Tests whether a list is empty and not being modified
int list_empty_careful(const struct list_head * head);
head
the list to test
tests whether a list is empty _and_ checks that no other CPU might be in the process of modifying either member (next or prev)
using list_empty_careful without synchronization can only be safe if the only activity that can happen to the list entry is list_del_init. Eg. it cannot be used if another CPU could re-list_add it.