From owner-svn-src-head@FreeBSD.ORG Fri Dec 3 17:07:18 2010 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id D51E9106564A; Fri, 3 Dec 2010 17:07:18 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from cyrus.watson.org (cyrus.watson.org [65.122.17.42]) by mx1.freebsd.org (Postfix) with ESMTP id 9DF798FC14; Fri, 3 Dec 2010 17:07:18 +0000 (UTC) Received: from bigwig.baldwin.cx (66.111.2.69.static.nyinternet.net [66.111.2.69]) by cyrus.watson.org (Postfix) with ESMTPSA id 2DC8646B7E; Fri, 3 Dec 2010 12:07:18 -0500 (EST) Received: from jhbbsd.localnet (smtp.hudson-trading.com [209.249.190.9]) by bigwig.baldwin.cx (Postfix) with ESMTPSA id 364CC8A009; Fri, 3 Dec 2010 12:07:17 -0500 (EST) From: John Baldwin To: Bruce Cran Date: Fri, 3 Dec 2010 10:31:32 -0500 User-Agent: KMail/1.13.5 (FreeBSD/7.3-CBSD-20101102; KDE/4.4.5; amd64; ; ) References: <201012022219.oB2MJUx5031472@svn.freebsd.org> <20101203144103.00005a78@unknown> In-Reply-To: <20101203144103.00005a78@unknown> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201012031031.33073.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.6 (bigwig.baldwin.cx); Fri, 03 Dec 2010 12:07:17 -0500 (EST) X-Virus-Scanned: clamav-milter 0.96.3 at bigwig.baldwin.cx X-Virus-Status: Clean X-Spam-Status: No, score=-1.9 required=4.2 tests=BAYES_00 autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on bigwig.baldwin.cx Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, Ivan Voras , Bruce Evans , Bruce Cran , svn-src-head@freebsd.org Subject: Re: svn commit: r216134 - in head: share/man/man9 sys/amd64/include sys/arm/include sys/i386/include sys/ia64/include sys/mips/include sys/pc98/include sys/powerpc/include sys/sparc64/include sys/sun4v... X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 03 Dec 2010 17:07:18 -0000 On Friday, December 03, 2010 9:41:03 am Bruce Cran wrote: > On Fri, 3 Dec 2010 15:27:13 +0100 > Ivan Voras wrote: > > > I'd say it depends on if the "specific case that hps raised a few > > years ago" sentence part refers to an actual problem; i.e. did it > > happen in practice? If yes, leaving KASSERTs looks like the best > > option. > > I've found hps's original email thread, which is at > http://lists.freebsd.org/pipermail/freebsd-hackers/2005-June/012342.html . > > The argument for allowing zero-length reads/writes is at > http://lists.freebsd.org/pipermail/freebsd-hackers/2005-June/012348.html . > > I suspect the mistake occurred due to a misunderstanding of the API. > NetBSD have documented it in their man page but not added asserts in > the code: > > "Functions which take a count of bytes have undefined results if the > specified count is zero." I think that is excellent wording and that this case is actually very rare. -- John Baldwin