Merge branch 'asoc-4.19' into asoc-4.20 for rt5682 deps.
[linux-2.6-block.git] / drivers / dax / device.c
1 /*
2  * Copyright(c) 2016 - 2017 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 #include <linux/pagemap.h>
14 #include <linux/module.h>
15 #include <linux/device.h>
16 #include <linux/pfn_t.h>
17 #include <linux/cdev.h>
18 #include <linux/slab.h>
19 #include <linux/dax.h>
20 #include <linux/fs.h>
21 #include <linux/mm.h>
22 #include <linux/mman.h>
23 #include "dax-private.h"
24 #include "dax.h"
25
26 static struct class *dax_class;
27
28 /*
29  * Rely on the fact that drvdata is set before the attributes are
30  * registered, and that the attributes are unregistered before drvdata
31  * is cleared to assume that drvdata is always valid.
32  */
33 static ssize_t id_show(struct device *dev,
34                 struct device_attribute *attr, char *buf)
35 {
36         struct dax_region *dax_region = dev_get_drvdata(dev);
37
38         return sprintf(buf, "%d\n", dax_region->id);
39 }
40 static DEVICE_ATTR_RO(id);
41
42 static ssize_t region_size_show(struct device *dev,
43                 struct device_attribute *attr, char *buf)
44 {
45         struct dax_region *dax_region = dev_get_drvdata(dev);
46
47         return sprintf(buf, "%llu\n", (unsigned long long)
48                         resource_size(&dax_region->res));
49 }
50 static struct device_attribute dev_attr_region_size = __ATTR(size, 0444,
51                 region_size_show, NULL);
52
53 static ssize_t align_show(struct device *dev,
54                 struct device_attribute *attr, char *buf)
55 {
56         struct dax_region *dax_region = dev_get_drvdata(dev);
57
58         return sprintf(buf, "%u\n", dax_region->align);
59 }
60 static DEVICE_ATTR_RO(align);
61
62 static struct attribute *dax_region_attributes[] = {
63         &dev_attr_region_size.attr,
64         &dev_attr_align.attr,
65         &dev_attr_id.attr,
66         NULL,
67 };
68
69 static const struct attribute_group dax_region_attribute_group = {
70         .name = "dax_region",
71         .attrs = dax_region_attributes,
72 };
73
74 static const struct attribute_group *dax_region_attribute_groups[] = {
75         &dax_region_attribute_group,
76         NULL,
77 };
78
79 static void dax_region_free(struct kref *kref)
80 {
81         struct dax_region *dax_region;
82
83         dax_region = container_of(kref, struct dax_region, kref);
84         kfree(dax_region);
85 }
86
87 void dax_region_put(struct dax_region *dax_region)
88 {
89         kref_put(&dax_region->kref, dax_region_free);
90 }
91 EXPORT_SYMBOL_GPL(dax_region_put);
92
93 static void dax_region_unregister(void *region)
94 {
95         struct dax_region *dax_region = region;
96
97         sysfs_remove_groups(&dax_region->dev->kobj,
98                         dax_region_attribute_groups);
99         dax_region_put(dax_region);
100 }
101
102 struct dax_region *alloc_dax_region(struct device *parent, int region_id,
103                 struct resource *res, unsigned int align, void *addr,
104                 unsigned long pfn_flags)
105 {
106         struct dax_region *dax_region;
107
108         /*
109          * The DAX core assumes that it can store its private data in
110          * parent->driver_data. This WARN is a reminder / safeguard for
111          * developers of device-dax drivers.
