libnvdimm: pmem label sets and namespace instantiation.
[linux-2.6-block.git] / drivers / nvdimm / bus.c
1 /*
2  * Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of version 2 of the GNU General Public License as
6  * published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful, but
9  * WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
11  * General Public License for more details.
12  */
13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14 #include <linux/vmalloc.h>
15 #include <linux/uaccess.h>
16 #include <linux/module.h>
17 #include <linux/fcntl.h>
18 #include <linux/async.h>
19 #include <linux/ndctl.h>
20 #include <linux/sched.h>
21 #include <linux/slab.h>
22 #include <linux/fs.h>
23 #include <linux/io.h>
24 #include <linux/mm.h>
25 #include <linux/nd.h>
26 #include "nd-core.h"
27 #include "nd.h"
28
29 int nvdimm_major;
30 static int nvdimm_bus_major;
31 static struct class *nd_class;
32
33 static int to_nd_device_type(struct device *dev)
34 {
35         if (is_nvdimm(dev))
36                 return ND_DEVICE_DIMM;
37         else if (is_nd_pmem(dev))
38                 return ND_DEVICE_REGION_PMEM;
39         else if (is_nd_blk(dev))
40                 return ND_DEVICE_REGION_BLK;
41         else if (is_nd_pmem(dev->parent) || is_nd_blk(dev->parent))
42                 return nd_region_to_nstype(to_nd_region(dev->parent));
43
44         return 0;
45 }
46
47 static int nvdimm_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
48 {
49         return add_uevent_var(env, "MODALIAS=" ND_DEVICE_MODALIAS_FMT,
50                         to_nd_device_type(dev));
51 }
52
53 static int nvdimm_bus_match(struct device *dev, struct device_driver *drv)
54 {
55         struct nd_device_driver *nd_drv = to_nd_device_driver(drv);
56
57         return test_bit(to_nd_device_type(dev), &nd_drv->type);
58 }
59
60 static struct module *to_bus_provider(struct device *dev)
61 {
62         /* pin bus providers while regions are enabled */
63         if (is_nd_pmem(dev) || is_nd_blk(dev)) {
64                 struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
65
66                 return nvdimm_bus->module;
67         }
68         return NULL;
69 }
70
71 static void nvdimm_bus_probe_start(struct nvdimm_bus *nvdimm_bus)
72 {
73         nvdimm_bus_lock(&nvdimm_bus->dev);
74         nvdimm_bus->probe_active++;
75         nvdimm_bus_unlock(&nvdimm_bus->dev);
76 }
77
78 static void nvdimm_bus_probe_end(struct nvdimm_bus *nvdimm_bus)
79 {
80         nvdimm_bus_lock(&nvdimm_bus->dev);
81         if (--nvdimm_bus->probe_active == 0)
82                 wake_up(&nvdimm_bus->probe_wait);
83         nvdimm_bus_unlock(&nvdimm_bus->dev);
84 }
85
86 static int nvdimm_bus_probe(struct device *dev)
87 {
88         struct nd_device_driver *nd_drv = to_nd_device_driver(dev->driver);
89         struct module *provider = to_bus_provider(dev);
90         struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
91         int rc;
92
93         if (!try_module_get(provider))
94                 return -ENXIO;
95
96         nvdimm_bus_probe_start(nvdimm_bus);
97         rc = nd_drv->probe(dev);
98         if (rc == 0)
99                 nd_region_probe_success(nvdimm_bus, dev);
100         else
101                 nd_region_disable(nvdimm_bus, dev);
102         nvdimm_bus_probe_end(nvdimm_bus);
103
104         dev_dbg(&nvdimm_bus->dev, "%s.probe(%s) = %d\n", dev->driver->name,
105                         dev_name(dev), rc);
106         if (rc != 0)
107                 module_put(provider);
108         return rc;
109 }
110
111 static int nvdimm_bus_remove(struct device *dev)
112 {
113         struct nd_device_driver *nd_drv = to_nd_device_driver(dev->driver);
114         struct module *provider = to_bus_provider(dev);
