x86, pmem: use memcpy_mcsafe() for memcpy_from_pmem()
[sfrench/cifs-2.6.git] / drivers / nvdimm / pmem.c
1 /*
2  * Persistent Memory Driver
3  *
4  * Copyright (c) 2014-2015, Intel Corporation.
5  * Copyright (c) 2015, Christoph Hellwig <hch@lst.de>.
6  * Copyright (c) 2015, Boaz Harrosh <boaz@plexistor.com>.
7  *
8  * This program is free software; you can redistribute it and/or modify it
9  * under the terms and conditions of the GNU General Public License,
10  * version 2, as published by the Free Software Foundation.
11  *
12  * This program is distributed in the hope it will be useful, but WITHOUT
13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
15  * more details.
16  */
17
18 #include <asm/cacheflush.h>
19 #include <linux/blkdev.h>
20 #include <linux/hdreg.h>
21 #include <linux/init.h>
22 #include <linux/platform_device.h>
23 #include <linux/module.h>
24 #include <linux/moduleparam.h>
25 #include <linux/badblocks.h>
26 #include <linux/memremap.h>
27 #include <linux/vmalloc.h>
28 #include <linux/pfn_t.h>
29 #include <linux/slab.h>
30 #include <linux/pmem.h>
31 #include <linux/nd.h>
32 #include "pfn.h"
33 #include "nd.h"
34
35 struct pmem_device {
36         struct request_queue    *pmem_queue;
37         struct gendisk          *pmem_disk;
38         struct nd_namespace_common *ndns;
39
40         /* One contiguous memory region per device */
41         phys_addr_t             phys_addr;
42         /* when non-zero this device is hosting a 'pfn' instance */
43         phys_addr_t             data_offset;
44         u64                     pfn_flags;
45         void __pmem             *virt_addr;
46         /* immutable base size of the namespace */
47         size_t                  size;
48         /* trim size when namespace capacity has been section aligned */
49         u32                     pfn_pad;
50         struct badblocks        bb;
51 };
52
53 static bool is_bad_pmem(struct badblocks *bb, sector_t sector, unsigned int len)
54 {
55         if (bb->count) {
56                 sector_t first_bad;
57                 int num_bad;
58
59                 return !!badblocks_check(bb, sector, len / 512, &first_bad,
60                                 &num_bad);
61         }
62
63         return false;
64 }
65
66 static void pmem_clear_poison(struct pmem_device *pmem, phys_addr_t offset,
67                 unsigned int len)
68 {
69         struct device *dev = disk_to_dev(pmem->pmem_disk);
70         sector_t sector;
71         long cleared;
72
73         sector = (offset - pmem->data_offset) / 512;
74         cleared = nvdimm_clear_poison(dev, pmem->phys_addr + offset, len);
75
76         if (cleared > 0 && cleared / 512) {
77                 dev_dbg(dev, "%s: %llx clear %ld sector%s\n",
78                                 __func__, (unsigned long long) sector,
79                                 cleared / 512, cleared / 512 > 1 ? "s" : "");
80                 badblocks_clear(&pmem->bb, sector, cleared / 512);
81         }
82         invalidate_pmem(pmem->virt_addr + offset, len);
83 }
84
85 static int pmem_do_bvec(struct pmem_device *pmem, struct page *page,
86                         unsigned int len, unsigned int off, int rw,
87                         sector_t sector)
88 {
89         int rc = 0;
90         bool bad_pmem = false;
91         void *mem = kmap_atomic(page);
92         phys_addr_t pmem_off = sector * 512 + pmem->data_offset;
93         void __pmem *pmem_addr = pmem->virt_addr + pmem_off;
94
95         if (unlikely(is_bad_pmem(&pmem->bb, sector, len)))
96                 bad_pmem = true;
97
98         if (rw == READ) {
99                 if (unlikely(bad_pmem))
100                         rc = -EIO;
101                 else {
102                         rc = memcpy_from_pmem(mem + off, pmem_addr, len);
103                         flush_dcache_page(page);
104                 }
105         } else {
106                 flush_dcache_page(page);
107                 memcpy_to_pmem(pmem_addr, mem + off, len);
108                 if (unlikely(bad_pmem)) {
109                         pmem_clear_poison(pmem, pmem_off, len);
110                         memcpy_to_pmem(pmem_addr, mem + off, len);
111                 }
112         }
113
114         kunmap_atomic(mem);
115         return rc;
116 }
117
118 static blk_qc_t pmem_make_request(struct request_queue *q, struct bio *bio)
119 {
120         int rc = 0;
121         bool do_acct;
122         unsigned long start;
123         struct bio_vec bvec;
124         struct bvec_iter iter;
125         struct block_device *bdev = bio->bi_bdev;
126         struct pmem_device *pmem = bdev->bd_disk->private_data;
127
128         do_acct = nd_iostat_start(bio, &start);
129         bio_for_each_segment(bvec, bio, iter) {
130                 rc = pmem_do_bvec(pmem, bvec.bv_page, bvec.bv_len,
131                                 bvec.bv_offset, bio_data_dir(bio),
132                                 iter.bi_sector);
133                 if (rc) {
134                         bio->bi_error = rc;
135                         break;
136                 }
137         }
138         if (do_acct)
139                 nd_iostat_end(bio, start);
140
141         if (bio_data_dir(bio))
142                 wmb_pmem();
143
144         bio_endio(bio);
145         return BLK_QC_T_NONE;
146 }
147
148 static int pmem_rw_page(struct block_device *bdev, sector_t sector,
149                        struct page *page, int rw)
150 {
151         struct pmem_device *pmem = bdev->bd_disk->private_data;
152         int rc;
153
154         rc = pmem_do_bvec(pmem, page, PAGE_CACHE_SIZE, 0, rw, sector);
155         if (rw & WRITE)
156                 wmb_pmem();
157
158         /*
159          * The ->rw_page interface is subtle and tricky.  The core
160          * retries on any error, so we can only invoke page_endio() in
161          * the successful completion case.  Otherwise, we'll see crashes
162          * caused by double completion.
163          */
164         if (rc == 0)
165                 page_endio(page, rw & WRITE, 0);
166
167         return rc;
168 }
169
170 static long pmem_direct_access(struct block_device *bdev, sector_t sector,
171                       void __pmem **kaddr, pfn_t *pfn)
172 {
173         struct pmem_device *pmem = bdev->bd_disk->private_data;
174         resource_size_t offset = sector * 512 + pmem->data_offset;
175
176         *kaddr = pmem->virt_addr + offset;
177         *pfn = phys_to_pfn_t(pmem->phys_addr + offset, pmem->pfn_flags);
178
179         return pmem->size - pmem->pfn_pad - offset;
180 }
181
182 static const struct block_device_operations pmem_fops = {
183         .owner =                THIS_MODULE,
184         .rw_page =              pmem_rw_page,
185         .direct_access =        pmem_direct_access,
186         .revalidate_disk =      nvdimm_revalidate_disk,
187 };
188
189 static struct pmem_device *pmem_alloc(struct device *dev,
190                 struct resource *res, int id)
191 {
192         struct pmem_device *pmem;
193         struct request_queue *q;
194
195         pmem = devm_kzalloc(dev, sizeof(*pmem), GFP_KERNEL);
196         if (!pmem)
197                 return ERR_PTR(-ENOMEM);
198
199         pmem->phys_addr = res->start;
200         pmem->size = resource_size(res);
201         if (!arch_has_wmb_pmem())
202                 dev_warn(dev, "unable to guarantee persistence of writes\n");
203
204         if (!devm_request_mem_region(dev, pmem->phys_addr, pmem->size,
205                         dev_name(dev))) {
206                 dev_warn(dev, "could not reserve region [0x%pa:0x%zx]\n",
207                                 &pmem->phys_addr, pmem->size);
208                 return ERR_PTR(-EBUSY);
209         }
210
211         q = blk_alloc_queue_node(GFP_KERNEL, dev_to_node(dev));
212         if (!q)
213                 return ERR_PTR(-ENOMEM);
214
215         pmem->pfn_flags = PFN_DEV;
216         if (pmem_should_map_pages(dev)) {
217                 pmem->virt_addr = (void __pmem *) devm_memremap_pages(dev, res,
218                                 &q->q_usage_counter, NULL);
219                 pmem->pfn_flags |= PFN_MAP;
220         } else