112          */
113         if (dev_get_drvdata(parent)) {
114                 dev_WARN(parent, "dax core failed to setup private data\n");
115                 return NULL;
116         }
117
118         if (!IS_ALIGNED(res->start, align)
119                         || !IS_ALIGNED(resource_size(res), align))
120                 return NULL;
121
122         dax_region = kzalloc(sizeof(*dax_region), GFP_KERNEL);
123         if (!dax_region)
124                 return NULL;
125
126         dev_set_drvdata(parent, dax_region);
127         memcpy(&dax_region->res, res, sizeof(*res));
128         dax_region->pfn_flags = pfn_flags;
129         kref_init(&dax_region->kref);
130         dax_region->id = region_id;
131         ida_init(&dax_region->ida);
132         dax_region->align = align;
133         dax_region->dev = parent;
134         dax_region->base = addr;
135         if (sysfs_create_groups(&parent->kobj, dax_region_attribute_groups)) {
136                 kfree(dax_region);
137                 return NULL;
138         }
139
140         kref_get(&dax_region->kref);
141         if (devm_add_action_or_reset(parent, dax_region_unregister, dax_region))
142                 return NULL;
143         return dax_region;
144 }
145 EXPORT_SYMBOL_GPL(alloc_dax_region);
146
147 static struct dev_dax *to_dev_dax(struct device *dev)
148 {
149         return container_of(dev, struct dev_dax, dev);
150 }
151
152 static ssize_t size_show(struct device *dev,
153                 struct device_attribute *attr, char *buf)
154 {
155         struct dev_dax *dev_dax = to_dev_dax(dev);
156         unsigned long long size = 0;
157         int i;
158
159         for (i = 0; i < dev_dax->num_resources; i++)
160                 size += resource_size(&dev_dax->res[i]);
161
162         return sprintf(buf, "%llu\n", size);
163 }
164 static DEVICE_ATTR_RO(size);
165
166 static struct attribute *dev_dax_attributes[] = {
167         &dev_attr_size.attr,
168         NULL,
169 };
170
171 static const struct attribute_group dev_dax_attribute_group = {
172         .attrs = dev_dax_attributes,
173 };
174
175 static const struct attribute_group *dax_attribute_groups[] = {
176         &dev_dax_attribute_group,
177         NULL,
178 };
179
180 static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
181                 const char *func)
182 {
183         struct dax_region *dax_region = dev_dax->region;
184         struct device *dev = &dev_dax->dev;
185         unsigned long mask;
186
187         if (!dax_alive(dev_dax->dax_dev))
188                 return -ENXIO;
189
190         /* prevent private mappings from being established */
191         if ((vma->vm_flags & VM_MAYSHARE) != VM_MAYSHARE) {
192                 dev_info_ratelimited(dev,
193                                 "%s: %s: fail, attempted private mapping\n",
194                                 current->comm, func);
195                 return -EINVAL;
196         }
197
198         mask = dax_region->align - 1;
199         if (vma->vm_start & mask || vma->vm_end & mask) {
200                 dev_info_ratelimited(dev,
201                                 "%s: %s: fail, unaligned vma (%#lx - %#lx, %#lx)\n",
202                                 current->comm, func, vma->vm_start, vma->vm_end,
203                                 mask);
204                 return -EINVAL;
205         }
206
207         if ((dax_region->pfn_flags & (PFN_DEV|PFN_MAP)) == PFN_DEV
208                         && (vma->vm_flags & VM_DONTCOPY) == 0) {
209                 dev_info_ratelimited(dev,
210                                 "%s: %s: fail, dax range requires MADV_DONTFORK\n",
211                                 current->comm, func);
212                 return -EINVAL;
213         }
214
215         if (!vma_is_dax(vma)) {
216                 dev_info_ratelimited(dev,
217                                 "%s: %s: fail, vma is not DAX capable\n",
218                                 current->comm, func);
219                 return -EINVAL;
220         }
221
222         return 0;
223 }
224
225 /* see "strong" declaration in tools/testing/nvdimm/dax-dev.c */
226 __weak phys_addr_t dax_pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff,
227                 unsigned long size)
228 {
229         struct resource *res;
230         /* gcc-4.6.3-nolibc for i386 complains that this is uninitialized */
231         phys_addr_t uninitialized_var(phys);
232         int i;
233
234         for (i = 0; i < dev_dax->num_resources; i++) {
235                 res = &dev_dax->res[i];
236                 phys = pgoff * PAGE_SIZE + res->start;
237                 if (phys >= res->start && phys <= res->end)
238                         break;
