From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43)
	id 1LirRv-00052F-CQ
	for qemu-devel@nongnu.org; Sun, 15 Mar 2009 10:36:23 -0400
Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43)
	id 1LirRq-00050v-Pn
	for qemu-devel@nongnu.org; Sun, 15 Mar 2009 10:36:22 -0400
Received: from [199.232.76.173] (port=50536 helo=monty-python.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1LirRq-00050s-Mh
	for qemu-devel@nongnu.org; Sun, 15 Mar 2009 10:36:18 -0400
Received: from mail-bw0-f162.google.com ([209.85.218.162]:65052)
	by monty-python.gnu.org with esmtp (Exim 4.60)
	(envelope-from <blauwirbel@gmail.com>) id 1LirRq-0007rl-AO
	for qemu-devel@nongnu.org; Sun, 15 Mar 2009 10:36:18 -0400
Received: by bwz6 with SMTP id 6so703377bwz.34
	for <qemu-devel@nongnu.org>; Sun, 15 Mar 2009 07:36:16 -0700 (PDT)
MIME-Version: 1.0
In-Reply-To: <20090314193127.GC3799@lst.de>
References: <20090314192701.GA3497@lst.de> <20090314193127.GC3799@lst.de>
Date: Sun, 15 Mar 2009 16:36:16 +0200
Message-ID: <f43fc5580903150736g21deaeccmc1aff8241f4b96d7@mail.gmail.com>
Subject: Re: [Qemu-devel] [PATCH 6/6] experimental native preadv/pwritev
	support for Linux
From: Blue Swirl <blauwirbel@gmail.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Reply-To: qemu-devel@nongnu.org
List-Id: qemu-devel.nongnu.org
List-Unsubscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/pipermail/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: qemu-devel@nongnu.org

On 3/14/09, Christoph Hellwig <hch@lst.de> wrote:
>
>
>  This ties up Gerd Hoffmann's unmegred preadv/pwritev syscalls to qemu.  Use with
>  care as the syscall numbers aren't finalized yet.
>
>  If someone of the BSD folks is interested it should be trivial to tie this up
>  for the preadv/pwritev syscalls that have been around there for a while.

At least OpenBSD has preadv & pwritev.

>  Probably wants some optimization to not try preadv/pwritev again once we got
>  the first ENOSYS.

I'd add a check to configure to see if preadv exist and then define
HAVE_PREADV. Though it's not possible to see if the kernel supports
preadv if libc support does not exist (checking features by running
programs breaks cross compilation).