xref: /openbmc/linux/drivers/nvdimm/pmem.c (revision 5085e036)
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/vmalloc.h>
21 #include <linux/blk-mq.h>
22 #include <linux/pfn_t.h>
23 #include <linux/slab.h>
24 #include <linux/uio.h>
25 #include <linux/dax.h>
26 #include <linux/nd.h>
27 #include <linux/mm.h>
28 #include <asm/cacheflush.h>
29 #include "pmem.h"
30 #include "btt.h"
31 #include "pfn.h"
32 #include "nd.h"
33 
34 static struct device *to_dev(struct pmem_device *pmem)
35 {
36 	/*
37 	 * nvdimm bus services need a 'dev' parameter, and we record the device
38 	 * at init in bb.dev.
39 	 */
40 	return pmem->bb.dev;
41 }
42 
43 static struct nd_region *to_region(struct pmem_device *pmem)
44 {
45 	return to_nd_region(to_dev(pmem)->parent);
46 }
47 
48 static phys_addr_t to_phys(struct pmem_device *pmem, phys_addr_t offset)
49 {
50 	return pmem->phys_addr + offset;
51 }
52 
53 static sector_t to_sect(struct pmem_device *pmem, phys_addr_t offset)
54 {
55 	return (offset - pmem->data_offset) >> SECTOR_SHIFT;
56 }
57 
58 static phys_addr_t to_offset(struct pmem_device *pmem, sector_t sector)
59 {
60 	return (sector << SECTOR_SHIFT) + pmem->data_offset;
61 }
62 
63 static void pmem_mkpage_present(struct pmem_device *pmem, phys_addr_t offset,
64 		unsigned int len)
65 {
66 	phys_addr_t phys = to_phys(pmem, offset);
67 	unsigned long pfn_start, pfn_end, pfn;
68 
69 	/* only pmem in the linear map supports HWPoison */
70 	if (is_vmalloc_addr(pmem->virt_addr))
71 		return;
72 
73 	pfn_start = PHYS_PFN(phys);
74 	pfn_end = pfn_start + PHYS_PFN(len);
75 	for (pfn = pfn_start; pfn < pfn_end; pfn++) {
76 		struct page *page = pfn_to_page(pfn);
77 
78 		/*
79 		 * Note, no need to hold a get_dev_pagemap() reference
80 		 * here since we're in the driver I/O path and
81 		 * outstanding I/O requests pin the dev_pagemap.
82 		 */
83 		if (test_and_clear_pmem_poison(page))
84 			clear_mce_nospec(pfn);
85 	}
86 }
87 
88 static void pmem_clear_bb(struct pmem_device *pmem, sector_t sector, long blks)
89 {
90 	if (blks == 0)
91 		return;
92 	badblocks_clear(&pmem->bb, sector, blks);
93 	if (pmem->bb_state)
94 		sysfs_notify_dirent(pmem->bb_state);
95 }
96 
97 static long __pmem_clear_poison(struct pmem_device *pmem,
98 		phys_addr_t offset, unsigned int len)
99 {
100 	phys_addr_t phys = to_phys(pmem, offset);
101 	long cleared = nvdimm_clear_poison(to_dev(pmem), phys, len);
102 
103 	if (cleared > 0) {
104 		pmem_mkpage_present(pmem, offset, cleared);
105 		arch_invalidate_pmem(pmem->virt_addr + offset, len);
106 	}
107 	return cleared;
108 }
109 
110 static blk_status_t pmem_clear_poison(struct pmem_device *pmem,
111 		phys_addr_t offset, unsigned int len)
112 {
113 	long cleared = __pmem_clear_poison(pmem, offset, len);
114 
115 	if (cleared < 0)
116 		return BLK_STS_IOERR;
117 
118 	pmem_clear_bb(pmem, to_sect(pmem, offset), cleared >> SECTOR_SHIFT);
119 	if (cleared < len)
120 		return BLK_STS_IOERR;
121 	return BLK_STS_OK;
122 }
123 
124 static void write_pmem(void *pmem_addr, struct page *page,
125 		unsigned int off, unsigned int len)
126 {
127 	unsigned int chunk;
128 	void *mem;
129 
130 	while (len) {
131 		mem = kmap_atomic(page);
132 		chunk = min_t(unsigned int, len, PAGE_SIZE - off);
133 		memcpy_flushcache(pmem_addr, mem + off, chunk);
134 		kunmap_atomic(mem);
135 		len -= chunk;
136 		off = 0;
137 		page++;
138 		pmem_addr += chunk;
