Driver Core: add ability for class_for_each_device to start in middle of list
This mirrors the functionality that driver_for_each_device has as well.
We add a start variable, and all callers of the function are fixed up at
the same time.
The block layer will be using this new functionality in a follow-on
patch.
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/base/class.c b/drivers/base/class.c
index 71ce3ff..2eb7048 100644
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -256,11 +256,14 @@
/**
* class_for_each_device - device iterator
* @class: the class we're iterating
+ * @start: the device to start with in the list, if any.
* @data: data for the callback
* @fn: function to be called for each device
*
* Iterate over @class's list of devices, and call @fn for each,
- * passing it @data.
+ * passing it @data. If @start is set, the list iteration will start
+ * there, otherwise if it is NULL, the iteration starts at the
+ * beginning of the list.
*
* We check the return of @fn each time. If it returns anything
* other than 0, we break out and return that value.
@@ -269,8 +272,8 @@
* re-acquired in @fn, otherwise it will self-deadlocking. For
* example, calls to add or remove class members would be verboten.
*/
-int class_for_each_device(struct class *class, void *data,
- int (*fn)(struct device *, void *))
+int class_for_each_device(struct class *class, struct device *start,
+ void *data, int (*fn)(struct device *, void *))
{
struct device *dev;
int error = 0;
@@ -279,12 +282,14 @@
return -EINVAL;
down(&class->sem);
list_for_each_entry(dev, &class->devices, node) {
+ if (start) {
+ if (start == dev)
+ start = NULL;
+ continue;
+ }
dev = get_device(dev);
- if (dev) {
- error = fn(dev, data);
- put_device(dev);
- } else
- error = -ENODEV;
+ error = fn(dev, data);
+ put_device(dev);
if (error)
break;
}