstrtol(buf, 0, &new); if (ret) return ret; if (new > INT_MAX || new < INT_MIN) return -EINVAL; *(int *)(ea->var) = new; /* Always return full write size even if we didn't consume all */ return size; } EXPORT_SYMBOL_GPL(device_store_int); ssize_t device_show_int(struct device *dev, struct device_attribute *attr, char *buf) { struct dev_ext_attribute *ea = to_ext_attr(attr); return snprintf(buf, PAGE_SIZE, "%d\n", *(int *)(ea->var)); } EXPORT_SYMBOL_GPL(device_show_int); ssize_t device_store_bool(struct device *dev, struct device_attribute *attr, const char *buf, size_t size) { struct dev_ext_attribute *ea = to_ext_attr(attr); if (strtobool(buf, ea->var) < 0) return -EINVAL; return size; } EXPORT_SYMBOL_GPL(device_store_bool); ssize_t device_show_bool(struct device *dev, struct device_attribute *attr, char *buf) { struct dev_ext_attribute *ea = to_ext_attr(attr); return snprintf(buf, PAGE_SIZE, "%d\n", *(bool *)(ea->var)); } EXPORT_SYMBOL_GPL(device_show_bool); /** * device_release - free device structure. * @kobj: device's kobject. * * This is called once the reference count for the object * reaches 0. We forward the call to the device's release * method, which should handle actually freeing the structure. */ static void device_release(struct kobject *kobj) { struct device *dev = kobj_to_dev(kobj); struct device_private *p = dev->p; /* * Some platform devices are driven without driver attached * and managed resources may have been acquired. Make sure * all resources are released. * * Drivers still can add resources into device after device * is deleted but alive, so release devres here to avoid * possible memory leak. */ devres_release_all(dev); if (dev->release) dev->release(dev); else if (dev->type && dev->type->release) dev->type->release(dev); else if (dev->class && dev->class->dev_release) dev->class->dev_release(dev); else WARN(1, KERN_ERR "Device '%s' does not have a release() function, it is broken and must be fixed. See Documentation/core-api/kobject.rst.\n", dev_name(dev)); kfree(p); } static const void *device_namespace(struct kobject *kobj) { struct device *dev = kobj_to_dev(kobj); const void *ns = NULL; if (dev->class && dev->class->ns_type) ns = dev->class->namespace(dev); return ns; } static void device_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid) { struct device *dev = kobj_to_dev(kobj); if (dev->class && dev->class->get_ownership) dev->class->get_ownership(dev, uid, gid); } static struct kobj_type device_ktype = { .release = device_release, .sysfs_ops = &dev_sysfs_ops, .namespace = device_namespace, .get_ownership = device_get_ownership, }; static int dev_uevent_filter(struct kset *kset, struct kobject *kobj) { struct kobj_type *ktype = get_ktype(kobj); if (ktype == &device_ktype) { struct device *dev = kobj_to_dev(kobj); if (dev->bus) return 1; if (dev->class) return 1; } return 0; } static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj) { struct device *dev = kobj_to_dev(kobj); if (dev->bus) return dev->bus->name; if (dev->class) return dev->class->name; return NULL; } static int dev_uevent(struct kset *kset, struct kobject *kobj, struct kobj_uevent_env *env) { struct device *dev = kobj_to_dev(kobj); int retval = 0; /* add device node properties if present */ if (MAJOR(dev->devt)) { const char *tmp; const char *name; umode_t mode = 0; kuid_t uid = GLOBAL_ROOT_UID; kgid_t gid = GLOBAL_ROOT_GID; add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt)); add_uevent_var(env, "MINOR=%u", MINOR(dev->devt)); name = device_get_devnode(dev, &mode, &uid, &gid, &tmp); if (name) { add_uevent_var(env, "DEVNAME=%s", name); if (mode) add_uevent_var(env, "DEVMODE=%#o", mode & 0777); if (!uid_eq(uid, GLOBAL_ROOT_UID)) add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid)); if (!gid_eq(gid, GLOBAL_ROOT_GID)) add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid)); kfree(tmp); } } if (dev->type && dev->type->name) add_uevent_var(env, "DEVTYPE=%s", dev->type->name); if (dev->driver) add_uevent_var(env, "DRIVER=%s", dev->driver->name); /* Add common DT information about the device */ of_device_uevent(dev, env); /* have the bus specific function add its stuff */ if (dev->bus && dev->bus->uevent) { retval = dev->bus->uevent(dev, env); if (retval) pr_debug("device: '%s': %s: bus uevent() returned %d\n", dev_name(dev), __func__, retval); } /* have the class specific function add its stuff */ if (dev->class && dev->class->dev_uevent) { retval = dev->class->dev_uevent(dev, env); if (retval) pr_debug("device: '%s': %s: class uevent() " "returned %d\n", dev_name(dev), __func__, retval); } /* have the device type specific function add its stuff */ if (dev->type && dev->type->uevent) { retval = dev->type->uevent(dev, env); if (retval) pr_debug("device: '%s': %s: dev_type uevent() " "returned %d\n", dev_name(dev), __func__, retval); } return retval; } static const struct kset_uevent_ops device_uevent_ops = { .filter = dev_uevent_filter, .name = dev_uevent_name, .uevent = dev_uevent, }; static ssize_t uevent_show(struct device *dev, struct device_attribute *attr, char *buf) { struct kobject *top_kobj; struct kset *kset; struct kobj_uevent_env *env = NULL; int i; size_t count = 0; int retval; /* search the kset, the device belongs to */ top_kobj = &dev->kobj; while (!top_kobj->kset && top_kobj->parent) top_kobj = top_kobj->parent; if (!top_kobj->kset) goto out; kset = top_kobj->kset; if (!kset->uevent_ops || !kset->uevent_ops->uevent) goto out; /* respect filter */ if (kset->uevent_ops && kset->uevent_ops->filter) if (!kset->uevent_ops->filter(kset, &dev->kobj)) goto out; env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL); if (!env) return -ENOMEM; /* let the kset specific function add its keys */ retval = kset->uevent_ops->uevent(kset, &dev->kobj, env); if (retval) goto out; /* copy keys to file */ for (i = 0; i < env->envp_idx; i++) count += sprintf(&buf[count], "%s\n", env->envp[i]); out: kfree(env); return count; } static ssize_t uevent_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { int rc; rc = kobject_synth_uevent(&dev->kobj, buf, count); if (rc) { dev_err(dev, "uevent: failed to send synthetic uevent\n"); return rc; } return count; } static DEVICE_ATTR_RW(uevent); static ssize_t online_show(struct device *dev, struct device_attribute *attr, char *buf) { bool val; device_lock(dev); val = !dev->offline; device_unlock(dev); return sprintf(buf, "%u\n", val); } static ssize_t online_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { bool val; int ret; ret = strtobool(buf, &val); if (ret < 0) return ret; ret = lock_device_hotplug_sysfs(); if (ret) return ret; ret = val ? device_online(dev) : device_offline(dev); unlock_device_hotplug(); return ret < 0 ? ret : count; } static DEVICE_ATTR_RW(online); int device_add_groups(struct device *dev, const struct attribute_group **groups) { return sysfs_create_groups(&dev->kobj, groups); } EXPORT_SYMBOL_GPL(device_add_groups); void device_remove_groups(struct device *dev, const struct attribute_group **groups) { sysfs_remove_groups(&dev->kobj, groups); } EXPORT_SYMBOL_GPL(device_remove_groups); union device_attr_group_devres { const struct attribute_group *group; const struct attribute_group **groups; }; static int devm_attr_group_match(struct device *dev, void *res, void *data) { return ((union device_attr_group_devres *)res)->group == data; } static void devm_attr_group_remove(struct device *dev, void *res) { union device_attr_group_devres *devres = res; const struct attribute_group *group = devres->group; dev_dbg(dev, "%s: removing group %p\n", __func__, group); sysfs_remove_group(&dev->kobj, group); } static void devm_attr_groups_remove(struct device *dev, void *res) { union device_attr_group_devres *devres = res; const struct attribute_group **groups = devres->groups; dev_dbg(dev, "%s: removing groups %p\n", __func__, groups); sysfs_remove_groups(&dev->kobj, groups); } /** * devm_device_add_group - given a device, create a