From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id C13AAE77197 for ; Tue, 7 Jan 2025 04:06:38 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 174AA6B00C2; Mon, 6 Jan 2025 23:06:38 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1246F6B00C3; Mon, 6 Jan 2025 23:06:38 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 012776B00C4; Mon, 6 Jan 2025 23:06:37 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id D7FF26B00C2 for ; Mon, 6 Jan 2025 23:06:37 -0500 (EST) Received: from smtpin22.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 5C1771C7169 for ; Tue, 7 Jan 2025 04:06:37 +0000 (UTC) X-FDA: 82979319234.22.427CE1E Received: from zeniv.linux.org.uk (zeniv.linux.org.uk [62.89.141.173]) by imf03.hostedemail.com (Postfix) with ESMTP id 7BEB620004 for ; Tue, 7 Jan 2025 04:06:35 +0000 (UTC) Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=linux.org.uk header.s=zeniv-20220401 header.b="jeI/VsGl"; spf=none (imf03.hostedemail.com: domain of viro@ftp.linux.org.uk has no SPF policy when checking 62.89.141.173) smtp.mailfrom=viro@ftp.linux.org.uk; dmarc=pass (policy=none) header.from=zeniv.linux.org.uk ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1736222795; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=m0JMwU97t9w9EN1iZ2e5OZiTPXXyjI7/akgnWZVa9bw=; b=Jxfeu+68OAfnmR00w2BZBd1swqVVtYeyzG8/3iXnvGv3J3DGtOXBQ5sY61TURN+CqOTHmi pKM5+6NKKchGMlG/IVmvSyl2FQC1LJzpZT3Y2bnZbApQ9cpkPcBzfhyjLV5dUQ864HluWk O85XTtDy482+T4RcPfQs9q8p6rb3Gqo= ARC-Authentication-Results: i=1; imf03.hostedemail.com; dkim=pass header.d=linux.org.uk header.s=zeniv-20220401 header.b="jeI/VsGl"; spf=none (imf03.hostedemail.com: domain of viro@ftp.linux.org.uk has no SPF policy when checking 62.89.141.173) smtp.mailfrom=viro@ftp.linux.org.uk; dmarc=pass (policy=none) header.from=zeniv.linux.org.uk ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1736222795; a=rsa-sha256; cv=none; b=DOgH+Hgox0kYMZQZiv7ZT8DNHIjY+LIjfaC4mSFifwVh7RjHxUHsibNEnC59piWVhgM/h7 opjJChEz62GYnVRR+NygTpHChBgkMp3M1Nv586T2/czh2QeR7+xNqB2Fr8+zy2k37lDugZ 64cQzcmqB4AdmuExihkNUCFvsef0OoM= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=linux.org.uk; s=zeniv-20220401; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=m0JMwU97t9w9EN1iZ2e5OZiTPXXyjI7/akgnWZVa9bw=; b=jeI/VsGlhbYOxswSd9TmlJ1qUU ca38y7Oz57oWbhlXk3/DYhw517w0dZjY5QFcFf8icI2sYZQgyZy6HD6unLCpAHwhrNdpAhepADlL2 myFst8rP9stsY1sDd8zHG/4sQ9skzyLRwj7jMyjRy1Tp25SgC+7cGpILrqJaBiI2Z12Q3uv63LJ8Y jGRIgLWIg4F5eEIelaaos+j+yIU2uNAR2Rdqp0fxsEweNnV4H+iGA0J6apsZgpC2fCqXB81h3ewI4 oMLBxeFZzkPNZrNJ3uIiypd3p5SX2eTnYVlQuDNrC1zNJLvMeCiY3sB1mO3YPG4Fde2oBDHqAD5co Uops42aA==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.98 #2 (Red Hat Linux)) id 1tV0rP-0000000GOfJ-0eyd; Tue, 07 Jan 2025 04:06:31 +0000 Date: Tue, 7 Jan 2025 04:06:31 +0000 From: Al Viro To: Kenny Cheng Cc: hannes@cmpxchg.org, muchun.song@linux.dev, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, c.s.cheng@realtek.com Subject: Re: [PATCH] mm: avoid implicit type conversion Message-ID: <20250107040631.GN1977892@ZenIV> References: <20250107035141.2858582-1-chao.shun.cheng.tw@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250107035141.2858582-1-chao.shun.cheng.tw@gmail.com> X-Rspamd-Server: rspam05 X-Stat-Signature: 1f8xcxqgiikmwbzzpf359dqzhigjb17n X-Rspamd-Queue-Id: 7BEB620004 X-Rspam-User: X-HE-Tag: 1736222795-509031 X-HE-Meta: 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 mtqq3irl 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Jan 07, 2025 at 11:51:41AM +0800, Kenny Cheng wrote: > The function 'task_in_memcg_oom' returns a 'struct mem_cgroup *' type. > If the compiler does not inline this function, a compile error occurs, > as shown below: > > ./include/linux/memcontrol.h:961:9: error: incompatible pointer to > integer conversion returning 'struct mem_cgroup *' from a function with > result type 'unsigned char' [-Wint-conversion] What does inlining have to do with anything? And where has unsigned char come from in that? > This patch avoids the implicit type conversion by ensuring the return > type is correct. > > Signed-off-by: Kenny Cheng > --- > include/linux/memcontrol.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h > index 5502aa8e138e..47acf1e4f5a7 100644 > --- a/include/linux/memcontrol.h > +++ b/include/linux/memcontrol.h > @@ -1826,7 +1826,7 @@ bool mem_cgroup_oom_synchronize(bool wait); > > static inline bool task_in_memcg_oom(struct task_struct *p) > { > - return p->memcg_in_oom; > + return !!p->memcg_in_oom; > } That makes no sense. Do you have bool (or _Bool) defined or typedefed to unsigned char somewhere? If so, that's the bug that needs to be fixed.