239                 pgoff -= PHYS_PFN(resource_size(res));
240         }
241
242         if (i < dev_dax->num_resources) {
243                 res = &dev_dax->res[i];
244                 if (phys + size - 1 <= res->end)
245                         return phys;
246         }
247
248         return -1;
249 }
250
251 static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax,
252                                 struct vm_fault *vmf, pfn_t *pfn)
253 {
254         struct device *dev = &dev_dax->dev;
255         struct dax_region *dax_region;
256         phys_addr_t phys;
257         unsigned int fault_size = PAGE_SIZE;
258
259         if (check_vma(dev_dax, vmf->vma, __func__))
260                 return VM_FAULT_SIGBUS;
261
262         dax_region = dev_dax->region;
263         if (dax_region->align > PAGE_SIZE) {
264                 dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
265                         dax_region->align, fault_size);
266                 return VM_FAULT_SIGBUS;
267         }
268
269         if (fault_size != dax_region->align)
270                 return VM_FAULT_SIGBUS;
271
272         phys = dax_pgoff_to_phys(dev_dax, vmf->pgoff, PAGE_SIZE);
273         if (phys == -1) {
274                 dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", vmf->pgoff);
275                 return VM_FAULT_SIGBUS;
276         }
277
278         *pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);
279
280         return vmf_insert_mixed(vmf->vma, vmf->address, *pfn);
281 }
282
283 static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax,
284                                 struct vm_fault *vmf, pfn_t *pfn)
285 {
286         unsigned long pmd_addr = vmf->address & PMD_MASK;
287         struct device *dev = &dev_dax->dev;
288         struct dax_region *dax_region;
289         phys_addr_t phys;
290         pgoff_t pgoff;
291         unsigned int fault_size = PMD_SIZE;
292
293         if (check_vma(dev_dax, vmf->vma, __func__))
294                 return VM_FAULT_SIGBUS;
295
296         dax_region = dev_dax->region;
297         if (dax_region->align > PMD_SIZE) {
298                 dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
299                         dax_region->align, fault_size);
300                 return VM_FAULT_SIGBUS;
301         }
302
303         /* dax pmd mappings require pfn_t_devmap() */
304         if ((dax_region->pfn_flags & (PFN_DEV|PFN_MAP)) != (PFN_DEV|PFN_MAP)) {
305                 dev_dbg(dev, "region lacks devmap flags\n");
306                 return VM_FAULT_SIGBUS;
307         }
308
309         if (fault_size < dax_region->align)
310                 return VM_FAULT_SIGBUS;
311         else if (fault_size > dax_region->align)
312                 return VM_FAULT_FALLBACK;
313
314         /* if we are outside of the VMA */
315         if (pmd_addr < vmf->vma->vm_start ||
316                         (pmd_addr + PMD_SIZE) > vmf->vma->vm_end)
317                 return VM_FAULT_SIGBUS;
318
319         pgoff = linear_page_index(vmf->vma, pmd_addr);
320         phys = dax_pgoff_to_phys(dev_dax, pgoff, PMD_SIZE);
321         if (phys == -1) {
322                 dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", pgoff);
323                 return VM_FAULT_SIGBUS;
324         }
325
326         *pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);
327
328         return vmf_insert_pfn_pmd(vmf->vma, vmf->address, vmf->pmd, *pfn,
329                         vmf->flags & FAULT_FLAG_WRITE);
330 }
331
332 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
333 static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
334                                 struct vm_fault *vmf, pfn_t *pfn)
335 {
336         unsigned long pud_addr = vmf->address & PUD_MASK;
337         struct device *dev = &dev_dax->dev;
338         struct dax_region *dax_region;
339         phys_addr_t phys;
340         pgoff_t pgoff;
341         unsigned int fault_size = PUD_SIZE;
342
343
344         if (check_vma(dev_dax, vmf->vma, __func__))
345                 return VM_FAULT_SIGBUS;
346
347         dax_region = dev_dax->region;
348         if (dax_region->align > PUD_SIZE) {
349                 dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
350                         dax_region->align, fault_size);
351                 return VM_FAULT_SIGBUS;
352         }
353
354         /* dax pud mappings require pfn_t_devmap() */
355         if ((dax_region->pfn_flags & (PFN_DEV|PFN_MAP)) != (PFN_DEV|PFN_MAP)) {
356                 dev_dbg(dev, "region lacks devmap flags\n");
357                 return VM_FAULT_SIGBUS;
358         }
359
360         if (fault_size < dax_region->align)
361                 return VM_FAULT_SIGBUS;
