From mboxrd@z Thu Jan 1 00:00:00 1970 From: hch@lst.de (Christoph Hellwig) Date: Wed, 5 Sep 2018 23:13:51 +0200 Subject: [PATCH v5 07/13] block: Add PCI P2P flag for request queue and check support for requests In-Reply-To: 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> Message-ID: <20180905211351.GA2927@lst.de> On Wed, Sep 05, 2018@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 thought about that when reviewing the previous series, and even started hacking it up. In the end I decided against it for the above reason - it just adds code, but doesn't actually help with anything as it is trivial to forget, and not using it will in fact just work.