From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <SRS0=FvrY=LY=vger.kernel.org=linux-kernel-owner@kernel.org>
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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,
	MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 28558C4321E
	for <linux-kernel@archiver.kernel.org>; Mon, 10 Sep 2018 16:37:29 +0000 (UTC)
Received: from vger.kernel.org (vger.kernel.org [209.132.180.67])
	by mail.kernel.org (Postfix) with ESMTP id D292B20645
	for <linux-kernel@archiver.kernel.org>; Mon, 10 Sep 2018 16:37:28 +0000 (UTC)
DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D292B20645
Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de
Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1728583AbeIJVcV (ORCPT
        <rfc822;linux-kernel@archiver.kernel.org>);
        Mon, 10 Sep 2018 17:32:21 -0400
Received: from verein.lst.de ([213.95.11.211]:38583 "EHLO newverein.lst.de"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1728137AbeIJVcV (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Mon, 10 Sep 2018 17:32:21 -0400
Received: by newverein.lst.de (Postfix, from userid 2407)
        id 2A5D167357; Mon, 10 Sep 2018 18:41:44 +0200 (CEST)
Date:   Mon, 10 Sep 2018 18:41:44 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Logan Gunthorpe <logang@deltatee.com>
Cc:     Jens Axboe <axboe@kernel.dk>, Christoph Hellwig <hch@lst.de>,
        linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
        linux-nvme@lists.infradead.org, linux-rdma@vger.kernel.org,
        linux-nvdimm@lists.01.org, linux-block@vger.kernel.org,
        Stephen Bates <sbates@raithlin.com>,
        Keith Busch <keith.busch@intel.com>,
        Sagi Grimberg <sagi@grimberg.me>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Jason Gunthorpe <jgg@mellanox.com>,
        Max Gurtovoy <maxg@mellanox.com>,
        Dan Williams <dan.j.williams@intel.com>,
        =?iso-8859-1?B?Suly9G1l?= Glisse <jglisse@redhat.com>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Alex Williamson <alex.williamson@redhat.com>,
        Christian =?iso-8859-1?Q?K=F6nig?= <christian.koenig@amd.com>
Subject: Re: [PATCH v5 07/13] block: Add PCI P2P flag for request queue and
 check support for requests
Message-ID: <20180910164144.GA24591@lst.de>
References: <20180905195647.GA1626@lst.de> <bcc1b3cf-2fd9-fa61-9cfb-b0e4d84e5d94@kernel.dk> <20180905201152.GA1893@lst.de> <eb42fb94-9da6-955b-8524-0a0f5ac4bd19@deltatee.com> <2a3394bd-5f13-4818-43f4-dfc61f501e05@kernel.dk> <e3ef26e6-6c8d-25b8-fa64-14594a51263c@deltatee.com> <3af4d1d4-da07-c0a6-8464-9ddc1378f2f4@kernel.dk> <f9e660cd-b597-bb6e-56a2-82fe71cb3649@deltatee.com> <34d9b2f7-9e6d-4a0a-77e5-ec0e99610f5c@kernel.dk> <c41c802c-9235-5383-2dfa-af9c1553f11b@deltatee.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <c41c802c-9235-5383-2dfa-af9c1553f11b@deltatee.com>
User-Agent: Mutt/1.5.17 (2007-11-01)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Wed, Sep 05, 2018 at 03:03:18PM -0600, Logan Gunthorpe wrote:
> There is no special p2p submission process. In the nvme-of case we are
> using the existing process and with the code in blk-core it didn't
> change it's process at all. Creating a helper will create one and I can
> look at making a pci_p2pdma_submit_bio() for v6; but if the developer
> screws up and still calls the regular submit_bio() things will only be
> very subtly broken and that won't be obvious.

I just saw you added that "helper" in your tree.  Please don't, it is
a negative value add as it doesn't help anything with the checking.