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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 72DA9C3DA78 for ; Tue, 17 Jan 2023 08:27:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235525AbjAQI1F (ORCPT ); Tue, 17 Jan 2023 03:27:05 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39734 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236075AbjAQI1E (ORCPT ); Tue, 17 Jan 2023 03:27:04 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7C3A610C4 for ; Tue, 17 Jan 2023 00:26:17 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1673943976; 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=CGG6nTGxkZXGoYdS9YZATBVEC4tK6YnOhWeyJms4Rik=; b=a6qoxQu4nSQ3KMLmZkeTmYHxbypK8YT7W/Uz785DsVQCevM4YCa8GIJCFy3sC/jqYzWn4h 3vxh+T95TEKDvJoLVFVWygssWsCHdx7im86Q9zjG8WAKEWkE+xuU2VlZIdP073aMeoagYY 1gD+ToYcVJpcSyT0rkZ7f8uc2Cqy7Vw= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-468-vQEnYVWdPSevVZXYYs2M1A-1; Tue, 17 Jan 2023 03:26:11 -0500 X-MC-Unique: vQEnYVWdPSevVZXYYs2M1A-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id B31ED3C22740; Tue, 17 Jan 2023 08:26:10 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.33.36.23]) by smtp.corp.redhat.com (Postfix) with ESMTP id 659F140C2064; Tue, 17 Jan 2023 08:26:09 +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: References: <167391047703.2311931.8115712773222260073.stgit@warthog.procyon.org.uk> <167391056047.2311931.6772604381276147664.stgit@warthog.procyon.org.uk> To: Christoph Hellwig Cc: dhowells@redhat.com, Al Viro , Jens Axboe , Jan Kara , Christoph Hellwig , Matthew Wilcox , Logan Gunthorpe , linux-block@vger.kernel.org, Jeff Layton , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v6 11/34] iov_iter, block: Make bio structs pin pages rather than ref'ing if appropriate MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <2330753.1673943968.1@warthog.procyon.org.uk> Date: Tue, 17 Jan 2023 08:26:08 +0000 Message-ID: <2330754.1673943968@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Christoph Hellwig wrote: > > + bio_clear_flag(bio, BIO_PAGE_REFFED); > > .. and this should not be needed. Instead: > > > + cleanup_mode = iov_iter_extract_mode(iter, gup_flags); > > + if (cleanup_mode & FOLL_GET) > > + bio_set_flag(bio, BIO_PAGE_REFFED); > > + if (cleanup_mode & FOLL_PIN) > > + bio_set_flag(bio, BIO_PAGE_PINNED); > > We could warn if a not match flag is set here if we really care. Um... With these patches, BIO_PAGE_REFFED is set by default when the bio is initialised otherwise every user of struct bio that currently adds pages directly (assuming there are any) rather than going through bio_iov_iter_get_pages() will have to set the flag, hence the need to clear it. Actually, I could do: if (!(cleanup_mode & FOLL_GET)) bio_clear_flag(bio, BIO_PAGE_REFFED); if (cleanup_mode & FOLL_PIN) bio_set_flag(bio, BIO_PAGE_PINNED); which should also work. David