libnvdimm, nvdimm: dimm driver and base libnvdimm device-driver infrastructure

* Implement the device-model infrastructure for loading modules and
  attaching drivers to nvdimm devices.  This is a simple association of a
  nd-device-type number with a driver that has a bitmask of supported
  device types.  To facilitate userspace bind/unbind operations 'modalias'
  and 'devtype', that also appear in the uevent, are added as generic
  sysfs attributes for all nvdimm devices.  The reason for the device-type
  number is to support sub-types within a given parent devtype, be it a
  vendor-specific sub-type or otherwise.

* The first consumer of this infrastructure is the driver
  for dimm devices.  It simply uses control messages to retrieve and
  store the configuration-data image (label set) from each dimm.

Note: nd_device_register() arranges for asynchronous registration of
      nvdimm bus devices by default.

Cc: Greg KH <[email protected]>
Cc: Neil Brown <[email protected]>
Acked-by: Christoph Hellwig <[email protected]>
Tested-by: Toshi Kani <[email protected]>
Signed-off-by: Dan Williams <[email protected]>

drivers/nvdimm/Makefile

@@ -3,3 +3,4 @@ obj-$(CONFIG_LIBNVDIMM) += libnvdimm.o
 libnvdimm-y := core.o
 libnvdimm-y += bus.o
 libnvdimm-y += dimm_devs.o
+libnvdimm-y += dimm.o

drivers/nvdimm/bus.c

@@ -16,20 +16,184 @@
 #include <linux/fcntl.h>
 #include <linux/async.h>
 #include <linux/ndctl.h>
+#include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/fs.h>
 #include <linux/io.h>
 #include <linux/mm.h>
+#include <linux/nd.h>
 #include "nd-core.h"
+#include "nd.h"
 
 int nvdimm_major;
 static int nvdimm_bus_major;
 static struct class *nd_class;
 
-struct bus_type nvdimm_bus_type = {
+static int to_nd_device_type(struct device *dev)
+{
+	if (is_nvdimm(dev))
+		return ND_DEVICE_DIMM;
+
+	return 0;
+}
+
+static int nvdimm_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	return add_uevent_var(env, "MODALIAS=" ND_DEVICE_MODALIAS_FMT,
+			to_nd_device_type(dev));
+}
+
+static int nvdimm_bus_match(struct device *dev, struct device_driver *drv)
+{
+	struct nd_device_driver *nd_drv = to_nd_device_driver(drv);
+
+	return test_bit(to_nd_device_type(dev), &nd_drv->type);
+}
+
+static int nvdimm_bus_probe(struct device *dev)
+{
+	struct nd_device_driver *nd_drv = to_nd_device_driver(dev->driver);
+	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
+	int rc;
+
+	rc = nd_drv->probe(dev);
+	dev_dbg(&nvdimm_bus->dev, "%s.probe(%s) = %d\n", dev->driver->name,
+			dev_name(dev), rc);
+	return rc;
+}
+
+static int nvdimm_bus_remove(struct device *dev)
+{
+	struct nd_device_driver *nd_drv = to_nd_device_driver(dev->driver);
+	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
+	int rc;
+
+	rc = nd_drv->remove(dev);
+	dev_dbg(&nvdimm_bus->dev, "%s.remove(%s) = %d\n", dev->driver->name,
+			dev_name(dev), rc);
+	return rc;
+}
+
+static struct bus_type nvdimm_bus_type = {
 	.name = "nd",
+	.uevent = nvdimm_bus_uevent,
+	.match = nvdimm_bus_match,
+	.probe = nvdimm_bus_probe,
+	.remove = nvdimm_bus_remove,
 };
 
