From: "Ewan D. Milne" <[email protected]> These functions are needed to expose an iterator for SCSI usage.
>From a patch originally developed by David Jeffery <[email protected]> Signed-off-by: Ewan D. Milne <[email protected]> --- drivers/base/bus.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/device.h | 5 +++++ 2 files changed, 64 insertions(+) diff --git a/drivers/base/bus.c b/drivers/base/bus.c index 5005924..a472e46 100644 --- a/drivers/base/bus.c +++ b/drivers/base/bus.c @@ -318,6 +318,65 @@ int bus_for_each_dev(struct bus_type *bus, struct device *start, EXPORT_SYMBOL_GPL(bus_for_each_dev); /** + * bus_device_iter_init - Initialize an iterator for walking a bus's devices. + * @iter: iterator structure to initialize + * @bus: bus type + * + * Initializes an iterator for safely walking a bus's list of devices. The + * iterator can be used by bus_device_iter_next() to safely walk the list, even + * if a device is removed from the list while being examined. Needs to be + * matched with a call to bus_device_iter_exit() to clean up the iterator when + * finished. + * + * Return 0 on success, non-zero on failure. Iterator cannot be used + * for a non-zero result + */ +int bus_device_iter_init(struct klist_iter *iter, + struct bus_type *bus) +{ + if (!bus || !bus->p) + return -EINVAL; + + klist_iter_init_node(&bus->p->klist_devices, iter, NULL); + return 0; +} +EXPORT_SYMBOL_GPL(bus_device_iter_init); + +/** + * bus_device_iter_next - Get a bus's next device from the iterator. + * @iter: iterator structure from bus_device_iter_init() + * + * Finds the next valid device entry on a bus's device list. Allows the list + * to be safely traversed by the caller even when other tasks remove devices + * from the list. + * + * Returns a reference to the next device, or NULL if no more devices. + */ +struct device *bus_device_iter_next(struct klist_iter *iter) +{ + struct device *dev; + + while ((dev = next_device(iter))) + if (get_device(dev)) + break; + + return dev; +} +EXPORT_SYMBOL_GPL(bus_device_iter_next); + +/** + * bus_device_iter_exit - Clean up an iterator from walking a bus's device list. + * @iter: iterator structure from bus_device_iter_init() to clean up + * + * Clean up any remaining state after finishing walking a bus's device list. + */ +void bus_device_iter_exit(struct klist_iter *iter) +{ + klist_iter_exit(iter); +} +EXPORT_SYMBOL_GPL(bus_device_iter_exit); + +/** * bus_find_device - device iterator for locating a particular device. * @bus: bus type * @start: Device to begin with diff --git a/include/linux/device.h b/include/linux/device.h index b8f411b..a44d912 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -151,6 +151,11 @@ void subsys_dev_iter_exit(struct subsys_dev_iter *iter); int bus_for_each_dev(struct bus_type *bus, struct device *start, void *data, int (*fn)(struct device *dev, void *data)); + +int bus_device_iter_init(struct klist_iter *iter, struct bus_type *bus); +struct device *bus_device_iter_next(struct klist_iter *iter); +void bus_device_iter_exit(struct klist_iter *iter); + struct device *bus_find_device(struct bus_type *bus, struct device *start, void *data, int (*match)(struct device *dev, void *data)); -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