362         else if (fault_size > dax_region->align)
363                 return VM_FAULT_FALLBACK;
364
365         /* if we are outside of the VMA */
366         if (pud_addr < vmf->vma->vm_start ||
367                         (pud_addr + PUD_SIZE) > vmf->vma->vm_end)
368                 return VM_FAULT_SIGBUS;
369
370         pgoff = linear_page_index(vmf->vma, pud_addr);
371         phys = dax_pgoff_to_phys(dev_dax, pgoff, PUD_SIZE);
372         if (phys == -1) {
373                 dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", pgoff);
374                 return VM_FAULT_SIGBUS;
375         }
376
377         *pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);
378
379         return vmf_insert_pfn_pud(vmf->vma, vmf->address, vmf->pud, *pfn,
380                         vmf->flags & FAULT_FLAG_WRITE);
381 }
382 #else
383 static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
384                                 struct vm_fault *vmf, pfn_t *pfn)
385 {
386         return VM_FAULT_FALLBACK;
387 }
388 #endif /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
389
390 static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf,
391                 enum page_entry_size pe_size)
392 {
393         struct file *filp = vmf->vma->vm_file;
394         unsigned long fault_size;
395         int rc, id;
396         pfn_t pfn;
397         struct dev_dax *dev_dax = filp->private_data;
398
399         dev_dbg(&dev_dax->dev, "%s: %s (%#lx - %#lx) size = %d\n", current->comm,
400                         (vmf->flags & FAULT_FLAG_WRITE) ? "write" : "read",
401                         vmf->vma->vm_start, vmf->vma->vm_end, pe_size);
402
403         id = dax_read_lock();
404         switch (pe_size) {
405         case PE_SIZE_PTE:
406                 fault_size = PAGE_SIZE;
407                 rc = __dev_dax_pte_fault(dev_dax, vmf, &pfn);
408                 break;
409         case PE_SIZE_PMD:
410                 fault_size = PMD_SIZE;
411                 rc = __dev_dax_pmd_fault(dev_dax, vmf, &pfn);
412                 break;
413         case PE_SIZE_PUD:
414                 fault_size = PUD_SIZE;
415                 rc = __dev_dax_pud_fault(dev_dax, vmf, &pfn);
416                 break;
417         default:
418                 rc = VM_FAULT_SIGBUS;
419         }
420
421         if (rc == VM_FAULT_NOPAGE) {
422                 unsigned long i;
423                 pgoff_t pgoff;
424
425                 /*
426                  * In the device-dax case the only possibility for a
427                  * VM_FAULT_NOPAGE result is when device-dax capacity is
428                  * mapped. No need to consider the zero page, or racing
429                  * conflicting mappings.
430                  */
431                 pgoff = linear_page_index(vmf->vma, vmf->address
432                                 & ~(fault_size - 1));
433                 for (i = 0; i < fault_size / PAGE_SIZE; i++) {
434                         struct page *page;
435
436                         page = pfn_to_page(pfn_t_to_pfn(pfn) + i);
437                         if (page->mapping)
438                                 continue;
439                         page->mapping = filp->f_mapping;
440                         page->index = pgoff + i;
441                 }
442         }
443         dax_read_unlock(id);
444
445         return rc;
446 }
447
448 static vm_fault_t dev_dax_fault(struct vm_fault *vmf)
449 {
450         return dev_dax_huge_fault(vmf, PE_SIZE_PTE);
451 }
452
453 static int dev_dax_split(struct vm_area_struct *vma, unsigned long addr)
454 {
455         struct file *filp = vma->vm_file;
456         struct dev_dax *dev_dax = filp->private_data;
457         struct dax_region *dax_region = dev_dax->region;
458
459         if (!IS_ALIGNED(addr, dax_region->align))
460                 return -EINVAL;
461         return 0;
462 }
463
464 static unsigned long dev_dax_pagesize(struct vm_area_struct *vma)
465 {
466         struct file *filp = vma->vm_file;
467         struct dev_dax *dev_dax = filp->private_data;
468         struct dax_region *dax_region = dev_dax->region;
469
470         return dax_region->align;
471 }
472
473 static const struct vm_operations_struct dax_vm_ops = {
474         .fault = dev_dax_fault,
475         .huge_fault = dev_dax_huge_fault,
476         .split = dev_dax_split,
477         .pagesize = dev_dax_pagesize,
478 };
479
480 static int dax_mmap(struct file *filp, struct vm_area_struct *vma)
481 {
482         struct dev_dax *dev_dax = filp->private_data;
483         int rc, id;
484
485         dev_dbg(&dev_dax->dev, "trace\n");
486
487         /*
488          * We lock to check dax_dev liveness and will re-check at
489          * fault time.
490          */
491         id = dax_read_lock();
492         rc = check_vma(dev_dax, vma, __func__);
493         dax_read_unlock(id);
494         if (rc)
495                 return rc;
496
497         vma->vm_ops = &dax_vm_ops;
498         vma->vm_flags |= VM_HUGEPAGE;
499         return 0;
500 }
501
502 /* return an unmapped area aligned to the dax region specified alignment */
503 static unsigned long dax_get_unmapped_area(struct file *filp,
504                 unsigned long addr, unsigned long len, unsigned long pgoff,
505                 unsigned long flags)
506 {
507         unsigned long off, off_end, off_align, len_align, addr_align, align;
508         struct dev_dax *dev_dax = filp ? filp->private_data : NULL;
509         struct dax_region *dax_region;
510
511         if (!dev_dax || addr)
512                 goto out;
513
514         dax_region = dev_dax->region;
515         align = dax_region->align;
516         off = pgoff << PAGE_SHIFT;
517         off_end = off + len;
518         off_align = round_up(off, align);
519
520         if ((off_end <= off_align) || ((off_end - off_align) < align))
521                 goto out;
522
523         len_align = len + align;
524         if ((off + len_align) < off)
525                 goto out;
526
527         addr_align = current->mm->get_unmapped_area(filp, addr, len_align,
528                         pgoff, flags);
529         if (!IS_ERR_VALUE(addr_align)) {
530                 addr_align += (off - addr_align) & (align - 1);
531                 return addr_align;
532         }
533  out:
534         return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags);
535 }
536
537 static int dax_open(struct inode *inode, struct file *filp)
538 {
539         struct dax_device *dax_dev = inode_dax(inode);
540         struct inode *__dax_inode = dax_inode(dax_dev);
541         struct dev_dax *dev_dax = dax_get_private(dax_dev);
542
543         dev_dbg(&dev_dax->dev, "trace\n");
544         inode->i_mapping = __dax_inode->i_mapping;
545         inode->i_mapping->host = __dax_inode;
546         filp->f_mapping = inode->i_mapping;
547         filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
548         filp->private_data = dev_dax;
549         inode->i_flags = S_DAX;
550
551         return 0;
552 }
553
554 static int dax_release(struct inode *inode, struct file *filp)
555 {
556         struct dev_dax *dev_dax = filp->private_data;
557
558         dev_dbg(&dev_dax->dev, "trace\n");
559         return 0;
560 }
561
562 static const struct file_operations dax_fops = {
563         .llseek = noop_llseek,
564         .owner = THIS_MODULE,
565         .open = dax_open,
566         .release = dax_release,
567         .get_unmapped_area = dax_get_unmapped_area,
568         .mmap = dax_mmap,
569         .mmap_supported_flags = MAP_SYNC,
570 };
571
572 static void dev_dax_release(struct device *dev)
573 {
574         struct dev_dax *dev_dax = to_dev_dax(dev);
575         struct dax_region *dax_region = dev_dax->region;
576         struct dax_device *dax_dev = dev_dax->dax_dev;
577
578         if (dev_dax->id >= 0)
579                 ida_simple_remove(&dax_region->ida, dev_dax->id);
580         dax_region_put(dax_region);
581         put_dax(dax_dev);
582         kfree(dev_dax);
583 }
584
585 static void kill_dev_dax(struct dev_dax *dev_dax)
586 {
587         struct dax_device *dax_dev = dev_dax->dax_dev;
588         struct inode *inode = dax_inode(dax_dev);
589
590         kill_dax(dax_dev);
591         unmap_mapping_range(inode->i_mapping, 0, 0, 1);
592 }
593
594 static void unregister_dev_dax(void *dev)
595 {
596         struct dev_dax *dev_dax = to_dev_dax(dev);
597         struct dax_device *dax_dev = dev_dax->dax_dev;
598         struct inode *inode = dax_inode(dax_dev);
599         struct cdev *cdev = inode->i_cdev;
600