221                 pmem->virt_addr = (void __pmem *) devm_memremap(dev,
222                                 pmem->phys_addr, pmem->size,
223                                 ARCH_MEMREMAP_PMEM);
224
225         if (IS_ERR(pmem->virt_addr)) {
226                 blk_cleanup_queue(q);
227                 return (void __force *) pmem->virt_addr;
228         }
229
230         pmem->pmem_queue = q;
231         return pmem;
232 }
233
234 static void pmem_detach_disk(struct pmem_device *pmem)
235 {
236         if (!pmem->pmem_disk)
237                 return;
238
239         del_gendisk(pmem->pmem_disk);
240         put_disk(pmem->pmem_disk);
241         blk_cleanup_queue(pmem->pmem_queue);
242 }
243
244 static int pmem_attach_disk(struct device *dev,
245                 struct nd_namespace_common *ndns, struct pmem_device *pmem)
246 {
247         int nid = dev_to_node(dev);
248         struct gendisk *disk;
249
250         blk_queue_make_request(pmem->pmem_queue, pmem_make_request);
251         blk_queue_physical_block_size(pmem->pmem_queue, PAGE_SIZE);
252         blk_queue_max_hw_sectors(pmem->pmem_queue, UINT_MAX);
253         blk_queue_bounce_limit(pmem->pmem_queue, BLK_BOUNCE_ANY);
254         queue_flag_set_unlocked(QUEUE_FLAG_NONROT, pmem->pmem_queue);
255
256         disk = alloc_disk_node(0, nid);
257         if (!disk) {
258                 blk_cleanup_queue(pmem->pmem_queue);
259                 return -ENOMEM;
260         }
261
262         disk->fops              = &pmem_fops;
263         disk->private_data      = pmem;
264         disk->queue             = pmem->pmem_queue;
265         disk->flags             = GENHD_FL_EXT_DEVT;
266         nvdimm_namespace_disk_name(ndns, disk->disk_name);
267         disk->driverfs_dev = dev;
268         set_capacity(disk, (pmem->size - pmem->pfn_pad - pmem->data_offset)
269                         / 512);
270         pmem->pmem_disk = disk;
271         devm_exit_badblocks(dev, &pmem->bb);
272         if (devm_init_badblocks(dev, &pmem->bb))
273                 return -ENOMEM;
274         nvdimm_namespace_add_poison(ndns, &pmem->bb, pmem->data_offset);
275
276         disk->bb = &pmem->bb;
277         add_disk(disk);
278         revalidate_disk(disk);
279
280         return 0;
281 }
282
283 static int pmem_rw_bytes(struct nd_namespace_common *ndns,
284                 resource_size_t offset, void *buf, size_t size, int rw)
285 {
286         struct pmem_device *pmem = dev_get_drvdata(ndns->claim);
287
288         if (unlikely(offset + size > pmem->size)) {
289                 dev_WARN_ONCE(&ndns->dev, 1, "request out of range\n");
290                 return -EFAULT;
291         }
292
293         if (rw == READ) {
294                 unsigned int sz_align = ALIGN(size + (offset & (512 - 1)), 512);
295
296                 if (unlikely(is_bad_pmem(&pmem->bb, offset / 512, sz_align)))
297                         return -EIO;
298                 return memcpy_from_pmem(buf, pmem->virt_addr + offset, size);
299         } else {
300                 memcpy_to_pmem(pmem->virt_addr + offset, buf, size);
301                 wmb_pmem();
302         }
303
304         return 0;
305 }
306
307 static int nd_pfn_init(struct nd_pfn *nd_pfn)
308 {
309         struct nd_pfn_sb *pfn_sb = kzalloc(sizeof(*pfn_sb), GFP_KERNEL);
310         struct pmem_device *pmem = dev_get_drvdata(&nd_pfn->dev);
311         struct nd_namespace_common *ndns = nd_pfn->ndns;
312         u32 start_pad = 0, end_trunc = 0;
313         resource_size_t start, size;
314         struct nd_namespace_io *nsio;
315         struct nd_region *nd_region;
316         unsigned long npfns;
317         phys_addr_t offset;
318         u64 checksum;
319         int rc;
320
321         if (!pfn_sb)
322                 return -ENOMEM;
323
324         nd_pfn->pfn_sb = pfn_sb;
325         rc = nd_pfn_validate(nd_pfn);
326         if (rc == -ENODEV)
327                 /* no info block, do init */;
328         else
329                 return rc;
330
331         nd_region = to_nd_region(nd_pfn->dev.parent);
332         if (nd_region->ro) {
333                 dev_info(&nd_pfn->dev,