managed attribute group * @dev: The device to create the group for * @grp: The attribute group to create * * This function creates a group for the first time. It will explicitly * warn and error if any of the attribute files being created already exist. * * Returns 0 on success or error code on failure. */ int devm_device_add_group(struct device *dev, const struct attribute_group *grp) { union device_attr_group_devres *devres; int error; devres = devres_alloc(devm_attr_group_remove, sizeof(*devres), GFP_KERNEL); if (!devres) return -ENOMEM; error = sysfs_create_group(&dev->kobj, grp); if (error) { devres_free(devres); return error; } devres->group = grp; devres_add(dev, devres); return 0; } EXPORT_SYMBOL_GPL(devm_device_add_group); /** * devm_device_remove_group: remove a managed group from a device * @dev: device to remove the group from * @grp: group to remove * * This function removes a group of attributes from a device. The attributes * previously have to have been created for this group, otherwise it will fail. */ void devm_device_remove_group(struct device *dev, const struct attribute_group *grp) { WARN_ON(devres_release(dev, devm_attr_group_remove, devm_attr_group_match, /* cast away const */ (void *)grp)); } EXPORT_SYMBOL_GPL(devm_device_remove_group); /** * devm_device_add_groups - create a bunch of managed attribute groups * @dev: The device to create the group for * @groups: The attribute groups to create, NULL terminated * * This function creates a bunch of managed attribute groups. If an error * occurs when creating a group, all previously created groups will be * removed, unwinding everything back to the original state when this * function was called. It will explicitly warn and error if any of the * attribute files being created already exist. * * Returns 0 on success or error code from sysfs_create_group on failure. */ int devm_device_add_groups(struct device *dev, const struct attribute_group **groups) { union device_attr_group_devres *devres; int error; devres = devres_alloc(devm_attr_groups_remove, sizeof(*devres), GFP_KERNEL); if (!devres) return -ENOMEM; error = sysfs_create_groups(&dev->kobj, groups); if (error) { devres_free(devres); return error; } devres->groups = groups; devres_add(dev, devres); return 0; } EXPORT_SYMBOL_GPL(devm_device_add_groups); /** * devm_device_remove_groups - remove a list of managed groups * * @dev: The device for the groups to be removed from * @groups: NULL terminated list of groups to be removed * * If groups is not NULL, remove the specified groups from the device. */ void devm_device_remove_groups(struct device *dev, const struct attribute_group **groups) { WARN_ON(devres_release(dev, devm_attr_groups_remove, devm_attr_group_match, /* cast away const */ (void *)groups)); } EXPORT_SYMBOL_GPL(devm_device_remove_groups); static int device_add_attrs(struct device *dev) { struct class *class = dev->class; const struct device_type *type = dev->type; int error; if (class) { error = device_add_groups(dev, class->dev_groups); if (error) return error; } if (type) { error = device_add_groups(dev, type->groups); if (error) goto err_remove_class_groups; } error = device_add_groups(dev, dev->groups); if (error) goto err_remove_type_groups; if (device_supports_offline(dev) && !dev->offline_disabled) { error = device_create_file(dev, &dev_attr_online); if (error) goto err_remove_dev_groups; } return 0; err_remove_dev_groups: device_remove_groups(dev, dev->groups); err_remove_type_groups: if (type) device_remove_groups(dev, type->groups); err_remove_class_groups: if (class) device_remove_groups(dev, class->dev_groups); return error; } static void device_remove_attrs(struct device *dev) { struct class *class = dev->class; const struct device_type *type = dev->type; device_remove_file(dev, &dev_attr_online); device_remove_groups(dev, dev->groups); if (type) device_remove_groups(dev, type->groups); if (class) device_remove_groups(dev, class->dev_groups); } static ssize_t dev_show(struct device *dev, struct device_attribute *attr, char *buf) { return print_dev_t(buf, dev->devt); } static DEVICE_ATTR_RO(dev); /* /sys/devices/ */ struct kset *devices_kset; /** * devices_kset_move_before - Move device in the devices_kset's list. * @deva: Device to move. * @devb: Device @deva should come before. */ static void devices_kset_move_before(struct device *deva, struct device *devb) { if (!devices_kset) return; pr_debug("devices_kset: Moving %s before %s\n", dev_name(deva), dev_name(devb)); spin_lock(&devices_kset->list_lock); list_move_tail(&deva->kobj.entry, &devb->kobj.entry); spin_unlock(&devices_kset->list_lock); } /** * devices_kset_move_after - Move device in the devices_kset's list. * @deva: Device to move * @devb: Device @deva should come after. */ static void devices_kset_move_after(struct device *deva, struct device *devb) { if (!devices_kset) return; pr_debug("devices_kset: Moving %s after %s\n", dev_name(deva), dev_name(devb)); spin_lock(&devices_kset->list_lock); list_move(&deva->kobj.entry, &devb->kobj.entry); spin_unlock(&devices_kset->list_lock); } /** * devices_kset_move_last - move the device to the end of devices_kset's list. * @dev: device to move */ void devices_kset_move_last(struct device *dev) { if (!devices_kset) return; pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev)); spin_lock(&devices_kset->list_lock); list_move_tail(&dev->kobj.entry, &devices_kset->list); spin_unlock(&devices_kset->list_lock); } /** * device_create_file - create sysfs attribute file for device. * @dev: device. * @attr: device attribute descriptor. */ int device_create_file(struct device *dev, const struct device_attribute *attr) { int error = 0; if (dev) { WARN(((attr->attr.mode & S_IWUGO) && !attr->store), "Attribute %s: write permission without 'store'\n", attr->attr.name); WARN(((attr->attr.mode & S_IRUGO) && !attr->show), "Attribute %s: read permission without 'show'\n", attr->attr.name); error = sysfs_create_file(&dev->kobj, &attr->attr); } return error; } EXPORT_SYMBOL_GPL(device_create_file); /** * device_remove_file - remove sysfs attribute file. * @dev: device. * @attr: device attribute descriptor. */ void device_remove_file(struct device *dev, const struct device_attribute *attr) { if (dev) sysfs_remove_file(&dev->kobj, &attr->attr); } EXPORT_SYMBOL_GPL(device_remove_file); /** * device_remove_file_self - remove sysfs attribute file from its own method. * @dev: device. * @attr: device attribute descriptor. * * See kernfs_remove_self() for details. */ bool device_remove_file_self(struct device *dev, const struct device_attribute *attr) { if (dev) return sysfs_remove_file_self(&dev->kobj, &attr->attr); else return false; } EXPORT_SYMBOL_GPL(device_remove_file_self); /** * device_create_bin_file - create sysfs binary attribute file for device. * @dev: device. * @attr: device binary attribute descriptor. */ int device_create_bin_file(struct device *dev, const struct bin_attribute *attr) { int error = -EINVAL; if (dev) error = sysfs_create_bin_file(&dev->kobj, attr); return error; } EXPORT_SYMBOL_GPL(device_create_bin_file); /** * device_remove_bin_file - remove sysfs binary attribute file * @dev: device. * @attr: device binary attribute descriptor. */ void device_remove_bin_file(struct device *dev, const struct bin_attribute *attr) { if (dev) sysfs_remove_bin_file(&dev->kobj, attr); } EXPORT_SYMBOL_GPL(device_remove_bin_file); static void klist_children_get(struct klist_node *n) { struct device_private *p = to_device_private_parent(n); struct device *dev = p->device; get_device(dev); } static void klist_children_put(struct klist_node *n) { struct device_private *p = to_device_private_parent(n); struct device *dev = p->device; put_device(dev); } /** * device_initialize - init device structure. * @dev: device. * * This prepares the device for use by other layers by initializing * its fields. * It is the first half of device_register(), if called by * that function, though