139 	}
140 }
141 
142 static blk_status_t read_pmem(struct page *page, unsigned int off,
143 		void *pmem_addr, unsigned int len)
144 {
145 	unsigned int chunk;
146 	unsigned long rem;
147 	void *mem;
148 
149 	while (len) {
150 		mem = kmap_atomic(page);
151 		chunk = min_t(unsigned int, len, PAGE_SIZE - off);
152 		rem = copy_mc_to_kernel(mem + off, pmem_addr, chunk);
153 		kunmap_atomic(mem);
154 		if (rem)
155 			return BLK_STS_IOERR;
156 		len -= chunk;
157 		off = 0;
158 		page++;
159 		pmem_addr += chunk;
160 	}
161 	return BLK_STS_OK;
162 }
163 
164 static blk_status_t pmem_do_read(struct pmem_device *pmem,
165 			struct page *page, unsigned int page_off,
166 			sector_t sector, unsigned int len)
167 {
168 	blk_status_t rc;
169 	phys_addr_t pmem_off = to_offset(pmem, sector);
170 	void *pmem_addr = pmem->virt_addr + pmem_off;
171 
172 	if (unlikely(is_bad_pmem(&pmem->bb, sector, len)))
173 		return BLK_STS_IOERR;
174 
175 	rc = read_pmem(page, page_off, pmem_addr, len);
176 	flush_dcache_page(page);
177 	return rc;
178 }
179 
180 static blk_status_t pmem_do_write(struct pmem_device *pmem,
181 			struct page *page, unsigned int page_off,
182 			sector_t sector, unsigned int len)
183 {
184 	phys_addr_t pmem_off = to_offset(pmem, sector);
185 	void *pmem_addr = pmem->virt_addr + pmem_off;
186 
187 	if (unlikely(is_bad_pmem(&pmem->bb, sector, len))) {
188 		blk_status_t rc = pmem_clear_poison(pmem, pmem_off, len);
189 
190 		if (rc != BLK_STS_OK)
191 			return rc;
192 	}
193 
194 	flush_dcache_page(page);
195 	write_pmem(pmem_addr, page, page_off, len);
196 
197 	return BLK_STS_OK;
198 }
199 
200 static void pmem_submit_bio(struct bio *bio)
201 {
202 	int ret = 0;
203 	blk_status_t rc = 0;
204 	bool do_acct;
205 	unsigned long start;
206 	struct bio_vec bvec;
207 	struct bvec_iter iter;
208 	struct pmem_device *pmem = bio->bi_bdev->bd_disk->private_data;
209 	struct nd_region *nd_region = to_region(pmem);
210 
211 	if (bio->bi_opf & REQ_PREFLUSH)
212 		ret = nvdimm_flush(nd_region, bio);
213 
214 	do_acct = blk_queue_io_stat(bio->bi_bdev->bd_disk->queue);
215 	if (do_acct)
216 		start = bio_start_io_acct(bio);
217 	bio_for_each_segment(bvec, bio, iter) {
218 		if (op_is_write(bio_op(bio)))
219 			rc = pmem_do_write(pmem, bvec.bv_page, bvec.bv_offset,
220 				iter.bi_sector, bvec.bv_len);
221 		else
222 			rc = pmem_do_read(pmem, bvec.bv_page, bvec.bv_offset,
223 				iter.bi_sector, bvec.bv_len);
224 		if (rc) {
225 			bio->bi_status = rc;
226 			break;
227 		}
228 	}
229 	if (do_acct)
230 		bio_end_io_acct(bio, start);
231 
232 	if (bio->bi_opf & REQ_FUA)
233 		ret = nvdimm_flush(nd_region, bio);
234 
235 	if (ret)
236 		bio->bi_status = errno_to_blk_status(ret);
237 
238 	bio_endio(bio);
239 }
240 
241 static int pmem_rw_page(struct block_device *bdev, sector_t sector,
242 		       struct page *page, unsigned int op)
243 {
244 	struct pmem_device *pmem = bdev->bd_disk->private_data;
245 	blk_status_t rc;
246 
247 	if (op_is_write(op))
248 		rc = pmem_do_write(pmem, page, 0, sector, thp_size(page));
249 	else
250 		rc = pmem_do_read(pmem, page, 0, sector, thp_size(page));
251 	/*
252 	 * The ->rw_page interface is subtle and tricky.  The core
253 	 * retries on any error, so we can only invoke page_endio() in
254 	 * the successful completion case.  Otherwise, we'll see crashes
255 	 * caused by double completion.