+static ASYNC_DOMAIN_EXCLUSIVE(nd_async_domain);
+
+void nd_synchronize(void)
+{
+	async_synchronize_full_domain(&nd_async_domain);
+}
+EXPORT_SYMBOL_GPL(nd_synchronize);
+
+static void nd_async_device_register(void *d, async_cookie_t cookie)
+{
+	struct device *dev = d;
+
+	if (device_add(dev) != 0) {
+		dev_err(dev, "%s: failed\n", __func__);
+		put_device(dev);
+	}
+	put_device(dev);
+}
+
+static void nd_async_device_unregister(void *d, async_cookie_t cookie)
+{
+	struct device *dev = d;
+
+	device_unregister(dev);
+	put_device(dev);
+}
+
+void nd_device_register(struct device *dev)
+{
+	dev->bus = &nvdimm_bus_type;
+	device_initialize(dev);
+	get_device(dev);
+	async_schedule_domain(nd_async_device_register, dev,
+			&nd_async_domain);
+}
+EXPORT_SYMBOL(nd_device_register);
+
+void nd_device_unregister(struct device *dev, enum nd_async_mode mode)
+{
+	switch (mode) {
+	case ND_ASYNC:
+		get_device(dev);
+		async_schedule_domain(nd_async_device_unregister, dev,
+				&nd_async_domain);
+		break;
+	case ND_SYNC:
+		nd_synchronize();
+		device_unregister(dev);
+		break;
+	}
+}
+EXPORT_SYMBOL(nd_device_unregister);
+
+/**
+ * __nd_driver_register() - register a region or a namespace driver
+ * @nd_drv: driver to register
+ * @owner: automatically set by nd_driver_register() macro
+ * @mod_name: automatically set by nd_driver_register() macro
+ */
+int __nd_driver_register(struct nd_device_driver *nd_drv, struct module *owner,
+		const char *mod_name)
+{
+	struct device_driver *drv = &nd_drv->drv;
+
+	if (!nd_drv->type) {
+		pr_debug("driver type bitmask not set (%pf)\n",
+				__builtin_return_address(0));
+		return -EINVAL;
+	}
+
+	if (!nd_drv->probe || !nd_drv->remove) {
+		pr_debug("->probe() and ->remove() must be specified\n");
+		return -EINVAL;
+	}
+
+	drv->bus = &nvdimm_bus_type;
+	drv->owner = owner;
+	drv->mod_name = mod_name;
+
+	return driver_register(drv);
+}
+EXPORT_SYMBOL(__nd_driver_register);
+
+static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
+		char *buf)
+{
+	return sprintf(buf, ND_DEVICE_MODALIAS_FMT "\n",
+			to_nd_device_type(dev));
+}
+static DEVICE_ATTR_RO(modalias);
+
+static ssize_t devtype_show(struct device *dev, struct device_attribute *attr,
+		char *buf)
+{
+	return sprintf(buf, "%s\n", dev->type->name);
+}
+static DEVICE_ATTR_RO(devtype);
+
+static struct attribute *nd_device_attributes[] = {
+	&dev_attr_modalias.attr,
+	&dev_attr_devtype.attr,
+	NULL,
+};
+
+/**
+ * nd_device_attribute_group - generic attributes for all devices on an nd bus
+ */
+struct attribute_group nd_device_attribute_group = {
+	.attrs = nd_device_attributes,
+};
+EXPORT_SYMBOL_GPL(nd_device_attribute_group);
+
 int nvdimm_bus_create_ndctl(struct nvdimm_bus *nvdimm_bus)
 {
 	dev_t devt = MKDEV(nvdimm_bus_major, nvdimm_bus->id);
@@ -404,7 +568,7 @@ int __init nvdimm_bus_init(void)
 	return rc;
 }
 
-void __exit nvdimm_bus_exit(void)
+void nvdimm_bus_exit(void)
 {
 	class_destroy(nd_class);
 	unregister_chrdev(nvdimm_bus_major, "ndctl");

drivers/nvdimm/core.c

@@ -18,6 +18,7 @@
 #include <linux/mutex.h>
 #include <linux/slab.h>
 #include "nd-core.h"
+#include "nd.h"
 
 LIST_HEAD(nvdimm_bus_list);
 DEFINE_MUTEX(nvdimm_bus_list_mutex);
@@ -98,8 +99,33 @@ static ssize_t provider_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(provider);
 
