#endif
/* Device links support. */
+static LIST_HEAD(wait_for_suppliers);
+static DEFINE_MUTEX(wfs_lock);
#ifdef CONFIG_SRCU
static DEFINE_MUTEX(device_links_lock);
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;
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.
* 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
* 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
{
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)))
}
}
+ if (!(flags & DL_FLAG_STATELESS))
+ flags |= DL_FLAG_MANAGED;
+
device_links_write_lock();
device_pm_lock();
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);
}
if (flags & DL_FLAG_STATELESS) {
+ link->flags |= DL_FLAG_STATELESS;
kref_get(&link->kref);
goto out;
}
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;
}
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
}
EXPORT_SYMBOL_GPL(device_link_add);
+/**
+ * device_link_wait_for_supplier - Mark device as waiting for supplier
+ * @consumer: Consumer device
+ *
+ * Marks the consumer device as waiting for suppliers to become available. The
+ * consumer device will never be probed until it's unmarked as waiting for
+ * suppliers. The caller is responsible for adding the link to the supplier
+ * once the supplier device is present.
+ *
+ * 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)
+{
+ mutex_lock(&wfs_lock);
+ list_add_tail(&consumer->links.needs_suppliers, &wait_for_suppliers);
+ mutex_unlock(&wfs_lock);
+}
+
+/**
+ * device_link_remove_from_wfs - Unmark device as waiting for supplier
+ * @consumer: Consumer device
+ *
+ * Unmark the consumer device as waiting for suppliers to become available.
+ */
+void device_link_remove_from_wfs(struct device *consumer)
+{
+ mutex_lock(&wfs_lock);
+ list_del_init(&consumer->links.needs_suppliers);
+ mutex_unlock(&wfs_lock);
+}
+
+/**
+ * device_link_check_waiting_consumers - Try to unmark waiting consumers
+ *
+ * Loops through all consumers waiting on suppliers and tries to add all their
+ * supplier links. If that succeeds, the consumer device is unmarked as waiting
+ * for suppliers. Otherwise, they are left marked as waiting on suppliers,
+ *
+ * The add_links bus 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_check_waiting_consumers(void)
+{
+ struct device *dev, *tmp;
+ int ret;
+
+ mutex_lock(&wfs_lock);
+ list_for_each_entry_safe(dev, tmp, &wait_for_suppliers,
+ links.needs_suppliers) {
+ ret = 0;
+ if (dev->has_edit_links)
+ ret = driver_edit_links(dev);
+ else if (dev->bus->add_links)
+ ret = dev->bus->add_links(dev);
+ if (!ret)
+ list_del_init(&dev->links.needs_suppliers);
+ }
+ mutex_unlock(&wfs_lock);
+}
+
static void device_link_free(struct device_link *link)
{
while (refcount_dec_not_one(&link->rpm_active))
* 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)
{
struct device_link *link;
int ret = 0;
+ /*
+ * If a device is waiting for one or more suppliers (in
+ * wait_for_suppliers list), it is not ready to probe yet. So just
+ * return -EPROBE_DEFER without having to check the links with existing
+ * suppliers.
+ */
+ mutex_lock(&wfs_lock);
+ if (!list_empty(&dev->links.needs_suppliers)) {
+ 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_STATELESS)
+ if (!(link->flags & DL_FLAG_MANAGED))
continue;
if (link->status != DL_STATE_AVAILABLE) {
*
* 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)
{
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;
/*
}
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);
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.
* 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);
* %__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)
{
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;
/*
* 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)
{
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);
*/
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);
}
*
* 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)
{
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
* 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)
{
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;
{
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).
#endif
INIT_LIST_HEAD(&dev->links.consumers);
INIT_LIST_HEAD(&dev->links.suppliers);
+ INIT_LIST_HEAD(&dev->links.needs_suppliers);
dev->links.status = DL_DEV_NO_DRIVER;
}
EXPORT_SYMBOL_GPL(device_initialize);
*/
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);
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 happe 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.
+ */
+ device_link_check_waiting_consumers();
+
+ if (dev->bus && dev->bus->add_links && dev->bus->add_links(dev))
+ device_link_wait_for_supplier(dev);
+
bus_probe_device(dev);
if (parent)
klist_add_tail(&dev->p->knode_parent,
}
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
{
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);
}
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);
projects / linux.git / blobdiff