115         struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
116         int rc;
117
118         rc = nd_drv->remove(dev);
119         nd_region_disable(nvdimm_bus, dev);
120
121         dev_dbg(&nvdimm_bus->dev, "%s.remove(%s) = %d\n", dev->driver->name,
122                         dev_name(dev), rc);
123         module_put(provider);
124         return rc;
125 }
126
127 static struct bus_type nvdimm_bus_type = {
128         .name = "nd",
129         .uevent = nvdimm_bus_uevent,
130         .match = nvdimm_bus_match,
131         .probe = nvdimm_bus_probe,
132         .remove = nvdimm_bus_remove,
133 };
134
135 static ASYNC_DOMAIN_EXCLUSIVE(nd_async_domain);
136
137 void nd_synchronize(void)
138 {
139         async_synchronize_full_domain(&nd_async_domain);
140 }
141 EXPORT_SYMBOL_GPL(nd_synchronize);
142
143 static void nd_async_device_register(void *d, async_cookie_t cookie)
144 {
145         struct device *dev = d;
146
147         if (device_add(dev) != 0) {
148                 dev_err(dev, "%s: failed\n", __func__);
149                 put_device(dev);
150         }
151         put_device(dev);
152 }
153
154 static void nd_async_device_unregister(void *d, async_cookie_t cookie)
155 {
156         struct device *dev = d;
157
158         device_unregister(dev);
159         put_device(dev);
160 }
161
162 void nd_device_register(struct device *dev)
163 {
164         dev->bus = &nvdimm_bus_type;
165         device_initialize(dev);
166         get_device(dev);
167         async_schedule_domain(nd_async_device_register, dev,
168                         &nd_async_domain);
169 }
170 EXPORT_SYMBOL(nd_device_register);
171
172 void nd_device_unregister(struct device *dev, enum nd_async_mode mode)
173 {
174         switch (mode) {
175         case ND_ASYNC:
176                 get_device(dev);
177                 async_schedule_domain(nd_async_device_unregister, dev,
178                                 &nd_async_domain);
179                 break;
180         case ND_SYNC:
181                 nd_synchronize();
182                 device_unregister(dev);
183                 break;
184         }
185 }
186 EXPORT_SYMBOL(nd_device_unregister);
187
188 /**
189  * __nd_driver_register() - register a region or a namespace driver
190  * @nd_drv: driver to register
191  * @owner: automatically set by nd_driver_register() macro
192  * @mod_name: automatically set by nd_driver_register() macro
193  */
194 int __nd_driver_register(struct nd_device_driver *nd_drv, struct module *owner,
195                 const char *mod_name)
196 {
197         struct device_driver *drv = &nd_drv->drv;
198
199         if (!nd_drv->type) {
200                 pr_debug("driver type bitmask not set (%pf)\n",
201                                 __builtin_return_address(0));
202                 return -EINVAL;
203         }
204
205         if (!nd_drv->probe || !nd_drv->remove) {
206                 pr_debug("->probe() and ->remove() must be specified\n");
207                 return -EINVAL;
208         }
209
210         drv->bus = &nvdimm_bus_type;
211         drv->owner = owner;
212         drv->mod_name = mod_name;
213
214         return driver_register(drv);
215 }
216 EXPORT_SYMBOL(__nd_driver_register);
217
218 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
219                 char *buf)
220 {
221         return sprintf(buf, ND_DEVICE_MODALIAS_FMT "\n",
222                         to_nd_device_type(dev));
223 }
224 static DEVICE_ATTR_RO(modalias);
225
226 static ssize_t devtype_show(struct device *dev, struct device_attribute *attr,
227                 char *buf)
228 {
229         return sprintf(buf, "%s\n", dev->type->name);
230 }
231 static DEVICE_ATTR_RO(devtype);
232
233 static struct attribute *nd_device_attributes[] = {
234         &dev_attr_modalias.attr,
