Message-ID: <5048D6DE.8090805@gmail.com>
Date: Thu, 06 Sep 2012 19:01:18 +0200
From: Sasha Levin <levinsasha928@gmail.com>
MIME-Version: 1.0
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Steven Rostedt <rostedt@goodmis.org>,
        Josh Triplett <josh@joshtriplett.org>, Pedro Alves <palves@redhat.com>,
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Subject: Re: [PATCH v3 01/17] hashtable: introduce a small and naive hashtable
References: <20120828230050.GA3337@Krystal> <1346772948.27919.9.camel@gandalf.local.home> <50462C99.5000007@redhat.com> <50462EE8.1090903@redhat.com> <20120904170138.GB31934@Krystal> <5048AAF6.5090101@gmail.com> <20120906145545.GA17332@leaf> <5048C615.4070204@gmail.com> <1346947206.1680.36.camel@gandalf.local.home> <5048CDA2.10300@gmail.com> <20120906165055.GC7385@Krystal>
In-Reply-To: <20120906165055.GC7385@Krystal>
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Sender: linux-nfs-owner@vger.kernel.org

On 09/06/2012 06:50 PM, Mathieu Desnoyers wrote:
> * Sasha Levin (levinsasha928@gmail.com) wrote:
>> On 09/06/2012 06:00 PM, Steven Rostedt wrote:
>>>>> 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