334                                 "%s is read-only, unable to init metadata\n",
335                                 dev_name(&nd_region->dev));
336                 goto err;
337         }
338
339         memset(pfn_sb, 0, sizeof(*pfn_sb));
340
341         /*
342          * Check if pmem collides with 'System RAM' when section aligned and
343          * trim it accordingly
344          */
345         nsio = to_nd_namespace_io(&ndns->dev);
346         start = PHYS_SECTION_ALIGN_DOWN(nsio->res.start);
347         size = resource_size(&nsio->res);
348         if (region_intersects(start, size, IORESOURCE_SYSTEM_RAM,
349                                 IORES_DESC_NONE) == REGION_MIXED) {
350
351                 start = nsio->res.start;
352                 start_pad = PHYS_SECTION_ALIGN_UP(start) - start;
353         }
354
355         start = nsio->res.start;
356         size = PHYS_SECTION_ALIGN_UP(start + size) - start;
357         if (region_intersects(start, size, IORESOURCE_SYSTEM_RAM,
358                                 IORES_DESC_NONE) == REGION_MIXED) {
359                 size = resource_size(&nsio->res);
360                 end_trunc = start + size - PHYS_SECTION_ALIGN_DOWN(start + size);
361         }
362
363         if (start_pad + end_trunc)
364                 dev_info(&nd_pfn->dev, "%s section collision, truncate %d bytes\n",
365                                 dev_name(&ndns->dev), start_pad + end_trunc);
366
367         /*
368          * Note, we use 64 here for the standard size of struct page,
369          * debugging options may cause it to be larger in which case the
370          * implementation will limit the pfns advertised through
371          * ->direct_access() to those that are included in the memmap.
372          */
373         start += start_pad;
374         npfns = (pmem->size - start_pad - end_trunc - SZ_8K) / SZ_4K;
375         if (nd_pfn->mode == PFN_MODE_PMEM)
376                 offset = ALIGN(start + SZ_8K + 64 * npfns, nd_pfn->align)
377                         - start;
378         else if (nd_pfn->mode == PFN_MODE_RAM)
379                 offset = ALIGN(start + SZ_8K, nd_pfn->align) - start;
380         else
381                 goto err;
382
383         if (offset + start_pad + end_trunc >= pmem->size) {
384                 dev_err(&nd_pfn->dev, "%s unable to satisfy requested alignment\n",
385                                 dev_name(&ndns->dev));
386                 goto err;
387         }
388
389         npfns = (pmem->size - offset - start_pad - end_trunc) / SZ_4K;
390         pfn_sb->mode = cpu_to_le32(nd_pfn->mode);
391         pfn_sb->dataoff = cpu_to_le64(offset);
392         pfn_sb->npfns = cpu_to_le64(npfns);
393         memcpy(pfn_sb->signature, PFN_SIG, PFN_SIG_LEN);
394         memcpy(pfn_sb->uuid, nd_pfn->uuid, 16);
395         memcpy(pfn_sb->parent_uuid, nd_dev_to_uuid(&ndns->dev), 16);
396         pfn_sb->version_major = cpu_to_le16(1);
397         pfn_sb->version_minor = cpu_to_le16(1);
398         pfn_sb->start_pad = cpu_to_le32(start_pad);
399         pfn_sb->end_trunc = cpu_to_le32(end_trunc);
400         checksum = nd_sb_checksum((struct nd_gen_sb *) pfn_sb);
401         pfn_sb->checksum = cpu_to_le64(checksum);
402
403         rc = nvdimm_write_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb));
404         if (rc)
405                 goto err;
406
407         return 0;
408  err:
409         nd_pfn->pfn_sb = NULL;
410         kfree(pfn_sb);
411         return -ENXIO;
412 }
413
414 static int nvdimm_namespace_detach_pfn(struct nd_namespace_common *ndns)
415 {
416         struct nd_pfn *nd_pfn = to_nd_pfn(ndns->claim);
417         struct pmem_device *pmem;
418
419         /* free pmem disk */
420         pmem = dev_get_drvdata(&nd_pfn->dev);
421         pmem_detach_disk(pmem);
422
423         /* release nd_pfn resources */
424         kfree(nd_pfn->pfn_sb);
425         nd_pfn->pfn_sb = NULL;
426
427         return 0;
428 }
429
430 /*
431  * We hotplug memory at section granularity, pad the reserved area from
432  * the previous section base to the namespace base address.
