On Fri, Oct 09, 2015 at 05:14:42PM +0200, Thomas Petazzoni wrote: > Julia: some of the Device Tree iterator functions have a somewhat > "interesting" behavior in that they take the reference on the current > child when entering the loop, and release it before entering the next > iteration (which will also take a reference to the next child). > > This means that if you have an exit point inside the loop (break or > return), you are loosing a reference. For example, > http://lxr.free-electrons.com/source/arch/arm/mach-shmobile/pm-rmobile.c#L367 > is wrong because there is a missing of_node_put(np) before the "return > -ENOMEM". > > So essentially, every exit point in such Device Tree iteration loops > should make to call of_node_put() on the current element before exiting > the loop unexpectedly. There is an exception to that... if the loop is part of a DT node lookup function, which would return a DT node based on some search criteria, it would be valid to break out of the loop while holding a reference. For example, of_get_child_by_name(), of_find_next_cache_node(), of_graph_get_port_by_id(), are valid breaker-outer cases. ;) However, of_platform_bus_probe(), of_platform_populate(), of_overlay_apply_one(), overlay_subtree_check() are examples of incorrect break-out cases. -- FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