235         &dev_attr_devtype.attr,
236         NULL,
237 };
238
239 /**
240  * nd_device_attribute_group - generic attributes for all devices on an nd bus
241  */
242 struct attribute_group nd_device_attribute_group = {
243         .attrs = nd_device_attributes,
244 };
245 EXPORT_SYMBOL_GPL(nd_device_attribute_group);
246
247 int nvdimm_bus_create_ndctl(struct nvdimm_bus *nvdimm_bus)
248 {
249         dev_t devt = MKDEV(nvdimm_bus_major, nvdimm_bus->id);
250         struct device *dev;
251
252         dev = device_create(nd_class, &nvdimm_bus->dev, devt, nvdimm_bus,
253                         "ndctl%d", nvdimm_bus->id);
254
255         if (IS_ERR(dev)) {
256                 dev_dbg(&nvdimm_bus->dev, "failed to register ndctl%d: %ld\n",
257                                 nvdimm_bus->id, PTR_ERR(dev));
258                 return PTR_ERR(dev);
259         }
260         return 0;
261 }
262
263 void nvdimm_bus_destroy_ndctl(struct nvdimm_bus *nvdimm_bus)
264 {
265         device_destroy(nd_class, MKDEV(nvdimm_bus_major, nvdimm_bus->id));
266 }
267
268 static const struct nd_cmd_desc __nd_cmd_dimm_descs[] = {
269         [ND_CMD_IMPLEMENTED] = { },
270         [ND_CMD_SMART] = {
271                 .out_num = 2,
272                 .out_sizes = { 4, 8, },
273         },
274         [ND_CMD_SMART_THRESHOLD] = {
275                 .out_num = 2,
276                 .out_sizes = { 4, 8, },
277         },
278         [ND_CMD_DIMM_FLAGS] = {
279                 .out_num = 2,
280                 .out_sizes = { 4, 4 },
281         },
282         [ND_CMD_GET_CONFIG_SIZE] = {
283                 .out_num = 3,
284                 .out_sizes = { 4, 4, 4, },
285         },
286         [ND_CMD_GET_CONFIG_DATA] = {
287                 .in_num = 2,
288                 .in_sizes = { 4, 4, },
289                 .out_num = 2,
290                 .out_sizes = { 4, UINT_MAX, },
291         },
292         [ND_CMD_SET_CONFIG_DATA] = {
293                 .in_num = 3,
294                 .in_sizes = { 4, 4, UINT_MAX, },
295                 .out_num = 1,
296                 .out_sizes = { 4, },
297         },
298         [ND_CMD_VENDOR] = {
299                 .in_num = 3,
300                 .in_sizes = { 4, 4, UINT_MAX, },
301                 .out_num = 3,
302                 .out_sizes = { 4, 4, UINT_MAX, },
303         },
304 };
305
306 const struct nd_cmd_desc *nd_cmd_dimm_desc(int cmd)
307 {
308         if (cmd < ARRAY_SIZE(__nd_cmd_dimm_descs))
309                 return &__nd_cmd_dimm_descs[cmd];
310         return NULL;
311 }
312 EXPORT_SYMBOL_GPL(nd_cmd_dimm_desc);
313
314 static const struct nd_cmd_desc __nd_cmd_bus_descs[] = {
315         [ND_CMD_IMPLEMENTED] = { },
316         [ND_CMD_ARS_CAP] = {
317                 .in_num = 2,
318                 .in_sizes = { 8, 8, },
319                 .out_num = 2,
320                 .out_sizes = { 4, 4, },
321         },
322         [ND_CMD_ARS_START] = {
323                 .in_num = 4,
324                 .in_sizes = { 8, 8, 2, 6, },
325                 .out_num = 1,
326                 .out_sizes = { 4, },
327         },
328         [ND_CMD_ARS_STATUS] = {
329                 .out_num = 2,
330                 .out_sizes = { 4, UINT_MAX, },
331         },
332 };
333
334 const struct nd_cmd_desc *nd_cmd_bus_desc(int cmd)
335 {
336         if (cmd < ARRAY_SIZE(__nd_cmd_bus_descs))
337                 return &__nd_cmd_bus_descs[cmd];
338         return NULL;
339 }
340 EXPORT_SYMBOL_GPL(nd_cmd_bus_desc);
341
342 u32 nd_cmd_in_size(struct nvdimm *nvdimm, int cmd,
343                 const struct nd_cmd_desc *desc, int idx, void *buf)
344 {
345         if (idx >= desc->in_num)
346                 return UINT_MAX;
347
348         if (desc->in_sizes[idx] < UINT_MAX)