+static int flush_namespaces(struct device *dev, void *data)
+{
+	device_lock(dev);
+	device_unlock(dev);
+	return 0;
+}
+
+static int flush_regions_dimms(struct device *dev, void *data)
+{
+	device_lock(dev);
+	device_unlock(dev);
+	device_for_each_child(dev, NULL, flush_namespaces);
+	return 0;
+}
+
+static ssize_t wait_probe_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	nd_synchronize();
+	device_for_each_child(dev, NULL, flush_regions_dimms);
+	return sprintf(buf, "1\n");
+}
+static DEVICE_ATTR_RO(wait_probe);
+
 static struct attribute *nvdimm_bus_attributes[] = {
 	&dev_attr_commands.attr,
+	&dev_attr_wait_probe.attr,
 	&dev_attr_provider.attr,
 	NULL,
 };
@@ -161,7 +187,7 @@ static int child_unregister(struct device *dev, void *data)
 	if (dev->class)
 		/* pass */;
 	else
-		device_unregister(dev);
+		nd_device_unregister(dev, ND_SYNC);
 	return 0;
 }
 
@@ -174,6 +200,7 @@ void nvdimm_bus_unregister(struct nvdimm_bus *nvdimm_bus)
 	list_del_init(&nvdimm_bus->list);
 	mutex_unlock(&nvdimm_bus_list_mutex);
 
+	nd_synchronize();
 	device_for_each_child(&nvdimm_bus->dev, NULL, child_unregister);
 	nvdimm_bus_destroy_ndctl(nvdimm_bus);
 
@@ -183,12 +210,24 @@ EXPORT_SYMBOL_GPL(nvdimm_bus_unregister);
 
 static __init int libnvdimm_init(void)
 {
-	return nvdimm_bus_init();
+	int rc;
+
+	rc = nvdimm_bus_init();
+	if (rc)
+		return rc;
+	rc = nvdimm_init();
+	if (rc)
+		goto err_dimm;
+	return 0;
+ err_dimm:
+	nvdimm_bus_exit();
+	return rc;
 }
 
 static __exit void libnvdimm_exit(void)
 {
 	WARN_ON(!list_empty(&nvdimm_bus_list));
+	nvdimm_exit();
 	nvdimm_bus_exit();
 }
 

drivers/nvdimm/dimm.c

@@ -0,0 +1,92 @@
+/*
+ * Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+#include <linux/vmalloc.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/sizes.h>
+#include <linux/ndctl.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/nd.h>
+#include "nd.h"
+
+static void free_data(struct nvdimm_drvdata *ndd)
+{
+	if (!ndd)
+		return;
+
+	if (ndd->data && is_vmalloc_addr(ndd->data))
+		vfree(ndd->data);
+	else
+		kfree(ndd->data);
+	kfree(ndd);
+}
+
+static int nvdimm_probe(struct device *dev)
+{
+	struct nvdimm_drvdata *ndd;
+	int rc;
+
+	ndd = kzalloc(sizeof(*ndd), GFP_KERNEL);
+	if (!ndd)
+		return -ENOMEM;
+
+	dev_set_drvdata(dev, ndd);
+	ndd->dev = dev;
+
+	rc = nvdimm_init_nsarea(ndd);
+	if (rc)
+		goto err;
+
+	rc = nvdimm_init_config_data(ndd);
+	if (rc)
+		goto err;
+
+	dev_dbg(dev, "config data size: %d\n", ndd->nsarea.config_size);
+
+	return 0;
+
+ err:
+	free_data(ndd);
+	return rc;
+}
+
+static int nvdimm_remove(struct device *dev)
+{
+	struct nvdimm_drvdata *ndd = dev_get_drvdata(dev);
+
+	free_data(ndd);
+
+	return 0;
+}
+
+static struct nd_device_driver nvdimm_driver = {
+	.probe = nvdimm_probe,
+	.remove = nvdimm_remove,
+	.drv = {
+		.name = "nvdimm",
+	},
+	.type = ND_DRIVER_DIMM,
+};
+
+int __init nvdimm_init(void)
+{
+	return nd_driver_register(&nvdimm_driver);
+}
+
+void __exit nvdimm_exit(void)
+{
+	driver_unregister(&nvdimm_driver.drv);
+}
+
+MODULE_ALIAS_ND_DEVICE(ND_DEVICE_DIMM);

