From patchwork Tue Aug 16 17:09:49 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 9284285 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 1F70D60839 for ; Tue, 16 Aug 2016 17:12:35 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0D8D6286C1 for ; Tue, 16 Aug 2016 17:12:35 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 01CE0286C5; Tue, 16 Aug 2016 17:12:34 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id F21DA286C1 for ; Tue, 16 Aug 2016 17:12:32 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 2E4061A1DF2; Tue, 16 Aug 2016 10:12:32 -0700 (PDT) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by ml01.01.org (Postfix) with ESMTP id 582AE1A1DF2 for ; Tue, 16 Aug 2016 10:12:30 -0700 (PDT) Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga104.fm.intel.com with ESMTP; 16 Aug 2016 10:12:20 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos; i="5.28,529,1464678000"; d="scan'208"; a="1026462868" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.14]) by fmsmga001.fm.intel.com with ESMTP; 16 Aug 2016 10:12:12 -0700 Subject: [PATCH 4/4] dax: register seed device From: Dan Williams To: linux-nvdimm@lists.01.org Date: Tue, 16 Aug 2016 10:09:49 -0700 Message-ID: <147136738895.26813.7749212910378676162.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <147136736786.26813.5042217541564666020.stgit@dwillia2-desk3.amr.corp.intel.com> References: <147136736786.26813.5042217541564666020.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.17.1-9-g687f MIME-Version: 1.0 X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-kernel@vger.kernel.org Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP 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 cbc765c81600..51334bcb5aa7 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; }; @@ -111,8 +115,29 @@ static ssize_t available_size_show(struct device *dev, } static DEVICE_ATTR_RO(available_size); +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_seed.attr, NULL, }; @@ -242,6 +267,9 @@ 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); } @@ -638,7 +666,10 @@ 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); @@ -743,6 +774,16 @@ 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: