diff options
| -rw-r--r-- | Documentation/driver-api/device_link.rst | 4 | ||||
| -rw-r--r-- | drivers/base/core.c | 176 | ||||
| -rw-r--r-- | drivers/base/power/runtime.c | 4 | ||||
| -rw-r--r-- | include/linux/device.h | 4 |
4 files changed, 106 insertions, 82 deletions
diff --git a/Documentation/driver-api/device_link.rst b/Documentation/driver-api/device_link.rst index ae1e3d0394b0..1b5020ec6517 100644 --- a/Documentation/driver-api/device_link.rst +++ b/Documentation/driver-api/device_link.rst @@ -78,8 +78,8 @@ typically deleted in its ``->remove`` callback for symmetry. That way, if the driver is compiled as a module, the device link is added on module load and orderly deleted on unload. The same restrictions that apply to device link addition (e.g. exclusion of a parallel suspend/resume transition) apply equally -to deletion. Device links with ``DL_FLAG_STATELESS`` unset (i.e. managed -device links) are deleted automatically by the driver core. +to deletion. Device links managed by the driver core are deleted automatically +by it. Several flags may be specified on device link addition, two of which have already been mentioned above: ``DL_FLAG_STATELESS`` to express that no diff --git a/drivers/base/core.c b/drivers/base/core.c index da84a73f2ba6..21cd08162219 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -124,6 +124,50 @@ 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 +209,10 @@ 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) + /** * device_link_add - Create a link between two devices. * @consumer: Consumer end of the link. @@ -179,9 +227,9 @@ 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 +249,16 @@ 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 @@ -220,10 +275,8 @@ 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)) || + (flags & ~(DL_FLAG_STATELESS | DL_MANAGED_LINK_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 +289,9 @@ 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 +318,6 @@ 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 +328,7 @@ 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 +347,11 @@ 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 +378,10 @@ 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 +543,7 @@ 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 +553,7 @@ 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 +578,7 @@ 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 +587,7 @@ 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 +608,7 @@ 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 +620,13 @@ 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 +637,18 @@ 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 +665,7 @@ 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 +674,7 @@ 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 +702,7 @@ 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 +711,7 @@ 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 +724,7 @@ 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 +746,7 @@ 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 +756,7 @@ 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 +786,7 @@ 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 +798,7 @@ 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; diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c index b75335508d2c..45a8fbe6987a 100644 --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -1624,7 +1624,7 @@ void pm_runtime_remove(struct device *dev) * runtime PM references to the device, drop the usage counter of the device * (as many times as needed). * - * Links with the DL_FLAG_STATELESS flag set are ignored. + * Links with the DL_FLAG_MANAGED flag unset are ignored. * * Since the device is guaranteed to be runtime-active at the point this is * called, nothing else needs to be done here. @@ -1641,7 +1641,7 @@ void pm_runtime_clean_up_links(struct device *dev) idx = device_links_read_lock(); list_for_each_entry_rcu(link, &dev->links.consumers, s_node) { - if (link->flags & DL_FLAG_STATELESS) + if (!(link->flags & DL_FLAG_MANAGED)) continue; while (refcount_dec_not_one(&link->rpm_active)) diff --git a/include/linux/device.h b/include/linux/device.h index c330b75c6c57..c1c489921e4c 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -833,12 +833,13 @@ enum device_link_state { /* * Device link flags. * - * STATELESS: The core won't track the presence of supplier/consumer drivers. + * STATELESS: The core will not remove this link automatically. * AUTOREMOVE_CONSUMER: Remove the link automatically on consumer driver unbind. * PM_RUNTIME: If set, the runtime PM framework will use this link. * RPM_ACTIVE: Run pm_runtime_get_sync() on the supplier during link creation. * AUTOREMOVE_SUPPLIER: Remove the link automatically on supplier driver unbind. * AUTOPROBE_CONSUMER: Probe consumer driver automatically after supplier binds. + * MANAGED: The core tracks presence of supplier/consumer drivers (internal). */ #define DL_FLAG_STATELESS BIT(0) #define DL_FLAG_AUTOREMOVE_CONSUMER BIT(1) @@ -846,6 +847,7 @@ enum device_link_state { #define DL_FLAG_RPM_ACTIVE BIT(3) #define DL_FLAG_AUTOREMOVE_SUPPLIER BIT(4) #define DL_FLAG_AUTOPROBE_CONSUMER BIT(5) +#define DL_FLAG_MANAGED BIT(6) /** * struct device_link - Device link representation. |