diff options
Diffstat (limited to 'drivers/base')
-rw-r--r-- | drivers/base/bus.c | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/drivers/base/bus.c b/drivers/base/bus.c index 39b9b58c6974..5aee1c0169ea 100644 --- a/drivers/base/bus.c +++ b/drivers/base/bus.c @@ -980,6 +980,56 @@ struct klist *bus_get_device_klist(struct bus_type *bus) } EXPORT_SYMBOL_GPL(bus_get_device_klist); +/* + * Yes, this forcably breaks the klist abstraction temporarily. It + * just wants to sort the klist, not change reference counts and + * take/drop locks rapidly in the process. It does all this while + * holding the lock for the list, so objects can't otherwise be + * added/removed while we're swizzling. + */ +static void device_insertion_sort_klist(struct device *a, struct list_head *list, + int (*compare)(const struct device *a, + const struct device *b)) +{ + struct list_head *pos; + struct klist_node *n; + struct device *b; + + list_for_each(pos, list) { + n = container_of(pos, struct klist_node, n_node); + b = container_of(n, struct device, knode_bus); + if (compare(a, b) <= 0) { + list_move_tail(&a->knode_bus.n_node, + &b->knode_bus.n_node); + return; + } + } + list_move_tail(&a->knode_bus.n_node, list); +} + +void bus_sort_breadthfirst(struct bus_type *bus, + int (*compare)(const struct device *a, + const struct device *b)) +{ + LIST_HEAD(sorted_devices); + struct list_head *pos, *tmp; + struct klist_node *n; + struct device *dev; + struct klist *device_klist; + + device_klist = bus_get_device_klist(bus); + + spin_lock(&device_klist->k_lock); + list_for_each_safe(pos, tmp, &device_klist->k_list) { + n = container_of(pos, struct klist_node, n_node); + dev = container_of(n, struct device, knode_bus); + device_insertion_sort_klist(dev, &sorted_devices, compare); + } + list_splice(&sorted_devices, &device_klist->k_list); + spin_unlock(&device_klist->k_lock); +} +EXPORT_SYMBOL_GPL(bus_sort_breadthfirst); + int __init buses_init(void) { bus_kset = kset_create_and_add("bus", &bus_uevent_ops, NULL); |