Return-Path: Received: from verein.lst.de ([213.95.11.211]:59032 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725908AbeLFTP3 (ORCPT ); Thu, 6 Dec 2018 14:15:29 -0500 Date: Thu, 6 Dec 2018 20:15:27 +0100 From: Christoph Hellwig To: Jens Axboe Cc: Jeff Moyer , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, hch@lst.de Subject: Re: [PATCH 03/26] block: wire up block device iopoll method Message-ID: <20181206191527.GA30806@lst.de> References: <20181204233729.26776-1-axboe@kernel.dk> <20181204233729.26776-4-axboe@kernel.dk> <72b6acc7-5017-a72c-3fb0-90e5ad95ebb7@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <72b6acc7-5017-a72c-3fb0-90e5ad95ebb7@kernel.dk> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Thu, Dec 06, 2018 at 12:14:29PM -0700, Jens Axboe wrote: > On 12/6/18 12:11 PM, Jeff Moyer wrote: > > Jens Axboe writes: > > > >> From: Christoph Hellwig > >> > >> Just call blk_poll on the iocb cookie, we can derive the block device > >> from the inode trivially. > > > > Does this work for multi-device file systems? > > It should, that's the whole purpose of having fops->iopoll. You should > be able to derive it from inode + cookie. It still assumes the whole I/O will got to a single device. For XFS this is always tree, but for btrfs this might mean I/O could need splitting if ->iopoll was to be supported there.