it can also be called separately, so one * may use @dev's fields. In particular, get_device()/put_device() * may be used for reference counting of @dev after calling this * function. * * All fields in @dev must be initialized by the caller to 0, except * for those explicitly set to some other value. The simplest * approach is to use kzalloc() to allocate the structure containing * @dev. * * NOTE: Use put_device() to give up your reference instead of freeing * @dev directly once you have called this function. */ void device_initialize(struct device *dev) { dev->kobj.kset = devices_kset; kobject_init(&dev->kobj, &device_ktype); INIT_LIST_HEAD(&dev->dma_pools); mutex_init(&dev->mutex); #ifdef CONFIG_PROVE_LOCKING mutex_init(&dev->lockdep_mutex); #endif lockdep_set_novalidate_class(&dev->mutex); spin_lock_init(&dev->devres_lock); INIT_LIST_HEAD(&dev->devres_head); device_pm_init(dev); set_dev_node(dev, -1); #ifdef CONFIG_GENERIC_MSI_IRQ INIT_LIST_HEAD(&dev->msi_list); #endif INIT_LIST_HEAD(&dev->links.consumers); INIT_LIST_HEAD(&dev->links.suppliers); INIT_LIST_HEAD(&dev->links.needs_suppliers); INIT_LIST_HEAD(&dev->links.defer_hook); dev->links.status = DL_DEV_NO_DRIVER; } EXPORT_SYMBOL_GPL(device_initialize); struct kobject *virtual_device_parent(struct device *dev) { static struct kobject *virtual_dir = NULL; if (!virtual_dir) virtual_dir = kobject_create_and_add("virtual", &devices_kset->kobj); return virtual_dir; } struct class_dir { struct kobject kobj; struct class *class; }; #define to_class_dir(obj) container_of(obj, struct class_dir, kobj) static void class_dir_release(struct kobject *kobj) { struct class_dir *dir = to_class_dir(kobj); kfree(dir); } static const struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj) { struct class_dir *dir = to_class_dir(kobj); return dir->class->ns_type; } static struct kobj_type class_dir_ktype = { .release = class_dir_release, .sysfs_ops = &kobj_sysfs_ops, .child_ns_type = class_dir_child_ns_type }; static struct kobject * class_dir_create_and_add(struct class *class, struct kobject *parent_kobj) { struct class_dir *dir; int retval; dir = kzalloc(sizeof(*dir), GFP_KERNEL); if (!dir) return ERR_PTR(-ENOMEM); dir->class = class; kobject_init(&dir->kobj, &class_dir_ktype); dir->kobj.kset = &class->p->glue_dirs; retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name); if (retval < 0) { kobject_put(&dir->kobj); return ERR_PTR(retval); } return &dir->kobj; } static DEFINE_MUTEX(gdp_mutex); static struct kobject *get_device_parent(struct device *dev, struct device *parent) { if (dev->class) { struct kobject *kobj = NULL; struct kobject *parent_kobj; struct kobject *k; #ifdef CONFIG_BLOCK /* block disks show up in /sys/block */ if (sysfs_deprecated && dev->class == &block_class) { if (parent && parent->class == &block_class) return &parent->kobj; return &block_class.p->subsys.kobj; } #endif /* * If we have no parent, we live in "virtual". * Class-devices with a non class-device as parent, live * in a "glue" directory to prevent namespace collisions. */ if (parent == NULL) parent_kobj = virtual_device_parent(dev); else if (parent->class && !dev->class->ns_type) return &parent->kobj; else parent_kobj = &parent->kobj; mutex_lock(&gdp_mutex); /* find our class-directory at the parent and reference it */ spin_lock(&dev->class->p->glue_dirs.list_lock); list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry) if (k->parent == parent_kobj) { kobj = kobject_get(k); break; } spin_unlock(&dev->class->p->glue_dirs.list_lock); if (kobj) { mutex_unlock(&gdp_mutex); return kobj; } /* or create a new class-directory at the parent device */ k = class_dir_create_and_add(dev->class, parent_kobj); /* do not emit an uevent for this simple "glue" directory */ mutex_unlock(&gdp_mutex); return k; } /* subsystems can specify a default root directory for their devices */ if (!parent && dev->bus && dev->bus->dev_root) return &dev->bus->dev_root->kobj; if (parent) return &parent->kobj; return NULL; } static inline bool live_in_glue_dir(struct kobject *kobj, struct device *dev) { if (!kobj || !dev->class || kobj->kset != &dev->class->p->glue_dirs) return false; return true; } static inline struct kobject *get_glue_dir(struct device *dev) { return dev->kobj.parent; } /* * make sure cleaning up dir as the last step, we need to make * sure .release handler of kobject is run with holding the * global lock */ static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir) { unsigned int ref; /* see if we live in a "glue" directory */ if (!live_in_glue_dir(glue_dir, dev)) return; mutex_lock(&gdp_mutex); /** * There is a race condition between removing glue directory * and adding a new device under the glue directory. * * CPU1: CPU2: * * device_add() * get_device_parent() * class_dir_create_and_add() * kobject_add_internal() * create_dir() // create glue_dir * * device_add() * get_device_parent() * kobject_get() // get glue_dir * * device_del() * cleanup_glue_dir() * kobject_del(glue_dir) * * kobject_add() * kobject_add_internal() * create_dir() // in glue_dir * sysfs_create_dir_ns() * kernfs_create_dir_ns(sd) * * sysfs_remove_dir() // glue_dir->sd=NULL * sysfs_put() // free glue_dir->sd * * // sd is freed * kernfs_new_node(sd) * kernfs_get(glue_dir) * kernfs_add_one() * kernfs_put() * * Before CPU1 remove last child device under glue dir, if CPU2 add * a new device under glue dir, the glue_dir kobject reference count * will be increase to 2 in kobject_get(k). And CPU2 has been called * kernfs_create_dir_ns(). Meanwhile, CPU1 call sysfs_remove_dir() * and sysfs_put(). This result in glue_dir->sd is freed. * * Then the CPU2 will see a stale "empty" but still potentially used * glue dir around in kernfs_new_node(). * * In order to avoid this happening, we also should make sure that * kernfs_node for glue_dir is released in CPU1 only when refcount * for glue_dir kobj is 1. */ ref = kref_read(&glue_dir->kref); if (!kobject_has_children(glue_dir) && !--ref) kobject_del(glue_dir); kobject_put(glue_dir); mutex_unlock(&gdp_mutex); } static int device_add_class_symlinks(struct device *dev) { struct device_node *of_node = dev_of_node(dev); int error; if (of_node) { error = sysfs_create_link(&dev->kobj, of_node_kobj(of_node), "of_node"); if (error) dev_warn(dev, "Error %d creating of_node link\n",error); /* An error here doesn't warrant bringing down the device */ } if (!dev->class) return 0; error = sysfs_create_link(&dev->kobj, &dev->class->p->subsys.kobj, "subsystem"); if (error) goto out_devnode; if (dev->parent && device_is_not_partition(dev)) { error = sysfs_create_link(&dev->kobj, &dev->parent->kobj, "device"); if (error) goto out_subsys; } #ifdef CONFIG_BLOCK /* /sys/block has directories and does not need symlinks */ if (sysfs_deprecated && dev->class == &block_class) return 0; #endif /* link in the class directory pointing to the device */ error = sysfs_create_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev)); if (error) goto out_device; return 0; out_device: sysfs_remove_link(&dev->kobj, "device"); out_subsys: sysfs_remove_link(&dev->kobj, "subsystem"); out_devnode: sysfs_remove_link(&dev->kobj, "of_node"); return error; } static void device_remove_class_symlinks(struct device *dev) { if (dev_of_node(dev)) sysfs_remove_link(&dev->kobj, "of_node"); if (!dev->class) return; if (dev->parent && device_is_not_partition(dev)) sysfs_remove_link(&dev->kobj, "device"); sysfs_remove_link(&dev->kobj, "subsystem"); #ifdef CONFIG_BLOCK if (sysfs_deprecated && dev->class == &block_class) return; #endif sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev)); } /** * dev_set_name - set a device name * @dev: device * @fmt: format string for the device's name */ int dev_set_name(struct device *dev, const char *fmt, ...) { va_list vargs; int err; va_start(vargs, fmt); err = kobject_set_name_vargs(&dev->kobj, fmt, vargs); va_end(vargs); return err; } EXPORT_SYMBOL_GPL(dev_set_name); /** * device_to_dev_kobj - select a /sys/dev/ directory for the device * @dev: device * * By default we select char/ for new entries. Setting class->dev_obj * to NULL prevents an entry from being created. class->dev_kobj must * be set (or cleared) before any devices are registered to the class * otherwise device_create_sys_dev_entry() and * device_remove_sys_dev_entry() will disagree about the presence of * the link. */ static struct kobject *device_to_dev_kobj(struct device *dev) { struct kobject *kobj; if (dev->class) kobj = dev->class->dev_kobj; else kobj = sysfs_dev_char_kobj; return kobj; } static int device_create_sys_dev_entry(struct device *dev) { struct kobject *kobj = device_to_dev_kobj(dev); int error = 0; char devt_str[15]; if (kobj) { format_dev_t(devt_str, dev->devt); error = sysfs_create_link(kobj, &dev->kobj, devt_str); } return error; } static void device_remove_sys_dev_entry(struct device *dev) { struct kobject *kobj = device_to_dev_kobj(dev); char devt_str[15]; if (kobj) { format_dev_t(devt_str, dev->devt); sysfs_remove_link(kobj, devt_str); } } static int device_private_init(struct device *dev) { dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL); if (!dev->p) return -ENOMEM; dev->p->device = dev; klist_init(&dev->p->klist_children, klist_children_get, klist_children_put); INIT_LIST_HEAD(&dev->p->deferred_probe); return 0; } /** * device_add - add device to device hierarchy. * @dev: device. * * This is part 2 of device_register(), though may be called * separately _iff_ device_initialize() has been called separately. * * This adds @dev to the kobject hierarchy via kobject_add(), adds it * to the global and sibling lists for the device, then * adds it to the other relevant subsystems of the driver model. * * Do not call this routine or device_register() more than once for * any device structure. The driver model core is not designed to work * with devices that get unregistered and then spring back to life. * (Among other things, it's very hard to guarantee that all references * to the previous incarnation of @dev have been dropped.) Allocate * and register a fresh new struct device instead. * * NOTE: _Never_ directly free @dev after calling this function, even * if it returned an error! Always use put_device() to give up your * reference instead. * * Rule of thumb is: if device_add() succeeds, you should call * device_del() when you want to get rid of it. If device_add() has * *not* succeeded, use *only* put_device() to drop the reference * count. */ int device_add(struct device *dev) { struct device *parent; struct kobject *kobj; struct class_interface *class_intf; int error = -EINVAL; struct kobject *glue_dir = NULL; dev = get_device(dev); if (!dev) goto done; if (!dev->p) { error = device_private_init(dev); if (error) goto done; } /* * for statically allocated devices, which should all be converted * some day, we need to initialize the name. We prevent reading back * the name, and force the use of dev_name() */ if (dev->init_name) { dev_set_name(dev, "%s", dev->init_name); dev->init_name = NULL; } /* 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; goto name_error; } pr_debug("device: '%s': %s\n", dev_name(dev), __func__); parent = get_device(dev->parent); kobj = get_device_parent(dev, parent); if (IS_ERR(kobj)) { error = PTR_ERR(kobj); goto parent_error; } if (kobj) dev->kobj.parent = kobj; /* use parent numa_node */ if (parent && (dev_to_node(dev) == NUMA_NO_NODE)) set_dev_node(dev, dev_to_node(parent)); /* first, register with generic layer. */ /* we require the name to be set before, and pass NULL */ error = kobject_add(&dev->kobj, dev->kobj.parent, NULL); if (error) { glue_dir = get_glue_dir(dev); goto Error; } /* notify platform of device entry */ error = device_platform_notify(dev, KOBJ_ADD); if (error) goto platform_error; error = device_create_file(dev, &dev_attr_uevent); if (error) goto attrError; error = device_add_class_symlinks(dev); if (error) goto SymlinkError; error = device_add_attrs(dev); if (error) goto AttrsError; error = bus_add_device(dev); if (error) goto BusError; error = dpm_sysfs_add(dev); if (error) goto DPMError; device_pm_add(dev); if (MAJOR(dev->devt)) { error = device_create_file(dev, &dev_attr_dev); if (error) goto DevAttrError; error = device_create_sys_dev_entry(dev); if (error) goto SysEntryError; devtmpfs_create_node(dev); } /* Notify clients of device addition. This call must come * after dpm_sysfs_add() and before kobject_uevent(). */ if (dev->bus) blocking_notifier_call_chain(&dev->bus->p->bus_notifier, BUS_NOTIFY_ADD_DEVICE, dev); kobject_uevent(&dev->kobj, KOBJ_ADD); /* * Check if any of the other devices (consumers) have been waiting for * this device (supplier) to be added so that they can create a device * link to it. * * This needs to happen after device_pm_add() because device_link_add() * requires the supplier be registered before it's called. * * But this also needs to happen before bus_probe_device() to make sure * waiting consumers can link to it before the driver is bound to the * device and the driver sync_state callback is called for this device. */ if (dev->fwnode && !dev->fwnode->dev) { dev->fwnode->dev = dev; fw_devlink_link_device(dev); } bus_probe_device(dev); if (parent) klist_add_tail(&dev->p->knode_parent, &parent->p->klist_children); if (dev->class) { mutex_lock(&dev->class->p->mutex); /* tie the class to the device */ klist_add_tail(&dev->p->knode_class, &dev->class->p->klist_devices); /* notify any interfaces that the device is here */ list_for_each_entry(class_intf, &dev->class->p->interfaces, node) if (class_intf->add_dev) class_intf->add_dev(dev, class_intf); mutex_unlock(&dev->class->p->mutex); } done: put_device(dev); return error; SysEntryError: if (MAJOR(dev->devt)) device_remove_file(dev, &dev_attr_dev); DevAttrError: device_pm_remove(dev); dpm_sysfs_remove(dev); DPMError: bus_remove_device(dev); BusError: device_remove_attrs(dev); AttrsError: device_remove_class_symlinks(dev); SymlinkError: device_remove_file(dev, &dev_attr_uevent); attrError: device_platform_notify(dev, KOBJ_REMOVE); platform_error: kobject_uevent(&dev->kobj, KOBJ_REMOVE); glue_dir = get_glue_dir(dev); kobject_del(&dev->kobj); Error: cleanup_glue_dir(dev, glue_dir); parent_error: put_device(parent); name_error: kfree(dev->p); dev->p = NULL; goto done; } EXPORT_SYMBOL_GPL(device_add); /** * device_register - register a device with the system. * @dev: pointer to the device structure * * This happens in two clean steps - initialize the device * and add it to the system. The two steps can be called * separately, but this is the easiest and most common. * I.e. you should only call the two helpers separately if * have a clearly defined need to use and refcount the device * before it is added to the hierarchy. * * For more information, see the kerneldoc for device_initialize() * and device_add(). * * NOTE: _Never_ directly free @dev after calling this function, even * if it returned an error! Always use put_device() to give up the * reference initialized in this function instead. */ int device_register(struct device *dev) { device_initialize(dev); return device_add(dev); } EXPORT_SYMBOL_GPL(device_register); /** * get_device - increment reference count for device. * @dev: device. * * This simply forwards the call to kobject_get(), though * we do take care to provide for the case that we get a NULL * pointer passed in. */ struct device *get_device(struct device *dev) { return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL; } EXPORT_SYMBOL_GPL(get_device); /** * put_device - decrement reference count. * @dev: device in question. */ void put_device(struct device *dev) { /* might_sleep(); */ if (dev) kobject_put(&dev->kobj); } EXPORT_SYMBOL_GPL(put_device); bool kill_device(struct device *dev) { /* * Require the device lock and set the "dead" flag to guarantee that * the update behavior is consistent with the other bitfields near * it and that we cannot