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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 195EBC3A5A7 for ; Wed, 4 Sep 2019 06:47:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D6BD122CF5 for ; Wed, 4 Sep 2019 06:47:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="HeBw0PKM" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728853AbfIDGrR (ORCPT ); Wed, 4 Sep 2019 02:47:17 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:48320 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726033AbfIDGrR (ORCPT ); Wed, 4 Sep 2019 02:47:17 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=4CfBjJKF068cPJtXwRGO46BkBc5jRBangcaiofET358=; b=HeBw0PKMxSSUDF1vPFb91ZmWq zgC4LTQ+WFsmbBFO0V87OBx8UcJAPPhytsgxA7WWAkxoqbZR0oNXU44KXxGz/NZwZNQPhsugC5zSK Px8yrzj1hZojjA0lgZZCOxbD3LUhH6p+Ikx8LS7urj0t61oCM9Nok33FYg8E7aXVeXA2XXdjXfe2f maYv07v1TdeQIFyN2ADymFOf7oFcOKFsmWwI000ls1sJ2hSPUSxZ2U3/gvL4zAIzAoCigRvIrHm6O D5uQeVqMpA+/yom4NZ5wPY/dbrSEktfwNrAhg7fg8icP4z0P0NYiOncbTD65ckbOkRi1wkFJnHeDp 9g/Mu1fXg==; Received: from hch by bombadil.infradead.org with local (Exim 4.92 #3 (Red Hat Linux)) id 1i5P4W-0004aK-D8; Wed, 04 Sep 2019 06:47:16 +0000 Date: Tue, 3 Sep 2019 23:47:16 -0700 From: Christoph Hellwig To: Damien Le Moal Cc: Christoph Hellwig , "linux-block@vger.kernel.org" , Jens Axboe , "linux-scsi@vger.kernel.org" , "Martin K . Petersen" Subject: Re: [PATCH v2 5/7] block: Delay default elevator initialization Message-ID: <20190904064716.GA17496@infradead.org> References: <20190828022947.23364-1-damien.lemoal@wdc.com> <20190828022947.23364-6-damien.lemoal@wdc.com> <20190903090247.GE23783@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.4 (2019-03-13) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On Wed, Sep 04, 2019 at 02:07:39AM +0000, Damien Le Moal wrote: > OK. I will move the registration earlier in device_add_disk(), before the region > registration. > > However, I would still like to keep the queue freeze to protect against buggy > device drivers that call device_add_disk() with internal commands still going > on. I do not think that there are any such driver, but just want to avoid > problems. The queue freeze is also present for any user initiated elevator > change, so in this respect, this is not any different and should not be a big > problem. Thoughts ? I don't really see the point, but there should be no harm it either since a freeze of a non-busy queue should be fast.