AFAICS, it (and configfs_unregister_default_group()) will break if called with group non-empty (i.e. when rmdir(2) would've failed with -ENOTEMPTY); configfs_detach_prep() is called, but return value is completely ignored. Similar breakage happens in configfs_unregister_subsystem(), but there it looks like the drivers are responsible for not calling it that way. It yells if configfs_detach_prep() fails and AFAICS all callers do guarantee it never happens. configfs_unregister_group() is quiet; from my reading of the callers, only pci-endpoint might end up calling it for group that is not guaranteed to be empty. I'm not familiar with pci-endpoint guts, so I might very well be missing something there. Questions to configfs API maintainers (that'd be Christoph, these days, AFAIK) 1) should such a call be considered a driver bug? 2) should configfs_unregister_group() at least warn when that happens? and, to pci-endpoint maintainer 3) what, if anything, prevents such calls in pci-endpoint? Because as it is, configfs will break badly when that happens...