have an asynchronous probe routine trying * to run while we are tearing out the bus/class/sysfs from * underneath the device. */ lockdep_assert_held(&dev->mutex); if (dev->p->dead) return false; dev->p->dead = true; return true; } EXPORT_SYMBOL_GPL(kill_device); /** * device_del - delete device from system. * @dev: device. * * This is the first part of the device unregistration * sequence. This removes the device from the lists we control * from here, has it removed from the other driver model * subsystems it was added to in device_add(), and removes it * from the kobject hierarchy. * * NOTE: this should be called manually _iff_ device_add() was * also called manually. */ void device_del(struct device *dev) { struct device *parent = dev->parent; struct kobject *glue_dir = NULL; struct class_interface *class_intf; device_lock(dev); kill_device(dev); device_unlock(dev); if (dev->fwnode && dev->fwnode->dev == dev) dev->fwnode->dev = NULL; /* Notify clients of device removal. This call must come * before dpm_sysfs_remove(). */ if (dev->bus) blocking_notifier_call_chain(&dev->bus->p->bus_notifier, BUS_NOTIFY_DEL_DEVICE, dev); dpm_sysfs_remove(dev); if (parent) klist_del(&dev->p->knode_parent); if (MAJOR(dev->devt)) { devtmpfs_delete_node(dev); device_remove_sys_dev_entry(dev); device_remove_file(dev, &dev_attr_dev); } if (dev->class) { device_remove_class_symlinks(dev); mutex_lock(&dev->class->p->mutex); /* notify any interfaces that the device is now gone */ list_for_each_entry(class_intf, &dev->class->p->interfaces, node) if (class_intf->remove_dev) class_intf->remove_dev(dev, class_intf); /* remove the device from the class list */ klist_del(&dev->p->knode_class); mutex_unlock(&dev->class->p->mutex); } device_remove_file(dev, &dev_attr_uevent); device_remove_attrs(dev); bus_remove_device(dev); device_pm_remove(dev); driver_deferred_probe_del(dev); device_platform_notify(dev, KOBJ_REMOVE); device_remove_properties(dev); device_links_purge(dev); if (dev->bus) blocking_notifier_call_chain(&dev->bus->p->bus_notifier, BUS_NOTIFY_REMOVED_DEVICE, dev); kobject_uevent(&dev->kobj, KOBJ_REMOVE); glue_dir = get_glue_dir(dev); kobject_del(&dev->kobj); cleanup_glue_dir(dev, glue_dir); put_device(parent); } EXPORT_SYMBOL_GPL(device_del); /** * device_unregister - unregister device from system. * @dev: device going away. * * We do this in two parts, like we do device_register(). First, * we remove it from all the subsystems with device_del(), then * we decrement the reference count via put_device(). If that * is the final reference count, the device will be cleaned up * via device_release() above. Otherwise, the structure will * stick around until the final reference to the device is dropped. */ void device_unregister(struct device *dev) { pr_debug("device: '%s': %s\n", dev_name(dev), __func__); device_del(dev); put_device(dev); } EXPORT_SYMBOL_GPL(device_unregister); static struct device *prev_device(struct klist_iter *i) { struct klist_node *n = klist_prev(i); struct device *dev = NULL; struct device_private *p; if (n) { p = to_device_private_parent(n); dev = p->device; } return dev; } static struct device *next_device(struct klist_iter *i) { struct klist_node *n = klist_next(i); struct device *dev = NULL; struct device_private *p; if (n) { p = to_device_private_parent(n); dev = p->device; } return dev; } /** * device_get_devnode - path of device node file * @dev: device * @mode: returned file access mode * @uid: returned file owner * @gid: returned file group * @tmp: possibly allocated string * * Return the relative path of a possible device node. * Non-default names may need to allocate a memory to compose * a name. This memory is returned in tmp and needs to be * freed by the caller. */ const char *device_get_devnode(struct device *dev, umode_t *mode, kuid_t *uid, kgid_t *gid, const char **tmp) { char *s; *tmp = NULL; /* the device type may provide a specific name */ if (dev->type && dev->type->devnode) *tmp = dev->type->devnode(dev, mode, uid, gid); if (*tmp) return *tmp; /* the class may provide a specific name */ if (dev->class && dev->class->devnode) *tmp = dev->class->devnode(dev, mode); if (*tmp) return *tmp; /* return name without allocation, tmp == NULL */ if (strchr(dev_name(dev), '!') == NULL) return dev_name(dev); /* replace '!' in the name with '/' */ s = kstrdup(dev_name(dev), GFP_KERNEL); if (!s) return NULL; strreplace(s, '!', '/'); return *tmp = s; } /** * device_for_each_child - device child iterator. * @parent: parent struct device. * @fn: function to be called for each device. * @data: data for the callback. * * Iterate over @parent's child devices, and call @fn for each, * passing it @data. * * We check the return of @fn each time. If it returns anything * other than 0, we break out and return that value. */ int device_for_each_child(struct device *parent, void *data, int (*fn)(struct device *dev, void *data)) { struct klist_iter i; struct device *child; int error = 0; if (!parent->p) return 0; klist_iter_init(&parent->p->klist_children, &i); while (!error && (child = next_device(&i))) error = fn(child, data); klist_iter_exit(&i); return error; } EXPORT_SYMBOL_GPL(device_for_each_child); /** * device_for_each_child_reverse - device child iterator in reversed order. * @parent: parent struct device. * @fn: function to be called for each device. * @data: data for the callback. * * Iterate over @parent's child devices, and call @fn for each, * passing it @data. * * We check the return of @fn each time. If it returns anything * other than 0, we break out and return that value. */ int device_for_each_child_reverse(struct device *parent, void *data, int (*fn)(struct device *dev, void *data)) { struct klist_iter i; struct device *child; int error = 0; if (!parent->p) return 0; klist_iter_init(&parent->p->klist_children, &i); while ((child = prev_device(&i)) && !error) error = fn(child, data); klist_iter_exit(&i); return error; } EXPORT_SYMBOL_GPL(device_for_each_child_reverse); /** * device_find_child - device iterator for locating a particular device. * @parent: parent struct device * @match: Callback function to check device * @data: Data to pass to match function * * This is similar to the device_for_each_child() function above, but it * returns a reference to a device that is 'found' for later use, as * determined by the @match callback. * * The callback should return 0 if the device doesn't match and non-zero * if it does. If the callback returns non-zero and a reference to the * current device can be obtained, this function will return to the caller * and not iterate over any more devices. * * NOTE: you will need to drop the reference with put_device() after use. */ struct device *device_find_child(struct device *parent, void *data, int (*match)(struct device *dev, void *data)) { struct klist_iter i; struct device *child; if (!parent) return NULL; klist_iter_init(&parent->p->klist_children, &i); while ((child = next_device(&i))) if (match(child, data) && get_device(child)) break; klist_iter_exit(&i); return child; } EXPORT_SYMBOL_GPL(device_find_child); /** * device_find_child_by_name - device iterator for locating a child device. * @parent: parent struct device * @name: name of the child device * * This is similar to the device_find_child() function above, but it * returns a reference to a device that has the name @name. * * NOTE: you will need to drop the reference with put_device() after use. */ struct device *device_find_child_by_name(struct device *parent, const char *name) { struct klist_iter i; struct device *child; if (!parent) return NULL; klist_iter_init(&parent->p->klist_children, &i); while ((child = next_device(&i))) if (!strcmp(dev_name(child), name) && get_device(child)) break; klist_iter_exit(&i); return child; } EXPORT_SYMBOL_GPL(device_find_child_by_name); int __init devices_init(void) { devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL); if (!devices_kset) return -ENOMEM; dev_kobj = kobject_create_and_add("dev", NULL); if (!dev_kobj) goto dev_kobj_err; sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj); if (!sysfs_dev_block_kobj) goto block_kobj_err; sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj); if (!sysfs_dev_char_kobj) goto char_kobj_err; return 0; char_kobj_err: kobject_put(sysfs_dev_block_kobj); block_kobj_err: kobject_put(dev_kobj); dev_kobj_err: kset_unregister(devices_kset); return -ENOMEM; } static int device_check_offline(struct device *dev, void *not_used) { int ret; ret = device_for_each_child(dev, NULL, device_check_offline); if (ret) return ret; return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0; } /** * device_offline - Prepare the device for hot-removal. * @dev: Device to be put offline. * * Execute the device bus type's .offline() callback, if present, to prepare * the device for a subsequent hot-removal. If that succeeds, the device must * not be used until either it is removed or its bus type's .online() callback * is executed. * * Call under device_hotplug_lock. */ int device_offline(struct device *dev) { int ret; if (dev->offline_disabled) return -EPERM; ret = device_for_each_child(dev, NULL, device_check_offline); if (ret) return ret; device_lock(dev); if (device_supports_offline(dev)) { if (dev->offline) { ret = 1; } else { ret = dev->bus->offline(dev); if (!ret) { kobject_uevent(&dev->kobj, KOBJ_OFFLINE); dev->offline = true; } } } device_unlock(dev); return ret; } /** * device_online - Put the device back online after successful device_offline(). * @dev: Device to be put back online. * * If device_offline() has been successfully executed for @dev, but the device * has not been removed subsequently, execute its bus type's .online() callback * to indicate that the device can be used again. * * Call under device_hotplug_lock. */ int device_online(struct device *dev) { int ret = 0; device_lock(dev); if (device_supports_offline(dev)) { if (dev->offline) { ret = dev->bus->online(dev); if (!ret) { kobject_uevent(&dev->kobj, KOBJ_ONLINE); dev->offline = false; } } else { ret = 1; } } device_unlock(dev); return ret; } struct root_device { struct device dev; struct module *owner; }; static inline struct root_device *to_root_device(struct device *d) { return container_of(d, struct root_device, dev); } static void root_device_release(struct device *dev) { kfree(to_root_device(dev)); } /** * __root_device_register - allocate and register a root device * @name: root device name * @owner: owner module of the root device, usually THIS_MODULE * * This function allocates a root device and registers it * using device_register(). In order to free the returned * device, use root_device_unregister(). * * Root devices are dummy devices which allow other devices * to be grouped under /sys/devices. Use this function to * allocate a root device and then use it as the parent of * any device which should appear under /sys/devices/{name} * * The /sys/devices/{name} directory will also contain a * 'module' symlink which points to the @owner directory * in sysfs. * * Returns &struct device pointer on success, or ERR_PTR() on error. * * Note: You probably want to use root_device_register(). */ struct device *__root_device_register(const char *name, struct module *owner) { struct root_device *root; int err = -ENOMEM; root = kzalloc(sizeof(struct root_device), GFP_KERNEL); if (!root) return ERR_PTR(err); err = dev_set_name(&root->dev, "%s", name); if (err) { kfree(root); return ERR_PTR(err); } root->dev.release = root_device_release; err = device_register(&root->dev); if (err) { put_device(&root->dev); return ERR_PTR(err); } #ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */ if (owner) { struct module_kobject *mk = &owner->mkobj; err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module"); if (err) { device_unregister(&root->dev); return ERR_PTR(err); } root->owner = owner; } #endif return &root->dev; } EXPORT_SYMBOL_GPL(__root_device_register); /** * root_device_unregister - unregister and free a root device * @dev: device going away * * This function unregisters and cleans up a device that was created by * root_device_register(). */ void root_device_unregister(struct device *dev) { struct root_device *root = to_root_device(dev); if (root->owner) sysfs_remove_link(&root->dev.kobj, "module"); device_unregister(dev); } EXPORT_SYMBOL_GPL(root_device_unregister); static void device_create_release(struct device *dev) { pr_debug("device: '%s': %s\n", dev_name(dev), __func__); kfree(dev); } static __printf(6, 0) struct device * device_create_groups_vargs(struct class *class, struct device *parent, dev_t devt, void *drvdata, const struct attribute_group **groups, const char *fmt, va_list args) { struct device *dev = NULL; int retval = -ENODEV; if (class == NULL || IS_ERR(class)) goto error; dev = kzalloc(sizeof(*dev), GFP_KERNEL); if (!dev) { retval = -ENOMEM; goto error; } device_initialize(dev); dev->devt = devt; dev->class = class; dev->parent = parent; dev->groups = groups; dev->release = device_create_release; dev_set_drvdata(dev, drvdata); retval = kobject_set_name_vargs(&dev->kobj, fmt, args); if (retval) goto error; retval = device_add(dev); if (retval) goto error; return dev; error: put_device(dev); return ERR_PTR(retval); } /** * device_create - creates a device and registers it with sysfs * @class: pointer to the struct class that this device should be registered to * @parent: pointer to the parent struct device of this new device, if any * @devt: the dev_t for the char device to be added * @drvdata: the data to be added to the device for callbacks * @fmt: string for the device's name * * This function can be used by char device classes. A struct device * will be created in sysfs, registered to the specified class. * * A "dev" file will be created, showing the dev_t for the device, if * the dev_t is not 0,0. * If a pointer to a parent struct device is passed in, the newly created * struct device will be a child of that device in sysfs. * The pointer to the struct device will be returned from the call. * Any further sysfs files that might be required can be created using this * pointer. * * Returns &struct device pointer on success, or ERR_PTR() on error. * * Note: the struct class passed to this function must have previously * been created with a call to class_create(). */ struct device *device_create(struct class *class, struct device *parent, dev_t devt, void *drvdata, const char *fmt, ...) { va_list vargs; struct device *dev; va_start(vargs, fmt); dev = device_create_groups_vargs(class, parent, devt, drvdata, NULL, fmt, vargs); va_end(vargs); return dev; } EXPORT_SYMBOL_GPL(device_create); /** * device_create_with_groups - creates a device and registers it with sysfs * @class: pointer to the struct class that this device should be registered to * @parent: pointer to the parent struct device of this new device, if any * @devt: the dev_t for the char device to be added * @drvdata: the data to be added to the device for callbacks * @groups: NULL-terminated list of attribute groups to be created * @fmt: string for the device's name * * This function can be used by char device classes. A struct device * will be created in sysfs, registered to the specified class. * Additional attributes specified in the groups parameter will also * be created automatically. * * A "dev" file will be created, showing the dev_t for the device, if * the dev_t is not 0,0. * If a pointer to a parent struct device is passed in, the newly created * struct device will be a child of that device in sysfs. * The pointer to the struct device will be returned from the call. * Any further sysfs files that might be required can be created using this * pointer. * * Returns &struct device pointer on success, or ERR_PTR() on error. * * Note: the struct class passed to this function must have previously * been created with a call to class_create(). */ struct device *device_create_with_groups(struct