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=-6.5 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,URIBL_BLOCKED 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 CD633C432BE for ; Thu, 12 Aug 2021 13:38:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AEDF96101E for ; Thu, 12 Aug 2021 13:38:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231172AbhHLNic (ORCPT ); Thu, 12 Aug 2021 09:38:32 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:30481 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230033AbhHLNib (ORCPT ); Thu, 12 Aug 2021 09:38:31 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1628775485; 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=oiGXmDTLhiS3oN2r9OJ7cRVpEzCCbBrauFWnA55fp7U=; b=MIJVBZ0jKfYyJ4j2GQPf05diYRdHNBgbu/Akj1HHtxb8jrvizsp+GNw/vt4ZVIaEC1pjvU 5ttLB2tfUaVRbiW6O0Z4Xc0xGkijQtIkPDdfKBp/h52kMSO+ISAy7xJrYMf/68yND4IhW3 luQqvOtjQ3Wjk/iQwGoj7zhRIc/+T3Y= 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-490-TZtzByDUPuGJ6gxXgq_XZA-1; Thu, 12 Aug 2021 09:38:04 -0400 X-MC-Unique: TZtzByDUPuGJ6gxXgq_XZA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C80358015C7; Thu, 12 Aug 2021 13:38:02 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.22.32.7]) by smtp.corp.redhat.com (Postfix) with ESMTP id B0F335D9C6; Thu, 12 Aug 2021 13:38:00 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <3088327.1628774588@warthog.procyon.org.uk> References: <3088327.1628774588@warthog.procyon.org.uk> <162876946134.3068428.15475611190876694695.stgit@warthog.procyon.org.uk> <162876947840.3068428.12591293664586646085.stgit@warthog.procyon.org.uk> To: Matthew Wilcox Cc: dhowells@redhat.com, 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() MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <3088957.1628775479.1@warthog.procyon.org.uk> Date: Thu, 12 Aug 2021 14:37:59 +0100 Message-ID: <3088958.1628775479@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org David Howells wrote: > Matthew Wilcox wrote: > > > After submitting the IO here ... > > > > > + if (ret != -EIOCBQUEUED) > > > + swapfile_read_complete(&ki->iocb, ret, 0); > > > > We only touch the 'ki' here ... if the caller didn't call read_complete > > > > > + swapfile_put_kiocb(ki); > > > > Except for here, which is only touched in order to put the refcount. > > > > So why can't swapfile_read_complete() do the work of freeing the ki? > > When I was doing something similar for cachefiles, I couldn't get it to work > like that. I'll have another look at that. Ah, yes. generic_file_direct_write() accesses in the kiocb *after* calling ->direct_IO(), so the kiocb *must not* go away until after generic_file_direct_write() has returned. David