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 7787EC77B7F for ; Tue, 16 May 2023 14:36:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233994AbjEPOgp convert rfc822-to-8bit (ORCPT ); Tue, 16 May 2023 10:36:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46880 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233282AbjEPOgh (ORCPT ); Tue, 16 May 2023 10:36:37 -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 ESMTPS id 457637DB1 for ; Tue, 16 May 2023 07:36:33 -0700 (PDT) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with both STARTTLS and AUTH (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mta-8-yAXuvbLIMxym3I4uiJP6oA-1; Tue, 16 May 2023 15:36:31 +0100 X-MC-Unique: yAXuvbLIMxym3I4uiJP6oA-1 Received: from AcuMS.Aculab.com (10.202.163.6) by AcuMS.aculab.com (10.202.163.6) with Microsoft SMTP Server (TLS) id 15.0.1497.48; Tue, 16 May 2023 15:36:30 +0100 Received: from AcuMS.Aculab.com ([::1]) by AcuMS.aculab.com ([::1]) with mapi id 15.00.1497.048; Tue, 16 May 2023 15:36:30 +0100 From: David Laight To: 'Chuck Lever III' CC: Azeem Shaikh , Jeff Layton , "linux-hardening@vger.kernel.org" , "Linux NFS Mailing List" , "linux-kernel@vger.kernel.org" Subject: RE: [PATCH v3] NFSD: Remove open coding of string copy Thread-Topic: [PATCH v3] NFSD: Remove open coding of string copy Thread-Index: AQHZhtarLR7mMXSOG0mD9inDFwvZGq9cpMAQgAA9NACAABfNkA== Date: Tue, 16 May 2023 14:36:29 +0000 Message-ID: <6af8294f4a744cfc8bad3de754047b0a@AcuMS.aculab.com> References: <20230515024044.2677124-1-azeemshaikh38@gmail.com> <63008A50-48CC-4915-88D6-71EA1B289322@oracle.com> In-Reply-To: <63008A50-48CC-4915-88D6-71EA1B289322@oracle.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 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: linux-kernel@vger.kernel.org From: Chuck Lever III > Sent: 16 May 2023 15:11 > > > On May 16, 2023, at 5:33 AM, David Laight wrote: > > > > From: Azeem Shaikh > >> Sent: 15 May 2023 03:41 > >> > >> Instead of open coding a __dynamic_array(), use the __string() and > >> __assign_str() helper macros that exist for this kind of use case. > > > > Is this actually a dynamic array, or just a char[8] ? > > On 64 bit copying a short fixed-length string is far better > > than any kind of dynamic sized allocation. > > I'd prefer to use a string helper, since the netid is a string, > and this documents the data type better and it is not subject > to sudden breakage if someone creates a standard netid longer > than 8 characters. > > The nfsd_cb_setup tracepoint is not in a performance-sensitive > path. > > In addition, trace consumers should be able to count on the > string helpers to perform memory copies without overrunning > either the source or destination buffers... one less source > of error. That is an entirely different justification :-) David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)