class *class, struct device *parent, dev_t devt, void *drvdata, const struct attribute_group **groups, const char *fmt, ...) { va_list vargs; struct device *dev; va_start(vargs, fmt); dev = device_create_groups_vargs(class, parent, devt, drvdata, groups, fmt, vargs); va_end(vargs); return dev; } EXPORT_SYMBOL_GPL(device_create_with_groups); /** * device_destroy - removes a device that was created with device_create() * @class: pointer to the struct class that this device was registered with * @devt: the dev_t of the device that was previously registered * * This call unregisters and cleans up a device that was created with a * call to device_create(). */ void device_destroy(struct class *class, dev_t devt) { struct device *dev; dev = class_find_device_by_devt(class, devt); if (dev) { put_device(dev); device_unregister(dev); } } EXPORT_SYMBOL_GPL(device_destroy); /** * device_rename - renames a device * @dev: the pointer to the struct device to be renamed * @new_name: the new name of the device * * It is the responsibility of the caller to provide mutual * exclusion between two different calls of device_rename * on the same device to ensure that new_name is valid and * won't conflict with other devices. * * Note: Don't call this function. Currently, the networking layer calls this * function, but that will change. The following text from Kay Sievers offers * some insight: * * Renaming devices is racy at many levels, symlinks and other stuff are not * replaced atomically, and you get a "move" uevent, but it's not easy to * connect the event to the old and new device. Device nodes are not renamed at * all, there isn't even support for that in the kernel now. * * In the meantime, during renaming, your target name might be taken by another * driver, creating conflicts. Or the old name is taken directly after you * renamed it -- then you get events for the same DEVPATH, before you even see * the "move" event. It's just a mess, and nothing new should ever rely on * kernel device renaming. Besides that, it's not even implemented now for * other things than (driver-core wise very simple) network devices. * * We are currently about to change network renaming in udev to completely * disallow renaming of devices in the same namespace as the kernel uses, * because we can't solve the problems properly, that arise with swapping names * of multiple interfaces without races. Means, renaming of eth[0-9]* will only * be allowed to some other name than eth[0-9]*, for the aforementioned * reasons. * * Make up a "real" name in the driver before you register anything, or add * some other attributes for userspace to find the device, or use udev to add * symlinks -- but never rename kernel devices later, it's a complete mess. We * don't even want to get into that and try to implement the missing pieces in * the core. We really have other pieces to fix in the driver core mess. :) */ int device_rename(struct device *dev, const char *new_name) { struct kobject *kobj = &dev->kobj; char *old_device_name = NULL; int error; dev = get_device(dev); if (!dev) return -EINVAL; dev_dbg(dev, "renaming to %s\n", new_name); old_device_name = kstrdup(dev_name(dev), GFP_KERNEL); if (!old_device_name) { error = -ENOMEM; goto out; } if (dev->class) { error = sysfs_rename_link_ns(&dev->class->p->subsys.kobj, kobj, old_device_name, new_name, kobject_namespace(kobj)); if (error) goto out; } error = kobject_rename(kobj, new_name); if (error) goto out; out: put_device(dev); kfree(old_device_name); return error; } EXPORT_SYMBOL_GPL(device_rename); static int device_move_class_links(struct device *dev, struct device *old_parent, struct device *new_parent) { int error = 0; if (old_parent) sysfs_remove_link(&dev->kobj, "device"); if (new_parent) error = sysfs_create_link(&dev->kobj, &new_parent->kobj, "device"); return error; } /** * device_move - moves a device to a new parent * @dev: the pointer to the struct device to be moved * @new_parent: the new parent of the device (can be NULL) * @dpm_order: how to reorder the dpm_list */ int device_move(struct device *dev, struct device *new_parent, enum dpm_order dpm_order) { int error; struct device *old_parent; struct kobject *new_parent_kobj; dev = get_device(dev); if (!dev) return -EINVAL; device_pm_lock(); new_parent = get_device(new_parent); new_parent_kobj = get_device_parent(dev, new_parent); if (IS_ERR(new_parent_kobj)) { error = PTR_ERR(new_parent_kobj); put_device(new_parent); goto out; } pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev), __func__, new_parent ? dev_name(new_parent) : "<NULL>"); error = kobject_move(&dev->kobj, new_parent_kobj); if (error) { cleanup_glue_dir(dev, new_parent_kobj); put_device(new_parent); goto out; } old_parent = dev->parent; dev->parent = new_parent; if (old_parent) klist_remove(&dev->p->knode_parent); if (new_parent) { klist_add_tail(&dev->p->knode_parent, &new_parent->p->klist_children); set_dev_node(dev, dev_to_node(new_parent)); } if (dev->class) { error = device_move_class_links(dev, old_parent, new_parent); if (error) { /* We ignore errors on cleanup since we're hosed anyway... */ device_move_class_links(dev, new_parent, old_parent); if (!kobject_move(&dev->kobj, &old_parent->kobj)) { if (new_parent) klist_remove(&dev->p->knode_parent); dev->parent = old_parent; if (old_parent) { klist_add_tail(&dev->p->knode_parent, &old_parent->p->klist_children); set_dev_node(dev, dev_to_node(old_parent)); } } cleanup_glue_dir(dev, new_parent_kobj); put_device(new_parent); goto out; } } switch (dpm_order) { case DPM_ORDER_NONE: break; case DPM_ORDER_DEV_AFTER_PARENT: device_pm_move_after(dev, new_parent); devices_kset_move_after(dev, new_parent); break; case DPM_ORDER_PARENT_BEFORE_DEV: device_pm_move_before(new_parent, dev); devices_kset_move_before(new_parent, dev); break; case DPM_ORDER_DEV_LAST: device_pm_move_last(dev); devices_kset_move_last(dev); break; } put_device(old_parent); out: device_pm_unlock(); put_device(dev); return error; } EXPORT_SYMBOL_GPL(device_move); static int device_attrs_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid) { struct kobject *kobj = &dev->kobj; struct class *class = dev->class; const struct device_type *type = dev->type; int error; if (class) { /* * Change the device groups of the device class for @dev to * @kuid/@kgid. */ error = sysfs_groups_change_owner(kobj, class->dev_groups, kuid, kgid); if (error) return error; } if (type) { /* * Change the device groups of the device type for @dev to * @kuid/@kgid. */ error = sysfs_groups_change_owner(kobj, type->groups, kuid, kgid); if (error) return error; } /* Change the device groups of @dev to @kuid/@kgid. */ error = sysfs_groups_change_owner(kobj, dev->groups, kuid, kgid); if (error) return error; if (device_supports_offline(dev) && !dev->offline_disabled) { /* Change online device attributes of @dev to @kuid/@kgid. */ error = sysfs_file_change_owner(kobj, dev_attr_online.attr.name, kuid, kgid); if (error) return error; } return 0; } /** * device_change_owner - change the owner of an existing device. * @dev: device. * @kuid: new owner's kuid * @kgid: new owner's kgid * * This changes the owner of @dev and its corresponding sysfs entries to * @kuid/@kgid. This function closely mirrors how @dev was added via driver * core. * * Returns 0 on success or error code on failure. */ int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid) { int error; struct kobject *kobj = &dev->kobj; dev = get_device(dev); if (!dev) return -EINVAL; /* * Change the kobject and the default attributes and groups of the * ktype associated with it to @kuid/@kgid. */ error = sysfs_change_owner(kobj, kuid, kgid); if (error) goto out; /* * Change the uevent file for @dev to the new owner. The uevent file * was created in a separate step when @dev got added and we mirror * that step here. */ error = sysfs_file_change_owner(kobj, dev_attr_uevent.attr.name, kuid, kgid); if (error) goto out; /* * Change the device groups, the device groups associated with the * device class, and the groups associated with the device type of @dev * to @kuid/@kgid. */ error = device_attrs_change_owner(dev, kuid, kgid); if (error) goto out; error = dpm_sysfs_change_owner(dev, kuid, kgid); if (error) goto out; #ifdef CONFIG_BLOCK if (sysfs_deprecated && dev->class == &block_class) goto out; #endif /* * Change the owner of the symlink located in the class directory of * the device class associated with @dev which points to the actual * directory entry for @dev to @kuid/@kgid. This ensures that the * symlink shows the same permissions as its target. */ error = sysfs_link_change_owner(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev), kuid, kgid); if (error) goto out; out: put_device(dev); return error; } EXPORT_SYMBOL_GPL(device_change_owner); /** * device_shutdown - call ->shutdown() on each device to shutdown. */ void device_shutdown(void) { struct device *dev, *parent; wait_for_device_probe(); device_block_probing(); cpufreq_suspend(); spin_lock(&devices_kset->list_lock); /* * Walk the devices list backward, shutting down each in turn. * Beware that device unplug events may also start pulling * devices offline, even as the system is shutting down. */ while (!list_empty(&devices_kset->list)) { dev = list_entry(devices_kset->list.prev, struct device, kobj.entry); /* * hold reference count of device's parent to * prevent it from being freed because parent's * lock is to be held */ parent = get_device(dev->parent); get_device(dev); /* * Make sure the device is off the kset list, in the * event that dev->*->shutdown() doesn't remove it. */ list_del_init(&dev->kobj.entry); spin_unlock(&devices_kset->list_lock); /* hold lock to avoid race with probe/release */ if (parent) device_lock(parent); device_lock(dev); /* Don't allow any more runtime suspends */ pm_runtime_get_noresume(dev); pm_runtime_barrier(dev); if (dev->class && dev->class->shutdown_pre) { if (initcall_debug) dev_info(dev, "shutdown_pre\n"); dev->class->shutdown_pre(dev); } if (dev->bus && dev->bus->shutdown) { if (initcall_debug) dev_info(dev, "shutdown\n"); dev->bus->shutdown(dev); } else if (dev->driver && dev->driver->shutdown) { if (initcall_debug) dev_info(dev, "shutdown\n"); dev->driver->shutdown(dev); } device_unlock(dev); if (parent) device_unlock(parent); put_device(dev); put_device(parent); spin_lock(&devices_kset->list_lock); } spin_unlock(&devices_kset->list_lock); } /* * Device logging functions */ #ifdef CONFIG_PRINTK static int create_syslog_header(const struct device *dev, char *hdr, size_t hdrlen) { const char *subsys; size_t pos = 0; if (dev->class) subsys = dev->class->name; else if (dev->bus) subsys = dev->bus->name; else return 0; pos += snprintf(hdr + pos, hdrlen - pos, "SUBSYSTEM=%s", subsys); if (pos >= hdrlen) goto overflow; /* * Add device identifier DEVICE=: * b12:8 block dev_t * c127:3 char dev_t * n8 netdev ifindex * +sound:card0 subsystem:devname */ if (MAJOR(dev->devt)) { char c; if (strcmp(subsys, "block") == 0) c = 'b'; else c = 'c'; pos++; pos += snprintf(hdr + pos, hdrlen - pos, "DEVICE=%c%u:%u", c, MAJOR(dev->devt), MINOR(dev->devt)); } else if (strcmp(subsys, "net") == 0) { struct net_device *net = to_net_dev(dev); pos++; pos += snprintf(hdr + pos, hdrlen - pos, "DEVICE=n%u", net->ifindex); } else { pos++; pos += snprintf(hdr + pos, hdrlen - pos, "DEVICE=+%s:%s", subsys, dev_name(dev)); } if (pos >= hdrlen) goto overflow; return pos; overflow: dev_WARN(dev, "device/subsystem name too long"); return 0; } int dev_vprintk_emit(int level, const struct device *dev, const char *fmt, va_list args) { char hdr[128]; size_t hdrlen; hdrlen = create_syslog_header(dev, hdr, sizeof(hdr)); return vprintk_emit(0, level, hdrlen ? hdr : NULL, hdrlen, fmt, args); } EXPORT_SYMBOL(dev_vprintk_emit); int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...) { va_list args; int r; va_start(args, fmt); r = dev_vprintk_emit(level, dev, fmt, args); va_end(args); return r; } EXPORT_SYMBOL(dev_printk_emit); static void __dev_printk(const char *level, const struct device *dev, struct va_format *vaf) { if (dev) dev_printk_emit(level[1] - '0', dev, "%s %s: %pV", dev_driver_string(dev), dev_name(dev), vaf); else printk("%s(NULL device *): %pV", level, vaf); } void dev_printk(const char *level, const struct device *dev, const char *fmt, ...) { struct va_format vaf; va_list args; va_start(args, fmt); vaf.fmt = fmt; vaf.va = &args; __dev_printk(level, dev, &vaf); va_end(args); } EXPORT_SYMBOL(dev_printk); #define define_dev_printk_level(func, kern_level) \ void func(const struct device *dev, const char *fmt, ...) \ { \ struct va_format vaf; \ va_list args; \ \ va_start(args, fmt); \ \ vaf.fmt = fmt; \ vaf.va = &args; \ \ __dev_printk(kern_level, dev, &vaf); \ \ va_end(args); \ } \ EXPORT_SYMBOL(func); define_dev_printk_level(_dev_emerg, KERN_EMERG); define_dev_printk_level(_dev_alert, KERN_ALERT); define_dev_printk_level(_dev_crit, KERN_CRIT); define_dev_printk_level(_dev_err, KERN_ERR); define_dev_printk_level(_dev_warn, KERN_WARNING); define_dev_printk_level(_dev_notice, KERN_NOTICE); define_dev_printk_level(_dev_info, KERN_INFO); #endif static inline bool fwnode_is_primary(struct fwnode_handle *fwnode) { return fwnode && !IS_ERR(fwnode->secondary); } /** * set_primary_fwnode - Change the primary firmware node of a given device. * @dev: Device to handle. * @fwnode: New primary firmware node of the device. * * Set the device's firmware node pointer to @fwnode, but if a secondary * firmware node of the device is present, preserve it. */ void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode) { if (fwnode) { struct fwnode_handle *fn = dev->fwnode; if (fwnode_is_primary(fn)) fn = fn->secondary; if (fn) { WARN_ON(fwnode->secondary); fwnode->secondary = fn; } dev->fwnode = fwnode; } else { dev->fwnode = fwnode_is_primary(dev->fwnode) ? dev->fwnode->secondary : NULL; } } EXPORT_SYMBOL_GPL(set_primary_fwnode); /** * set_secondary_fwnode - Change the secondary firmware node of a given device. * @dev: Device to handle. * @fwnode: New secondary firmware node of the device. * * If a primary firmware node of the device is present, set its secondary * pointer to @fwnode. Otherwise, set the device's firmware node pointer to * @fwnode. */ void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode) { if (fwnode) fwnode->secondary = ERR_PTR(-ENODEV); if (fwnode_is_primary(dev->fwnode)) dev->fwnode->secondary = fwnode; else dev->fwnode = fwnode; } EXPORT_SYMBOL_GPL(set_secondary_fwnode); /** * device_set_of_node_from_dev - reuse device-tree node of another device * @dev: device whose device-tree node is being set * @dev2: device whose device-tree node is being reused * * Takes another reference to the new device-tree node after first dropping * any reference held to the old node. */ void device_set_of_node_from_dev(struct device *dev, const struct device *dev2) { of_node_put(dev->of_node); dev->of_node = of_node_get(dev2->of_node); dev->of_node_reused = true; } EXPORT_SYMBOL_GPL(device_set_of_node_from_dev); int device_match_name(struct device *dev, const void *name) { return sysfs_streq(dev_name(dev), name); } EXPORT_SYMBOL_GPL(device_match_name); int device_match_of_node(struct device *dev, const void *np) { return dev->of_node == np; } EXPORT_SYMBOL_GPL(device_match_of_node); int device_match_fwnode(struct device *dev, const void *fwnode) { return dev_fwnode(dev) == fwnode; } EXPORT_SYMBOL_GPL(device_match_fwnode); int device_match_devt(struct device *dev, const void *pdevt) { return dev->devt == *(dev_t *)pdevt; } EXPORT_SYMBOL_GPL(device_match_devt); int device_match_acpi_dev(struct device *dev, const void *adev) { return ACPI_COMPANION(dev) == adev; } EXPORT_SYMBOL(device_match_acpi_dev); int device_match_any(struct device *dev, const void *unused) { return 1; } EXPORT_SYMBOL_GPL(device_match_any);
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