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=-7.2 required=3.0 tests=BAYES_00,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 2E4BEC83012 for ; Thu, 3 Dec 2020 06:41:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D8FF0206F9 for ; Thu, 3 Dec 2020 06:41:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727725AbgLCGlf (ORCPT ); Thu, 3 Dec 2020 01:41:35 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:52212 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728185AbgLCGle (ORCPT ); Thu, 3 Dec 2020 01:41:34 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1606977608; 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=4a+ZpQmjLgoV6jCwYnyDxtAMBa2ORCm8AqUKIqPXkLU=; b=TNOg+tW5w6bLytas0nSPWClyY/6LwEw+YxX6eGXqK1YNB/lYtTWxP8JyD6ekoEQNi4WdG1 Ie0gvSaUGR/xLwQ1zAKeam+ud4/vOm20eDNF69VymJP2qPtWxdAKufh3FIgjPmmwFuRjND VDM37lko99uPbQRKRHXAMYdAKh7QprQ= 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-95-jcc9ZzulNrKGkc15zcOW0Q-1; Thu, 03 Dec 2020 01:40:06 -0500 X-MC-Unique: jcc9ZzulNrKGkc15zcOW0Q-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 BB5018030D5; Thu, 3 Dec 2020 06:40:04 +0000 (UTC) Received: from T590 (ovpn-13-173.pek2.redhat.com [10.72.13.173]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C920C1A890; Thu, 3 Dec 2020 06:39:51 +0000 (UTC) Date: Thu, 3 Dec 2020 14:39:41 +0800 From: Ming Lei To: Christoph Hellwig Cc: Jens Axboe , Tejun Heo , Coly Li , Song Liu , dm-devel@redhat.com, linux-bcache@vger.kernel.org, linux-raid@vger.kernel.org, linux-s390@vger.kernel.org, linux-block@vger.kernel.org Subject: Re: [PATCH 3/9] block: store a block_device pointer in struct bio Message-ID: <20201203063941.GA629758@T590> References: <20201201165424.2030647-1-hch@lst.de> <20201201165424.2030647-4-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201201165424.2030647-4-hch@lst.de> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: linux-raid@vger.kernel.org On Tue, Dec 01, 2020 at 05:54:18PM +0100, Christoph Hellwig wrote: > Replace the gendisk pointer in struct bio with a pointer to the newly > improved struct block device. From that the gendisk can be trivially > accessed with an extra indirection, but it also allows to directly > look up all information related to partition remapping. The extra indirection is often done in fast path, so just wondering why you don't consider to embed gendisk into block_device? Then the extra indirection can be avoided. Thanks, Ming 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=-7.2 required=3.0 tests=BAYES_00,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 8F650C63777 for ; Thu, 3 Dec 2020 06:40:24 +0000 (UTC) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [63.128.21.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E59FB206B6 for ; Thu, 3 Dec 2020 06:40:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E59FB206B6 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=tempfail smtp.mailfrom=dm-devel-bounces@redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1606977622; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:list-id:list-help: list-unsubscribe:list-subscribe:list-post; bh=Q4jxjS5wVE4xwFfhx09nOD6VaFnzIH49NqgEawIFtKU=; b=Mqyz2QGfHRRr+eAMG6Oc0w2Bjy3tFFaeXDoB37j93G4/mEa+lhEnLGWD60lHGf2eefVW/O JHKtBE0ZmwC+Oy7Uhf7xEbUl07mitTiyF9yoKIgghESxaNIYG5cJHNthnbizgWpi1b1FlH 6b428VnO55cYmZKSr+Bv6xQj0cm261s= 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-590-EGSunLRsOFGqjybtoEBIKQ-1; Thu, 03 Dec 2020 01:40:21 -0500 X-MC-Unique: EGSunLRsOFGqjybtoEBIKQ-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 53A68185E489; Thu, 3 Dec 2020 06:40:15 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.20]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 28D7060BF1; Thu, 3 Dec 2020 06:40:13 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id 9F695180954D; Thu, 3 Dec 2020 06:40:06 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id 0B36e4DZ029969 for ; Thu, 3 Dec 2020 01:40:04 -0500 Received: by smtp.corp.redhat.com (Postfix) id B91231D7; Thu, 3 Dec 2020 06:40:04 +0000 (UTC) Received: from T590 (ovpn-13-173.pek2.redhat.com [10.72.13.173]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C920C1A890; Thu, 3 Dec 2020 06:39:51 +0000 (UTC) Date: Thu, 3 Dec 2020 14:39:41 +0800 From: Ming Lei To: Christoph Hellwig Message-ID: <20201203063941.GA629758@T590> References: <20201201165424.2030647-1-hch@lst.de> <20201201165424.2030647-4-hch@lst.de> MIME-Version: 1.0 In-Reply-To: <20201201165424.2030647-4-hch@lst.de> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-loop: dm-devel@redhat.com Cc: Jens Axboe , linux-s390@vger.kernel.org, linux-bcache@vger.kernel.org, Coly Li , linux-raid@vger.kernel.org, Song Liu , dm-devel@redhat.com, linux-block@vger.kernel.org, Tejun Heo Subject: Re: [dm-devel] [PATCH 3/9] block: store a block_device pointer in struct bio X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dm-devel-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Tue, Dec 01, 2020 at 05:54:18PM +0100, Christoph Hellwig wrote: > Replace the gendisk pointer in struct bio with a pointer to the newly > improved struct block device. From that the gendisk can be trivially > accessed with an extra indirection, but it also allows to directly > look up all information related to partition remapping. The extra indirection is often done in fast path, so just wondering why you don't consider to embed gendisk into block_device? Then the extra indirection can be avoided. Thanks, Ming -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel