xref: /linux/drivers/nvdimm/pmem.c (revision 34dc1baba215b826e454b8d19e4f24adbeb7d00d)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Persistent Memory Driver
4  *
5  * Copyright (c) 2014-2015, Intel Corporation.
6  * Copyright (c) 2015, Christoph Hellwig <hch@lst.de>.
7  * Copyright (c) 2015, Boaz Harrosh <boaz@plexistor.com>.
8  */
9 
10 #include <linux/blkdev.h>
11 #include <linux/pagemap.h>
12 #include <linux/hdreg.h>
13 #include <linux/init.h>
14 #include <linux/platform_device.h>
15 #include <linux/set_memory.h>
16 #include <linux/module.h>
17 #include <linux/moduleparam.h>
18 #include <linux/badblocks.h>
19 #include <linux/memremap.h>
20 #include <linux/kstrtox.h>
21 #include <linux/vmalloc.h>
22 #include <linux/blk-mq.h>
23 #include <linux/pfn_t.h>
24 #include <linux/slab.h>
25 #include <linux/uio.h>
26 #include <linux/dax.h>
27 #include <linux/nd.h>
28 #include <linux/mm.h>
29 #include <asm/cacheflush.h>
30 #include "pmem.h"
31 #include "btt.h"
32 #include "pfn.h"
33 #include "nd.h"
34 
35 static struct device *to_dev(struct pmem_device *pmem)
36 {
37 	/*
38 	 * nvdimm bus services need a 'dev' parameter, and we record the device
39 	 * at init in bb.dev.
40 	 */
41 	return pmem->bb.dev;
42 }
43 
44 static struct nd_region *to_region(struct pmem_device *pmem)
45 {
46 	return to_nd_region(to_dev(pmem)->parent);
47 }
48 
49 static phys_addr_t pmem_to_phys(struct pmem_device *pmem, phys_addr_t offset)
50 {
51 	return pmem->phys_addr + offset;
52 }
53 
54 static sector_t to_sect(struct pmem_device *pmem, phys_addr_t offset)
55 {
56 	return (offset - pmem->data_offset) >> SECTOR_SHIFT;
57 }
58 
59 static phys_addr_t to_offset(struct pmem_device *pmem, sector_t sector)
60 {
61 	return (sector << SECTOR_SHIFT) + pmem->data_offset;
62 }
63 
64 static void pmem_mkpage_present(struct pmem_device *pmem, phys_addr_t offset,
65 		unsigned int len)
66 {
67 	phys_addr_t phys = pmem_to_phys(pmem, offset);
68 	unsigned long pfn_start, pfn_end, pfn;
69 
70 	/* only pmem in the linear map supports HWPoison */
71 	if (is_vmalloc_addr(pmem->virt_addr))
72 		return;
73 
74 	pfn_start = PHYS_PFN(phys);
75 	pfn_end = pfn_start + PHYS_PFN(len);
76 	for (pfn = pfn_start; pfn < pfn_end; pfn++) {
77 		struct page *page = pfn_to_page(pfn);
78 
79 		/*
80 		 * Note, no need to hold a get_dev_pagemap() reference
81 		 * here since we're in the driver I/O path and
82 		 * outstanding I/O requests pin the dev_pagemap.
