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 743EB189907; Wed, 21 Aug 2024 11:48:06 +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=1724240888; cv=none; b=iTCscWvhDLnzYzqm392Se46DarUnIlGP7E+Cd5Uq02TME1BKvPhPDU8L5b3OKWQ45eHOhAvT4yiJL1acnuE/uclt75i48vTmC9YqTGLmXdYi9hJ5ziyUQF8y37UmyPxyyk/BfXs+0FIHPKxv7jh4+HCm4vuR/waDCUTaF/M11oI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724240888; c=relaxed/simple; bh=5UJza2ct5uFviMUue2skQT9c6gKWFscFOlvH1a6cUCo=; h=Date:From:To:CC:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=KE5PSZPuV+sW3ddNKOPeNIalsjZY0J3dFrOM8NmT3ZbSMPQOWfUbV9qrT1gYZA4Xlk/hJIL/kL8r7+0fYwOMkP0539R39nZHkBLdhqP44UPb90waRW+sf6FSgQuJcFzrD08FOETXebpwLTpfpVjSUSwN7Q5mKgobycjVDI5es6I= 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 [172.18.186.216]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Wpkyx6hvRz6J7nH; Wed, 21 Aug 2024 19:44:57 +0800 (CST) Received: from lhrpeml500005.china.huawei.com (unknown [7.191.163.240]) by mail.maildlp.com (Postfix) with ESMTPS id C2AA1140119; Wed, 21 Aug 2024 19:48:03 +0800 (CST) Received: from localhost (10.203.177.66) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Wed, 21 Aug 2024 12:48:03 +0100 Date: Wed, 21 Aug 2024 12:48:02 +0100 From: Jonathan Cameron To: Krzysztof Kozlowski CC: Ulf Hansson , "Rafael J. Wysocki" , Daniel Lezcano , Anup Patel , Paul Walmsley , "Palmer Dabbelt" , Albert Ou , , , , Subject: Re: [PATCH 2/4] cpuidle: riscv-sbi: Use scoped device node handling to simplify error paths Message-ID: <20240821124802.00000c35@Huawei.com> In-Reply-To: References: <20240816150931.142208-1-krzysztof.kozlowski@linaro.org> <20240816150931.142208-2-krzysztof.kozlowski@linaro.org> <20240819171313.00004677@Huawei.com> <20240819171954.0000600d@Huawei.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) Precedence: bulk X-Mailing-List: linux-pm@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: lhrpeml100002.china.huawei.com (7.191.160.241) To lhrpeml500005.china.huawei.com (7.191.163.240) On Tue, 20 Aug 2024 11:36:32 +0200 Krzysztof Kozlowski wrote: > On 19/08/2024 18:19, Jonathan Cameron wrote: > > On Mon, 19 Aug 2024 17:13:13 +0100 > > Jonathan Cameron wrote: > > > >> On Fri, 16 Aug 2024 17:09:29 +0200 > >> Krzysztof Kozlowski wrote: > >> > >>> Obtain the device node reference with scoped/cleanup.h to reduce error > >>> handling and make the code a bit simpler. > >>> > >>> Signed-off-by: Krzysztof Kozlowski > >> The original code looks suspect. See below. > > > > Whilst here... Why not do similar for state_node to avoid > > the delayed return check. > > Existing code > > { > > state_node = of_get_cpu_state_node(cpu_node, i - 1); > > if (!state_node) > > break; > > I don't see how __free() helps here. You can return regardless of __free(). > > > > > ret = sbi_dt_parse_state_node(state_node, &states[i]); > > of_node_put(state_node); > > ... and this code is quite easy to read: you get reference and > immediately release it. > > > > > if (ret) > > //another bug here on holding cpu_node btw. > > return ret; > > pr_debug("sbi-state %#x index %d\n", states[i], i); > > } > > //I think only path to this is is early break above. > > if (i != state_count) { > > ret = -ENODEV; > > goto fail; > > } > > Can be something like > > > > { > > struct device_node *state_node __free(device_node) = > > = of_get-cpu_State_nod(cpu_node, i - 1); > > > > if (!state_node) > > return -ENODEV; > > > > ret = sbi_dt_parse_state_node(state_node, &states[i]); > > if (ret) > > return ret; > > > > pr_debug("sbi-state %#x index %d\n", states[i], i); > > } > > > > Maybe I miss something, but I do not see how the __free() simplifies > here anything. Personal preference. To my eyes, it does, but indeed not a huge advantage. Jonathan > > Best regards, > Krzysztof >