256 	 */
257 	if (rc == 0)
258 		page_endio(page, op_is_write(op), 0);
259 
260 	return blk_status_to_errno(rc);
261 }
262 
263 /* see "strong" declaration in tools/testing/nvdimm/pmem-dax.c */
264 __weak long __pmem_direct_access(struct pmem_device *pmem, pgoff_t pgoff,
265 		long nr_pages, enum dax_access_mode mode, void **kaddr,
266 		pfn_t *pfn)
267 {
268 	resource_size_t offset = PFN_PHYS(pgoff) + pmem->data_offset;
269 	sector_t sector = PFN_PHYS(pgoff) >> SECTOR_SHIFT;
270 	unsigned int num = PFN_PHYS(nr_pages) >> SECTOR_SHIFT;
271 	struct badblocks *bb = &pmem->bb;
272 	sector_t first_bad;
273 	int num_bad;
274 
275 	if (kaddr)
276 		*kaddr = pmem->virt_addr + offset;
277 	if (pfn)
278 		*pfn = phys_to_pfn_t(pmem->phys_addr + offset, pmem->pfn_flags);
279 
280 	if (bb->count &&
281 	    badblocks_check(bb, sector, num, &first_bad, &num_bad)) {
282 		long actual_nr;
283 
284 		if (mode != DAX_RECOVERY_WRITE)
285 			return -EIO;
286 
287 		/*
288 		 * Set the recovery stride is set to kernel page size because
289 		 * the underlying driver and firmware clear poison functions
290 		 * don't appear to handle large chunk(such as 2MiB) reliably.
291 		 */
292 		actual_nr = PHYS_PFN(
293 			PAGE_ALIGN((first_bad - sector) << SECTOR_SHIFT));
294 		dev_dbg(pmem->bb.dev, "start sector(%llu), nr_pages(%ld), first_bad(%llu), actual_nr(%ld)\n",
295 				sector, nr_pages, first_bad, actual_nr);
296 		if (actual_nr)
297 			return actual_nr;
298 		return 1;
299 	}
300 
301 	/*
302 	 * If badblocks are present but not in the range, limit known good range
303 	 * to the requested range.
304 	 */
305 	if (bb->count)
306 		return nr_pages;
307 	return PHYS_PFN(pmem->size - pmem->pfn_pad - offset);
308 }
309 
310 static const struct block_device_operations pmem_fops = {
311 	.owner =		THIS_MODULE,
312 	.submit_bio =		pmem_submit_bio,
313 	.rw_page =		pmem_rw_page,
314 };
315 
316 static int pmem_dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
317 				    size_t nr_pages)
318 {
319 	struct pmem_device *pmem = dax_get_private(dax_dev);
320 
321 	return blk_status_to_errno(pmem_do_write(pmem, ZERO_PAGE(0), 0,
322 				   PFN_PHYS(pgoff) >> SECTOR_SHIFT,
323 				   PAGE_SIZE));
324 }
325 
326 static long pmem_dax_direct_access(struct dax_device *dax_dev,
327 		pgoff_t pgoff, long nr_pages, enum dax_access_mode mode,
328 		void **kaddr, pfn_t *pfn)
329 {
330 	struct pmem_device *pmem = dax_get_private(dax_dev);
331 
332 	return __pmem_direct_access(pmem, pgoff, nr_pages, mode, kaddr, pfn);
333 }
334 
335 /*
336  * The recovery write thread started out as a normal pwrite thread and
337  * when the filesystem was told about potential media error in the
338  * range, filesystem turns the normal pwrite to a dax_recovery_write.
