From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965912AbcBDPA1 (ORCPT ); Thu, 4 Feb 2016 10:00:27 -0500 Received: from mout.kundenserver.de ([217.72.192.73]:53696 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965756AbcBDPAZ (ORCPT ); Thu, 4 Feb 2016 10:00:25 -0500 From: Arnd Bergmann To: Andrzej Hajda Cc: Andrew Morton , Bartlomiej Zolnierkiewicz , Marek Szyprowski , open list , Bob Peterson Subject: Re: [PATCH v3] err.h: allow IS_ERR_VALUE to handle properly more types Date: Thu, 04 Feb 2016 16:00:09 +0100 Message-ID: <2230609.SaGfiizDHl@wuerfel> User-Agent: KMail/4.11.5 (Linux/3.16.0-10-generic; KDE/4.11.5; x86_64; ; ) In-Reply-To: <56B363E3.9050007@samsung.com> References: <20160202163350.f7d42f4b97f48756f3900e9a@linux-foundation.org> <13351313.c4ZqBbQEld@wuerfel> <56B363E3.9050007@samsung.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V03:K0:4YzkBr0M5AYgblLqoGQAuERLkJA8FW9BgGZytvbkyLORQVJnMEE ZKnm8Q/Dp/nM6POgdVw6OZsxhJIpkB1wVPiEhJShGB8ilDgwSt5hEvvEjmhPTqcfBDBdfnm yV1JWYjTmNM9d/2vSwt3+WgEzNtQjjIavVf4pZiFztnn8bSOGClli6yZleZNpJsdRlDojMK Iur7mQzewXx2eebtLmwZw== X-UI-Out-Filterresults: notjunk:1;V01:K0:XSgLDK/y4ho=:TbjAAssmd1vJKZ2Di5cKxV 9trca70fvl1l69j5NaMIDcwFfDpZi7gNjuhd0+/qVdATuZZzEHC8/oB8nlcjn//nxHQBw43Ta S+LQ4OMikIe2/zJkxjRqXisQmKLFwxfV1BEVn0t7kr5vDu+uKbeLDt6XinViSUo79NUkVTAdi FJhdcHvMcTANORUu781GyCD6GW+G9fwIucGkCh9e2HsymZoVtBa3z03pbCXuDobbxubFmCqSW eRvhxGVKpelS4pkZmKboRYpDpSpPBbWkMky8V4ybn1g79lY0jYeZnviSWh1+6pjXvG9BQj7Gi JAtgNSSR/hPabf1wRN/aiVsXJS3ROyjFGxbCzDH+wiavyZK34SGw3JykAeXXpHc06GQxMSsJh gzVlLL4eE7crYIsjUf51J+qCL7nP49HTKKjbCYXThGWngKV+8A9MGwjvprGGEyOv7q7VIi9uO NkWJ+NFW828MNK8jMxZym0DhwjQdjYTAqeL7dWQRGvy6Wnt5tnz7fBDVb9VZ9R37J3dEqXm/g LMRm9OJTWIWQtMDOZGaqDhCucCwSEQll6YlkFgrdYJtUY+23IFlh1BBr7BkSs0miX07lACylu gxN8u4CqkYJ/v60Ut5WH+0ifmxoMcI1YoxFVTt21iO2nDi4aW+r8aYLLzRtU7BdqnH2px4y3b 0dIoAsIz9Towu0fsrHdvdgQZgCTEycBfl6dkGj/gd0SCO6BIqO0ZOi7degXAGojg7RzyDgKyh NUJnbHMYR/rdSR1R Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 04 February 2016 15:44:51 Andrzej Hajda wrote: > On 02/04/2016 01:40 PM, Arnd Bergmann wrote: > > On Wednesday 03 February 2016 14:15:28 Andrzej Hajda wrote: > >> diff --git a/include/linux/err.h b/include/linux/err.h > >> index 56762ab..b7d4a9f 100644 > >> --- a/include/linux/err.h > >> +++ b/include/linux/err.h > >> @@ -18,7 +18,9 @@ > >> > >> #ifndef __ASSEMBLY__ > >> > >> -#define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO) > >> +#define IS_ERR_VALUE(x) ((typeof(x))(-1) <= 0 \ > >> + ? unlikely((x) <= -1) \ > >> + : unlikely((x) >= (typeof(x))-MAX_ERRNO)) > >> > >> static inline void * __must_check ERR_PTR(long error) > >> { > >> > > This has caused a warning to reappear that I had fixed before: > > > > fs/gfs2/dir.c: In function 'get_first_leaf': > > fs/gfs2/dir.c:802:9: warning: 'leaf_no' may be used uninitialized in this function [-Wmaybe-uninitialized] > > error = get_leaf(dip, leaf_no, bh_out); > > ^ > > fs/gfs2/dir.c: In function 'dir_split_leaf': > > fs/gfs2/dir.c:1021:8: warning: 'leaf_no' may be used uninitialized in this function [-Wmaybe-uninitialized] > > error = get_leaf(dip, leaf_no, &obh); > > What gcc/arch/build options do you use? I cannot reproduce it in my > environment. > I use an ARM gcc-5.3 with an allmodconfig kernel and CONFIG_CC_OPTIMIZE_FOR_SIZE disabled. I see the same warning with any gcc version since 4.9, but not earlier. With the IS_ERR_VALUE() macro I sent, I don't see the warning on any gcc version. I have now also checked that the behavior on x86 gcc-.4.9 is the same that I see on ARM (I don't have a large collection of x86 gcc versions though): same warning with linux-next, no warning with my version or after reverting your patch. Arnd