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 B641CC54EAA for ; Thu, 26 Jan 2023 23:59:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232662AbjAZX7A (ORCPT ); Thu, 26 Jan 2023 18:59:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36922 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232524AbjAZX6y (ORCPT ); Thu, 26 Jan 2023 18:58:54 -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 4740C49018 for ; Thu, 26 Jan 2023 15:57:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1674777422; 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=kKThdaP2GlTwXMt/TnWZotCXGuKPxiAvQX1pLLF779E=; b=Wu6uPOX1OsmT6VApdJXy7TrZzHyjftKE4091el0KPXmZRzIzczeoHacZQYh+osuLVOusSp LwhhPlNKkywnDop7l1qb8BpdUas6zrtOu45psBghUcyJIAjqZ/GZoNf5eLpqazPWqY9yF+ 633LmDQQa3DMG5PGgXFjsd24p3eetus= 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-518-L1RQGqy5MLmeSuxJlfKllQ-1; Thu, 26 Jan 2023 18:56:55 -0500 X-MC-Unique: L1RQGqy5MLmeSuxJlfKllQ-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 6C43E3C025CC; Thu, 26 Jan 2023 23:56:54 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.33.36.97]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8C732492C14; Thu, 26 Jan 2023 23:56:51 +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: <20230126141626.2809643-1-dhowells@redhat.com> <20230126141626.2809643-3-dhowells@redhat.com> To: David Hildenbrand Cc: dhowells@redhat.com, Al Viro , Christoph Hellwig , Matthew Wilcox , Jens Axboe , Jan Kara , Jeff Layton , Jason Gunthorpe , Logan Gunthorpe , linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Christoph Hellwig , John Hubbard Subject: Re: [PATCH v11 2/8] iov_iter: Add a function to extract a page list from an iterator MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <2907149.1674777410.1@warthog.procyon.org.uk> Date: Thu, 26 Jan 2023 23:56:50 +0000 Message-ID: <2907150.1674777410@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Al says that pinning a page (ie. FOLL_PIN) could cause a deadlock if a page is vmspliced into a pipe with the pipe holding a pin on it because pinned pages are removed from all page tables. Is this actually the case? I can't see offhand where in mm/gup.c it does this. David