339  *
340  * The recovery write consists of clearing media poison, clearing page
341  * HWPoison bit, reenable page-wide read-write permission, flush the
342  * caches and finally write.  A competing pread thread will be held
343  * off during the recovery process since data read back might not be
344  * valid, and this is achieved by clearing the badblock records after
345  * the recovery write is complete. Competing recovery write threads
346  * are already serialized by writer lock held by dax_iomap_rw().
347  */
348 static size_t pmem_recovery_write(struct dax_device *dax_dev, pgoff_t pgoff,
349 		void *addr, size_t bytes, struct iov_iter *i)
350 {
351 	struct pmem_device *pmem = dax_get_private(dax_dev);
352 	size_t olen, len, off;
353 	phys_addr_t pmem_off;
354 	struct device *dev = pmem->bb.dev;
355 	long cleared;
356 
357 	off = offset_in_page(addr);
358 	len = PFN_PHYS(PFN_UP(off + bytes));
359 	if (!is_bad_pmem(&pmem->bb, PFN_PHYS(pgoff) >> SECTOR_SHIFT, len))
360 		return _copy_from_iter_flushcache(addr, bytes, i);
361 
362 	/*
363 	 * Not page-aligned range cannot be recovered. This should not
364 	 * happen unless something else went wrong.
365 	 */
366 	if (off || !PAGE_ALIGNED(bytes)) {
367 		dev_dbg(dev, "Found poison, but addr(%p) or bytes(%#zx) not page aligned\n",
368 			addr, bytes);
369 		return 0;
370 	}
371 
372 	pmem_off = PFN_PHYS(pgoff) + pmem->data_offset;
373 	cleared = __pmem_clear_poison(pmem, pmem_off, len);
374 	if (cleared > 0 && cleared < len) {
375 		dev_dbg(dev, "poison cleared only %ld out of %zu bytes\n",
376 			cleared, len);
377 		return 0;
378 	}
379 	if (cleared < 0) {
380 		dev_dbg(dev, "poison clear failed: %ld\n", cleared);
381 		return 0;
382 	}
383 
384 	olen = _copy_from_iter_flushcache(addr, bytes, i);
385 	pmem_clear_bb(pmem, to_sect(pmem, pmem_off), cleared >> SECTOR_SHIFT);
386 
387 	return olen;
388 }
389 
390 static const struct dax_operations pmem_dax_ops = {
391 	.direct_access = pmem_dax_direct_access,
392 	.zero_page_range = pmem_dax_zero_page_range,
393 	.recovery_write = pmem_recovery_write,
394 };
395 
396 static ssize_t write_cache_show(struct device *dev,
397 		struct device_attribute *attr, char *buf)
398 {
399 	struct pmem_device *pmem = dev_to_disk(dev)->private_data;
400 
401 	return sprintf(buf, "%d\n", !!dax_write_cache_enabled(pmem->dax_dev));
402 }
403 
404 static ssize_t write_cache_store(struct device *dev,
405 		struct device_attribute *attr, const char *buf, size_t len)
406 {
407 	struct pmem_device *pmem = dev_to_disk(dev)->private_data;
408 	bool write_cache;
409 	int rc;
410 
411 	rc = strtobool(buf, &write_cache);
412 	if (rc)
413 		return rc;
414 	dax_write_cache(pmem->dax_dev, write_cache);
415 	return len;
416 }
417 static DEVICE_ATTR_RW(write_cache);
418 
419 static umode_t dax_visible(struct kobject *kobj, struct attribute *a, int n)
420 {
421 #ifndef CONFIG_ARCH_HAS_PMEM_API
422 	if (a == &dev_attr_write_cache.attr)
423 		return 0;
424 #endif
425 	return a->mode;
426 }
427 
428 static struct attribute *dax_attributes[] = {
