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 X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0F45CC35240 for ; Sun, 26 Jan 2020 03:43:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D0C442071E for ; Sun, 26 Jan 2020 03:43:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729094AbgAZDnL (ORCPT ); Sat, 25 Jan 2020 22:43:11 -0500 Received: from szxga05-in.huawei.com ([45.249.212.191]:9678 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728842AbgAZDnL (ORCPT ); Sat, 25 Jan 2020 22:43:11 -0500 Received: from DGGEMS413-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id D63A14F71DFAEED73DB5; Sun, 26 Jan 2020 11:43:07 +0800 (CST) Received: from [127.0.0.1] (10.45.216.243) by DGGEMS413-HUB.china.huawei.com (10.3.19.213) with Microsoft SMTP Server id 14.3.439.0; Sun, 26 Jan 2020 11:42:58 +0800 Subject: Re: [PATCH for-next] RDMA/hns: Add support for extended atomic in userspace To: Jason Gunthorpe CC: , , , References: <1579052546-11746-1-git-send-email-liweihang@huawei.com> <20200115205611.GG25201@ziepe.ca> <9b7a3629-0564-6643-f6e7-c2f098afd010@huawei.com> <20200116195118.GG10759@ziepe.ca> <20200123225447.GA15167@ziepe.ca> From: Weihang Li Message-ID: Date: Sun, 26 Jan 2020 11:42:49 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200123225447.GA15167@ziepe.ca> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.45.216.243] X-CFilter-Loop: Reflected Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On 2020/1/24 6:54, Jason Gunthorpe wrote: > On Wed, Jan 22, 2020 at 04:54:55PM +0800, Weihang Li wrote: >> >> >> On 2020/1/17 3:51, Jason Gunthorpe wrote: >>>>> What happens to your userspace if it runs on an old kernel and tries >>>>> to use extended atomic? >>>>> >>>>> Jason >>>>> >>>> Hi Jason, >>>> >>>> If the hns userspace runs with old kernel, the hardware will report a asynchronous >>>> event for the extended atomic operation and modify the qp to error state because >>>> the enable bit in this qp's context hasn't been set. >>>> >>>> The driver will print like this: >>>> >>>> [ 1252.240921] hns3 0000:7d:00.0: Invalid request local work queue 0x9 error. >>>> [ 1252.247772] hns3 0000:7d:00.0: no hr_qp can be found! >>> Ideally the provider will not set >>> IBV_PCI_ATOMIC_OPERATION_4_BYTE_SIZE_SUP and related without kernel >>> support.. >>> >>> I've applied this patch, but I feel like you may need a followup to >>> fix the capability reporting? >>> >>> Jason >> >> Hi Jason, >> >> Thank for your suggestions. >> >> But I'm confuse about the relationship between "PCI ATOMIC" in this macro >> and atomic operations in RDMA. >> >> I found the related series on patchwork: >> https://patchwork.kernel.org/cover/10782873/ > > I may have got the wrong capability bit here, I'm not sure where the > capability bits for extended atomics are actually > > Jason Hi Jason, Thank you anyway. There seems no capability bit for extended atomic currently. We will try to add one. Weihang >