From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753412AbcLKGcx (ORCPT ); Sun, 11 Dec 2016 01:32:53 -0500 Received: from mga14.intel.com ([192.55.52.115]:22034 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753308AbcLKGcu (ORCPT ); Sun, 11 Dec 2016 01:32:50 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.33,331,1477983600"; d="scan'208";a="41057211" Subject: [PATCH 3/8] dax: register seed device From: Dan Williams To: linux-nvdimm@ml01.01.org Cc: linux-kernel@vger.kernel.org Date: Sat, 10 Dec 2016 22:28:41 -0800 Message-ID: <148143772092.10950.13962446376991710280.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <148143770485.10950.13227732273892953675.stgit@dwillia2-desk3.amr.corp.intel.com> References: <148143770485.10950.13227732273892953675.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.17.1-9-g687f MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Towards adding support for sub-dividing device-dax regions, add a seed device. Similar to libnvdimm a 'seed' device is un-configured device that is enabled after setting configuration parameters. After a given seed device is enabled another is created and this process repeats until no more seed devices can be activated due to dax_available_size being exhausted. For now, this simply registers a seed instance after the first dax device instance is established. Signed-off-by: Dan Williams --- drivers/dax/dax.c | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c index da2962b6f8de..c9ba011e333b 100644 --- a/drivers/dax/dax.c +++ b/drivers/dax/dax.c @@ -40,8 +40,10 @@ MODULE_PARM_DESC(nr_dax, "max number of device-dax instances"); * @kref: to pin while other agents have a need to do lookups * @lock: synchronize changes / consistent-access to the resource tree (@res) * @dev: parent device backing this region + * @seed: next device for dynamic allocation / configuration * @align: allocation and mapping alignment for child dax devices * @res: physical address range of the region + * @child_count: number of registered dax device instances * @pfn_flags: identify whether the pfns are paged back or not */ struct dax_region { @@ -51,8 +53,10 @@ struct dax_region { struct kref kref; struct mutex lock; struct device *dev; + struct device *seed; unsigned int align; struct resource res; + atomic_t child_count; unsigned long pfn_flags; }; @@ -161,10 +165,31 @@ static ssize_t align_show(struct device *dev, } static DEVICE_ATTR_RO(align); +static ssize_t seed_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dax_region *dax_region; + ssize_t rc = -ENXIO; + + device_lock(dev); + dax_region = dev_get_drvdata(dev); + if (dax_region) { + mutex_lock(&dax_region->lock); + if (dax_region->seed) + rc = sprintf(buf, "%s\n", dev_name(dax_region->seed)); + mutex_unlock(&dax_region->lock); + } + device_unlock(dev); + + return rc; +} +static DEVICE_ATTR_RO(seed); + static struct attribute *dax_region_attributes[] = { &dev_attr_available_size.attr, &dev_attr_region_size.attr, &dev_attr_align.attr, + &dev_attr_seed.attr, &dev_attr_id.attr, NULL, }; @@ -295,6 +320,9 @@ static void dax_region_free(struct kref *kref) struct dax_region *dax_region; dax_region = container_of(kref, struct dax_region, kref); + WARN(atomic_read(&dax_region->child_count), + "%s: child count not zero\n", + dev_name(dax_region->dev)); kfree(dax_region); } @@ -691,7 +719,10 @@ static void unregister_dax_dev(void *dev) for (i = 0; i < dax_dev->num_resources; i++) __release_region(&dax_region->res, dax_dev->res[i]->start, resource_size(dax_dev->res[i])); + if (dax_region->seed == dev) + dax_region->seed = NULL; mutex_unlock(&dax_region->lock); + atomic_dec(&dax_region->child_count); cdev_del(cdev); device_unregister(dev); @@ -796,6 +827,16 @@ struct dax_dev *devm_create_dax_dev(struct dax_region *dax_region, if (rc) return ERR_PTR(rc); + if (atomic_inc_return(&dax_region->child_count) == 1) { + struct dax_dev *seed; + + seed = devm_create_dax_dev(dax_region, NULL, 0); + if (IS_ERR(seed)) + dev_warn(parent, "failed to create region seed\n"); + else + dax_region->seed = &seed->dev; + } + return dax_dev; err_cdev: