From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2CEA081ACA; Mon, 16 Dec 2024 15:23:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.176.79.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734362596; cv=none; b=Lo2nLw7WqsMSEIaV/vT86VeokQjOc+2737mI9gm6hjNai7R6D86RNFHZFCPOnF1AT7p9nrEuzSNfNhboLozcCMZjGph0jeT5wcWogQ+/LDCgiVBFhXn7rME9iKjb9C9sgMs2ItWHEL5m9FDpZkRzUzL2fcm1djweIeMSn/D9kew= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734362596; c=relaxed/simple; bh=X+6Euz+YRO3cFSrjBuxH+jB845sPJQlAgYntR4V7fCE=; h=Date:From:To:CC:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=R0e56h1sb09RNkvGFGxXdlBceQ0yYgRHrYYb1nonhx5KwLkQZcytpuLC+RCnau1OKQ6sHceo80OoGdHLLTE2zXe3c+F2rbU3Hkm5eYOo25BDoZPjb439cAuroE1dvdqxsFlzwuPdu9MvilsyzI3Js+ce1e0HbQQaZ6o+Fi9+Gwc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=185.176.79.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.18.186.31]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4YBkBj6Sctz6K5VY; Mon, 16 Dec 2024 23:19:41 +0800 (CST) Received: from frapeml500008.china.huawei.com (unknown [7.182.85.71]) by mail.maildlp.com (Postfix) with ESMTPS id 5067E140445; Mon, 16 Dec 2024 23:23:12 +0800 (CST) Received: from localhost (10.203.177.66) by frapeml500008.china.huawei.com (7.182.85.71) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Mon, 16 Dec 2024 16:23:11 +0100 Date: Mon, 16 Dec 2024 15:23:10 +0000 From: Jonathan Cameron To: Zijun Hu CC: Greg Kroah-Hartman , "Rafael J. Wysocki" , Tejun Heo , Josef Bacik , Jens Axboe , Boris Burkov , Davidlohr Bueso , Dave Jiang , Alison Schofield , Vishal Verma , Ira Weiny , Dan Williams , , , , , Zijun Hu Subject: Re: [PATCH v3 7/9] driver core: Correct parameter check for API device_for_each_child_reverse_from() Message-ID: <20241216152310.0000166a@huawei.com> In-Reply-To: <20241212-class_fix-v3-7-04e20c4f0971@quicinc.com> References: <20241212-class_fix-v3-0-04e20c4f0971@quicinc.com> <20241212-class_fix-v3-7-04e20c4f0971@quicinc.com> X-Mailer: Claws Mail 4.3.0 (GTK 3.24.42; x86_64-w64-mingw32) Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: lhrpeml500004.china.huawei.com (7.191.163.9) To frapeml500008.china.huawei.com (7.182.85.71) On Thu, 12 Dec 2024 21:38:43 +0800 Zijun Hu wrote: > From: Zijun Hu > > device_for_each_child_reverse_from() checks (!parent->p) for its > parameter @parent, and that is not consistent with other APIs of > its cluster as shown below: > > device_for_each_child_reverse_from() // check (!parent->p) > device_for_each_child_reverse() // check (!parent || !parent->p) > device_for_each_child() // same above > device_find_child() // same above > > Correct the API's parameter @parent check by (!parent || !parent->p). > > Signed-off-by: Zijun Hu Given that 'from' implies continuation of an iteration I can see why it might not ever be relevant to check parent. It's harmless, but to my mind unnecessary. Jonathan > --- > drivers/base/core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/base/core.c b/drivers/base/core.c > index 69bb6bf4bd12395226ee3c99e2f63d15c7e342a5..34fb13f914b3db47e6a047fdabf3c9b18ecc08cc 100644 > --- a/drivers/base/core.c > +++ b/drivers/base/core.c > @@ -4050,7 +4050,7 @@ int device_for_each_child_reverse_from(struct device *parent, > struct device *child; > int error = 0; > > - if (!parent->p) > + if (!parent || !parent->p) > return 0; > > klist_iter_init_node(&parent->p->klist_children, &i, >