drivers/nvdimm/dimm_devs.c

@@ -11,6 +11,7 @@
  * General Public License for more details.
  */
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/vmalloc.h>
 #include <linux/device.h>
 #include <linux/ndctl.h>
 #include <linux/slab.h>
@@ -18,9 +19,115 @@
 #include <linux/fs.h>
 #include <linux/mm.h>
 #include "nd-core.h"
+#include "nd.h"
 
 static DEFINE_IDA(dimm_ida);
 
+/*
+ * Retrieve bus and dimm handle and return if this bus supports
+ * get_config_data commands
+ */
+static int __validate_dimm(struct nvdimm_drvdata *ndd)
+{
+	struct nvdimm *nvdimm;
+
+	if (!ndd)
+		return -EINVAL;
+
+	nvdimm = to_nvdimm(ndd->dev);
+
+	if (!nvdimm->dsm_mask)
+		return -ENXIO;
+	if (!test_bit(ND_CMD_GET_CONFIG_DATA, nvdimm->dsm_mask))
+		return -ENXIO;
+
+	return 0;
+}
+
+static int validate_dimm(struct nvdimm_drvdata *ndd)
+{
+	int rc = __validate_dimm(ndd);
+
+	if (rc && ndd)
+		dev_dbg(ndd->dev, "%pf: %s error: %d\n",
+				__builtin_return_address(0), __func__, rc);
+	return rc;
+}
+
+/**
+ * nvdimm_init_nsarea - determine the geometry of a dimm's namespace area
+ * @nvdimm: dimm to initialize
+ */
+int nvdimm_init_nsarea(struct nvdimm_drvdata *ndd)
+{
+	struct nd_cmd_get_config_size *cmd = &ndd->nsarea;
+	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(ndd->dev);
+	struct nvdimm_bus_descriptor *nd_desc;
+	int rc = validate_dimm(ndd);
+
+	if (rc)
+		return rc;
+
+	if (cmd->config_size)
+		return 0; /* already valid */
+
+	memset(cmd, 0, sizeof(*cmd));
+	nd_desc = nvdimm_bus->nd_desc;
+	return nd_desc->ndctl(nd_desc, to_nvdimm(ndd->dev),
+			ND_CMD_GET_CONFIG_SIZE, cmd, sizeof(*cmd));
+}
+
+int nvdimm_init_config_data(struct nvdimm_drvdata *ndd)
+{
+	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(ndd->dev);
+	struct nd_cmd_get_config_data_hdr *cmd;
+	struct nvdimm_bus_descriptor *nd_desc;
+	int rc = validate_dimm(ndd);
+	u32 max_cmd_size, config_size;
+	size_t offset;
+
+	if (rc)
+		return rc;
+
+	if (ndd->data)
+		return 0;
+
+	if (ndd->nsarea.status || ndd->nsarea.max_xfer == 0)
+		return -ENXIO;
+
+	ndd->data = kmalloc(ndd->nsarea.config_size, GFP_KERNEL);
+	if (!ndd->data)
+		ndd->data = vmalloc(ndd->nsarea.config_size);
+
+	if (!ndd->data)
+		return -ENOMEM;
+
+	max_cmd_size = min_t(u32, PAGE_SIZE, ndd->nsarea.max_xfer);
+	cmd = kzalloc(max_cmd_size + sizeof(*cmd), GFP_KERNEL);
+	if (!cmd)
+		return -ENOMEM;
+
+	nd_desc = nvdimm_bus->nd_desc;
+	for (config_size = ndd->nsarea.config_size, offset = 0;
+			config_size; config_size -= cmd->in_length,
+			offset += cmd->in_length) {
+		cmd->in_length = min(config_size, max_cmd_size);
+		cmd->in_offset = offset;
+		rc = nd_desc->ndctl(nd_desc, to_nvdimm(ndd->dev),
+				ND_CMD_GET_CONFIG_DATA, cmd,
+				cmd->in_length + sizeof(*cmd));
+		if (rc || cmd->status) {
+			rc = -ENXIO;
+			break;
+		}
+		memcpy(ndd->data + offset, cmd->out_buf, cmd->in_length);
+	}
+	dev_dbg(ndd->dev, "%s: len: %zu rc: %d\n", __func__, offset, rc);
+	kfree(cmd);
+
+	return rc;
+}
+
 static void nvdimm_release(struct device *dev)
 {
 	struct nvdimm *nvdimm = to_nvdimm(dev);
@@ -111,14 +218,33 @@ struct nvdimm *nvdimm_create(struct nvdimm_bus *nvdimm_bus, void *provider_data,
 	dev_set_name(dev, "nmem%d", nvdimm->id);
 	dev->parent = &nvdimm_bus->dev;
 	dev->type = &nvdimm_device_type;
-	dev->bus = &nvdimm_bus_type;
 	dev->devt = MKDEV(nvdimm_major, nvdimm->id);
 	dev->groups = groups;
-	if (device_register(dev) != 0) {
-		put_device(dev);
-		return NULL;
-	}
+	nd_device_register(dev);
 