433  */
434 static unsigned long init_altmap_base(resource_size_t base)
435 {
436         unsigned long base_pfn = PHYS_PFN(base);
437
438         return PFN_SECTION_ALIGN_DOWN(base_pfn);
439 }
440
441 static unsigned long init_altmap_reserve(resource_size_t base)
442 {
443         unsigned long reserve = PHYS_PFN(SZ_8K);
444         unsigned long base_pfn = PHYS_PFN(base);
445
446         reserve += base_pfn - PFN_SECTION_ALIGN_DOWN(base_pfn);
447         return reserve;
448 }
449
450 static int __nvdimm_namespace_attach_pfn(struct nd_pfn *nd_pfn)
451 {
452         int rc;
453         struct resource res;
454         struct request_queue *q;
455         struct pmem_device *pmem;
456         struct vmem_altmap *altmap;
457         struct device *dev = &nd_pfn->dev;
458         struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
459         struct nd_namespace_common *ndns = nd_pfn->ndns;
460         u32 start_pad = __le32_to_cpu(pfn_sb->start_pad);
461         u32 end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
462         struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
463         resource_size_t base = nsio->res.start + start_pad;
464         struct vmem_altmap __altmap = {
465                 .base_pfn = init_altmap_base(base),
466                 .reserve = init_altmap_reserve(base),
467         };
468
469         pmem = dev_get_drvdata(dev);
470         pmem->data_offset = le64_to_cpu(pfn_sb->dataoff);
471         pmem->pfn_pad = start_pad + end_trunc;
472         nd_pfn->mode = le32_to_cpu(nd_pfn->pfn_sb->mode);
473         if (nd_pfn->mode == PFN_MODE_RAM) {
474                 if (pmem->data_offset < SZ_8K)
475                         return -EINVAL;
476                 nd_pfn->npfns = le64_to_cpu(pfn_sb->npfns);
477                 altmap = NULL;
478         } else if (nd_pfn->mode == PFN_MODE_PMEM) {
479                 nd_pfn->npfns = (pmem->size - pmem->pfn_pad - pmem->data_offset)
480                         / PAGE_SIZE;
481                 if (le64_to_cpu(nd_pfn->pfn_sb->npfns) > nd_pfn->npfns)
482                         dev_info(&nd_pfn->dev,
483                                         "number of pfns truncated from %lld to %ld\n",
484                                         le64_to_cpu(nd_pfn->pfn_sb->npfns),
485                                         nd_pfn->npfns);
486                 altmap = & __altmap;
487                 altmap->free = PHYS_PFN(pmem->data_offset - SZ_8K);
488                 altmap->alloc = 0;
489         } else {
490                 rc = -ENXIO;
491                 goto err;
492         }
493
494         /* establish pfn range for lookup, and switch to direct map */
495         q = pmem->pmem_queue;
496         memcpy(&res, &nsio->res, sizeof(res));
497         res.start += start_pad;
498         res.end -= end_trunc;
499         devm_memunmap(dev, (void __force *) pmem->virt_addr);
500         pmem->virt_addr = (void __pmem *) devm_memremap_pages(dev, &res,
501                         &q->q_usage_counter, altmap);
502         pmem->pfn_flags |= PFN_MAP;
503         if (IS_ERR(pmem->virt_addr)) {
504                 rc = PTR_ERR(pmem->virt_addr);
505                 goto err;
506         }
507
508         /* attach pmem disk in "pfn-mode" */
509         rc = pmem_attach_disk(dev, ndns, pmem);
510         if (rc)
511                 goto err;
512
513         return rc;
514  err:
515         nvdimm_namespace_detach_pfn(ndns);
516         return rc;
517
518 }
519
520 static int nvdimm_namespace_attach_pfn(struct nd_namespace_common *ndns)
521 {
522         struct nd_pfn *nd_pfn = to_nd_pfn(ndns->claim);
523         int rc;
524
525         if (!nd_pfn->uuid || !nd_pfn->ndns)
