From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-f199.google.com (mail-pg1-f199.google.com [209.85.215.199]) by kanga.kvack.org (Postfix) with ESMTP id A7DD46B000C for ; Mon, 22 Oct 2018 16:18:43 -0400 (EDT) Received: by mail-pg1-f199.google.com with SMTP id v10-v6so1561067pgs.15 for ; Mon, 22 Oct 2018 13:18:43 -0700 (PDT) Received: from mga05.intel.com (mga05.intel.com. [192.55.52.43]) by mx.google.com with ESMTPS id r15-v6si34776466pgh.88.2018.10.22.13.18.42 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 22 Oct 2018 13:18:42 -0700 (PDT) Subject: [PATCH 4/9] dax/kmem: allow PMEM devices to bind to KMEM driver From: Dave Hansen Date: Mon, 22 Oct 2018 13:13:24 -0700 References: <20181022201317.8558C1D8@viggo.jf.intel.com> In-Reply-To: <20181022201317.8558C1D8@viggo.jf.intel.com> Message-Id: <20181022201324.EBB64302@viggo.jf.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org Cc: Dave Hansen , dan.j.williams@intel.com, dave.jiang@intel.com, zwisler@kernel.org, vishal.l.verma@intel.com, thomas.lendacky@amd.com, akpm@linux-foundation.org, mhocko@suse.com, linux-nvdimm@lists.01.org, linux-mm@kvack.org, ying.huang@intel.com, fengguang.wu@intel.com Currently, a persistent memory device's mode must be coordinated with the driver to which it needs to bind. To change it from the fsdax to the device-dax driver, you first change the mode of the device itself. Instead of adding a new device mode, allow the PMEM mode to also bind to the KMEM driver. As I write this, I'm realizing that it might have just been better to add a new device mode, rather than hijacking the PMEM eode. If this is the case, please speak up, NVDIMM folks. :) Cc: Dan Williams Cc: Dave Jiang Cc: Ross Zwisler Cc: Vishal Verma Cc: Tom Lendacky Cc: Andrew Morton Cc: Michal Hocko Cc: linux-nvdimm@lists.01.org Cc: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org Cc: Huang Ying Cc: Fengguang Wu --- b/drivers/nvdimm/bus.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff -puN drivers/nvdimm/bus.c~dax-kmem-try-again-2018-3-bus-match-override drivers/nvdimm/bus.c --- a/drivers/nvdimm/bus.c~dax-kmem-try-again-2018-3-bus-match-override 2018-10-22 13:12:22.522930391 -0700 +++ b/drivers/nvdimm/bus.c 2018-10-22 13:12:22.525930391 -0700 @@ -464,11 +464,24 @@ static struct nd_device_driver nd_bus_dr static int nvdimm_bus_match(struct device *dev, struct device_driver *drv) { struct nd_device_driver *nd_drv = to_nd_device_driver(drv); + bool match; if (is_nvdimm_bus(dev) && nd_drv == &nd_bus_driver) return true; - return !!test_bit(to_nd_device_type(dev), &nd_drv->type); + match = !!test_bit(to_nd_device_type(dev), &nd_drv->type); + + /* + * We allow PMEM devices to be bound to the KMEM driver. + * Force a match if we detect a PMEM device type but + * a KMEM device driver. + */ + if (!match && + (to_nd_device_type(dev) == ND_DEVICE_DAX_PMEM) && + (nd_drv->type == ND_DRIVER_DAX_KMEM)) + match = true; + + return match; } static ASYNC_DOMAIN_EXCLUSIVE(nd_async_domain); _