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From: Thomas Graf <tgr@reeler.org>
To: lartc@vger.kernel.org
Subject: Re: [LARTC] LIST_FIND in netfilter_ipv4/listhelp.h
Date: Tue, 07 Oct 2003 14:25:08 +0000	[thread overview]
Message-ID: <marc-lartc-106553681118337@msgid-missing> (raw)
In-Reply-To: <marc-lartc-106545160904735@msgid-missing>

Hi

* jeremie le-hen <20031006144458.GD24864@carpediem.epita.fr> 2003-10-06 16:44

> Unless I really drank too much yesterday evening, I'm pretty sure this
> algorithm will fail if the list has only one element, returning NULL
> immediately without even trying to compare the element.
> On the other hand, it seems to work pretty well for months, since it is
> widely used accross the NetFilter conntrack code. So where am I wrong ?

The code is correct.

Check include/linux/list.h, it's a cyclic list:
head->next points to first element
head->prev points to last element

the list iteration code will make it clear:
#define __list_for_each(pos, head) \
    for (pos = (head)->next; pos != (head); pos = pos->next)

Regards

-- 
Thomas GRAF <tgraf@suug.ch>
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      reply	other threads:[~2003-10-07 14:25 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-10-06 14:44 [LARTC] LIST_FIND in netfilter_ipv4/listhelp.h jeremie le-hen
2003-10-07 14:25 ` Thomas Graf [this message]

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