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=-10.6 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 CE270C433DB for ; Sat, 27 Feb 2021 01:13:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A591E64EE7 for ; Sat, 27 Feb 2021 01:13:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229953AbhB0BN3 (ORCPT ); Fri, 26 Feb 2021 20:13:29 -0500 Received: from szxga07-in.huawei.com ([45.249.212.35]:13382 "EHLO szxga07-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229618AbhB0BN1 (ORCPT ); Fri, 26 Feb 2021 20:13:27 -0500 Received: from DGGEMS412-HUB.china.huawei.com (unknown [172.30.72.58]) by szxga07-in.huawei.com (SkyGuard) with ESMTP id 4DnT4907d3z7qtt; Sat, 27 Feb 2021 09:11:05 +0800 (CST) Received: from [10.136.110.154] (10.136.110.154) by smtp.huawei.com (10.3.19.212) with Microsoft SMTP Server (TLS) id 14.3.498.0; Sat, 27 Feb 2021 09:12:40 +0800 Subject: Re: [f2fs-dev] [PATCH v3] f2fs: compress: Allow modular (de)compression algorithms To: Geert Uytterhoeven CC: Jaegeuk Kim , Chao Yu , "Masahiro Yamada" , Randy Dunlap , , , References: <20210226155142.2909545-1-geert@linux-m68k.org> From: Chao Yu Message-ID: Date: Sat, 27 Feb 2021 09:12:40 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20210226155142.2909545-1-geert@linux-m68k.org> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.136.110.154] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/2/26 23:51, Geert Uytterhoeven wrote: > If F2FS_FS is modular, enabling the compressions options > F2FS_FS_{LZ4,LZ4HZ,LZO,LZORLE,ZSTD} will make the (de)compression > algorithms {LZ4,LZ4HC,LZO,ZSTD}_{,DE}COMPRESS builtin instead of > modular, as the former depend on an intermediate boolean > F2FS_FS_COMPRESSION, which in-turn depends on tristate F2FS_FS. > > Indeed, if a boolean symbol A depends directly on a tristate symbol B > and selects another tristate symbol C: > > tristate B > > tristate C > > bool A > depends on B > select C > > and B is modular, then C will also be modular. > > However, if there is an intermediate boolean D in the dependency chain > between A and B: > > tristate B > > tristate C > > bool D > depends on B > > bool A > depends on D > select C > > then the modular state won't propagate from B to C, and C will be > builtin instead of modular. > > As modular dependency propagation through intermediate symbols is > obscure, fix this in a robust way by moving the selection of tristate > (de)compression algorithms from the boolean compression options to the > tristate main F2FS_FS option. > > Signed-off-by: Geert Uytterhoeven Reviewed-by: Chao Yu Thanks,