diff options
Diffstat (limited to 'drivers/base/core.c')
| -rw-r--r-- | drivers/base/core.c | 284 |
1 files changed, 197 insertions, 87 deletions
diff --git a/drivers/base/core.c b/drivers/base/core.c index 636058bbf48a..2db62d98e395 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -68,6 +68,11 @@ void device_links_read_unlock(int idx) { srcu_read_unlock(&device_links_srcu, idx); } + +int device_links_read_lock_held(void) +{ + return srcu_read_lock_held(&device_links_srcu); +} #else /* !CONFIG_SRCU */ static DECLARE_RWSEM(device_links_lock); @@ -91,6 +96,13 @@ 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 */ /** @@ -124,6 +136,50 @@ static int device_is_dependent(struct device *dev, void *target) 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; @@ -165,6 +221,13 @@ void device_pm_move_to_tail(struct device *dev) device_links_read_unlock(idx); } +#define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \ + DL_FLAG_AUTOREMOVE_SUPPLIER | \ + DL_FLAG_AUTOPROBE_CONSUMER) + +#define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \ + DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE) + /** * device_link_add - Create a link between two devices. * @consumer: Consumer end of the link. @@ -179,9 +242,9 @@ void device_pm_move_to_tail(struct device *dev) * 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 link is not going to be managed by - * the driver core and, in particular, the caller of this function is expected - * to drop the reference to the link acquired by it directly. + * 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 @@ -201,9 +264,16 @@ void device_pm_move_to_tail(struct device *dev) * 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 either DL_FLAG_AUTOREMOVE_CONSUMER - * or DL_FLAG_AUTOREMOVE_SUPPLIER set in @flags at the same time is invalid and - * will cause NULL to be returned upfront. + * 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 @@ -219,11 +289,8 @@ struct device_link *device_link_add(struct device *consumer, { struct device_link *link; - if (!consumer || !supplier || - (flags & DL_FLAG_STATELESS && - flags & (DL_FLAG_AUTOREMOVE_CONSUMER | - DL_FLAG_AUTOREMOVE_SUPPLIER | - DL_FLAG_AUTOPROBE_CONSUMER)) || + if (!consumer || !supplier || flags & ~DL_ADD_VALID_FLAGS || + (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) || (flags & DL_FLAG_AUTOPROBE_CONSUMER && flags & (DL_FLAG_AUTOREMOVE_CONSUMER | DL_FLAG_AUTOREMOVE_SUPPLIER))) @@ -236,6 +303,9 @@ struct device_link *device_link_add(struct device *consumer, } } + if (!(flags & DL_FLAG_STATELESS)) + flags |= DL_FLAG_MANAGED; + device_links_write_lock(); device_pm_lock(); @@ -262,15 +332,6 @@ struct device_link *device_link_add(struct device *consumer, if (link->consumer != consumer) continue; - /* - * Don't return a stateless link if the caller wants a stateful - * one and vice versa. - */ - if (WARN_ON((flags & DL_FLAG_STATELESS) != (link->flags & DL_FLAG_STATELESS))) { - link = NULL; - goto out; - } - if (flags & DL_FLAG_PM_RUNTIME) { if (!(link->flags & DL_FLAG_PM_RUNTIME)) { pm_runtime_new_link(consumer); @@ -281,6 +342,7 @@ struct device_link *device_link_add(struct device *consumer, } if (flags & DL_FLAG_STATELESS) { + link->flags |= DL_FLAG_STATELESS; kref_get(&link->kref); goto out; } @@ -299,6 +361,11 @@ struct device_link *device_link_add(struct device *consumer, link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER | DL_FLAG_AUTOREMOVE_SUPPLIER); } + if (!(link->flags & DL_FLAG_MANAGED)) { + kref_get(&link->kref); + link->flags |= DL_FLAG_MANAGED; + device_link_init_status(link, consumer, supplier); + } goto out; } @@ -325,48 +392,10 @@ struct device_link *device_link_add(struct device *consumer, kref_init(&link->kref); /* Determine the initial link state. */ - if (flags & DL_FLAG_STATELESS) { + if (flags & DL_FLAG_STATELESS) link->status = DL_STATE_NONE; - } else { - 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; - } - } + else + device_link_init_status(link, consumer, supplier); /* * Some callers expect the link creation during consumer driver probe to @@ -528,7 +557,7 @@ static void device_links_missing_supplier(struct device *dev) * mark the link as "consumer probe in progress" to make the supplier removal * wait for us to complete (or bad things may happen). * - * Links with the DL_FLAG_STATELESS flag set are ignored. + * Links without the DL_FLAG_MANAGED flag set are ignored. */ int device_links_check_suppliers(struct device *dev) { @@ -538,7 +567,7 @@ int device_links_check_suppliers(struct device *dev) device_links_write_lock(); list_for_each_entry(link, &dev->links.suppliers, c_node) { - if (link->flags & DL_FLAG_STATELESS) + if (!(link->flags & DL_FLAG_MANAGED)) continue; if (link->status != DL_STATE_AVAILABLE) { @@ -563,7 +592,7 @@ int device_links_check_suppliers(struct device *dev) * * Also change the status of @dev's links to suppliers to "active". * - * Links with the DL_FLAG_STATELESS flag set are ignored. + * Links without the DL_FLAG_MANAGED flag set are ignored. */ void device_links_driver_bound(struct device *dev) { @@ -572,7 +601,7 @@ void device_links_driver_bound(struct device *dev) device_links_write_lock(); list_for_each_entry(link, &dev->links.consumers, s_node) { - if (link->flags & DL_FLAG_STATELESS) + if (!