83 		 */
84 		if (test_and_clear_pmem_poison(page))
85 			clear_mce_nospec(pfn);
86 	}
87 }
88 
89 static void pmem_clear_bb(struct pmem_device *pmem, sector_t sector, long blks)
90 {
91 	if (blks == 0)
92 		return;
93 	badblocks_clear(&pmem->bb, sector, blks);
94 	if (pmem->bb_state)
95 		sysfs_notify_dirent(pmem->bb_state);
96 }
97 
98 static long __pmem_clear_poison(struct pmem_device *pmem,
99 		phys_addr_t offset, unsigned int len)
100 {
101 	phys_addr_t phys = pmem_to_phys(pmem, offset);
102 	long cleared = nvdimm_clear_poison(to_dev(pmem), phys, len);
103 
104 	if (cleared > 0) {
105 		pmem_mkpage_present(pmem, offset, cleared);
106 		arch_invalidate_pmem(pmem->virt_addr + offset, len);
107 	}
108 	return cleared;
109 }
110 
111 static blk_status_t pmem_clear_poison(struct pmem_device *pmem,
112 		phys_addr_t offset, unsigned int len)
113 {
114 	long cleared = __pmem_clear_poison(pmem, offset, len);
115 
116 	if (cleared < 0)
117 		return BLK_STS_IOERR;
118 
119 	pmem_clear_bb(pmem, to_sect(pmem, offset), cleared >> SECTOR_SHIFT);
120 	if (cleared < len)
121 		return BLK_STS_IOERR;
122 	return BLK_STS_OK;
123 }
124 
125 static void write_pmem(void *pmem_addr, struct page *page,
126 		unsigned int off, unsigned int len)
127 {
128 	unsigned int chunk;
129 	void *mem;
130 
131 	while (len) {
132 		mem = kmap_atomic(page);
133 		chunk = min_t(unsigned int, len, PAGE_SIZE - off);
134 		memcpy_flushcache(pmem_addr, mem + off, chunk);
135 		kunmap_atomic(mem);
136 		len -= chunk;
137 		off = 0;
138 		page++;
139 		pmem_addr += chunk;
140 	}
141 }
142 
143 static blk_status_t read_pmem(struct page *page, unsigned int off,
144 		void *pmem_addr, unsigned int len)
145 {
146 	unsigned int chunk;
147 	unsigned long rem;
148 	void *mem;
149 
150 	while (len) {
151 		mem = kmap_atomic(page);
152 		chunk = min_t(unsigned int, len, PAGE_SIZE - off);
153 		rem = copy_mc_to_kernel(mem + off, pmem_addr, chunk);
154 		kunmap_atomic(mem);
155 		if (rem)
156 			return BLK_STS_IOERR;
157 		len -= chunk;
158 		off = 0;
159 		page++;
160 		pmem_addr += chunk;
161 	}
162 	return BLK_STS_OK;
163 }
164 
165 static blk_status_t pmem_do_read(struct pmem_device *pmem,
166 			struct page *page, unsigned int page_off,
167 			sector_t sector, unsigned int len)
168 {
169 	blk_status_t rc;
170 	phys_addr_t pmem_off = to_offset(pmem, sector);
171 	void *pmem_addr = pmem->virt_addr + pmem_off;
172 
173 	if (unlikely(is_bad_pmem(&pmem->bb, sector, len)))
174 		return BLK_STS_IOERR;
175 
176 	rc = read_pmem(page, page_off, pmem_addr, len);
177 	flush_dcache_page(page);
178 	return rc;
179 }
180 
181 static blk_status_t pmem_do_write(struct pmem_device *pmem,
182 			struct page *page, unsigned int page_off,
183 			sector_t sector, unsigned int len)
184 {
185 	phys_addr_t pmem_off = to_offset(pmem, sector);
186 	void *pmem_addr = pmem->virt_addr + pmem_off;
187 
188 	if (unlikely(is_bad_pmem(&pmem->bb, sector, len))) {
189 		blk_status_t rc = pmem_clear_poison(pmem, pmem_off, len);
190 
191 		if (rc != BLK_STS_OK)
192 			return rc;
193 	}
194 
195 	flush_dcache_page(page);
196 	write_pmem(pmem_addr, page, page_off, len);
197 
198 	return BLK_STS_OK;
199 }
200 
201 static void pmem_submit_bio(struct bio *bio)
202 {
203 	int ret = 0;
204 	blk_status_t rc = 0;
205 	bool do_acct;
206 	unsigned long start;
207 	struct bio_vec bvec;
208 	struct bvec_iter iter;
209 	struct pmem_device *pmem = bio->bi_bdev->bd_disk->private_data;
210 	struct nd_region *nd_region = to_region(pmem);
211 
212 	if (bio->bi_opf & REQ_PREFLUSH)
213 		ret = nvdimm_flush(nd_region, bio);
214 
215 	do_acct = blk_queue_io_stat(bio->bi_bdev->bd_disk->queue);
216 	if (do_acct)
217 		start = bio_start_io_acct(bio);
218 	bio_for_each_segment(bvec, bio, iter) {
219 		if (op_is_write(bio_op(bio)))
220 			rc = pmem_do_write(pmem, bvec.bv_page, bvec.bv_offset,
221 				iter.bi_sector, bvec.bv_len);
222 		else
223 			rc = pmem_do_read(pmem, bvec.bv_page, bvec.bv_offset,
224 				iter.bi_sector, bvec.bv_len);
225 		if (rc) {
226 			bio->bi_status = rc;
227 			break;
228 		}
229 	}
230 	if (do_acct)
231 		bio_end_io_acct(bio, start);
232 
233 	if (bio->bi_opf & REQ_FUA)
234 		ret = nvdimm_flush(nd_region, bio);
235 
236 	if (ret)
237 		bio->bi_status = errno_to_blk_status(ret);
238 
239 	bio_endio(bio);
240 }
241 
242 /* see "strong" declaration in tools/testing/nvdimm/pmem-dax.c */
243 __weak long __pmem_direct_access(struct pmem_device *pmem, pgoff_t pgoff,
244 		long nr_pages, enum dax_access_mode mode, void **kaddr,
245 		pfn_t *pfn)
246 {
247 	resource_size_t offset = PFN_PHYS(pgoff) + pmem->data_offset;
248 	sector_t sector = PFN_PHYS(pgoff) >> SECTOR_SHIFT;
249 	unsigned int num = PFN_PHYS(nr_pages) >> SECTOR_SHIFT;
250 	struct badblocks *bb = &pmem->bb;
251 	sector_t first_bad;
252 	int num_bad;
253 
254 	if (kaddr)
255 		*kaddr = pmem->virt_addr + offset;
256 	if (pfn)
257 		*pfn = phys_to_pfn_t(pmem->phys_addr + offset, pmem->pfn_flags);
258 
259 	if (bb->count &&
260 	    badblocks_check(bb, sector, num, &first_bad, &num_bad)) {
261 		long actual_nr;
262 
263 		if (mode != DAX_RECOVERY_WRITE)
264 			return -EHWPOISON;
265 
266 		/*
267 		 * Set the recovery stride is set to kernel page size because
268 		 * the underlying driver and firmware clear poison functions
269 		 * don't appear to handle large chunk(such as 2MiB) reliably.
270 		 */
271 		actual_nr = PHYS_PFN(
272 			PAGE_ALIGN((first_bad - sector) << SECTOR_SHIFT));
273 		dev_dbg(pmem->bb.dev, "start sector(%llu), nr_pages(%ld), first_bad(%llu), actual_nr(%ld)\n",
274 				sector, nr_pages, first_bad, actual_nr);
275 		if (actual_nr)
276 			return actual_nr;
277 		return 1;
278 	}
279 
280 	/*
281 	 * If badblocks are present but not in the range, limit known good range
282 	 * to the requested range.
283 	 */
284 	if (bb->count)
285 		return nr_pages;
286 	return PHYS_PFN(pmem->size - pmem->pfn_pad - offset);
287 }
288 
289 static const struct block_device_operations pmem_fops = {
290 	.owner =		THIS_MODULE,
291 	.submit_bio =		pmem_submit_bio,
292 };
293 
294 static int pmem_dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
295 				    size_t nr_pages)
296 {
297 	struct pmem_device *pmem = dax_get_private(dax_dev);
298 
299 	return blk_status_to_errno(pmem_do_write(pmem, ZERO_PAGE(0), 0,
300 				   PFN_PHYS(pgoff) >> SECTOR_SHIFT,
301 				   PAGE_SIZE));
302 }
303 
304 static long pmem_dax_direct_access(struct dax_device *dax_dev,
305 		pgoff_t pgoff, long nr_pages, enum dax_access_mode mode,
306 		void **kaddr, pfn_t *pfn)
307 {
308 	struct pmem_device *pmem = dax_get_private(dax_dev);
309 
310 	return __pmem_direct_access(pmem, pgoff, nr_pages, mode, kaddr, pfn);
311 }
312 
313 /*
314  * The recovery write thread started out as a normal pwrite thread and
315  * when the filesystem was told about potential media error in the
316  * range, filesystem turns the normal pwrite to a dax_recovery_write.
317  *
318  * The recovery write consists of clearing media poison, clearing page
319  * HWPoison bit, reenable page-wide read-write permission, flush the
320  * caches and finally write.  A competing pread thread will be held
321  * off during the recovery process since data read back might not be
322  * valid, and this is achieved by clearing the badblock records after
323  * the recovery write is complete. Competing recovery write threads
324  * are already serialized by writer lock held by dax_iomap_rw().
