From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:55763 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728185AbgLCGlg (ORCPT ); Thu, 3 Dec 2020 01:41:36 -0500 Date: Thu, 3 Dec 2020 14:39:41 +0800 From: Ming Lei 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> List-ID: 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 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