526                 return -ENODEV;
527
528         rc = nd_pfn_init(nd_pfn);
529         if (rc)
530                 return rc;
531         /* we need a valid pfn_sb before we can init a vmem_altmap */
532         return __nvdimm_namespace_attach_pfn(nd_pfn);
533 }
534
535 static int nd_pmem_probe(struct device *dev)
536 {
537         struct nd_region *nd_region = to_nd_region(dev->parent);
538         struct nd_namespace_common *ndns;
539         struct nd_namespace_io *nsio;
540         struct pmem_device *pmem;
541
542         ndns = nvdimm_namespace_common_probe(dev);
543         if (IS_ERR(ndns))
544                 return PTR_ERR(ndns);
545
546         nsio = to_nd_namespace_io(&ndns->dev);
547         pmem = pmem_alloc(dev, &nsio->res, nd_region->id);
548         if (IS_ERR(pmem))
549                 return PTR_ERR(pmem);
550
551         pmem->ndns = ndns;
552         dev_set_drvdata(dev, pmem);
553         ndns->rw_bytes = pmem_rw_bytes;
554         if (devm_init_badblocks(dev, &pmem->bb))
555                 return -ENOMEM;
556         nvdimm_namespace_add_poison(ndns, &pmem->bb, 0);
557
558         if (is_nd_btt(dev)) {
559                 /* btt allocates its own request_queue */
560                 blk_cleanup_queue(pmem->pmem_queue);
561                 pmem->pmem_queue = NULL;
562                 return nvdimm_namespace_attach_btt(ndns);
563         }
564
565         if (is_nd_pfn(dev))
566                 return nvdimm_namespace_attach_pfn(ndns);
567
568         if (nd_btt_probe(ndns, pmem) == 0 || nd_pfn_probe(ndns, pmem) == 0) {
569                 /*
570                  * We'll come back as either btt-pmem, or pfn-pmem, so
571                  * drop the queue allocation for now.
572                  */
573                 blk_cleanup_queue(pmem->pmem_queue);
574                 return -ENXIO;
575         }
576
577         return pmem_attach_disk(dev, ndns, pmem);
578 }
579
580 static int nd_pmem_remove(struct device *dev)
581 {
582         struct pmem_device *pmem = dev_get_drvdata(dev);
583
584         if (is_nd_btt(dev))
585                 nvdimm_namespace_detach_btt(pmem->ndns);
586         else if (is_nd_pfn(dev))
587                 nvdimm_namespace_detach_pfn(pmem->ndns);
588         else
589                 pmem_detach_disk(pmem);
590
591         return 0;
592 }
593
594 static void nd_pmem_notify(struct device *dev, enum nvdimm_event event)
595 {
596         struct pmem_device *pmem = dev_get_drvdata(dev);
597         struct nd_namespace_common *ndns = pmem->ndns;
598
599         if (event != NVDIMM_REVALIDATE_POISON)
600                 return;
601
602         if (is_nd_btt(dev))
603                 nvdimm_namespace_add_poison(ndns, &pmem->bb, 0);
604         else
605                 nvdimm_namespace_add_poison(ndns, &pmem->bb, pmem->data_offset);
606 }
607
608 MODULE_ALIAS("pmem");
609 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_IO);
610 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_PMEM);
611 static struct nd_device_driver nd_pmem_driver = {
612         .probe = nd_pmem_probe,
613         .remove = nd_pmem_remove,
614         .notify = nd_pmem_notify,
615         .drv = {
616                 .name = "nd_pmem",
617         },
618         .type = ND_DRIVER_NAMESPACE_IO | ND_DRIVER_NAMESPACE_PMEM,
619 };
620
621 static int __init pmem_init(void)
622 {
623         return nd_driver_register(&nd_pmem_driver);
624 }
625 module_init(pmem_init);
626
627 static void pmem_exit(void)
628 {
629         driver_unregister(&nd_pmem_driver.drv);
630 }
631 module_exit(pmem_exit);
632
633 MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>");
634 MODULE_LICENSE("GPL v2");