Q: (stupid) can't we "fix" hlist_for_each_entry() ?

[Oleg Nesterov <oleg@tv-sign.ru>]

hlist_for_each_entry/hlist_for_each_entry_rcu doesn't actually need 4
arguments, it could be

#define hlist_for_each_entry_rcu(pos, head, member)		 			\
	for (pos = hlist_entry((head)->first, typeof(*(pos)), member);			\
	     rcu_dereference(pos) != hlist_entry(NULL, typeof(*(pos)), member) &&	\
		({ prefetch((pos)->member.next); 1; });					\
	     (pos) = hlist_entry((pos)->member.next, typeof(*(pos)), member))

Or,

#define hlist_for_each_entry_rcu(pos, head, member)		 			\
	for (pos = (void*)(head)->first;						\
	     rcu_dereference(pos) && ({ prefetch(((hlist_node*)pos)->next); 1; }) &&	\
		({ (pos) = hlist_entry((void*)(pos), typeof(*(pos)), member)); 1; });	\
	     (pos) = (void*)(pos)->member.next)

Q: is it worth "fixing" ?

If yes, what is the "right" way to do this? These macros are spread all over
the kernel...

Oleg.