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=-2.4 required=3.0 tests=DKIM_SIGNED, MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID,USER_AGENT_MUTT 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 2463AC46470 for ; Sun, 5 Aug 2018 23:15:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C0E03219A6 for ; Sun, 5 Aug 2018 23:15:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="c9q+fRkf" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C0E03219A6 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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 S1726934AbeHFBWI (ORCPT ); Sun, 5 Aug 2018 21:22:08 -0400 Received: from mail-pg1-f194.google.com ([209.85.215.194]:43071 "EHLO mail-pg1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726647AbeHFBWI (ORCPT ); Sun, 5 Aug 2018 21:22:08 -0400 Received: by mail-pg1-f194.google.com with SMTP id d17-v6so5317113pgv.10; Sun, 05 Aug 2018 16:15:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=xk+Ahdq6AFV4FhDrII76CuafDL6QRo5TpDnOtB5nxrw=; b=c9q+fRkf+30A87Q7qFbWDnwUDGMefPmbr0XWvuRFSxNZ6M5mnWlc6DE5hyRzUpbWS/ ljRBemOqH1f1ee9r4fMeG8NLydHRDBAaspuIDx3T4mA1M0TKwMsSFZAdzfLVoASXWARn JtGvstWzPf04+jzmoVKka//bYtsgKOrPZy83PUN0OJXBswA9+38psDEnl6VPwPahEy+t wgJcOe8h/e7+j1vrnALOen0M8UGgnZLxH1q0uBvsWLP/KspzEisV4qoSjmxSqtrjOaS7 0bFd/B2ChjWSNQEEXy4i/Tuc3L4hgSFrp0BAUtTZPbBPWGvipthwmxS91B4yXFS2/gmn jj7A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=xk+Ahdq6AFV4FhDrII76CuafDL6QRo5TpDnOtB5nxrw=; b=BHlGF/XS70sd/wWYc1xYOAVPm1qZBQbvYPA++HgU7IJbxxtl9q5BBNtrbuc8puLU+4 hlDiX2mFAjG7scpW23leuCQzx6Wlahag23rh84hny6KxolY/Pjp8F0TmZg0Ohe3VtMxD NKrbGz1XStvYwp2ftZ51Tp6K4zc67aHZMvzD7eDK6z7AzxeG/xMMzgFrfiZ4SCuKJBxb l2vifI/xRecwVZU84RtU2GUeJXXeQ1MCoH+nFMxIussXhtrUPyPvJ7kOZrgrndDG0J2l sRv4SbZ4Dht0gOp3MJ37d/izcsBbuCa16fBW+McGNHrjLgf5KflquGa+3xA6IRkDl5H6 i+4w== X-Gm-Message-State: AOUpUlE+J9NXgzew7LXmt6AH7P/Wau0cKkt3lB1GvLvhJ/dTGIDAfmb0 GEYlcifJMV2HY4YyBngF7dk= X-Google-Smtp-Source: AAOMgpdBLCR47+I7VU+y6xqHiTdZX117aEkNiCiw4ExUqkXcwIZZG3XTXRSXv9MLPfdKGs6mCjXwvg== X-Received: by 2002:a62:8387:: with SMTP id h129-v6mr14474985pfe.79.1533510950902; Sun, 05 Aug 2018 16:15:50 -0700 (PDT) Received: from rodete-desktop-imager.corp.google.com ([2401:fa00:d:10:affa:813f:5380:6613]) by smtp.gmail.com with ESMTPSA id v23-v6sm13253622pfm.80.2018.08.05.16.15.47 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Sun, 05 Aug 2018 16:15:49 -0700 (PDT) Date: Mon, 6 Aug 2018 08:15:44 +0900 From: Minchan Kim To: Andrew Morton Cc: LKML , Sergey Senozhatsky , Tino Lehnig , stable@vger.kernel.org, Jens Axboe Subject: Re: [PATCH 1/2] zram: remove BD_CAP_SYNCHRONOUS_IO with writeback feature Message-ID: <20180805231544.GA209075@rodete-desktop-imager.corp.google.com> References: <20180802051112.86174-1-minchan@kernel.org> <20180802141304.d0589ddc5f8213429ab3b565@linux-foundation.org> <20180803025143.GA86818@rodete-desktop-imager.corp.google.com> <20180803162818.8c4719232d6dfece21ebea30@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180803162818.8c4719232d6dfece21ebea30@linux-foundation.org> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Andrew, On Fri, Aug 03, 2018 at 04:28:18PM -0700, Andrew Morton wrote: > On Fri, 3 Aug 2018 11:51:43 +0900 Minchan Kim wrote: > > > > Is it legitimate to be altering the bdi capabilities at this level? Or > > > is this hacky? > > > > Most of device's bdi capability seems to be static but there are few drivers > > which can change capability. For example, BDI_CAP_STABLE_WRITES > > > > drivers/scsi/iscsi_tcp.c > > drivers/md/raid5.c > > > > I believe it's driver itself advertisement stuff so I hope it's not hack. > > The bdi is per-disk (per-queue). So if zram changes the bdi for a > particular partition then it is accidentally mucking with the other > partitions as well, and it shouldn't do that. At least, I think that's Aha, I didn't know that. Thanks for the heads up. However, I think zram doesn't support partitioning due to lacking of probe feature via blk_register_region. ;-)