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=-5.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MSGID_FROM_MTA_HEADER,SPF_HELO_NONE,SPF_PASS 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 B4E08C433E0 for ; Mon, 1 Mar 2021 17:46:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8A63764DF4 for ; Mon, 1 Mar 2021 17:46:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235322AbhCARqD (ORCPT ); Mon, 1 Mar 2021 12:46:03 -0500 Received: from hqnvemgate24.nvidia.com ([216.228.121.143]:17885 "EHLO hqnvemgate24.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238617AbhCARnM (ORCPT ); Mon, 1 Mar 2021 12:43:12 -0500 Received: from hqmail.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate24.nvidia.com (using TLS: TLSv1.2, AES256-SHA) id ; Mon, 01 Mar 2021 09:35:44 -0800 Received: from HQMAIL111.nvidia.com (172.20.187.18) by HQMAIL101.nvidia.com (172.20.187.10) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Mon, 1 Mar 2021 17:35:44 +0000 Received: from NAM10-BN7-obe.outbound.protection.outlook.com (104.47.70.101) by HQMAIL111.nvidia.com (172.20.187.18) with Microsoft SMTP Server (TLS) id 15.0.1497.2 via Frontend Transport; Mon, 1 Mar 2021 17:35:44 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=Qru+AAqpiMjUP9qElSOF3UC9SpX8LsKZxs9a8tGlDPUAj9MwFwqw21/wZK7ChHgzEBtlfSTky/5dZEsz2CgrJVcwgcYaWrS6L35xMwT+f8c6JmXfKj+UEWxTJJcZodWE3piH4onn6s883Sl/Y5jwl0pTtP1W/qomZNgC+dIOufemgfIZDF7eqxTqpO4uRqEno8MDtAzUzoaR7NbKAACUjs0EesfZQoAPN8OIU6aJU7rN6WxeKPfrrUYUnapvV5qOQhngV8oOVpNsivIgJ3ybrbnoAfTdr8Ku0UVQm8BO4vhl0jG+VNySUq9EpcGNLoXVZc3JIf3Wl1bzVHTNq+/khw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=S8DhnkGv1pdn/zKfkb4yhnXue7UH6nm8CUZsJb6/3ys=; b=TIlROjSOExBKjnGEbF9PHllTRastUXkkrbJxN9RZpO1I6S3cCodDVcNvf6hIpHfIH+FRPyI0zLUj0z7zOlto+YoUbRXhO1nhxkR/SeRcPjZLvEMQCsIl1Tzl43SAfC0Qf2fDNsLVjyKqfGr0dzlL23nQFZTBcDgey56W/zof/Yh+CJsGm1jUKP+O4XwAtBtDeON/DfBAMW2xe/SUjowAnugzvSzTtMVsrIMlllin+7h1g6dZoDTcFXcogPaF5TYEz0XCH+6lsOnpwziL+McGtvl/xeK3lUfW4RcsKU/pVtxLQlIp/L0CDfP5RlyPuzMYAdTW8wr1c5/lE601M4amhg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none Received: from DM6PR12MB3834.namprd12.prod.outlook.com (2603:10b6:5:14a::12) by DM6PR12MB3210.namprd12.prod.outlook.com (2603:10b6:5:185::10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3890.19; Mon, 1 Mar 2021 17:35:42 +0000 Received: from DM6PR12MB3834.namprd12.prod.outlook.com ([fe80::1c62:7fa3:617b:ab87]) by DM6PR12MB3834.namprd12.prod.outlook.com ([fe80::1c62:7fa3:617b:ab87%6]) with mapi id 15.20.3890.026; Mon, 1 Mar 2021 17:35:42 +0000 Date: Mon, 1 Mar 2021 13:35:40 -0400 From: Jason Gunthorpe To: Bob Pearson CC: Leon Romanovsky , , , Frank Zago Subject: Re: [PATCH for-next] RDMA/rxe: Fix ib_device reference counting (again) Message-ID: <20210301173540.GN4247@nvidia.com> References: <20210214222630.3901-1-rpearson@hpe.com> <48dcbdc5-35a3-2fe3-3e3d-bff37c2d8053@gmail.com> <20210226233301.GA4247@nvidia.com> <3165add7-518d-9485-fa12-6d7822ed9165@gmail.com>

Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: MN2PR05CA0022.namprd05.prod.outlook.com (2603:10b6:208:c0::35) To DM6PR12MB3834.namprd12.prod.outlook.com (2603:10b6:5:14a::12) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from mlx.ziepe.ca (142.162.115.133) by MN2PR05CA0022.namprd05.prod.outlook.com (2603:10b6:208:c0::35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3912.9 via Frontend Transport; Mon, 1 Mar 2021 17:35:42 +0000 Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1lGmSK-0033bM-9o; Mon, 01 Mar 2021 13:35:40 -0400 X-Header: ProcessedBy-CMR-outbound DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1614620144; bh=S8DhnkGv1pdn/zKfkb4yhnXue7UH6nm8CUZsJb6/3ys=; h=ARC-Seal:ARC-Message-Signature:ARC-Authentication-Results:Date: From:To:CC:Subject:Message-ID:References:Content-Type: Content-Disposition:In-Reply-To:X-ClientProxiedBy:MIME-Version: X-MS-Exchange-MessageSentRepresentingType:X-Header; b=iRaZpJo16vTFvJZMPjv8omd8EFke0W8egReRjr77T9YfrY2I5I4Tuy32ubZ8Ug/RW SocIzUx+Ye5/O4/AEsONOWl1Fq5kCow1L4wDX6Jd9UzzM9dTLp67lnScMWVndZuQQq +dbwknqbcKKHGwCyY8FYmNG3XAL1zYs15lCnDiBRcnnO59jD6gQBy9WmPYFGu1Sitt X6RnX3ubQaRJ7fMAibM8+FRVXeygOmBixb9IRrQogNDylxNoRKvIpx+Tyuiw1ogEMJ y26lrRaQyBd0xLocvCBuWdq6KqNhwsCdgXxHfyhd9P683Eny+rbJIwaQJ1sDGb99Nt w9IaicsC/4t3g== Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Mon, Mar 01, 2021 at 10:54:21AM -0600, Bob Pearson wrote: > I agree that ib_device_get/put is attempting to solve a problem that it not > really very critical since ib_device is very unlikely to be shut down in the > middle of a data transfer. The driver never worried about this for years. > But now that it's been put on the table it should be done right. A data packet > arriving is completely independent of the verbs API which *could* delete all the > QPs and shut down the HCA while it was wondering around the universe or worse > yet while the packet is being processed. If driver shutdown can guarentee that all pointers involved in multicast are revoked before shutdown can finish then you don't need this refcounting. It was only brought up because the API that returns the ib_device from the netdev requires the refcounts as it is general purpose Jason