325  */
326 static size_t pmem_recovery_write(struct dax_device *dax_dev, pgoff_t pgoff,
327 		void *addr, size_t bytes, struct iov_iter *i)
328 {
329 	struct pmem_device *pmem = dax_get_private(dax_dev);
330 	size_t olen, len, off;
331 	phys_addr_t pmem_off;
332 	struct device *dev = pmem->bb.dev;
333 	long cleared;
334 
335 	off = offset_in_page(addr);
336 	len = PFN_PHYS(PFN_UP(off + bytes));
337 	if (!is_bad_pmem(&pmem->bb, PFN_PHYS(pgoff) >> SECTOR_SHIFT, len))
338 		return _copy_from_iter_flushcache(addr, bytes, i);
339 
340 	/*
341 	 * Not page-aligned range cannot be recovered. This should not
342 	 * happen unless something else went wrong.
343 	 */
344 	if (off || !PAGE_ALIGNED(bytes)) {
345 		dev_dbg(dev, "Found poison, but addr(%p) or bytes(%#zx) not page aligned\n",
346 			addr, bytes);
347 		return 0;
348 	}
349 
350 	pmem_off = PFN_PHYS(pgoff) + pmem->data_offset;
351 	cleared = __pmem_clear_poison(pmem, pmem_off, len);
352 	if (cleared > 0 && cleared < len) {
353 		dev_dbg(dev, "poison cleared only %ld out of %zu bytes\n",
354 			cleared, len);
355 		return 0;
356 	}
357 	if (cleared < 0) {
358 		dev_dbg(dev, "poison clear failed: %ld\n", cleared);
359 		return 0;
360 	}
361 
362 	olen = _copy_from_iter_flushcache(addr, bytes, i);
363 	pmem_clear_bb(pmem, to_sect(pmem, pmem_off), cleared >> SECTOR_SHIFT);
364 
365 	return olen;
366 }
367 
368 static const struct dax_operations pmem_dax_ops = {
369 	.direct_access = pmem_dax_direct_access,
370 	.zero_page_range = pmem_dax_zero_page_range,
371 	.recovery_write = pmem_recovery_write,
372 };
373 
374 static ssize_t write_cache_show(struct device *dev,
375 		struct device_attribute *attr, char *buf)
376 {
377 	struct pmem_device *pmem = dev_to_disk(dev)->private_data;
378 
379 	return sprintf(buf, "%d\n", !!dax_write_cache_enabled(pmem->dax_dev));
380 }
381 
382 static ssize_t write_cache_store(struct device *dev,
383 		struct device_attribute *attr, const char *buf, size_t len)
384 {
385 	struct pmem_device *pmem = dev_to_disk(dev)->private_data;
386 	bool write_cache;
387 	int rc;
388 
389 	rc = kstrtobool(buf, &write_cache);
390 	if (rc)
391 		return rc;
392 	dax_write_cache(pmem->dax_dev, write_cache);
393 	return len;
394 }
395 static DEVICE_ATTR_RW(write_cache);
396 
397 static umode_t dax_visible(struct kobject *kobj, struct attribute *a, int n)
398 {
399 #ifndef CONFIG_ARCH_HAS_PMEM_API
400 	if (a == &dev_attr_write_cache.attr)
401 		return 0;
402 #endif
403 	return a->mode;
404 }
405 
406 static struct attribute *dax_attributes[] = {
407 	&dev_attr_write_cache.attr,
408 	NULL,
409 };
410 
411 static const struct attribute_group dax_attribute_group = {
412 	.name		= "dax",
413 	.attrs		= dax_attributes,
414 	.is_visible	= dax_visible,
415 };
416 
417 static const struct attribute_group *pmem_attribute_groups[] = {
418 	&dax_attribute_group,
419 	NULL,
420 };
421 
422 static void pmem_release_disk(void *__pmem)
423 {
424 	struct pmem_device *pmem = __pmem;
425 
426 	dax_remove_host(pmem->disk);
427 	kill_dax(pmem->dax_dev);
428 	put_dax(pmem->dax_dev);
429 	del_gendisk(pmem->disk);
430 
431 	put_disk(pmem->disk);
