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_PASS 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 B396CECDE30 for ; Wed, 17 Oct 2018 10:11:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 56BEE2150D for ; Wed, 17 Oct 2018 10:11:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 56BEE2150D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ACULAB.COM Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727101AbeJQSGr convert rfc822-to-8bit (ORCPT ); Wed, 17 Oct 2018 14:06:47 -0400 Received: from eu-smtp-delivery-151.mimecast.com ([207.82.80.151]:20666 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726904AbeJQSGr (ORCPT ); Wed, 17 Oct 2018 14:06:47 -0400 Received: from AcuMS.aculab.com (156.67.243.126 [156.67.243.126]) (Using TLS) by eu-smtp-1.mimecast.com with ESMTP id uk-mta-162-tXQJyXWYNJehtBXiAgLmfQ-1; Wed, 17 Oct 2018 11:11:44 +0100 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b::d117) by AcuMS.aculab.com (fd9f:af1c:a25b::d117) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Wed, 17 Oct 2018 11:11:47 +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; Wed, 17 Oct 2018 11:11:47 +0100 From: David Laight To: 'Phillip Potter' , "dushistov@mail.ru" CC: "linux-kernel@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" Subject: RE: [PATCH] fs: ufs: Remove switch statement from ufs_set_de_type function Thread-Topic: [PATCH] fs: ufs: Remove switch statement from ufs_set_de_type function Thread-Index: AQHUZgFURKmy3AiM50iT9d1crP1xJaUjNyFw Date: Wed, 17 Oct 2018 10:11:47 +0000 Message-ID: References: <20181017100809.GA9070@pathfinder> In-Reply-To: <20181017100809.GA9070@pathfinder> 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-MC-Unique: tXQJyXWYNJehtBXiAgLmfQ-1 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Phillip Potter > Sent: 17 October 2018 11:08 > > Remove switch statement from ufs_set_de_type function in fs/ufs/util.h > header and replace with simple assignment. For each case, S_IFx >> 12 > is equal to DT_x, so in valid cases (mode & S_IFMT) >> 12 should give > us the correct file type. For invalid cases, upper layer validation > catches this anyway, so this improves readability and arguably > performance by assigning (mode & S_IFMT) >> 12 directly. > ... > - case S_IFIFO: > - de->d_u.d_44.d_type = DT_FIFO; > - break; > - default: > - de->d_u.d_44.d_type = DT_UNKNOWN; > - } > + de->d_u.d_44.d_type = (mode & S_IFMT) >> S_SHIFT; This requires that the two sets of constants are correctly aligned. If they aren't defined in terms of each other then you probably ought to add compile-time asserts that the values match. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)