On 09/06/2012 06:50 PM, Mathieu Desnoyers wrote:

* Sasha Levin (levinsasha928-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org) wrote:

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On 09/06/2012 06:00 PM, Steven Rostedt wrote:

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I think that that code doesn't make sense. The users of hlist_for_each_* aren't
supposed to be changing the loop cursor.

I totally agree. Modifying the 'node' pointer is just asking for issues.
Yes that is error prone, but not due to the double loop. It's due to the
modifying of the node pointer that is used internally by the loop
counter. Don't do that :-)

While we're on this subject, I haven't actually seen hlist_for_each_entry() code
that even *touches* 'pos'.

Will people yell at me loudly if I change the prototype of those macros to be:

	hlist_for_each_entry(tpos, head, member)

(Dropping the 'pos' parameter), and updating anything that calls those macros to
drop it as well?

I think the intent there is to keep hlist macros and list macros
slightly in sync. Given those are vastly used, I'm not sure you want to
touch them. But hey, that's just my 2 cents.

Actually, the corresponding list macro looks like this:

	list_for_each_entry(pos, head, member)

With 'pos' being the equivalent of 'tpos' in the hlist macros (the type *).
Changing hlist macro will make them both look as follows:

	hlist_for_each_entry(pos, head, member)
	list_for_each_entry(pos, head, member)

So following this suggesting will actually bring them back to sync...

The only issue I can see is that as you've said, they're used almost everywhere,
so doing something to change that will require some coordination.


Thanks,
Sasha