From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754433AbdIGHqO (ORCPT ); Thu, 7 Sep 2017 03:46:14 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:43514 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753312AbdIGHqN (ORCPT ); Thu, 7 Sep 2017 03:46:13 -0400 Date: Thu, 7 Sep 2017 00:46:12 -0700 From: Andrew Morton To: Stephen Rothwell Cc: "Zi Yan" , "Linux-Next Mailing List" , "Linux Kernel Mailing List" Subject: Re: linux-next: build failure after merge of the akpm-current tree Message-Id: <20170907004612.4ac130b0e89daaa0e51b2f40@linux-foundation.org> In-Reply-To: <20170907152355.16f4490a@canb.auug.org.au> References: <20170801163904.7d49881a@canb.auug.org.au> <20170801205054.17c8579f@canb.auug.org.au> <00BCCF64-C319-44F0-992B-7F78D4676B5E@cs.rutgers.edu> <20170802154554.2fe6515b@canb.auug.org.au> <20170802163137.064ba4bf@canb.auug.org.au> <20170907152355.16f4490a@canb.auug.org.au> X-Mailer: Sylpheed 3.5.0 (GTK+ 2.24.30; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 7 Sep 2017 15:23:55 +1000 Stephen Rothwell wrote: > Hi all, > > On Wed, 2 Aug 2017 16:31:45 +1000 Stephen Rothwell wrote: > > > > On Wed, 2 Aug 2017 15:45:54 +1000 Stephen Rothwell wrote: > > > > > > On Tue, 01 Aug 2017 09:08:01 -0400 "Zi Yan" wrote: > > > > > > > > I found two possible fixes. > > > > > > > > 1. This uses C++ zero initializer, GCC is OK with it. > > > > I tested with GCC 4.9.3 (has the initialization bug) and GCC 6.4.0. > > > > > > > > --- a/include/linux/swapops.h~a > > > > +++ a/include/linux/swapops.h > > > > @@ -217,7 +217,7 @@ static inline swp_entry_t pmd_to_swp_ent > > > > > > > > static inline pmd_t swp_entry_to_pmd(swp_entry_t entry) > > > > { > > > > - return (pmd_t){ 0 }; > > > > + return (pmd_t){}; > > > > } > > > > > > I have done that for today ... please decide which is best (or find > > > something better - maybe every platform really needs to have a __pmd() > > > definition) and submit a real fix patch to Andrew. > > > > OK, that failed for my compiler (gcc 5.2.0) like this: > > > > In file included from mm/vmscan.c:55:0: > > include/linux/swapops.h: In function 'swp_entry_to_pmd': > > include/linux/swapops.h:226:16: error: empty scalar initializer > > return (pmd_t){}; > > ^ > > include/linux/swapops.h:226:16: note: (near initialization for '(anonymous)') > > This has reappeared today :-( (for the arm multi_v7_defconfig build at > least) > > > So I used the other idea (on top of Andrew's current tree): > > The fix patch now looks like this: > > From: Stephen Rothwell > Date: Wed, 2 Aug 2017 15:55:02 +1000 > Subject: [PATCH] mm-thp-enable-thp-migration-in-generic-path-fix-fix > > Signed-off-by: Stephen Rothwell > --- > include/linux/swapops.h | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/include/linux/swapops.h b/include/linux/swapops.h > index 45b092aa6419..61cffa148a79 100644 > --- a/include/linux/swapops.h > +++ b/include/linux/swapops.h > @@ -223,7 +223,9 @@ static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd) > > static inline pmd_t swp_entry_to_pmd(swp_entry_t entry) > { > - return (pmd_t){}; > + pmd_t e; > + memset(&e, 0, sizeof(pmd_t)); > + return e; > } err, yeah. I didn't want to add that one :( At the very least we should add a good comment explaining why we had to resort to this.