Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751429AbdHFVws (ORCPT ); Sun, 6 Aug 2017 17:52:48 -0400 Received: from mail.kapsi.fi ([91.232.154.25]:48145 "EHLO mail.kapsi.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751345AbdHFVwr (ORCPT ); Sun, 6 Aug 2017 17:52:47 -0400 Date: Mon, 7 Aug 2017 00:52:44 +0300 From: Mikko Rapeli To: Willem de Bruijn Cc: LKML , Linux API , Willem de Bruijn , Soheil Hassas Yeganeh , Network Development Subject: Re: [PATCH v06 18/36] uapi linux/errqueue.h: include linux/time.h in user space Message-ID: <20170806215244.GB31101@lakka.kapsi.fi> References: <20170806164428.2273-1-mikko.rapeli@iki.fi> <20170806164428.2273-19-mikko.rapeli@iki.fi> <20170806205654.GF28459@lakka.kapsi.fi> <20170806213330.GA31101@lakka.kapsi.fi> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SA-Exim-Connect-IP: 2001:1bc8:1004::1 X-SA-Exim-Mail-From: mcfrisk@kapsi.fi X-SA-Exim-Scanned: No (on mail.kapsi.fi); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3090 Lines: 71 On Sun, Aug 06, 2017 at 05:42:13PM -0400, Willem de Bruijn wrote: > On Sun, Aug 6, 2017 at 5:33 PM, Mikko Rapeli wrote: > > On Sun, Aug 06, 2017 at 05:24:20PM -0400, Willem de Bruijn wrote: > >> >> > +#ifdef __KERNEL__ > >> >> > +#include > >> >> > +#else > >> >> > +#include > >> >> > +#endif /* __KERNEL__ */ > >> >> > >> >> This will break applications that include manually. > >> >> I previously sent a patch to use libc-compat to make compilation succeed > >> >> when both are included in the case where is included after > >> >> . > >> >> > >> >> https://lkml.org/lkml/2016/9/12/872 > >> >> > >> >> The inverse will require changes to the libc header to avoid redefining > >> >> symbols already defined by > >> >> > >> >> The second patch in that 2-patch set included > >> >> unconditionally after the fix. This broke builds that also included > >> >> in the wrong order. I did not resubmit the first patch as a > >> >> stand-alone, as it is not sufficient to avoid breakage. > >> > > >> > I wasn't aware of your change, but I was about to send this to fix the > >> > case when glibc is included before : > >> > > >> > https://github.com/mcfrisk/linux/commit/f3952a27b8a21c6478d26e6246055383483f6a66 > >> > >> There are a few differences between the two. Including does not > >> unconditionally define all the symbols. Some are conditional on additional > >> state, such as __timespec_defined. > > > > Yep, your patch seems better for libc-compat.h. Could you send it again? > > Okay. Or feel free to include it in the patchset if that helps resolve > dependencies. If you don't have the time, I will send tomorrow a new version of this patch which fixes the commit topic and before that your libc-compat.h change so both could be applied together. Feel free to be faster :) > >> > I don't like leaving a few dozen non-compiling header files into uapi. > >> > >> I agree, but I do not see a simple solution. > >> > >> Unless libc has the analogous change, including either or > >> in userspace can unfortunately cause breakage. > >> > >> The added include if __KERNEL__ is defined should be safe, though. > > > > Yes, for the kernel side, but your libc-compat change would nice for > > userspace, where something will break for sure, but providing source > > API compatibility is sometimes impossible. > > > > To summarize, this change from me, and your libc-compat.c for time.h, or? > > I'm still afraid that this patch as is will break builds that include > first. I agree, but I also want uapi headers to cleanly compile. I know this might break stuff on userspace side which rely on these broken header file dependencies, but if the fix to just re-order include statements I'm fine with it, also when the complaints hit my inbox. If I had the CPU time, memory and disk space, I'd do a full yocto distro build to see how badly userspace could break but I don't at home. -Mikko