From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E80D1C433EF for ; Wed, 20 Oct 2021 17:49:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D4B2C613AC for ; Wed, 20 Oct 2021 17:49:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230398AbhJTRvf (ORCPT ); Wed, 20 Oct 2021 13:51:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:55498 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230499AbhJTRvZ (ORCPT ); Wed, 20 Oct 2021 13:51:25 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 083B46128B; Wed, 20 Oct 2021 17:49:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1634752150; bh=UY7whghJ0CF+27cck+zPo8YHzcjinvyXjF/op8BsEto=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=FzW4GeyNS55sRWhnvPUiGcJuCKOtmL1+3Fs7GwIUyKZ1XEBZMiEtemmrwggcZrq1F o64alCGTeqAnnRBz2y3Emp++LUAf4k3xdQ/7i45jbng+qaCjnOCyCy+rwG4Nmnb3Pl fu3moUeh15d70HbM/1u/ab3BLII+F+Bkx4SnFx4g= Date: Wed, 20 Oct 2021 19:49:07 +0200 From: Greg Kroah-Hartman To: Jens Axboe , linux-usb@vger.kernel.org Cc: Christoph Hellwig , "linux-fsdevel@vger.kernel.org" , "linux-block@vger.kernel.org" Subject: Re: [PATCH] fs: kill unused ret2 argument from iocb->ki_complete() Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Wed, Oct 20, 2021 at 11:35:27AM -0600, Jens Axboe wrote: > On 10/20/21 11:30 AM, Christoph Hellwig wrote: > > On Wed, Oct 20, 2021 at 10:49:07AM -0600, Jens Axboe wrote: > >> It's not used for anything, and we're wasting time passing in zeroes > >> where we could just ignore it instead. Update all ki_complete users in > >> the kernel to drop that last argument. > >> > >> The exception is the USB gadget code, which passes in non-zero. But > >> since nobody every looks at ret2, it's still pointless. > > > > Yes, the USB gadget passes non-zero, and aio passes that on to > > userspace. So this is an ABI change. Does it actually matter? > > I don't know, but you could CC the relevant maintainers and list > > to try to figure that out. > > True, guess it does go out to userspace. Greg, is anyone using > it on the userspace side? I really do not know (adding linux-usb@vger) My interactions with the gadget code have not been through the aio api, thankfully :) Odds are it's fine, I think that something had to be passed in there so that was chosen? If the aio code didn't do anything with it, I can't see where the gadget code gets it back at anywhere, but I might be looking in the wrong place. Anyone else here know? thanks, greg k-h