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 26BF6C433F5 for ; Mon, 18 Apr 2022 18:40:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347417AbiDRSm7 (ORCPT ); Mon, 18 Apr 2022 14:42:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34530 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229900AbiDRSm5 (ORCPT ); Mon, 18 Apr 2022 14:42:57 -0400 Received: from mail-ej1-x62e.google.com (mail-ej1-x62e.google.com [IPv6:2a00:1450:4864:20::62e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 825E7165A9; Mon, 18 Apr 2022 11:40:17 -0700 (PDT) Received: by mail-ej1-x62e.google.com with SMTP id lc2so28346311ejb.12; Mon, 18 Apr 2022 11:40:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=message-id:date:mime-version:user-agent:subject:content-language:to :cc:references:from:in-reply-to:content-transfer-encoding; bh=vSMD5tZaQY3VxVrqnvWTg6ERREdi/3N3yoNkf/fiGwk=; b=AuVu10OK2iVJMn+A5X128j7vyLDMUbtjEgBXYjqXi84QJi6aOhLr2xa8diVl2AWRNx O/alJT5lPH6NS1nGBNQ8eLnGRlLjwZXiuuuVLJsbNj8XV1VBW3btSEoue9QMDzz4qkov wQyAYWB7D/Mlh1KlXJq3VbTMQmHOWtp/d1DGOE1GHRg8Po9GMTgPLU8L6GcGOJd0iN/h LXwlvsqX0z9bVbyZYxCDnP2qIDJdiS7Jd9IdcpSAUrpZikuLJNn2FQFbzX+nYt2bVg8N E8x43kp5ALuJNdV4JD2Z/gk2F1Xl3OITZuOcRb+npPWWgNOZgz3PF9WwrTEF8W006Vns g+aA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=vSMD5tZaQY3VxVrqnvWTg6ERREdi/3N3yoNkf/fiGwk=; b=dFFjcABN+KvvUciDf1AiQaMb2hz0h8ckT9Ij7Za3bU4I0iBPGu8HlzleZpW7Q5Drs8 dO1wS7MYqsKlQLVoOO69AA1pkOtbRO3gFYchRTe1B7XVbDqizLC4q1du+JbZA55NJwsY cl827fY7xFp80CWXIA3VPn5JzQj27qpMwedHEFfZVlzNW3IMk0ECsQ0F8oavSB45mJCR buJbc2l69lew7lVOOjRmlePoWv5uM74GtmHJb613PCRvwClDFKv/X6j8ddsrzJ11lEDO AL4uxKHPnovZlgVgbcDrMiwF5/bjn2+sMPNOY4rSPkEO3XrCogXsz7B0W1XhAKNXGspW JN1Q== X-Gm-Message-State: AOAM532yAf8qrQK3MQ0/BQKOcvXvPFti4rEbQ2okVMP/wOSXXvRb8Fje R9PkWsSf7k1ILO0CU87pExfq9k+Oxxg= X-Google-Smtp-Source: ABdhPJxzxb7vPsOwaDOgJoXth65vpTEOaoQRsQ/xMLYNQ/FXIeP7VKMyzVaN3l+uQ4WHMGZJcAFVjQ== X-Received: by 2002:a17:907:980a:b0:6db:799c:cb44 with SMTP id ji10-20020a170907980a00b006db799ccb44mr10063369ejc.485.1650307216042; Mon, 18 Apr 2022 11:40:16 -0700 (PDT) Received: from [192.168.178.40] (ipbcc1cfad.dynamic.kabel-deutschland.de. [188.193.207.173]) by smtp.gmail.com with ESMTPSA id dm11-20020a170907948b00b006cf488e72e3sm4835316ejc.25.2022.04.18.11.40.15 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 18 Apr 2022 11:40:15 -0700 (PDT) Message-ID: <5015edcc-0b62-4c1f-d4f4-ec0d7a1470d7@gmail.com> Date: Mon, 18 Apr 2022 20:40:14 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [PATCH v4] scsi: target: tcmu: Fix possible data corruption Content-Language: en-US To: Xiaoguang Wang , linux-scsi@vger.kernel.org, target-devel@vger.kernel.org Cc: linux-block@vger.kernel.org References: <20220417052604.120942-1-xiaoguang.wang@linux.alibaba.com> From: Bodo Stroesser In-Reply-To: <20220417052604.120942-1-xiaoguang.wang@linux.alibaba.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Hi, just some remarks regarding the new comment. Bodo On 17.04.22 07:26, Xiaoguang Wang wrote: ... snip ... > static const struct vm_operations_struct tcmu_vm_ops = { > @@ -3205,12 +3228,19 @@ static void find_free_blocks(void) > udev->dbi_max = block; > } > > + /* > + * Release the block pages. > + * Also note that since tcmu_vma_fault() gets one extra page > + * refcount, tcmu_blocks_release() won't free pages if pages > + * are in page fault procedure, which means it's safe to s/in page fault procedure/mapped/ > + * call tcmu_blocks_release() before unmap_mapping_range(). "... before unmap_mapping_range(), which drops the refcount of pages it unmaps and thus releases those pages." Please feel free to find an even better wording. > + */ > + pages_freed = tcmu_blocks_release(udev, start, end - 1); > + > /* Here will truncate the data area from off */ > off = udev->data_off + (loff_t)start * udev->data_blk_size; > unmap_mapping_range(udev->inode->i_mapping, off, 0, 1); > > - /* Release the block pages */ > - pages_freed = tcmu_blocks_release(udev, start, end - 1); > mutex_unlock(&udev->cmdr_lock); > > total_pages_freed += pages_freed;