EXPORT_SYMBOL_GPL() include/linux/export.h

Similar to EXPORT_SYMBOL() except that the symbols exported by EXPORT_SYMBOL_GPL() can only be seen by modules with a MODULE_LICENSE() that specifies a GPL compatible license. It implies that the function is considered an internal implementation issue, and not really an interface. Some maintainers and developers may however require EXPORT_SYMBOL_GPL() when adding any new APIs or functionality.