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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D236DC76196 for ; Tue, 11 Apr 2023 15:46:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229988AbjDKPqg (ORCPT ); Tue, 11 Apr 2023 11:46:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35692 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229704AbjDKPqd (ORCPT ); Tue, 11 Apr 2023 11:46:33 -0400 Received: from ale.deltatee.com (ale.deltatee.com [204.191.154.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F3857173A; Tue, 11 Apr 2023 08:46:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=deltatee.com; s=20200525; h=Subject:In-Reply-To:From:References:Cc:To: MIME-Version:Date:Message-ID:content-disposition; bh=s2GNIxiOdMRo32rxHLzkvUgx/1HWR5yuURrFTvxp/Ms=; b=nGulDQNO8k4wxugoP4ox8lB10X Quz/YHnoB03rzn2RP8SQaoFIaQRvAKAUw4oTnKl64D8X8EZEMCtMz+khxhsZ2BPIFzAChcy22h3K0 wPh7yq0MvzkJQ1n3wl7MMwjyG2IrzYGp0wky51ldKNx0LLufMI65/lLJGKUb0QGcjz0UmjyBJZjy2 2zSutM0P8g6n7EgvOraTASNqg9pDtPZUiPIKnbczqvn6TcinizL9IibVUlHt7bKltZEKAe1SghpG0 QGOPLHA9ebvMxxsoVOnF042WLXXky6SuWIqYouCAOMrtc9wAF+AiBuDPyynbk578QVht55whk+5aH PA7jzy4A==; Received: from guinness.priv.deltatee.com ([172.16.1.162]) by ale.deltatee.com with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.94.2) (envelope-from ) id 1pmGCH-006AQu-Fd; Tue, 11 Apr 2023 09:46:18 -0600 Message-ID: Date: Tue, 11 Apr 2023 09:46:14 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.9.0 Content-Language: en-CA To: Song Liu , Yu Kuai Cc: linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, yi.zhang@huawei.com, yangerkun@huawei.com, "yukuai (C)" References: <20230410113559.1610455-1-yukuai1@huaweicloud.com> <20230410113559.1610455-2-yukuai1@huaweicloud.com> From: Logan Gunthorpe In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 172.16.1.162 X-SA-Exim-Rcpt-To: song@kernel.org, yukuai1@huaweicloud.com, linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, yi.zhang@huawei.com, yangerkun@huawei.com, yukuai3@huawei.com X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [PATCH -next v5 1/6] md: pass a md_thread pointer to md_register_thread() X-SA-Exim-Version: 4.2.1 (built Sat, 13 Feb 2021 17:57:42 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023-04-10 23:26, Song Liu wrote: > On Mon, Apr 10, 2023 at 6:34 PM Yu Kuai wrote: >> >> Hi, >> >> 在 2023/04/11 9:15, Song Liu 写道: >>> On Mon, Apr 10, 2023 at 4:37 AM Yu Kuai wrote: >>>> >>>> From: Yu Kuai >>>> >>>> Prepare to protect md_thread with rcu, there are no functional changes. >>> >>> Why do we need this change? To add __rcu later? >> >> Add __rcu is one reason, more importantly is to assign md_thread inside >> md_register_thread in patch 6: >> >> rcu_assign_pointer(*threadp, thread); > > Got it. > >>> >>> Can we do something like: >>> >>> struct md_thread __rcu *md_register_thread(void (*run) (struct md_thread *), >>> struct mddev *mddev, const char *name) >> >> I think this is not necessary, if we don't want to change api, we must >> use rcu_assign_pointer for each caller to set md_thread. > > I think it is better to use rcu_assign_pointer at the caller side. I agree. Logan