432 }
433 
434 static int pmem_pagemap_memory_failure(struct dev_pagemap *pgmap,
435 		unsigned long pfn, unsigned long nr_pages, int mf_flags)
436 {
437 	struct pmem_device *pmem =
438 			container_of(pgmap, struct pmem_device, pgmap);
439 	u64 offset = PFN_PHYS(pfn) - pmem->phys_addr - pmem->data_offset;
440 	u64 len = nr_pages << PAGE_SHIFT;
441 
442 	return dax_holder_notify_failure(pmem->dax_dev, offset, len, mf_flags);
443 }
444 
445 static const struct dev_pagemap_ops fsdax_pagemap_ops = {
446 	.memory_failure		= pmem_pagemap_memory_failure,
447 };
448 
449 static int pmem_attach_disk(struct device *dev,
450 		struct nd_namespace_common *ndns)
451 {
452 	struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
453 	struct nd_region *nd_region = to_nd_region(dev->parent);
454 	int nid = dev_to_node(dev), fua;
455 	struct resource *res = &nsio->res;
456 	struct range bb_range;
457 	struct nd_pfn *nd_pfn = NULL;
458 	struct dax_device *dax_dev;
459 	struct nd_pfn_sb *pfn_sb;
460 	struct pmem_device *pmem;
461 	struct request_queue *q;
462 	struct gendisk *disk;
463 	void *addr;
464 	int rc;
465 
466 	pmem = devm_kzalloc(dev, sizeof(*pmem), GFP_KERNEL);
467 	if (!pmem)
468 		return -ENOMEM;
469 
470 	rc = devm_namespace_enable(dev, ndns, nd_info_block_reserve());
471 	if (rc)
472 		return rc;
473 
474 	/* while nsio_rw_bytes is active, parse a pfn info block if present */
475 	if (is_nd_pfn(dev)) {
476 		nd_pfn = to_nd_pfn(dev);
477 		rc = nvdimm_setup_pfn(nd_pfn, &pmem->pgmap);
478 		if (rc)
479 			return rc;
480 	}
481 
482 	/* we're attaching a block device, disable raw namespace access */
483 	devm_namespace_disable(dev, ndns);
484 
485 	dev_set_drvdata(dev, pmem);
486 	pmem->phys_addr = res->start;
487 	pmem->size = resource_size(res);
488 	fua = nvdimm_has_flush(nd_region);
489 	if (!IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) || fua < 0) {
490 		dev_warn(dev, "unable to guarantee persistence of writes\n");
491 		fua = 0;
492 	}
493 
494 	if (!devm_request_mem_region(dev, res->start, resource_size(res),
495 				dev_name(&ndns->dev))) {
496 		dev_warn(dev, "could not reserve region %pR\n", res);
497 		return -EBUSY;
498 	}
499 
500 	disk = blk_alloc_disk(nid);
501 	if (!disk)
502 		return -ENOMEM;
503 	q = disk->queue;
504 
505 	pmem->disk = disk;
506 	pmem->pgmap.owner = pmem;
507 	pmem->pfn_flags = PFN_DEV;
508 	if (is_nd_pfn(dev)) {
509 		pmem->pgmap.type = MEMORY_DEVICE_FS_DAX;
510 		pmem->pgmap.ops = &fsdax_pagemap_ops;
511 		addr = devm_memremap_pages(dev, &pmem->pgmap);
512 		pfn_sb = nd_pfn->pfn_sb;
513 		pmem->data_offset = le64_to_cpu(pfn_sb->dataoff);
514 		pmem->pfn_pad = resource_size(res) -
515 			range_len(&pmem->pgmap.range);
516 		pmem->pfn_flags |= PFN_MAP;
517 		bb_range = pmem->pgmap.range;
518 		bb_range.start += pmem->data_offset;
519 	} else if (pmem_should_map_pages(dev)) {
520 		pmem->pgmap.range.start = res->start;
521 		pmem->pgmap.range.end = res->end;
522 		pmem->pgmap.nr_range = 1;
523 		pmem->pgmap.type = MEMORY_DEVICE_FS_DAX;
524 		pmem->pgmap.ops = &fsdax_pagemap_ops;
525 		addr = devm_memremap_pages(dev, &pmem->pgmap);
