From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wj0-f198.google.com (mail-wj0-f198.google.com [209.85.210.198]) by kanga.kvack.org (Postfix) with ESMTP id 609096B0033 for ; Mon, 23 Jan 2017 07:24:13 -0500 (EST) Received: by mail-wj0-f198.google.com with SMTP id an2so26027951wjc.3 for ; Mon, 23 Jan 2017 04:24:13 -0800 (PST) Received: from mout.kundenserver.de (mout.kundenserver.de. [212.227.17.10]) by mx.google.com with ESMTPS id m80si14131634wmi.31.2017.01.23.04.24.12 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 23 Jan 2017 04:24:12 -0800 (PST) From: Arnd Bergmann Subject: [PATCH] mm: ensure alloc_flags in slow path are initialized Date: Mon, 23 Jan 2017 13:16:12 +0100 Message-Id: <20170123121649.3180300-1-arnd@arndb.de> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Arnd Bergmann , Vlastimil Babka , Mel Gorman , Michal Hocko , Johannes Weiner , Joonsoo Kim , linux-mm@kvack.org, linux-kernel@vger.kernel.org The __alloc_pages_slowpath() has gotten rather complex and gcc is no longer able to follow the gotos and prove that the alloc_flags variable is initialized at the time it is used: mm/page_alloc.c: In function '__alloc_pages_slowpath': mm/page_alloc.c:3565:15: error: 'alloc_flags' may be used uninitialized in this function [-Werror=maybe-uninitialized] To be honest, I can't figure that out either, maybe it is or maybe not, but moving the existing initialization up a little higher looks safe and makes it obvious to both me and gcc that the initialization comes before the first use. Fixes: 74eaa4a97e8e ("mm: consolidate GFP_NOFAIL checks in the allocator slowpath") Signed-off-by: Arnd Bergmann --- mm/page_alloc.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index cf641932c015..d9fa4564524f 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3591,6 +3591,13 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, (__GFP_ATOMIC|__GFP_DIRECT_RECLAIM))) gfp_mask &= ~__GFP_ATOMIC; + /* + * The fast path uses conservative alloc_flags to succeed only until + * kswapd needs to be woken up, and to avoid the cost of setting up + * alloc_flags precisely. So we do that now. + */ + alloc_flags = gfp_to_alloc_flags(gfp_mask); + retry_cpuset: compaction_retries = 0; no_progress_loops = 0; @@ -3607,14 +3614,6 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, if (!ac->preferred_zoneref->zone) goto nopage; - - /* - * The fast path uses conservative alloc_flags to succeed only until - * kswapd needs to be woken up, and to avoid the cost of setting up - * alloc_flags precisely. So we do that now. - */ - alloc_flags = gfp_to_alloc_flags(gfp_mask); - if (gfp_mask & __GFP_KSWAPD_RECLAIM) wake_all_kswapds(order, ac); -- 2.9.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org