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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,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 E87B7C4724C for ; Fri, 1 May 2020 08:33:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BA1452173E for ; Fri, 1 May 2020 08:33:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="fZpUdZcg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728369AbgEAIdz (ORCPT ); Fri, 1 May 2020 04:33:55 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:39593 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728345AbgEAIdz (ORCPT ); Fri, 1 May 2020 04:33:55 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1588322034; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=9m2SfPn+y7SUHxD1zi8RvVgtwkO6MdlJLiNdU9aPZ60=; b=fZpUdZcgs9WWiZkEeh92g3pVErWGe3hv3GRrt4qainFLw+OuXtMqis0KsemOr/cMSdgX2I TyXJpDGxAVJFC14hG9/FBj8UKQOVxKJiF7EqgRnQU4WzFiSdwR1sLvxqYor3sUzRkgfGya 83wZDW+NUXrM3DJI4OEuvkav2TtU5j0= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-396-Ijrp9sqPPFSBbseAd1AtHA-1; Fri, 01 May 2020 04:33:50 -0400 X-MC-Unique: Ijrp9sqPPFSBbseAd1AtHA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id DB263468; Fri, 1 May 2020 08:33:48 +0000 (UTC) Received: from T590 (ovpn-8-17.pek2.redhat.com [10.72.8.17]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E6AB22B4B6; Fri, 1 May 2020 08:33:41 +0000 (UTC) Date: Fri, 1 May 2020 16:33:37 +0800 From: Ming Lei To: Hannes Reinecke Cc: "Martin K. Petersen" , Christoph Hellwig , James Bottomley , John Garry , Bart van Assche , linux-scsi@vger.kernel.org Subject: Re: [PATCH RFC v3 22/41] block: implement persistent commands Message-ID: <20200501083337.GA1009055@T590> References: <20200430131904.5847-1-hare@suse.de> <20200430131904.5847-23-hare@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200430131904.5847-23-hare@suse.de> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On Thu, Apr 30, 2020 at 03:18:45PM +0200, Hannes Reinecke wrote: > Some LLDDs implement event handling by sending a command to the > firmware, which then will be completed once the firmware wants > to register an event. > So worst case a command is being sent to the firmware then the > driver initializes, and will be returned once the driver unloads. > To avoid these commands to block the queues during freezing or > quiescing this patch implements support for 'persistent' commands, > which will be excluded from blk_queue_enter() and blk_queue_exit() > calls. This way is quite dangerous from block layer viewpoint, and it should have been done in driver/device specific way instead of polluting block layer. thanks, Ming