From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keith Busch Subject: Re: [PATCH v8 09/13] nvme-pci: Use PCI p2pmem subsystem to manage the CMB Date: Thu, 27 Sep 2018 11:10:13 -0600 Message-ID: <20180927171013.GC19589@localhost.localdomain> References: <20180927165420.5290-1-logang@deltatee.com> <20180927165420.5290-10-logang@deltatee.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20180927165420.5290-10-logang-OTvnGxWRz7hWk0Htik3J/w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-nvdimm-bounces-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org Sender: "Linux-nvdimm" To: Logan Gunthorpe Cc: Jens Axboe , linux-nvdimm-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org, linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-nvme-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Christoph Hellwig , linux-block-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Alex Williamson , Jason Gunthorpe , =?iso-8859-1?B?Suly9G1l?= Glisse , Benjamin Herrenschmidt , Bjorn Helgaas , Max Gurtovoy , Christian =?iso-8859-1?Q?K=F6nig?= List-Id: linux-rdma@vger.kernel.org On Thu, Sep 27, 2018 at 10:54:16AM -0600, Logan Gunthorpe wrote: > Register the CMB buffer as p2pmem and use the appropriate allocation > functions to create and destroy the IO submission queues. > > If the CMB supports WDS and RDS, publish it for use as P2P memory > by other devices. > > Kernels without CONFIG_PCI_P2PDMA will also no longer support NVMe CMB. > However, seeing the main use-cases for the CMB is P2P operations, > this seems like a reasonable dependency. > > We drop the __iomem safety on the buffer seeing that, by convention, it's > safe to directly access memory mapped by memremap()/devm_memremap_pages(). > Architectures where this is not safe will not be supported by memremap() > and therefore will not be support PCI P2P and have no support for CMB. > > Signed-off-by: Logan Gunthorpe Looks good to me. Reviewed-by: Keith Busch