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=-5.3 required=3.0 tests=BAYES_00, 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 BFE98C433DB for ; Tue, 16 Feb 2021 10:26:20 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C460664DA8 for ; Tue, 16 Feb 2021 10:26:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C460664DA8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 0C2C98D016B; Tue, 16 Feb 2021 05:26:19 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 0730B8D0140; Tue, 16 Feb 2021 05:26:19 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id ECB2B8D016B; Tue, 16 Feb 2021 05:26:18 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0092.hostedemail.com [216.40.44.92]) by kanga.kvack.org (Postfix) with ESMTP id D86388D0140 for ; Tue, 16 Feb 2021 05:26:18 -0500 (EST) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 9E6631802850F for ; Tue, 16 Feb 2021 10:26:18 +0000 (UTC) X-FDA: 77823751236.29.time47_2a1633d27643 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin29.hostedemail.com (Postfix) with ESMTP id 85070180868F3 for ; Tue, 16 Feb 2021 10:26:18 +0000 (UTC) X-HE-Tag: time47_2a1633d27643 X-Filterd-Recvd-Size: 2097 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf23.hostedemail.com (Postfix) with ESMTP for ; Tue, 16 Feb 2021 10:26:17 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 9AA846736F; Tue, 16 Feb 2021 11:26:14 +0100 (CET) Date: Tue, 16 Feb 2021 11:26:14 +0100 From: Christoph Hellwig To: David Howells Cc: Trond Myklebust , Anna Schumaker , Steve French , Dominique Martinet , Alexander Viro , Christoph Hellwig , Matthew Wilcox , linux-mm@kvack.org, linux-cachefs@redhat.com, linux-afs@lists.infradead.org, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, ceph-devel@vger.kernel.org, v9fs-developer@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, Jeff Layton , David Wysochanski , linux-kernel@vger.kernel.org Subject: Re: [PATCH 04/33] vfs: Export rw_verify_area() for use by cachefiles Message-ID: <20210216102614.GA27555@lst.de> References: <161340385320.1303470.2392622971006879777.stgit@warthog.procyon.org.uk> <161340390150.1303470.509630287091953754.stgit@warthog.procyon.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <161340390150.1303470.509630287091953754.stgit@warthog.procyon.org.uk> User-Agent: Mutt/1.5.17 (2007-11-01) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Feb 15, 2021 at 03:45:01PM +0000, David Howells wrote: > Export rw_verify_area() for so that cachefiles can use it before issuing > call_read_iter() and call_write_iter() to effect async DIO operations > against the cache. This is analogous to aio_read() and aio_write(). I don't think this is the right thing to do. Instead of calling into ->read_iter / ->write_iter directly this should be using helpers. What prevents you from using vfs_iocb_iter_read and vfs_iocb_iter_write which seem the right level of abstraction for this?