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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 9EE3CC433E0 for ; Sun, 17 May 2020 19:38:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 82D7A20657 for ; Sun, 17 May 2020 19:38:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726288AbgEQTiH (ORCPT ); Sun, 17 May 2020 15:38:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51126 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726269AbgEQTiH (ORCPT ); Sun, 17 May 2020 15:38:07 -0400 Received: from shards.monkeyblade.net (shards.monkeyblade.net [IPv6:2620:137:e000::1:9]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 89C8EC061A0C; Sun, 17 May 2020 12:38:07 -0700 (PDT) Received: from localhost (unknown [IPv6:2601:601:9f00:477::3d5]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 14568128A2D8A; Sun, 17 May 2020 12:38:07 -0700 (PDT) Date: Sun, 17 May 2020 12:38:06 -0700 (PDT) Message-Id: <20200517.123806.1659008654334663086.davem@davemloft.net> To: jhubbard@nvidia.com Cc: linux-kernel@vger.kernel.org, kuba@kernel.org, netdev@vger.kernel.org, linux-rdma@vger.kernel.org, rds-devel@oss.oracle.com Subject: Re: [PATCH] rds: convert get_user_pages() --> pin_user_pages() From: David Miller In-Reply-To: <20200517012336.382624-1-jhubbard@nvidia.com> References: <20200517012336.382624-1-jhubbard@nvidia.com> X-Mailer: Mew version 6.8 on Emacs 26.3 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Sun, 17 May 2020 12:38:07 -0700 (PDT) Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org From: John Hubbard Date: Sat, 16 May 2020 18:23:36 -0700 > This code was using get_user_pages_fast(), in a "Case 2" scenario > (DMA/RDMA), using the categorization from [1]. That means that it's > time to convert the get_user_pages_fast() + put_page() calls to > pin_user_pages_fast() + unpin_user_pages() calls. > > There is some helpful background in [2]: basically, this is a small > part of fixing a long-standing disconnect between pinning pages, and > file systems' use of those pages. > > [1] Documentation/core-api/pin_user_pages.rst > > [2] "Explicit pinning of user-space pages": > https://lwn.net/Articles/807108/ > > Cc: David S. Miller > Cc: Jakub Kicinski > Cc: netdev@vger.kernel.org > Cc: linux-rdma@vger.kernel.org > Cc: rds-devel@oss.oracle.com > Signed-off-by: John Hubbard Applied to net-next, thanks.