429 	&dev_attr_write_cache.attr,
430 	NULL,
431 };
432 
433 static const struct attribute_group dax_attribute_group = {
434 	.name		= "dax",
435 	.attrs		= dax_attributes,
436 	.is_visible	= dax_visible,
437 };
438 
439 static const struct attribute_group *pmem_attribute_groups[] = {
440 	&dax_attribute_group,
441 	NULL,
442 };
443 
444 static void pmem_release_disk(void *__pmem)
445 {
446 	struct pmem_device *pmem = __pmem;
447 
448 	dax_remove_host(pmem->disk);
449 	kill_dax(pmem->dax_dev);
450 	put_dax(pmem->dax_dev);
451 	del_gendisk(pmem->disk);
452 
453 	blk_cleanup_disk(pmem->disk);
454 }
455 
456 static int pmem_attach_disk(struct device *dev,
457 		struct nd_namespace_common *ndns)
458 {
459 	struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
460 	struct nd_region *nd_region = to_nd_region(dev->parent);
461 	int nid = dev_to_node(dev), fua;
462 	struct resource *res = &nsio->res;
463 	struct range bb_range;
464 	struct nd_pfn *nd_pfn = NULL;
465 	struct dax_device *dax_dev;
466 	struct nd_pfn_sb *pfn_sb;
467 	struct pmem_device *pmem;
468 	struct request_queue *q;
469 	struct gendisk *disk;
470 	void *addr;
471 	int rc;
472 
473 	pmem = devm_kzalloc(dev, sizeof(*pmem), GFP_KERNEL);
474 	if (!pmem)
475 		return -ENOMEM;
476 
477 	rc = devm_namespace_enable(dev, ndns, nd_info_block_reserve());
478 	if (rc)
479 		return rc;
480 
481 	/* while nsio_rw_bytes is active, parse a pfn info block if present */
482 	if (is_nd_pfn(dev)) {
483 		nd_pfn = to_nd_pfn(dev);
484 		rc = nvdimm_setup_pfn(nd_pfn, &pmem->pgmap);
485 		if (rc)
486 			return rc;
487 	}
488 
489 	/* we're attaching a block device, disable raw namespace access */
490 	devm_namespace_disable(dev, ndns);
491 
492 	dev_set_drvdata(dev, pmem);
493 	pmem->phys_addr = res->start;
494 	pmem->size = resource_size(res);
495 	fua = nvdimm_has_flush(nd_region);
496 	if (!IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) || fua < 0) {
497 		dev_warn(dev, "unable to guarantee persistence of writes\n");
498 		fua = 0;
499 	}
500 
501 	if (!devm_request_mem_region(dev, res->start, resource_size(res),
502 				dev_name(&ndns->dev))) {
503 		dev_warn(dev, "could not reserve region %pR\n", res);
504 		return -EBUSY;
505 	}
506 
507 	disk = blk_alloc_disk(nid);
508 	if (!disk)
509 		return -ENOMEM;
510 	q = disk->queue;
511 
512 	pmem->disk = disk;
513 	pmem->pgmap.owner = pmem;
514 	pmem->pfn_flags = PFN_DEV;
515 	if (is_nd_pfn(dev)) {
516 		pmem->pgmap.type = MEMORY_DEVICE_FS_DAX;
517 		addr = devm_memremap_pages(dev, &pmem->pgmap);
518 		pfn_sb = nd_pfn->pfn_sb;
519 		pmem->data_offset = le64_to_cpu(pfn_sb->dataoff);
520 		pmem->pfn_pad = resource_size(res) -
521 			range_len(&pmem->pgmap.range);
522 		pmem->pfn_flags |= PFN_MAP;
523 		bb_range = pmem->pgmap.range;
524 		bb_range.start += pmem->data_offset;
525 	} else if (pmem_should_map_pages(dev)) {
526 		pmem->pgmap.range.start = res->start;
527 		pmem->pgmap.range.end = res->end;
528 		pmem->pgmap.nr_range = 1;
529 		pmem->pgmap.type = MEMORY_DEVICE_FS_DAX;
530 		addr = devm_memremap_pages(dev, &pmem->pgmap);
