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=-5.2 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 53CE8C43214 for ; Thu, 12 Aug 2021 12:21:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C53BD6104F for ; Thu, 12 Aug 2021 12:21:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236417AbhHLMVf (ORCPT ); Thu, 12 Aug 2021 08:21:35 -0400 Received: from verein.lst.de ([213.95.11.211]:44085 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237369AbhHLMVf (ORCPT ); Thu, 12 Aug 2021 08:21:35 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id D840468AFE; Thu, 12 Aug 2021 14:21:04 +0200 (CEST) Date: Thu, 12 Aug 2021 14:21:04 +0200 From: Christoph Hellwig To: David Howells Cc: willy@infradead.org, trond.myklebust@primarydata.com, darrick.wong@oracle.com, hch@lst.de, jlayton@kernel.org, sfrench@samba.org, torvalds@linux-foundation.org, linux-nfs@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] mm: Make swap_readpage() for SWP_FS_OPS use ->direct_IO() not ->readpage() Message-ID: <20210812122104.GB18532@lst.de> References: <162876946134.3068428.15475611190876694695.stgit@warthog.procyon.org.uk> <162876947840.3068428.12591293664586646085.stgit@warthog.procyon.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <162876947840.3068428.12591293664586646085.stgit@warthog.procyon.org.uk> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Thu, Aug 12, 2021 at 12:57:58PM +0100, David Howells wrote: > Make swap_readpage(), when accessing a swap file (SWP_FS_OPS) use > the ->direct_IO() method on the filesystem rather then ->readpage(). ->direct_IO is just a helper for ->read_iter and ->write_iter, so please don't call it directly. It actually is slowly on its way out, with at at least all of the iomap implementations not using it, as well as various other file systems. > + ki = kzalloc(sizeof(*ki), GFP_KERNEL); > + if (!ki) > + return -ENOMEM; for the synchronous case we could avoid this allocation and just use arguments on stack.