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=-15.4 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 1A014C4338F for ; Thu, 5 Aug 2021 09:29:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E662360238 for ; Thu, 5 Aug 2021 09:29:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237413AbhHEJ3n (ORCPT ); Thu, 5 Aug 2021 05:29:43 -0400 Received: from szxga02-in.huawei.com ([45.249.212.188]:12454 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229913AbhHEJ3n (ORCPT ); Thu, 5 Aug 2021 05:29:43 -0400 Received: from dggemv704-chm.china.huawei.com (unknown [172.30.72.54]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4GgNWh5By0zcl7t; Thu, 5 Aug 2021 17:25:52 +0800 (CST) Received: from dggema769-chm.china.huawei.com (10.1.198.211) by dggemv704-chm.china.huawei.com (10.3.19.47) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2176.2; Thu, 5 Aug 2021 17:29:27 +0800 Received: from [10.174.179.215] (10.174.179.215) by dggema769-chm.china.huawei.com (10.1.198.211) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Thu, 5 Aug 2021 17:29:26 +0800 Subject: Re: [PATCH -next] RDMA/hns: Fix return in hns_roce_rereg_user_mr() To: Leon Romanovsky CC: , , , , , , References: <20210804125939.20516-1-yuehaibing@huawei.com> From: YueHaibing Message-ID: <974d3309-3617-6413-5a8d-c92b1b2f8dfe@huawei.com> Date: Thu, 5 Aug 2021 17:29:25 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.5.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.179.215] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To dggema769-chm.china.huawei.com (10.1.198.211) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On 2021/8/5 11:40, Leon Romanovsky wrote: > On Thu, Aug 05, 2021 at 10:36:03AM +0800, YueHaibing wrote: >> On 2021/8/4 21:53, Leon Romanovsky wrote: >>> On Wed, Aug 04, 2021 at 08:59:39PM +0800, YueHaibing wrote: >>>> If re-registering an MR in hns_roce_rereg_user_mr(), we should >>>> return NULL instead of pass 0 to ERR_PTR. >>>> >>>> Fixes: 4e9fc1dae2a9 ("RDMA/hns: Optimize the MR registration process") >>>> Signed-off-by: YueHaibing >>>> --- >>>> drivers/infiniband/hw/hns/hns_roce_mr.c | 4 +++- >>>> 1 file changed, 3 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/drivers/infiniband/hw/hns/hns_roce_mr.c b/drivers/infiniband/hw/hns/hns_roce_mr.c >>>> index 006c84bb3f9f..7089ac780291 100644 >>>> --- a/drivers/infiniband/hw/hns/hns_roce_mr.c >>>> +++ b/drivers/infiniband/hw/hns/hns_roce_mr.c >>>> @@ -352,7 +352,9 @@ struct ib_mr *hns_roce_rereg_user_mr(struct ib_mr *ibmr, int flags, u64 start, >>>> free_cmd_mbox: >>>> hns_roce_free_cmd_mailbox(hr_dev, mailbox); >>>> >>>> - return ERR_PTR(ret); >>>> + if (ret) >>>> + return ERR_PTR(ret); >>>> + return NULL; >>>> } >>> >>> I don't understand this function, it returns or ERR_PTR() or NULL, but >>> should return &mr->ibmr in success path. How does it work? >> >> Did you means hns_roce_reg_user_mr()? >> >> hns_roce_rereg_user_mr() returns ERR_PTR() on failure, and return NULL on success, >> >> In ib_uverbs_rereg_mr(), old mr will be used if rereg_user_mr() return NULL, see: >> >> 829 new_mr = ib_dev->ops.rereg_user_mr(mr, cmd.flags, cmd.start, cmd.length, >> 830 cmd.hca_va, cmd.access_flags, new_pd, >> 831 &attrs->driver_udata); >> 832 if (IS_ERR(new_mr)) { >> 833 ret = PTR_ERR(new_mr); >> 834 goto put_new_uobj; >> 835 } >> 836 if (new_mr) { >> ..... >> 860 mr = new_mr; >> 861 } else { >> 862 if (cmd.flags & IB_MR_REREG_PD) { >> 863 atomic_dec(&orig_pd->usecnt); >> 864 mr->pd = new_pd; >> 865 atomic_inc(&new_pd->usecnt); >> 866 } >> 867 if (cmd.flags & IB_MR_REREG_TRANS) >> 868 mr->iova = cmd.hca_va; >> 869 } > > You overwrite various fields in old_mr when executing hns_roce_rereg_user_mr(). > For example mr->access flags, which is not returned to the original > state after all failures. IMO, if ibv_rereg_mr failed, the mr is in undefined state, user needs to call ibv_dereg_mr in order to release it, so there no need to recover the original state. Also， mlx4_ib_rereg_user_mr seems to do the same thing. > > Also I'm not so sure about if it is valid to return NULL in all flows. > > Thanks > >> >> >>> >>> Thanks >>> >>>> >>>> int hns_roce_dereg_mr(struct ib_mr *ibmr, struct ib_udata *udata) >>>> -- >>>> 2.17.1 >>>> >>> . >>> > . >