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=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 648D7FC6183 for ; Fri, 14 Sep 2018 05:05:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1B50D20882 for ; Fri, 14 Sep 2018 05:05:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="QNUZ7TUi" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1B50D20882 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.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 S1727092AbeINKS1 (ORCPT ); Fri, 14 Sep 2018 06:18:27 -0400 Received: from mail-yb1-f194.google.com ([209.85.219.194]:39346 "EHLO mail-yb1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726756AbeINKS1 (ORCPT ); Fri, 14 Sep 2018 06:18:27 -0400 Received: by mail-yb1-f194.google.com with SMTP id c4-v6so4291473ybl.6; Thu, 13 Sep 2018 22:05:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=JqrUnWv+B9rhHeVo/BJaqiQgDnER2A9r2DoAn6ut9yk=; b=QNUZ7TUinjYP8RU2Qjur9IwmdlI+p3aJfiCBFFRZ2Ng0QXIAhfpR+RMR75c2lq2p+e Hfu4N6GJ6QAX1zJAaM/pldrot/yK5EEDWuD2HpXaYDWiHQb46rcddGyZE3W7Dxw1/rvl zet7Fb2d5Ez3LQbguijwDRJK0u9ZCjmYXPIfwKql1Kkz2jgkdS8GjSN1HWIVehXUi2sJ fL5Juc3iigGhGM5+MFYzusNKiIN+aIa9JCrxK9zxxzHFlICoeDnpcUdrYveJGDGM4GHs Uw8Cs1yto0DeUMYxcrcZ2uMwSXkS/ovZJRSP88doEyktIejG3fKLcZWgzESgUUGUkWsL 5UJg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=JqrUnWv+B9rhHeVo/BJaqiQgDnER2A9r2DoAn6ut9yk=; b=g0ldfsmp4anoepQwFa3ABxG5O7+JR+fzxQ3/wg0NKOfQOF94NF8xVFbeMHYjaSkSy6 lNkTChNDDDMEBhkxQMiSiEWWojTR7bDa5qse6eXmFArEEhl3ChCMTrV3eMjIQjzt1pz4 E0oZhdm0P9RsdzwKKXIDuvPc380SSboC78KTA8ahhIgSEJsD/tUaqaKFdVz336x5rozD /jZBsMZKe1prbhQv942FGMsN0gRMYG62JPA7qCEmKf9tShSZck/fBMLTNIVKNHfgsHPZ FNjUTANCDAqBMJkaHbidqmoqz0IHptYQWavxRws8Wl8ROf69tMDpHtEVB8jXYCAL7Ma5 lLCw== X-Gm-Message-State: APzg51DzXmHNeJtawpuUUJh+b1ot//rtQ4XZxHwP8lGz2z71nTY7on8E 1wIKyyALGzNcHO4DtZWxaOhWvRg/5y+93xcabbQ= X-Google-Smtp-Source: ANB0VdbgwpTUHYN6vkd1sQlGs9mu6y60ukjpN21Qwzy8VvlCmS5rbOuL/8nJ2UtTKBrlVYh38Evodt/1v15RX+dNn+8= X-Received: by 2002:a5b:40c:: with SMTP id m12-v6mr4812828ybp.53.1536901542741; Thu, 13 Sep 2018 22:05:42 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a25:74d6:0:0:0:0:0 with HTTP; Thu, 13 Sep 2018 22:05:42 -0700 (PDT) In-Reply-To: <20180909115205.GA17732@ming.t460p> References: <20180906203719.209399-1-xueweiz@google.com> <20180909115205.GA17732@ming.t460p> From: =?UTF-8?Q?Maciej_=C5=BBenczykowski?= Date: Thu, 13 Sep 2018 22:05:42 -0700 Message-ID: Subject: Re: [PATCH] scsi: sd: Contribute to randomness when running rotational device To: Ming Lei Cc: Xuewei Zhang , "James E . J . Bottomley" , "Martin K . Petersen" , Hannes Reinecke , Christoph Hellwig , Paolo Bonzini , linux-scsi@vger.kernel.org, Linux Kernel Mailing List , Aditya Kali , "Theodore Ts'o" , Guenter Roeck Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Sep 9, 2018 at 4:52 AM, Ming Lei wrote: > On Thu, Sep 06, 2018 at 01:37:19PM -0700, Xuewei Zhang wrote: >> Currently a scsi device won't contribute to kernel randomness when it >> uses blk-mq. Since we commonly use scsi on rotational device with >> blk-mq, it make sense to keep contributing to kernel randomness in these >> cases. This is especially important for virtual machines. >> >> commit b5b6e8c8d3b4 ("scsi: virtio_scsi: fix IO hang caused by automatic >> irq vector affinity") made all virtio-scsi device to use blk-mq, which >> does not contribute to randomness today. So for a virtual machine only >> having virtio-scsi disk (which is common), it will simple stop getting >> randomness from its disks in today's implementation. >> >> With this patch, if the above VM has rotational virtio-scsi device, then >> it can still benefit from the entropy generated from the disk. >> >> Reported-by: Xuewei Zhang >> Signed-off-by: Xuewei Zhang >> --- >> drivers/scsi/sd.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c >> index b79b366a94f7..5e4f10d28065 100644 >> --- a/drivers/scsi/sd.c >> +++ b/drivers/scsi/sd.c >> @@ -2959,6 +2959,9 @@ static void sd_read_block_characteristics(struct s= csi_disk *sdkp) >> if (rot =3D=3D 1) { >> blk_queue_flag_set(QUEUE_FLAG_NONROT, q); >> blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, q); >> + } else { >> + blk_queue_flag_clear(QUEUE_FLAG_NONROT, q); >> + blk_queue_flag_set(QUEUE_FLAG_ADD_RANDOM, q); >> } >> >> if (sdkp->device->type =3D=3D TYPE_ZBC) { >> -- >> 2.19.0.rc2.392.g5ba43deb5a-goog >> > > Look reasonable, especially the disk randomness is added by SCSI itself. > > Reviewed-by: Ming Lei > > Thanks, > Ming Also, see: https://bugzilla.redhat.com/show_bug.cgi?id=3D1572944 where we're having randomness starvation problems on FC28 running 4.18.5 due to lack of virtio-rng device in VM. (VM boot takes 9+ hours or 2 haswell VMs) I'd kindly request we get this not only into 4.19 but also stable trees. (along with Ted's other randomization fixes) Reviewed-by: Maciej =C5=BBenczykowski