531 		pmem->pfn_flags |= PFN_MAP;
532 		bb_range = pmem->pgmap.range;
533 	} else {
534 		addr = devm_memremap(dev, pmem->phys_addr,
535 				pmem->size, ARCH_MEMREMAP_PMEM);
536 		bb_range.start =  res->start;
537 		bb_range.end = res->end;
538 	}
539 
540 	if (IS_ERR(addr)) {
541 		rc = PTR_ERR(addr);
542 		goto out;
543 	}
544 	pmem->virt_addr = addr;
545 
546 	blk_queue_write_cache(q, true, fua);
547 	blk_queue_physical_block_size(q, PAGE_SIZE);
548 	blk_queue_logical_block_size(q, pmem_sector_size(ndns));
549 	blk_queue_max_hw_sectors(q, UINT_MAX);
550 	blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
551 	if (pmem->pfn_flags & PFN_MAP)
552 		blk_queue_flag_set(QUEUE_FLAG_DAX, q);
553 
554 	disk->fops		= &pmem_fops;
555 	disk->private_data	= pmem;
556 	nvdimm_namespace_disk_name(ndns, disk->disk_name);
557 	set_capacity(disk, (pmem->size - pmem->pfn_pad - pmem->data_offset)
558 			/ 512);
559 	if (devm_init_badblocks(dev, &pmem->bb))
560 		return -ENOMEM;
561 	nvdimm_badblocks_populate(nd_region, &pmem->bb, &bb_range);
562 	disk->bb = &pmem->bb;
563 
564 	dax_dev = alloc_dax(pmem, &pmem_dax_ops);
565 	if (IS_ERR(dax_dev)) {
566 		rc = PTR_ERR(dax_dev);
567 		goto out;
568 	}
569 	set_dax_nocache(dax_dev);
570 	set_dax_nomc(dax_dev);
571 	if (is_nvdimm_sync(nd_region))
572 		set_dax_synchronous(dax_dev);
573 	rc = dax_add_host(dax_dev, disk);
574 	if (rc)
575 		goto out_cleanup_dax;
576 	dax_write_cache(dax_dev, nvdimm_has_cache(nd_region));
577 	pmem->dax_dev = dax_dev;
578 
579 	rc = device_add_disk(dev, disk, pmem_attribute_groups);
580 	if (rc)
581 		goto out_remove_host;
582 	if (devm_add_action_or_reset(dev, pmem_release_disk, pmem))
583 		return -ENOMEM;
584 
585 	nvdimm_check_and_set_ro(disk);
586 
587 	pmem->bb_state = sysfs_get_dirent(disk_to_dev(disk)->kobj.sd,
588 					  "badblocks");
589 	if (!pmem->bb_state)
590 		dev_warn(dev, "'badblocks' notification disabled\n");
591 	return 0;
592 
593 out_remove_host:
594 	dax_remove_host(pmem->disk);
595 out_cleanup_dax:
596 	kill_dax(pmem->dax_dev);
597 	put_dax(pmem->dax_dev);
598 out:
599 	blk_cleanup_disk(pmem->disk);
600 	return rc;
601 }
602 
603 static int nd_pmem_probe(struct device *dev)
604 {
605 	int ret;
606 	struct nd_namespace_common *ndns;
607 
608 	ndns = nvdimm_namespace_common_probe(dev);
609 	if (IS_ERR(ndns))
610 		return PTR_ERR(ndns);
611 
612 	if (is_nd_btt(dev))
613 		return nvdimm_namespace_attach_btt(ndns);
614 
615 	if (is_nd_pfn(dev))
616 		return pmem_attach_disk(dev, ndns);
617 
618 	ret = devm_namespace_enable(dev, ndns, nd_info_block_reserve());
619 	if (ret)
620 		return ret;
621 
622 	ret = nd_btt_probe(dev, ndns);
623 	if (ret == 0)
624 		return -ENXIO;
625 
626 	/*
627 	 * We have two failure conditions here, there is no
628 	 * info reserver block or we found a valid info reserve block
629 	 * but failed to initialize the pfn superblock.
630 	 *
631 	 * For the first case consider namespace as a raw pmem namespace
632 	 * and attach a disk.
633 	 *
634 	 * For the latter, consider this a success and advance the namespace
635 	 * seed.