(link->flags & DL_FLAG_MANAGED)) continue; /* @@ -593,7 +622,7 @@ void device_links_driver_bound(struct device *dev) } list_for_each_entry(link, &dev->links.suppliers, c_node) { - if (link->flags & DL_FLAG_STATELESS) + if (!(link->flags & DL_FLAG_MANAGED)) continue; WARN_ON(link->status != DL_STATE_CONSUMER_PROBE); @@ -605,6 +634,13 @@ void device_links_driver_bound(struct device *dev) device_links_write_unlock(); } +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_no_driver - Update links of a device without a driver. * @dev: Device without a drvier. @@ -615,18 +651,18 @@ void device_links_driver_bound(struct device *dev) * unless they already are in the "supplier unbind in progress" state in which * case they need not be updated. * - * Links with the DL_FLAG_STATELESS flag set are ignored. + * 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_STATELESS) + if (!(link->flags & DL_FLAG_MANAGED)) continue; if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) - __device_link_del(&link->kref); + device_link_drop_managed(link); else if (link->status == DL_STATE_CONSUMER_PROBE || link->status == DL_STATE_ACTIVE) WRITE_ONCE(link->status, DL_STATE_AVAILABLE); @@ -643,7 +679,7 @@ static void __device_links_no_driver(struct device *dev) * %__device_links_no_driver() to update links to suppliers for it as * appropriate. * - * Links with the DL_FLAG_STATELESS flag set are ignored. + * Links without the DL_FLAG_MANAGED flag set are ignored. */ void device_links_no_driver(struct device *dev) { @@ -652,7 +688,7 @@ void device_links_no_driver(struct device *dev) device_links_write_lock(); list_for_each_entry(link, &dev->links.consumers, s_node) { - if (link->flags & DL_FLAG_STATELESS) + if (!(link->flags & DL_FLAG_MANAGED)) continue; /* @@ -680,7 +716,7 @@ void device_links_no_driver(struct device *dev) * invoke %__device_links_no_driver() to update links to suppliers for it as * appropriate. * - * Links with the DL_FLAG_STATELESS flag set are ignored. + * Links without the DL_FLAG_MANAGED flag set are ignored. */ void device_links_driver_cleanup(struct device *dev) { @@ -689,7 +725,7 @@ void device_links_driver_cleanup(struct device *dev) device_links_write_lock(); list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) { - if (link->flags & DL_FLAG_STATELESS) + if (!(link->flags & DL_FLAG_MANAGED)) continue; WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER); @@ -702,7 +738,7 @@ void device_links_driver_cleanup(struct device *dev) */ if (link->status == DL_STATE_SUPPLIER_UNBIND && link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER) - __device_link_del(&link->kref); + device_link_drop_managed(link); WRITE_ONCE(link->status, DL_STATE_DORMANT); } @@ -724,7 +760,7 @@ void device_links_driver_cleanup(struct device *dev) * * Return 'false' if there are no probing or active consumers. * - * Links with the DL_FLAG_STATELESS flag set are ignored. + * Links without the DL_FLAG_MANAGED flag set are ignored. */ bool device_links_busy(struct device *dev) { @@ -734,7 +770,7 @@ bool device_links_busy(struct device *dev) device_links_write_lock(); list_for_each_entry(link, &dev->links.consumers, s_node) { - if (link->flags & DL_FLAG_STATELESS) + if (!(link->flags & DL_FLAG_MANAGED)) continue; if (link->status == DL_STATE_CONSUMER_PROBE @@ -764,7 +800,7 @@ bool device_links_busy(struct device *dev) * driver to unbind and start over (the consumer will not re-probe as we have * changed the state of the link already). * - * Links with the DL_FLAG_STATELESS flag set are ignored. + * Links without the DL_FLAG_MANAGED flag set are ignored. */ void device_links_unbind_consumers(struct device *dev) { @@ -776,7 +812,7 @@ void device_links_unbind_consumers(struct device *dev) list_for_each_entry(link, &dev->links.consumers, s_node) { enum device_link_state status; - if (link->flags & DL_FLAG_STATELESS) + if (!(link->flags & DL_FLAG_MANAGED)) continue; status = link->status; @@ -1823,12 +1859,63 @@ static inline struct kobject *get_glue_dir(struct device *dev) */ 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); - if (!kobject_has_children(glue_dir)) + /** + * 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); @@ -2881,13 +2968,6 @@ struct device *device_create_with_groups(struct class *class, } EXPORT_SYMBOL_GPL(device_create_with_groups); -static int __match_devt(struct device *dev, const void *data) -{ - const dev_t *devt = data; - - return dev->devt == *devt; -} - /** * device_destroy - removes a device that was created with device_create() * @class: pointer to the struct class that this device was registered with @@ -2900,7 +2980,7 @@ void device_destroy(struct class *class, dev_t devt) { struct device *dev; - dev = class_find_device(class, NULL, &devt, __match_devt); + dev = class_find_device_by_devt(class, devt); if (dev) { put_device(dev); device_unregister(dev); @@ -3371,8 +3451,38 @@ void device_set_of_node_from_dev(struct device *dev, const struct device *dev2) } 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); |