526 		pmem->pfn_flags |= PFN_MAP;
527 		bb_range = pmem->pgmap.range;
528 	} else {
529 		addr = devm_memremap(dev, pmem->phys_addr,
530 				pmem->size, ARCH_MEMREMAP_PMEM);
531 		bb_range.start =  res->start;
532 		bb_range.end = res->end;
533 	}
534 
535 	if (IS_ERR(addr)) {
536 		rc = PTR_ERR(addr);
537 		goto out;
538 	}
539 	pmem->virt_addr = addr;
540 
541 	blk_queue_write_cache(q, true, fua);
542 	blk_queue_physical_block_size(q, PAGE_SIZE);
543 	blk_queue_logical_block_size(q, pmem_sector_size(ndns));
544 	blk_queue_max_hw_sectors(q, UINT_MAX);
545 	blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
546 	blk_queue_flag_set(QUEUE_FLAG_SYNCHRONOUS, q);
547 	if (pmem->pfn_flags & PFN_MAP)
548 		blk_queue_flag_set(QUEUE_FLAG_DAX, q);
549 
550 	disk->fops		= &pmem_fops;
551 	disk->private_data	= pmem;
552 	nvdimm_namespace_disk_name(ndns, disk->disk_name);
553 	set_capacity(disk, (pmem->size - pmem->pfn_pad - pmem->data_offset)
554 			/ 512);
555 	if (devm_init_badblocks(dev, &pmem->bb))
556 		return -ENOMEM;
557 	nvdimm_badblocks_populate(nd_region, &pmem->bb, &bb_range);
558 	disk->bb = &pmem->bb;
559 
560 	dax_dev = alloc_dax(pmem, &pmem_dax_ops);
561 	if (IS_ERR(dax_dev)) {
562 		rc = PTR_ERR(dax_dev);
563 		goto out;
564 	}
565 	set_dax_nocache(dax_dev);
566 	set_dax_nomc(dax_dev);
567 	if (is_nvdimm_sync(nd_region))
568 		set_dax_synchronous(dax_dev);
569 	rc = dax_add_host(dax_dev, disk);
570 	if (rc)
571 		goto out_cleanup_dax;
572 	dax_write_cache(dax_dev, nvdimm_has_cache(nd_region));
573 	pmem->dax_dev = dax_dev;
574 
575 	rc = device_add_disk(dev, disk, pmem_attribute_groups);
576 	if (rc)
577 		goto out_remove_host;
578 	if (devm_add_action_or_reset(dev, pmem_release_disk, pmem))
579 		return -ENOMEM;
580 
581 	nvdimm_check_and_set_ro(disk);
582 
583 	pmem->bb_state = sysfs_get_dirent(disk_to_dev(disk)->kobj.sd,
584 					  "badblocks");
585 	if (!pmem->bb_state)
586 		dev_warn(dev, "'badblocks' notification disabled\n");
587 	return 0;
588 
589 out_remove_host:
590 	dax_remove_host(pmem->disk);
591 out_cleanup_dax:
592 	kill_dax(pmem->dax_dev);
593 	put_dax(pmem->dax_dev);
594 out:
595 	put_disk(pmem->disk);
596 	return rc;
597 }
598 
599 static int nd_pmem_probe(struct device *dev)
600 {
601 	int ret;
602 	struct nd_namespace_common *ndns;
603 
604 	ndns = nvdimm_namespace_common_probe(dev);
605 	if (IS_ERR(ndns))
606 		return PTR_ERR(ndns);
607 
608 	if (is_nd_btt(dev))
609 		return nvdimm_namespace_attach_btt(ndns);
610 
611 	if (is_nd_pfn(dev))
612 		return pmem_attach_disk(dev, ndns);
613 
614 	ret = devm_namespace_enable(dev, ndns, nd_info_block_reserve());
615 	if (ret)
616 		return ret;
617 
618 	ret = nd_btt_probe(dev, ndns);
619 	if (ret == 0)
620 		return -ENXIO;
621 
622 	/*
623 	 * We have two failure conditions here, there is no
624 	 * info reserver block or we found a valid info reserve block
625 	 * but failed to initialize the pfn superblock.
626 	 *
627 	 * For the first case consider namespace as a raw pmem namespace
628 	 * and attach a disk.
629 	 *
630 	 * For the latter, consider this a success and advance the namespace
631 	 * seed.
