From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ale.deltatee.com (ale.deltatee.com [207.54.116.67]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 9D7C321A07A92 for ; Mon, 10 Sep 2018 11:11:28 -0700 (PDT) References: <20180905195647.GA1626@lst.de> <20180905201152.GA1893@lst.de> <2a3394bd-5f13-4818-43f4-dfc61f501e05@kernel.dk> <3af4d1d4-da07-c0a6-8464-9ddc1378f2f4@kernel.dk> <34d9b2f7-9e6d-4a0a-77e5-ec0e99610f5c@kernel.dk> <20180910164144.GA24591@lst.de> From: Logan Gunthorpe Message-ID: Date: Mon, 10 Sep 2018 12:11:01 -0600 MIME-Version: 1.0 In-Reply-To: <20180910164144.GA24591@lst.de> Content-Language: en-US Subject: Re: [PATCH v5 07/13] block: Add PCI P2P flag for request queue and check support for requests List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Christoph Hellwig Cc: Jens Axboe , Alex Williamson , linux-nvdimm@lists.01.org, linux-rdma@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Jason Gunthorpe , Benjamin Herrenschmidt , Bjorn Helgaas , Max Gurtovoy , =?UTF-8?Q?Christian_K=c3=b6nig?= List-ID: On 10/09/18 10:41 AM, Christoph Hellwig wrote: > 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. Alright, so what's the consensus then? Just have a check in nvmet_bdev_execute_rw() to add REQ_NOMERGE when appropriate? Jens is pretty dead set against adding to the common path. Logan P.S. Here's the commit in question for anyone else on the list: https://github.com/sbates130272/linux-p2pmem/commit/eeabe0bc94491d3eec4fe872274a9e3b4cdea538 _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm