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=-15.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 50245C2B9F4 for ; Fri, 18 Jun 2021 02:52:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 332DA6135C for ; Fri, 18 Jun 2021 02:52:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231815AbhFRCy5 (ORCPT ); Thu, 17 Jun 2021 22:54:57 -0400 Received: from szxga01-in.huawei.com ([45.249.212.187]:11060 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231565AbhFRCy4 (ORCPT ); Thu, 17 Jun 2021 22:54:56 -0400 Received: from dggeme703-chm.china.huawei.com (unknown [172.30.72.55]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4G5k0s1c6lzZdGs; Fri, 18 Jun 2021 10:49:49 +0800 (CST) Received: from [10.174.176.146] (10.174.176.146) by dggeme703-chm.china.huawei.com (10.1.199.99) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Fri, 18 Jun 2021 10:52:45 +0800 Subject: Re: [PATCH v2 2/2] mm/zbud: don't export any zbud API To: Nathan Chancellor CC: , , , , References: <20210608114515.206992-1-linmiaohe@huawei.com> <20210608114515.206992-3-linmiaohe@huawei.com> <813ac556-4a48-1e29-ad87-1ddb74546ef1@huawei.com> <621684b8-7aac-97e5-198e-e62061c79301@kernel.org> From: Miaohe Lin Message-ID: Date: Fri, 18 Jun 2021 10:52:45 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <621684b8-7aac-97e5-198e-e62061c79301@kernel.org> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.176.146] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To dggeme703-chm.china.huawei.com (10.1.199.99) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/6/18 10:42, Nathan Chancellor wrote: > On 6/17/2021 7:28 PM, Miaohe Lin wrote: >> Hi: >> On 2021/6/18 8:44, Nathan Chancellor wrote: >>> On Tue, Jun 08, 2021 at 07:45:15PM +0800, Miaohe Lin wrote: >>>> The zbud doesn't need to export any API and it is meant to be used via >>>> zpool API since the commit 12d79d64bfd3 ("mm/zpool: update zswap to use >>>> zpool"). So we can remove the unneeded zbud.h and move down zpool API >>>> to avoid any forward declaration. >>>> >>>> Signed-off-by: Miaohe Lin >>> >> >> Thank you for help figure these warnings out. It seems zbud module won't do >> anything when CONFIG_ZPOOL is disabled. I think we should make zbud depends >> on ZPOOL and eliminate the CONFIG_ZPOOL macro in zbud.c like what z3fold does. >> Does this make sense for you? >> Thanks again. :) > > That seems logical to me. It probably makes sense to send that as a fix patch for this one so Andrew can squash it in. Sure. This is also what I meant to do. Will do it later. Many thanks! > > Cheers, > Nathan > >> diff --git a/mm/Kconfig b/mm/Kconfig >> index 8f748010f7ea..5dc28e9205e0 100644 >> --- a/mm/Kconfig >> +++ b/mm/Kconfig >> @@ -674,6 +674,7 @@ config ZPOOL >> >>   config ZBUD >>          tristate "Low (Up to 2x) density storage for compressed pages" >> +       depends on ZPOOL >>          help >>            A special purpose allocator for storing compressed pages. >>            It is designed to store up to two compressed pages per physical >> diff --git a/mm/zbud.c b/mm/zbud.c >> index 3f61304405cb..6348932430b8 100644 >> --- a/mm/zbud.c >> +++ b/mm/zbud.c >> @@ -111,10 +111,8 @@ struct zbud_pool { >>          struct list_head lru; >>          u64 pages_nr; >>          const struct zbud_ops *ops; >> -#ifdef CONFIG_ZPOOL >>          struct zpool *zpool; >>          const struct zpool_ops *zpool_ops; >> -#endif >>   }; >> >>   /* >> @@ -526,8 +524,6 @@ static u64 zbud_get_pool_size(struct zbud_pool *pool) >>    * zpool >>    ****************/ >> >> -#ifdef CONFIG_ZPOOL >> - >>   static int zbud_zpool_evict(struct zbud_pool *pool, unsigned long handle) >>   { >>          if (pool->zpool && pool->zpool_ops && pool->zpool_ops->evict) >> @@ -618,7 +614,6 @@ static struct zpool_driver zbud_zpool_driver = { >>   }; >> >>   MODULE_ALIAS("zpool-zbud"); >> -#endif /* CONFIG_ZPOOL */ >> >>   static int __init init_zbud(void) >>   { >> @@ -626,19 +621,14 @@ static int __init init_zbud(void) >>          BUILD_BUG_ON(sizeof(struct zbud_header) > ZHDR_SIZE_ALIGNED); >>          pr_info("loaded\n"); >> >> -#ifdef CONFIG_ZPOOL >>          zpool_register_driver(&zbud_zpool_driver); >> -#endif >> >>          return 0; >>   } >> >>   static void __exit exit_zbud(void) >>   { >> -#ifdef CONFIG_ZPOOL >>          zpool_unregister_driver(&zbud_zpool_driver); >> -#endif >> - >>          pr_info("unloaded\n"); >>   } >> >>> This patch causes several new warnings when CONFIG_ZPOOL is disabled: >>> >>> mm/zbud.c:222:26: warning: unused function 'zbud_create_pool' [-Wunused-function] >>> mm/zbud.c:246:13: warning: unused function 'zbud_destroy_pool' [-Wunused-function] >>> mm/zbud.c:270:12: warning: unused function 'zbud_alloc' [-Wunused-function] >>> mm/zbud.c:345:13: warning: unused function 'zbud_free' [-Wunused-function] >>> mm/zbud.c:417:12: warning: unused function 'zbud_reclaim_page' [-Wunused-function] >>> mm/zbud.c:499:14: warning: unused function 'zbud_map' [-Wunused-function] >>> mm/zbud.c:509:13: warning: unused function 'zbud_unmap' [-Wunused-function] >>> mm/zbud.c:520:12: warning: unused function 'zbud_get_pool_size' [-Wunused-function] >>> >>> It seems to me like all of these functions should be sunk into their >>> callers and eliminated entirely as part of this refactoring. I took a >>> whack at it but got lost with the kernel docs so someone who is familiar >>> with this should probably do it. >>> >>> Cheers, >>> Nathan >>> . >>> >> > > .