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 F2710C19F29 for ; Wed, 27 Jul 2022 08:36:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229919AbiG0Ig0 convert rfc822-to-8bit (ORCPT ); Wed, 27 Jul 2022 04:36:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54520 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229484AbiG0IgZ (ORCPT ); Wed, 27 Jul 2022 04:36:25 -0400 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.85.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id E7EA7459A0 for ; Wed, 27 Jul 2022 01:36:23 -0700 (PDT) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mta-216-G3MsD2lvP_O3H9T1lzIpBg-1; Wed, 27 Jul 2022 09:36:20 +0100 X-MC-Unique: G3MsD2lvP_O3H9T1lzIpBg-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) by AcuMS.aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) with Microsoft SMTP Server (TLS) id 15.0.1497.36; Wed, 27 Jul 2022 09:36:19 +0100 Received: from AcuMS.Aculab.com ([fe80::994c:f5c2:35d6:9b65]) by AcuMS.aculab.com ([fe80::994c:f5c2:35d6:9b65%12]) with mapi id 15.00.1497.036; Wed, 27 Jul 2022 09:36:19 +0100 From: David Laight To: 'Martin KaFai Lau' , "bpf@vger.kernel.org" , "netdev@vger.kernel.org" CC: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , David Miller , Eric Dumazet , Jakub Kicinski , "kernel-team@fb.com" , Paolo Abeni Subject: RE: [PATCH bpf-next 02/14] bpf: net: Avoid sock_setsockopt() taking sk lock when called from bpf Thread-Topic: [PATCH bpf-next 02/14] bpf: net: Avoid sock_setsockopt() taking sk lock when called from bpf Thread-Index: AQHYoX9rkSbmKz+Wykmj0IeOsCioUq2R48pw Date: Wed, 27 Jul 2022 08:36:18 +0000 Message-ID: <381439a429b54e8e8dda848e1d3d306f@AcuMS.aculab.com> References: <20220727060856.2370358-1-kafai@fb.com> <20220727060909.2371812-1-kafai@fb.com> In-Reply-To: <20220727060909.2371812-1-kafai@fb.com> Accept-Language: en-GB, 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 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=C51A453 smtp.mailfrom=david.laight@aculab.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Martin KaFai Lau > Sent: 27 July 2022 07:09 > > Most of the codes in bpf_setsockopt(SOL_SOCKET) are duplicated from > the sock_setsockopt(). The number of supported options are > increasing ever and so as the duplicated codes. > > One issue in reusing sock_setsockopt() is that the bpf prog > has already acquired the sk lock. sockptr_t is useful to handle this. > sockptr_t already has a bit 'is_kernel' to handle the kernel-or-user > memory copy. This patch adds a 'is_bpf' bit to tell if sk locking > has already been ensured by the bpf prog. That is a really horrid place to hide an 'is locked' bit. You'd be better off splitting sock_setsockopt() to add a function that is called with sk_lock held and the value read. That would also save the churn of all the callers. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)