349                 return desc->in_sizes[idx];
350
351         if (nvdimm && cmd == ND_CMD_SET_CONFIG_DATA && idx == 2) {
352                 struct nd_cmd_set_config_hdr *hdr = buf;
353
354                 return hdr->in_length;
355         } else if (nvdimm && cmd == ND_CMD_VENDOR && idx == 2) {
356                 struct nd_cmd_vendor_hdr *hdr = buf;
357
358                 return hdr->in_length;
359         }
360
361         return UINT_MAX;
362 }
363 EXPORT_SYMBOL_GPL(nd_cmd_in_size);
364
365 u32 nd_cmd_out_size(struct nvdimm *nvdimm, int cmd,
366                 const struct nd_cmd_desc *desc, int idx, const u32 *in_field,
367                 const u32 *out_field)
368 {
369         if (idx >= desc->out_num)
370                 return UINT_MAX;
371
372         if (desc->out_sizes[idx] < UINT_MAX)
373                 return desc->out_sizes[idx];
374
375         if (nvdimm && cmd == ND_CMD_GET_CONFIG_DATA && idx == 1)
376                 return in_field[1];
377         else if (nvdimm && cmd == ND_CMD_VENDOR && idx == 2)
378                 return out_field[1];
379         else if (!nvdimm && cmd == ND_CMD_ARS_STATUS && idx == 1)
380                 return ND_CMD_ARS_STATUS_MAX;
381
382         return UINT_MAX;
383 }
384 EXPORT_SYMBOL_GPL(nd_cmd_out_size);
385
386 void wait_nvdimm_bus_probe_idle(struct device *dev)
387 {
388         struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
389
390         do {
391                 if (nvdimm_bus->probe_active == 0)
392                         break;
393                 nvdimm_bus_unlock(&nvdimm_bus->dev);
394                 wait_event(nvdimm_bus->probe_wait,
395                                 nvdimm_bus->probe_active == 0);
396                 nvdimm_bus_lock(&nvdimm_bus->dev);
397         } while (true);
398 }
399
400 /* set_config requires an idle interleave set */
401 static int nd_cmd_clear_to_send(struct nvdimm *nvdimm, unsigned int cmd)
402 {
403         struct nvdimm_bus *nvdimm_bus;
404
405         if (!nvdimm || cmd != ND_CMD_SET_CONFIG_DATA)
406                 return 0;
407
408         nvdimm_bus = walk_to_nvdimm_bus(&nvdimm->dev);
409         wait_nvdimm_bus_probe_idle(&nvdimm_bus->dev);
410
411         if (atomic_read(&nvdimm->busy))
412                 return -EBUSY;
413         return 0;
414 }
415
416 static int __nd_ioctl(struct nvdimm_bus *nvdimm_bus, struct nvdimm *nvdimm,
417                 int read_only, unsigned int ioctl_cmd, unsigned long arg)
418 {
419         struct nvdimm_bus_descriptor *nd_desc = nvdimm_bus->nd_desc;
420         size_t buf_len = 0, in_len = 0, out_len = 0;
421         static char out_env[ND_CMD_MAX_ENVELOPE];
422         static char in_env[ND_CMD_MAX_ENVELOPE];
423         const struct nd_cmd_desc *desc = NULL;
424         unsigned int cmd = _IOC_NR(ioctl_cmd);
425         void __user *p = (void __user *) arg;
426         struct device *dev = &nvdimm_bus->dev;
427         const char *cmd_name, *dimm_name;
428         unsigned long dsm_mask;
429         void *buf;
430         int rc, i;
431
432         if (nvdimm) {
433                 desc = nd_cmd_dimm_desc(cmd);
434                 cmd_name = nvdimm_cmd_name(cmd);
435                 dsm_mask = nvdimm->dsm_mask ? *(nvdimm->dsm_mask) : 0;
436                 dimm_name = dev_name(&nvdimm->dev);
437         } else {
438                 desc = nd_cmd_bus_desc(cmd);
439                 cmd_name = nvdimm_bus_cmd_name(cmd);
440                 dsm_mask = nd_desc->dsm_mask;
441                 dimm_name = "bus";
442         }
443
444         if (!desc || (desc->out_num + desc->in_num == 0) ||
445                         !test_bit(cmd, &dsm_mask))
446                 return -ENOTTY;
447
448         /* fail write commands (when read-only) */
449         if (read_only)
