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=-4.0 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 33C44C64E75 for ; Tue, 24 Nov 2020 19:48:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CCE51206CA for ; Tue, 24 Nov 2020 19:48:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="jOV4zvc5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728154AbgKXTrQ (ORCPT ); Tue, 24 Nov 2020 14:47:16 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36134 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728160AbgKXTrM (ORCPT ); Tue, 24 Nov 2020 14:47:12 -0500 Received: from mail-qk1-x744.google.com (mail-qk1-x744.google.com [IPv6:2607:f8b0:4864:20::744]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0E715C0613D6; Tue, 24 Nov 2020 11:47:12 -0800 (PST) Received: by mail-qk1-x744.google.com with SMTP id v143so50574qkb.2; Tue, 24 Nov 2020 11:47:12 -0800 (PST) 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; bh=V2TOjLdoUaYrySYqHg0oeA6ickZUCz64YonJi1MX7zw=; b=jOV4zvc5ykqwIR5EZxEdhoTt8gbdvwT6+6X/TSUVT/z8HYM0C2tjvbbgLMctpzeJXh RGgnK/f6uWChM4BxAbOX4p18Fwq1/chEXov7aPAYOwuKTjdA655sPluEae6103/B37UZ mtHW9DvASGebX6RreWH7qhpVzv5BxklJgKQSxfx5joha57iIHUUTiDQJHNfLS9atfGSt ExNgjoQWPu/xgn5sRgfmq3jVVaBwbHob8XGT+JoMXjhTpfpEBrU2/+S555WpdkNVIh4j Jpy0MqgRWGJT79DbBEN/JVT9ea84He6RSeOcPWGIlVmK+xMy8dzyAD0z3NQbnkk9QV/T mQ+g== 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; bh=V2TOjLdoUaYrySYqHg0oeA6ickZUCz64YonJi1MX7zw=; b=YRvY7c2xKSnJV3yvYWiG08+v/DQ2nGoyc/2LGn2yAXfQgvGcXBfVhQMBmb3zE126uK OLjhKXOZITyqdTo5Gcy+54QehkGnPv4L0f29+vY3DcjSNPO45cNVK496RWvaZQjaL0YZ 2MYx2Eug6R8+AL9QZVcFc/FU9T0Q4veUpw7i8W3+NwysgxTfhcUjv89Tk9zrqqr7wRmY lqyx2ULkovbXTk3gX4j9G9N8PCaeqsa2HtrdBipfrdTueXzPwRS745nxuG/1/dOq9luo mifyXdkb2ILiafoajQXgxRy5QviOJIVhy+IMXu0xr86WAQ4i8XXUoOpZpBpbks9KSESM si8A== X-Gm-Message-State: AOAM530x4TWl6ZSFlbDmjo2ZU3HLerQ+An25XMWD3HRZWIfyww5wGlWS p7via9J4dEBPHwdj+V89fg8= X-Google-Smtp-Source: ABdhPJzCbEzsnsSHZbAP8aBMoagyKuXkYbNxYHgU470rrYkN9D5aTPe0QJyzDBb8iwv2DZpxdq68Ww== X-Received: by 2002:a37:6cd:: with SMTP id 196mr3775536qkg.96.1606247231211; Tue, 24 Nov 2020 11:47:11 -0800 (PST) Received: from localhost (dhcp-6c-ae-f6-dc-d8-61.cpe.echoes.net. [72.28.8.195]) by smtp.gmail.com with ESMTPSA id 137sm123792qkj.109.2020.11.24.11.47.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 Nov 2020 11:47:10 -0800 (PST) Sender: Tejun Heo Date: Tue, 24 Nov 2020 14:46:47 -0500 From: Tejun Heo To: Christoph Hellwig Cc: Jens Axboe , Josef Bacik , Konrad Rzeszutek Wilk , Coly Li , Mike Snitzer , Greg Kroah-Hartman , Jan Kara , Johannes Thumshirn , dm-devel@redhat.com, Richard Weinberger , Jan Kara , linux-block@vger.kernel.org, xen-devel@lists.xenproject.org, linux-bcache@vger.kernel.org, linux-mtd@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 24/45] blk-cgroup: stop abusing get_gendisk Message-ID: References: <20201124132751.3747337-1-hch@lst.de> <20201124132751.3747337-25-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201124132751.3747337-25-hch@lst.de> Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Tue, Nov 24, 2020 at 02:27:30PM +0100, Christoph Hellwig wrote: > Properly open the device instead of relying on deep internals by > using get_gendisk. Note that this uses FMODE_NDELAY without either > FMODE_READ or FMODE_WRITE, which is a special open mode to allow > for opening without media access, thus avoiding unexpexted interactions > especially on removable media. I'm not sure FMODE_NDELAY does that. e.g. sd_open() does media change check and full revalidation including disk spin up regadless of NDELAY and it's odd and can lead to nasty surprises to require cgroup configuration updates to wait for SCSI EH. Thanks. -- tejun