 	return nvdimm;
 }
 EXPORT_SYMBOL_GPL(nvdimm_create);
+
+static int count_dimms(struct device *dev, void *c)
+{
+	int *count = c;
+
+	if (is_nvdimm(dev))
+		(*count)++;
+	return 0;
+}
+
+int nvdimm_bus_check_dimm_count(struct nvdimm_bus *nvdimm_bus, int dimm_count)
+{
+	int count = 0;
+	/* Flush any possible dimm registration failures */
+	nd_synchronize();
+
+	device_for_each_child(&nvdimm_bus->dev, &count, count_dimms);
+	dev_dbg(&nvdimm_bus->dev, "%s: count: %d\n", __func__, count);
+	if (count != dimm_count)
+		return -ENXIO;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nvdimm_bus_check_dimm_count);

drivers/nvdimm/nd-core.h

@@ -17,7 +17,6 @@
 
 extern struct list_head nvdimm_bus_list;
 extern struct mutex nvdimm_bus_list_mutex;
-extern struct bus_type nvdimm_bus_type;
 extern int nvdimm_major;
 
 struct nvdimm_bus {
@@ -35,10 +34,11 @@ struct nvdimm {
 	int id;
 };
 
-bool is_nvdimm(struct device *dev);
 struct nvdimm_bus *walk_to_nvdimm_bus(struct device *nd_dev);
 int __init nvdimm_bus_init(void);
-void __exit nvdimm_bus_exit(void);
+void nvdimm_bus_exit(void);
 int nvdimm_bus_create_ndctl(struct nvdimm_bus *nvdimm_bus);
 void nvdimm_bus_destroy_ndctl(struct nvdimm_bus *nvdimm_bus);
+void nd_synchronize(void);
+bool is_nvdimm(struct device *dev);
 #endif /* __ND_CORE_H__ */

drivers/nvdimm/nd.h

@@ -0,0 +1,36 @@
+/*
+ * Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+#ifndef __ND_H__
+#define __ND_H__
+#include <linux/device.h>
+#include <linux/mutex.h>
+#include <linux/ndctl.h>
+
+struct nvdimm_drvdata {
+	struct device *dev;
+	struct nd_cmd_get_config_size nsarea;
+	void *data;
+};
+
+enum nd_async_mode {
+	ND_SYNC,
+	ND_ASYNC,
+};
+
+void nd_device_register(struct device *dev);
+void nd_device_unregister(struct device *dev, enum nd_async_mode mode);
+int __init nvdimm_init(void);
+void nvdimm_exit(void);
+int nvdimm_init_nsarea(struct nvdimm_drvdata *ndd);
+int nvdimm_init_config_data(struct nvdimm_drvdata *ndd);
+#endif /* __ND_H__ */