450                 switch (ioctl_cmd) {
451                 case ND_IOCTL_VENDOR:
452                 case ND_IOCTL_SET_CONFIG_DATA:
453                 case ND_IOCTL_ARS_START:
454                         dev_dbg(&nvdimm_bus->dev, "'%s' command while read-only.\n",
455                                         nvdimm ? nvdimm_cmd_name(cmd)
456                                         : nvdimm_bus_cmd_name(cmd));
457                         return -EPERM;
458                 default:
459                         break;
460                 }
461
462         /* process an input envelope */
463         for (i = 0; i < desc->in_num; i++) {
464                 u32 in_size, copy;
465
466                 in_size = nd_cmd_in_size(nvdimm, cmd, desc, i, in_env);
467                 if (in_size == UINT_MAX) {
468                         dev_err(dev, "%s:%s unknown input size cmd: %s field: %d\n",
469                                         __func__, dimm_name, cmd_name, i);
470                         return -ENXIO;
471                 }
472                 if (!access_ok(VERIFY_READ, p + in_len, in_size))
473                         return -EFAULT;
474                 if (in_len < sizeof(in_env))
475                         copy = min_t(u32, sizeof(in_env) - in_len, in_size);
476                 else
477                         copy = 0;
478                 if (copy && copy_from_user(&in_env[in_len], p + in_len, copy))
479                         return -EFAULT;
480                 in_len += in_size;
481         }
482
483         /* process an output envelope */
484         for (i = 0; i < desc->out_num; i++) {
485                 u32 out_size = nd_cmd_out_size(nvdimm, cmd, desc, i,
486                                 (u32 *) in_env, (u32 *) out_env);
487                 u32 copy;
488
489                 if (out_size == UINT_MAX) {
490                         dev_dbg(dev, "%s:%s unknown output size cmd: %s field: %d\n",
491                                         __func__, dimm_name, cmd_name, i);
492                         return -EFAULT;
493                 }
494                 if (!access_ok(VERIFY_WRITE, p + in_len + out_len, out_size))
495                         return -EFAULT;
496                 if (out_len < sizeof(out_env))
497                         copy = min_t(u32, sizeof(out_env) - out_len, out_size);
498                 else
499                         copy = 0;
500                 if (copy && copy_from_user(&out_env[out_len],
501                                         p + in_len + out_len, copy))
502                         return -EFAULT;
503                 out_len += out_size;
504         }
505
506         buf_len = out_len + in_len;
507         if (!access_ok(VERIFY_WRITE, p, sizeof(buf_len)))
508                 return -EFAULT;
509
510         if (buf_len > ND_IOCTL_MAX_BUFLEN) {
511                 dev_dbg(dev, "%s:%s cmd: %s buf_len: %zu > %d\n", __func__,
512                                 dimm_name, cmd_name, buf_len,
513                                 ND_IOCTL_MAX_BUFLEN);
514                 return -EINVAL;
515         }
516
517         buf = vmalloc(buf_len);
518         if (!buf)
519                 return -ENOMEM;
520
521         if (copy_from_user(buf, p, buf_len)) {
522                 rc = -EFAULT;
523                 goto out;
524         }
525
526         nvdimm_bus_lock(&nvdimm_bus->dev);
527         rc = nd_cmd_clear_to_send(nvdimm, cmd);
528         if (rc)
529                 goto out_unlock;
530
531         rc = nd_desc->ndctl(nd_desc, nvdimm, cmd, buf, buf_len);
532         if (rc < 0)
533                 goto out_unlock;
534         if (copy_to_user(p, buf, buf_len))
535                 rc = -EFAULT;
536  out_unlock:
537         nvdimm_bus_unlock(&nvdimm_bus->dev);
538  out:
