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 F111CC433F5 for ; Fri, 18 Mar 2022 12:57:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232974AbiCRM6l (ORCPT ); Fri, 18 Mar 2022 08:58:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34468 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234085AbiCRM6k (ORCPT ); Fri, 18 Mar 2022 08:58:40 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BAE61260C51 for ; Fri, 18 Mar 2022 05:57:19 -0700 (PDT) Received: from dggpeml500025.china.huawei.com (unknown [172.30.72.54]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4KKkX432jkzfYls; Fri, 18 Mar 2022 20:55:48 +0800 (CST) Received: from dggpeml500017.china.huawei.com (7.185.36.243) by dggpeml500025.china.huawei.com (7.185.36.35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.21; Fri, 18 Mar 2022 20:57:17 +0800 Received: from [10.40.238.78] (10.40.238.78) by dggpeml500017.china.huawei.com (7.185.36.243) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.21; Fri, 18 Mar 2022 20:57:17 +0800 Subject: Re: [PATCH for-next v4 05/12] RDMA/erdma: Add cmdq implementation To: Cheng Xu , , References: <20220314064739.81647-1-chengyou@linux.alibaba.com> <20220314064739.81647-6-chengyou@linux.alibaba.com> CC: , , , , From: Wenpeng Liang Message-ID: <7292f337-9532-d1b2-b755-fb2630ed55fb@huawei.com> Date: Fri, 18 Mar 2022 20:57:17 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 MIME-Version: 1.0 In-Reply-To: <20220314064739.81647-6-chengyou@linux.alibaba.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.40.238.78] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggpeml500017.china.huawei.com (7.185.36.243) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On 2022/3/14 14:47, Cheng Xu wrote: > Cmdq is the main control plane channel between erdma driver and hardware. > After erdma device is initialized, the cmdq channel will be active in the > whole lifecycle of this driver. <...> > +static int erdma_poll_cmd_completion(struct erdma_comp_wait *comp_ctx, > + struct erdma_cmdq *cmdq, u32 timeout) > +{ > + unsigned long comp_timeout = jiffies + msecs_to_jiffies(timeout); > + > + while (1) { > + erdma_polling_cmd_completions(cmdq); > + if (comp_ctx->cmd_status != ERDMA_CMD_STATUS_ISSUED) > + break; > + > + if (time_is_before_jiffies(comp_timeout)) > + return -ETIME; > + > + msleep(20); > + } Here I feel confused, why not use time_after as an exit condition? I would be grateful if you explain this timeout exit mechanism. Thanks, Wenpeng