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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 24D7FC433DF for ; Thu, 14 May 2020 09:51:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E4B020671 for ; Thu, 14 May 2020 09:51:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726094AbgENJvG convert rfc822-to-8bit (ORCPT ); Thu, 14 May 2020 05:51:06 -0400 Received: from eu-smtp-delivery-151.mimecast.com ([207.82.80.151]:48537 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726061AbgENJvF (ORCPT ); Thu, 14 May 2020 05:51:05 -0400 Received: from AcuMS.aculab.com (156.67.243.126 [156.67.243.126]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-28-HEHwcrXHOXCxTcoBkns_Pw-1; Thu, 14 May 2020 10:51:01 +0100 X-MC-Unique: HEHwcrXHOXCxTcoBkns_Pw-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) by AcuMS.aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Thu, 14 May 2020 10:51:00 +0100 Received: from AcuMS.Aculab.com ([fe80::43c:695e:880f:8750]) by AcuMS.aculab.com ([fe80::43c:695e:880f:8750%12]) with mapi id 15.00.1347.000; Thu, 14 May 2020 10:51:00 +0100 From: David Laight To: 'Marcelo Ricardo Leitner' , Christoph Hellwig CC: "David S. Miller" , Jakub Kicinski , Eric Dumazet , Alexey Kuznetsov , Hideaki YOSHIFUJI , Vlad Yasevich , Neil Horman , Jon Maloy , Ying Xue , "drbd-dev@lists.linbit.com" , "linux-block@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-rdma@vger.kernel.org" , "linux-nvme@lists.infradead.org" , "target-devel@vger.kernel.org" , "linux-afs@lists.infradead.org" , "linux-cifs@vger.kernel.org" , "cluster-devel@redhat.com" , "ocfs2-devel@oss.oracle.com" , "netdev@vger.kernel.org" , "linux-sctp@vger.kernel.org" , "ceph-devel@vger.kernel.org" , "rds-devel@oss.oracle.com" , "linux-nfs@vger.kernel.org" Subject: RE: [PATCH 32/33] sctp: add sctp_sock_get_primary_addr Thread-Topic: [PATCH 32/33] sctp: add sctp_sock_get_primary_addr Thread-Index: AQHWKVDpRRlTTX4YZEat3HB6AYvqqainVRxw Date: Thu, 14 May 2020 09:51:00 +0000 Message-ID: References: <20200513062649.2100053-1-hch@lst.de> <20200513062649.2100053-33-hch@lst.de> <20200513180302.GC2491@localhost.localdomain> In-Reply-To: <20200513180302.GC2491@localhost.localdomain> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org From: Marcelo Ricardo Leitner > Sent: 13 May 2020 19:03 > > On Wed, May 13, 2020 at 08:26:47AM +0200, Christoph Hellwig wrote: > > Add a helper to directly get the SCTP_PRIMARY_ADDR sockopt from kernel > > space without going through a fake uaccess. > > Same comment as on the other dlm/sctp patch. Wouldn't it be best to write sctp_[gs]etsockotp() that use a kernel buffer and then implement the user-space calls using a wrapper that does the copies to an on-stack (or malloced if big) buffer. That will also simplify the code be removing all the copies and -EFAULT returns. Only the size checks will be needed and the code can assume the buffer is at least the size of the on-stack buffer. Our SCTP code uses SO_REUSADDR, SCTP_EVENTS, SCTP_NODELAY, SCTP_STATUS, SCTP_INITMSG, IPV6_ONLY, SCTP_SOCKOPT_BINDX_ADD and SO_LINGER. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)