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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, 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 77329C2D0A3 for ; Sat, 24 Oct 2020 07:48:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2CEF722460 for ; Sat, 24 Oct 2020 07:48:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="dYXsFDWc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759936AbgJXHsM (ORCPT ); Sat, 24 Oct 2020 03:48:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48716 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759935AbgJXHsM (ORCPT ); Sat, 24 Oct 2020 03:48:12 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1B3ABC0613CE for ; Sat, 24 Oct 2020 00:48:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=/CnQE42MmBtHov937IKEzIAZe1qLD8zt2YNuzfv/CoU=; b=dYXsFDWcT1i7bG/RUtBykPynMy ObRmQQXH41RnQcdyjp3FGy7SrgPLoF9923yOhUv2irEtnQLPViKJr04jSduk4ODFMk3SDQq9MwZ02 Ap2ELMw0OTnTMZVrDowJC1wUYZCNgHdJkHabDalpQodzac92eMJIoiFd6eunkqgSlvzg8rNfwdZ2r ngWNgSkeR2PGtM/4Q0XZNoPoDIBd62Xgae1nDau9fsDaaqtyjiD+D4G3KXur0la6DVuwVl2hmj0Yz eGiQf9ryeSYScJeF/DJC9X2uTs7lZwHZt/VXjKguBhsBlC8t+XBpy0dStjPYNXiSK22N0rUGzVzZJ vZ0iIfSQ==; Received: from hch by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1kWEHX-0000yc-FR; Sat, 24 Oct 2020 07:48:07 +0000 Date: Sat, 24 Oct 2020 08:48:07 +0100 From: Christoph Hellwig To: Jason Gunthorpe Cc: Daniel Vetter , Jianxin Xiong , linux-rdma@vger.kernel.org, dri-devel@lists.freedesktop.org, Leon Romanovsky , Doug Ledford , Daniel Vetter , Christian Koenig Subject: Re: [PATCH v6 1/4] RDMA/umem: Support importing dma-buf as user memory region Message-ID: <20201024074807.GA3112@infradead.org> References: <1603471201-32588-1-git-send-email-jianxin.xiong@intel.com> <1603471201-32588-2-git-send-email-jianxin.xiong@intel.com> <20201023164911.GF401619@phenom.ffwll.local> <20201023182005.GP36674@ziepe.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201023182005.GP36674@ziepe.ca> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Fri, Oct 23, 2020 at 03:20:05PM -0300, Jason Gunthorpe wrote: > The problem is we have RDMA drivers that assume SGL's have a valid > struct page, and these hacky/wrong P2P sgls that DMABUF creates cannot > be passed into those drivers. RDMA drivers do not assume scatterlist have a valid struct page, scatterlists are defined to have a valid struct page. Any scatterlist without a struct page is completely buggy.