From: Theodore Tso <tytso@mit.edu>
To: Bill Davidsen <davidsen@tmr.com>
Cc: roel kluin <roel.kluin@gmail.com>,
adilger@sun.com, linux-ext4@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] ext3, ext4: do_split() fix loop, with obvious unsigned wrap
Date: Tue, 2 Dec 2008 16:57:58 -0500 [thread overview]
Message-ID: <20081202215758.GE20858@mit.edu> (raw)
In-Reply-To: <49356B96.7070900@tmr.com>
On Tue, Dec 02, 2008 at 12:08:38PM -0500, Bill Davidsen wrote:
> Sorry, you are reading it wrong, the i values inside the loop are
> identical to those in the original. The value of i starts at count, and
> the test comes *before* the value is used inside the loop. The values of
> i inside the loop start at count-1 and go to zero, just as it did in the
> original. That's why the "i--" is there, the test is on the
> unincremented value range count to one, but the value inside the loop is
> correct (or at least is the same as the original patch).
You're right; my bad. But with something like this:
>>> + for (i = count; i--; ) {
...where there is no third part of the for loop, and a decrement in
the second part of the loop, just for clarity's sake, it's much better
to write it as a while loop.
- Ted
next prev parent reply other threads:[~2008-12-02 21:58 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-01 19:28 [PATCH v2] ext3, ext4: do_split() fix loop, with obvious unsigned wrap roel kluin
2008-12-02 13:24 ` Theodore Tso
2008-12-02 17:08 ` Bill Davidsen
2008-12-02 19:47 ` Roel Kluin
2008-12-02 21:57 ` Theodore Tso [this message]
2008-12-02 23:17 ` Bill Davidsen
2008-12-03 14:25 ` Bill Davidsen
2008-12-03 6:05 ` Andrew Morton
2008-12-03 14:32 ` Bill Davidsen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20081202215758.GE20858@mit.edu \
--to=tytso@mit.edu \
--cc=adilger@sun.com \
--cc=davidsen@tmr.com \
--cc=linux-ext4@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=roel.kluin@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).