From: Wu Fengguang <fengguang.wu@intel.com>
To: Cesar Eduardo Barros <cesarb@cesarb.net>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] radix-tree: fix radix_tree_prev_hole underflow case
Date: Fri, 14 May 2010 10:37:37 +0800 [thread overview]
Message-ID: <20100514023737.GB8695@localhost> (raw)
In-Reply-To: <4BECB562.2080200@cesarb.net>
On Fri, May 14, 2010 at 10:28:50AM +0800, Cesar Eduardo Barros wrote:
> Em 13-05-2010 23:15, Wu Fengguang escreveu:
> > On Fri, May 14, 2010 at 10:05:24AM +0800, Cesar Eduardo Barros wrote:
> >> radix_tree_prev_hole() used LONG_MAX to detect underflow; however,
> >> ULONG_MAX is clearly what was intended, both here and by its only user
> >> (count_history_pages at mm/readahead.c).
> >
> > Good catch, thanks! I actually have a more smart
> > radix_tree_prev_hole() that uses ULONG_MAX.
>
> I saw it already ([PATCH 14/16] radixtree: speed up the search for
> hole), but it misses the LONG_MAX in the documentation comment.
Yes, thanks!
> > Andrew, fortunately this bug has little impact on readahead.
>
> I agree, if I read it correctly it should only have any impact either
> when very near LONG_MAX or in the unlikely case that there is no hole at
> ULONG_MAX. And even then, the impact should be limited.
Right.
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prev parent reply other threads:[~2010-05-14 2:37 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-14 2:05 [PATCH] radix-tree: fix radix_tree_prev_hole underflow case Cesar Eduardo Barros
2010-05-14 2:15 ` Wu Fengguang
2010-05-14 2:28 ` Cesar Eduardo Barros
2010-05-14 2:37 ` Wu Fengguang [this message]
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