601         dev_dbg(dev, "trace\n");
602
603         kill_dev_dax(dev_dax);
604         cdev_device_del(cdev, dev);
605         put_device(dev);
606 }
607
608 struct dev_dax *devm_create_dev_dax(struct dax_region *dax_region,
609                 int id, struct resource *res, int count)
610 {
611         struct device *parent = dax_region->dev;
612         struct dax_device *dax_dev;
613         struct dev_dax *dev_dax;
614         struct inode *inode;
615         struct device *dev;
616         struct cdev *cdev;
617         int rc, i;
618
619         if (!count)
620                 return ERR_PTR(-EINVAL);
621
622         dev_dax = kzalloc(struct_size(dev_dax, res, count), GFP_KERNEL);
623         if (!dev_dax)
624                 return ERR_PTR(-ENOMEM);
625
626         for (i = 0; i < count; i++) {
627                 if (!IS_ALIGNED(res[i].start, dax_region->align)
628                                 || !IS_ALIGNED(resource_size(&res[i]),
629                                         dax_region->align)) {
630                         rc = -EINVAL;
631                         break;
632                 }
633                 dev_dax->res[i].start = res[i].start;
634                 dev_dax->res[i].end = res[i].end;
635         }
636
637         if (i < count)
638                 goto err_id;
639
640         if (id < 0) {
641                 id = ida_simple_get(&dax_region->ida, 0, 0, GFP_KERNEL);
642                 dev_dax->id = id;
643                 if (id < 0) {
644                         rc = id;
645                         goto err_id;
646                 }
647         } else {
648                 /* region provider owns @id lifetime */
649                 dev_dax->id = -1;
650         }
651
652         /*
653          * No 'host' or dax_operations since there is no access to this
654          * device outside of mmap of the resulting character device.
655          */
656         dax_dev = alloc_dax(dev_dax, NULL, NULL);
657         if (!dax_dev) {
658                 rc = -ENOMEM;
659                 goto err_dax;
660         }
661
662         /* from here on we're committed to teardown via dax_dev_release() */
663         dev = &dev_dax->dev;
664         device_initialize(dev);
665
666         inode = dax_inode(dax_dev);
667         cdev = inode->i_cdev;
668         cdev_init(cdev, &dax_fops);
669         cdev->owner = parent->driver->owner;
670
671         dev_dax->num_resources = count;
672         dev_dax->dax_dev = dax_dev;
673         dev_dax->region = dax_region;
674         kref_get(&dax_region->kref);
675
676         dev->devt = inode->i_rdev;
677         dev->class = dax_class;
678         dev->parent = parent;
679         dev->groups = dax_attribute_groups;
680         dev->release = dev_dax_release;
681         dev_set_name(dev, "dax%d.%d", dax_region->id, id);
682
683         rc = cdev_device_add(cdev, dev);
684         if (rc) {
685                 kill_dev_dax(dev_dax);
686                 put_device(dev);
687                 return ERR_PTR(rc);
688         }
689
690         rc = devm_add_action_or_reset(dax_region->dev, unregister_dev_dax, dev);
691         if (rc)
692                 return ERR_PTR(rc);
693
694         return dev_dax;
695
696  err_dax:
697         if (dev_dax->id >= 0)
698                 ida_simple_remove(&dax_region->ida, dev_dax->id);
699  err_id:
700         kfree(dev_dax);
701
702         return ERR_PTR(rc);
703 }
704 EXPORT_SYMBOL_GPL(devm_create_dev_dax);
705
706 static int __init dax_init(void)
707 {
708         dax_class = class_create(THIS_MODULE, "dax");
709         return PTR_ERR_OR_ZERO(dax_class);
710 }
711
712 static void __exit dax_exit(void)
713 {
714         class_destroy(dax_class);
715 }
716
717 MODULE_AUTHOR("Intel Corporation");
718 MODULE_LICENSE("GPL v2");
719 subsys_initcall(dax_init);
720 module_exit(dax_exit);