539         vfree(buf);
540         return rc;
541 }
542
543 static long nd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
544 {
545         long id = (long) file->private_data;
546         int rc = -ENXIO, read_only;
547         struct nvdimm_bus *nvdimm_bus;
548
549         read_only = (O_RDWR != (file->f_flags & O_ACCMODE));
550         mutex_lock(&nvdimm_bus_list_mutex);
551         list_for_each_entry(nvdimm_bus, &nvdimm_bus_list, list) {
552                 if (nvdimm_bus->id == id) {
553                         rc = __nd_ioctl(nvdimm_bus, NULL, read_only, cmd, arg);
554                         break;
555                 }
556         }
557         mutex_unlock(&nvdimm_bus_list_mutex);
558
559         return rc;
560 }
561
562 static int match_dimm(struct device *dev, void *data)
563 {
564         long id = (long) data;
565
566         if (is_nvdimm(dev)) {
567                 struct nvdimm *nvdimm = to_nvdimm(dev);
568
569                 return nvdimm->id == id;
570         }
571
572         return 0;
573 }
574
575 static long nvdimm_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
576 {
577         int rc = -ENXIO, read_only;
578         struct nvdimm_bus *nvdimm_bus;
579
580         read_only = (O_RDWR != (file->f_flags & O_ACCMODE));
581         mutex_lock(&nvdimm_bus_list_mutex);
582         list_for_each_entry(nvdimm_bus, &nvdimm_bus_list, list) {
583                 struct device *dev = device_find_child(&nvdimm_bus->dev,
584                                 file->private_data, match_dimm);
585                 struct nvdimm *nvdimm;
586
587                 if (!dev)
588                         continue;
589
590                 nvdimm = to_nvdimm(dev);
591                 rc = __nd_ioctl(nvdimm_bus, nvdimm, read_only, cmd, arg);
592                 put_device(dev);
593                 break;
594         }
595         mutex_unlock(&nvdimm_bus_list_mutex);
596
597         return rc;
598 }
599
600 static int nd_open(struct inode *inode, struct file *file)
601 {
602         long minor = iminor(inode);
603
604         file->private_data = (void *) minor;
605         return 0;
606 }
607
608 static const struct file_operations nvdimm_bus_fops = {
609         .owner = THIS_MODULE,
610         .open = nd_open,
611         .unlocked_ioctl = nd_ioctl,
612         .compat_ioctl = nd_ioctl,
613         .llseek = noop_llseek,
614 };
615
616 static const struct file_operations nvdimm_fops = {
617         .owner = THIS_MODULE,
618         .open = nd_open,
619         .unlocked_ioctl = nvdimm_ioctl,
620         .compat_ioctl = nvdimm_ioctl,
621         .llseek = noop_llseek,
622 };
623
624 int __init nvdimm_bus_init(void)
625 {
626         int rc;
627
628         rc = bus_register(&nvdimm_bus_type);
629         if (rc)
630                 return rc;
631
632         rc = register_chrdev(0, "ndctl", &nvdimm_bus_fops);
633         if (rc < 0)
634                 goto err_bus_chrdev;
635         nvdimm_bus_major = rc;
636
637         rc = register_chrdev(0, "dimmctl", &nvdimm_fops);
638         if (rc < 0)
639                 goto err_dimm_chrdev;
640         nvdimm_major = rc;
641
642         nd_class = class_create(THIS_MODULE, "nd");
643         if (IS_ERR(nd_class))
644                 goto err_class;
645
646         return 0;
647
648  err_class:
649         unregister_chrdev(nvdimm_major, "dimmctl");
650  err_dimm_chrdev:
651         unregister_chrdev(nvdimm_bus_major, "ndctl");
652  err_bus_chrdev:
653         bus_unregister(&nvdimm_bus_type);
654
655         return rc;
656 }
657
658 void nvdimm_bus_exit(void)
659 {
660         class_destroy(nd_class);
661         unregister_chrdev(nvdimm_bus_major, "ndctl");
662         unregister_chrdev(nvdimm_major, "dimmctl");
663         bus_unregister(&nvdimm_bus_type);
664 }