From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f43.google.com (mail-pa0-f43.google.com [209.85.220.43]) by kanga.kvack.org (Postfix) with ESMTP id 5BAEE6B0259 for ; Fri, 13 Nov 2015 13:45:35 -0500 (EST) Received: by pacdm15 with SMTP id dm15so107563843pac.3 for ; Fri, 13 Nov 2015 10:45:35 -0800 (PST) Received: from mail-pa0-x235.google.com (mail-pa0-x235.google.com. [2607:f8b0:400e:c03::235]) by mx.google.com with ESMTPS id hy4si28911011pbb.210.2015.11.13.10.45.29 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 13 Nov 2015 10:45:34 -0800 (PST) Received: by pacdm15 with SMTP id dm15so107561764pac.3 for ; Fri, 13 Nov 2015 10:45:29 -0800 (PST) From: Yang Shi Subject: [PATCH] writeback: initialize m_dirty to avoid compile warning Date: Fri, 13 Nov 2015 10:26:41 -0800 Message-Id: <1447439201-32009-1-git-send-email-yang.shi@linaro.org> Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org, tj@kernel.org Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linaro-kernel@lists.linaro.org, yang.shi@linaro.org When building kernel with gcc 5.2, the below warning is raised: mm/page-writeback.c: In function 'balance_dirty_pages.isra.10': mm/page-writeback.c:1545:17: warning: 'm_dirty' may be used uninitialized in this function [-Wmaybe-uninitialized] unsigned long m_dirty, m_thresh, m_bg_thresh; The m_dirty{thresh, bg_thresh} are initialized in the block of "if (mdtc)", so if mdts is null, they won't be initialized before being used. Initialize m_dirty to zero, also initialize m_thresh and m_bg_thresh to keep consistency. They are used later by if condition: !mdtc || m_dirty <= dirty_freerun_ceiling(m_thresh, m_bg_thresh) If mdtc is null, dirty_freerun_ceiling will not be called at all, so the initialization will not change any behavior other than just ceasing the compile warning. Signed-off-by: Yang Shi --- mm/page-writeback.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 2c90357..ce726eb 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -1542,7 +1542,7 @@ static void balance_dirty_pages(struct address_space *mapping, for (;;) { unsigned long now = jiffies; unsigned long dirty, thresh, bg_thresh; - unsigned long m_dirty, m_thresh, m_bg_thresh; + unsigned long m_dirty = 0, m_thresh = 0, m_bg_thresh = 0; /* * Unstable writes are a feature of certain networked -- 2.0.2 -- 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