From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from huawei.com (szxga06-in.huawei.com [45.249.212.32]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 42L09Q5Jw9zF0h9 for ; Thu, 27 Sep 2018 00:06:31 +1000 (AEST) Message-ID: <5BAB925D.1030803@huawei.com> Date: Wed, 26 Sep 2018 22:06:21 +0800 From: zhong jiang MIME-Version: 1.0 To: Christophe LEROY CC: , , , , Subject: Re: [PATCH] powerpc: Move a dereference below a NULL test References: <1537962368-14019-1-git-send-email-zhongjiang@huawei.com> In-Reply-To: Content-Type: text/plain; charset="UTF-8" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 2018/9/26 21:58, Christophe LEROY wrote: > > > Le 26/09/2018 à 13:46, zhong jiang a écrit : >> It is safe to move dereference below a NULL test. >> >> Signed-off-by: zhong jiang >> --- >> arch/powerpc/kernel/cacheinfo.c | 5 ++--- >> 1 file changed, 2 insertions(+), 3 deletions(-) >> >> diff --git a/arch/powerpc/kernel/cacheinfo.c b/arch/powerpc/kernel/cacheinfo.c >> index a8f20e5..7f19714 100644 >> --- a/arch/powerpc/kernel/cacheinfo.c >> +++ b/arch/powerpc/kernel/cacheinfo.c >> @@ -401,14 +401,13 @@ static struct cache *cache_lookup_or_instantiate(struct device_node *node, >> struct cache *cache; >> cache = cache_lookup_by_node(node); >> + if (!cache) >> + cache = cache_do_one_devnode(node, level); > > But by doing this, you change the meaning of the following warning. Is that what you want ? In that case the text of the WARN_ONCE() should be changed, because the mismatch is not only on lookup now. > Yep, I forget the WARN_ONCE. I think we should just remove it. Thought? Thanks, zhong jiang > Christophe > >> WARN_ONCE(cache && cache->level != level, >> "cache level mismatch on lookup (got %d, expected %d)\n", >> cache->level, level); >> - if (!cache) >> - cache = cache_do_one_devnode(node, level); >> - >> return cache; >> } >> > > . >