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[23.128.96.18]) by mx.google.com with ESMTP id q21si13045112pgv.5.2022.01.31.02.02.22; Mon, 31 Jan 2022 02:02:34 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@free.fr header.s=smtp-20201208 header.b="R3hHWeb/"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=free.fr Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348380AbiA1MTN (ORCPT + 99 others); Fri, 28 Jan 2022 07:19:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40126 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243048AbiA1MTM (ORCPT ); Fri, 28 Jan 2022 07:19:12 -0500 Received: from smtp6-g21.free.fr (smtp6-g21.free.fr [IPv6:2a01:e0c:1:1599::15]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 318DCC061714; Fri, 28 Jan 2022 04:19:12 -0800 (PST) Received: from [IPV6:2a01:e0a:255:1000:3124:3dac:d662:6a32] (unknown [IPv6:2a01:e0a:255:1000:3124:3dac:d662:6a32]) (Authenticated sender: duncan.sands@free.fr) by smtp6-g21.free.fr (Postfix) with ESMTPSA id 3BF0E7802CE; Fri, 28 Jan 2022 13:19:05 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=free.fr; s=smtp-20201208; t=1643372349; bh=3L95F8XCRFzMRvjD9lkd7vEXaFEh+figQSC1zy0PMAo=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=R3hHWeb/x/FYlGZmhpiVGc1cJUhGrYQp31Oxxz8hU7ueiBupPlJ9rI81TN9hHsow5 TXVqSuTjPWeKBljSmFzydR5+QtArOCws+c2lFuheA+UwwoOo109tBjtoFdC8qtGvBe wnrddCuwjZhf3OxXBxVrN+KDR0gaqpf5+VDob6WsN04l8kJcDZjKRRkCjTLMYld1Dx pZFbntJ0ffBD7S8oRxx2Ml7F0qP/gRbWuOCGiz2mlnmITYFljLmEAbKK7cFJ24W//Q RXtHuEWiPFY3Ut8GfKUmk35BQp5Vz2Qsj5HoFaJmLUmOaguo4o36mexFInFvz7uFPd xeMheu3Z35nKg== Message-ID: Date: Fri, 28 Jan 2022 13:19:04 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH] usb: atm: Make use of the helper macro kthread_run() Content-Language: en-US To: Yin Xiujiang , gregkh@linuxfoundation.org Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org References: <20220127074744.845537-1-yinxiujiang@kylinos.cn> From: Duncan Sands In-Reply-To: <20220127074744.845537-1-yinxiujiang@kylinos.cn> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Yin Xiujiang, please see my earlier reply to Cai Huoqing for the same patch below. Did you do the analysis? >> instance->thread = t; >> - wake_up_process(t); > > doesn't this mean that the thread may now start running before instance->thread has been assigned? It's not clear to me what race conditions this may open up, if any (I haven't looked at the code in a long time), but it does need to be carefully analyzed. So I can't sign off on this as it stands. Best wishes, Duncan. On 27/01/2022 08:47, Yin Xiujiang wrote: > Repalce kthread_create/wake_up_process() with kthread_run() > to simplify the code. > > Signed-off-by: Yin Xiujiang > --- > drivers/usb/atm/usbatm.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/usb/atm/usbatm.c b/drivers/usb/atm/usbatm.c > index e3a49d837609..24ba739a85e0 100644 > --- a/drivers/usb/atm/usbatm.c > +++ b/drivers/usb/atm/usbatm.c > @@ -976,7 +976,7 @@ static int usbatm_heavy_init(struct usbatm_data *instance) > { > struct task_struct *t; > > - t = kthread_create(usbatm_do_heavy_init, instance, "%s", > + t = kthread_run(usbatm_do_heavy_init, instance, "%s", > instance->driver->driver_name); > if (IS_ERR(t)) { > usb_err(instance, "%s: failed to create kernel_thread (%ld)!\n", > @@ -985,7 +985,6 @@ static int usbatm_heavy_init(struct usbatm_data *instance) > } > > instance->thread = t; > - wake_up_process(t); > wait_for_completion(&instance->thread_started); > > return 0;