636 	 */
637 	ret = nd_pfn_probe(dev, ndns);
638 	if (ret == 0)
639 		return -ENXIO;
640 	else if (ret == -EOPNOTSUPP)
641 		return ret;
642 
643 	ret = nd_dax_probe(dev, ndns);
644 	if (ret == 0)
645 		return -ENXIO;
646 	else if (ret == -EOPNOTSUPP)
647 		return ret;
648 
649 	/* probe complete, attach handles namespace enabling */
650 	devm_namespace_disable(dev, ndns);
651 
652 	return pmem_attach_disk(dev, ndns);
653 }
654 
655 static void nd_pmem_remove(struct device *dev)
656 {
657 	struct pmem_device *pmem = dev_get_drvdata(dev);
658 
659 	if (is_nd_btt(dev))
660 		nvdimm_namespace_detach_btt(to_nd_btt(dev));
661 	else {
662 		/*
663 		 * Note, this assumes device_lock() context to not
664 		 * race nd_pmem_notify()
665 		 */
666 		sysfs_put(pmem->bb_state);
667 		pmem->bb_state = NULL;
668 	}
669 	nvdimm_flush(to_nd_region(dev->parent), NULL);
670 }
671 
672 static void nd_pmem_shutdown(struct device *dev)
673 {
674 	nvdimm_flush(to_nd_region(dev->parent), NULL);
675 }
676 
677 static void pmem_revalidate_poison(struct device *dev)
678 {
679 	struct nd_region *nd_region;
680 	resource_size_t offset = 0, end_trunc = 0;
681 	struct nd_namespace_common *ndns;
682 	struct nd_namespace_io *nsio;
683 	struct badblocks *bb;
684 	struct range range;
685 	struct kernfs_node *bb_state;
686 
687 	if (is_nd_btt(dev)) {
688 		struct nd_btt *nd_btt = to_nd_btt(dev);
689 
690 		ndns = nd_btt->ndns;
691 		nd_region = to_nd_region(ndns->dev.parent);
692 		nsio = to_nd_namespace_io(&ndns->dev);
693 		bb = &nsio->bb;
694 		bb_state = NULL;
695 	} else {
696 		struct pmem_device *pmem = dev_get_drvdata(dev);
697 
698 		nd_region = to_region(pmem);
699 		bb = &pmem->bb;
700 		bb_state = pmem->bb_state;
701 
702 		if (is_nd_pfn(dev)) {
703 			struct nd_pfn *nd_pfn = to_nd_pfn(dev);
704 			struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
705 
706 			ndns = nd_pfn->ndns;
707 			offset = pmem->data_offset +
708 					__le32_to_cpu(pfn_sb->start_pad);
709 			end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
710 		} else {
711 			ndns = to_ndns(dev);
712 		}
713 
714 		nsio = to_nd_namespace_io(&ndns->dev);
715 	}
716 
717 	range.start = nsio->res.start + offset;
718 	range.end = nsio->res.end - end_trunc;
719 	nvdimm_badblocks_populate(nd_region, bb, &range);
720 	if (bb_state)
721 		sysfs_notify_dirent(bb_state);
722 }
723 
724 static void pmem_revalidate_region(struct device *dev)
725 {
726 	struct pmem_device *pmem;
727 
728 	if (is_nd_btt(dev)) {
729 		struct nd_btt *nd_btt = to_nd_btt(dev);
730 		struct btt *btt = nd_btt->btt;
731 
732 		nvdimm_check_and_set_ro(btt->btt_disk);
733 		return;
734 	}
735 
736 	pmem = dev_get_drvdata(dev);
737 	nvdimm_check_and_set_ro(pmem->disk);
738 }
739 
740 static void nd_pmem_notify(struct device *dev, enum nvdimm_event event)
741 {
742 	switch (event) {
743 	case NVDIMM_REVALIDATE_POISON:
744 		pmem_revalidate_poison(dev);
745 		break;
746 	case NVDIMM_REVALIDATE_REGION:
747 		pmem_revalidate_region(dev);
748 		break;
749 	default:
750 		dev_WARN_ONCE(dev, 1, "notify: unknown event: %d\n", event);
751 		break;
752 	}
753 }
754 
755 MODULE_ALIAS("pmem");
756 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_IO);
757 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_PMEM);
758 static struct nd_device_driver nd_pmem_driver = {
759 	.probe = nd_pmem_probe,
760 	.remove = nd_pmem_remove,
761 	.notify = nd_pmem_notify,
762 	.shutdown = nd_pmem_shutdown,
763 	.drv = {
764 		.name = "nd_pmem",
765 	},
766 	.type = ND_DRIVER_NAMESPACE_IO | ND_DRIVER_NAMESPACE_PMEM,
767 };
768 
769 module_nd_driver(nd_pmem_driver);
770 
771 MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>");
772 MODULE_LICENSE("GPL v2");
773