632 	 */
633 	ret = nd_pfn_probe(dev, ndns);
634 	if (ret == 0)
635 		return -ENXIO;
636 	else if (ret == -EOPNOTSUPP)
637 		return ret;
638 
639 	ret = nd_dax_probe(dev, ndns);
640 	if (ret == 0)
641 		return -ENXIO;
642 	else if (ret == -EOPNOTSUPP)
643 		return ret;
644 
645 	/* probe complete, attach handles namespace enabling */
646 	devm_namespace_disable(dev, ndns);
647 
648 	return pmem_attach_disk(dev, ndns);
649 }
650 
651 static void nd_pmem_remove(struct device *dev)
652 {
653 	struct pmem_device *pmem = dev_get_drvdata(dev);
654 
655 	if (is_nd_btt(dev))
656 		nvdimm_namespace_detach_btt(to_nd_btt(dev));
657 	else {
658 		/*
659 		 * Note, this assumes device_lock() context to not
660 		 * race nd_pmem_notify()
661 		 */
662 		sysfs_put(pmem->bb_state);
663 		pmem->bb_state = NULL;
664 	}
665 	nvdimm_flush(to_nd_region(dev->parent), NULL);
666 }
667 
668 static void nd_pmem_shutdown(struct device *dev)
669 {
670 	nvdimm_flush(to_nd_region(dev->parent), NULL);
671 }
672 
673 static void pmem_revalidate_poison(struct device *dev)
674 {
675 	struct nd_region *nd_region;
676 	resource_size_t offset = 0, end_trunc = 0;
677 	struct nd_namespace_common *ndns;
678 	struct nd_namespace_io *nsio;
679 	struct badblocks *bb;
680 	struct range range;
681 	struct kernfs_node *bb_state;
682 
683 	if (is_nd_btt(dev)) {
684 		struct nd_btt *nd_btt = to_nd_btt(dev);
685 
686 		ndns = nd_btt->ndns;
687 		nd_region = to_nd_region(ndns->dev.parent);
688 		nsio = to_nd_namespace_io(&ndns->dev);
689 		bb = &nsio->bb;
690 		bb_state = NULL;
691 	} else {
692 		struct pmem_device *pmem = dev_get_drvdata(dev);
693 
694 		nd_region = to_region(pmem);
695 		bb = &pmem->bb;
696 		bb_state = pmem->bb_state;
697 
698 		if (is_nd_pfn(dev)) {
699 			struct nd_pfn *nd_pfn = to_nd_pfn(dev);
700 			struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
701 
702 			ndns = nd_pfn->ndns;
703 			offset = pmem->data_offset +
704 					__le32_to_cpu(pfn_sb->start_pad);
705 			end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
706 		} else {
707 			ndns = to_ndns(dev);
708 		}
709 
710 		nsio = to_nd_namespace_io(&ndns->dev);
711 	}
712 
713 	range.start = nsio->res.start + offset;
714 	range.end = nsio->res.end - end_trunc;
715 	nvdimm_badblocks_populate(nd_region, bb, &range);
716 	if (bb_state)
717 		sysfs_notify_dirent(bb_state);
718 }
719 
720 static void pmem_revalidate_region(struct device *dev)
721 {
722 	struct pmem_device *pmem;
723 
724 	if (is_nd_btt(dev)) {
725 		struct nd_btt *nd_btt = to_nd_btt(dev);
726 		struct btt *btt = nd_btt->btt;
727 
728 		nvdimm_check_and_set_ro(btt->btt_disk);
729 		return;
730 	}
731 
732 	pmem = dev_get_drvdata(dev);
733 	nvdimm_check_and_set_ro(pmem->disk);
734 }
735 
736 static void nd_pmem_notify(struct device *dev, enum nvdimm_event event)
737 {
738 	switch (event) {
739 	case NVDIMM_REVALIDATE_POISON:
740 		pmem_revalidate_poison(dev);
741 		break;
742 	case NVDIMM_REVALIDATE_REGION:
743 		pmem_revalidate_region(dev);
744 		break;
745 	default:
746 		dev_WARN_ONCE(dev, 1, "notify: unknown event: %d\n", event);
747 		break;
748 	}
749 }
750 
751 MODULE_ALIAS("pmem");
752 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_IO);
753 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_PMEM);
754 static struct nd_device_driver nd_pmem_driver = {
755 	.probe = nd_pmem_probe,
756 	.remove = nd_pmem_remove,
757 	.notify = nd_pmem_notify,
758 	.shutdown = nd_pmem_shutdown,
759 	.drv = {
760 		.name = "nd_pmem",
761 	},
762 	.type = ND_DRIVER_NAMESPACE_IO | ND_DRIVER_NAMESPACE_PMEM,
763 };
764 
765 module_nd_driver(nd_pmem_driver);
766 
767 MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>");
768 MODULE_LICENSE("GPL v2");
769