driver-core: use klist for class device list and implement iterator

Iterating over entries using callback usually isn't too fun especially
when the entry being iterated over can't be manipulated freely.  This
patch converts class->p->class_devices to klist and implements class
device iterator so that the users can freely build their own control
structure.  The users are also free to call back into class code
without worrying about locking.

class_for_each_device() and class_find_device() are converted to use
the new iterators, so their users don't have to worry about locking
anymore either.

Note: This depends on klist-dont-iterate-over-deleted-entries patch
because class_intf->add/remove_dev() depends on proper synchronization
with device removal.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/base/core.c b/drivers/base/core.c
index d021c98605b3..b98cb1416a2d 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -536,7 +536,6 @@ void device_initialize(struct device *dev)
         klist_init(&dev->klist_children, klist_children_get,
                    klist_children_put);
         INIT_LIST_HEAD(&dev->dma_pools);
-        INIT_LIST_HEAD(&dev->node);
         init_MUTEX(&dev->sem);
         spin_lock_init(&dev->devres_lock);
         INIT_LIST_HEAD(&dev->devres_head);
@@ -916,7 +915,8 @@ int device_add(struct device *dev)
         if (dev->class) {
                 mutex_lock(&dev->class->p->class_mutex);
                 /* tie the class to the device */
-                list_add_tail(&dev->node, &dev->class->p->class_devices);
+                klist_add_tail(&dev->knode_class,
+                               &dev->class->p->class_devices);
 
                 /* notify any interfaces that the device is here */
                 list_for_each_entry(class_intf,
@@ -1032,7 +1032,7 @@ void device_del(struct device *dev)
                         if (class_intf->remove_dev)
                                 class_intf->remove_dev(dev, class_intf);
                 /* remove the device from the class list */
-                list_del_init(&dev->node);
+                klist_del(&dev->knode_class);
                 mutex_unlock(&dev->class->p->class_mutex);
         }
         device_remove_file(dev, &uevent_attr);