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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright(c) 2017 Intel Corporation. All rights reserved.
4 */
5#include <linux/pagemap.h>
6#include <linux/module.h>
7#include <linux/mount.h>
8#include <linux/pseudo_fs.h>
9#include <linux/magic.h>
10#include <linux/genhd.h>
11#include <linux/pfn_t.h>
12#include <linux/cdev.h>
13#include <linux/hash.h>
14#include <linux/slab.h>
15#include <linux/uio.h>
16#include <linux/dax.h>
17#include <linux/fs.h>
18#include "dax-private.h"
19
20static dev_t dax_devt;
21DEFINE_STATIC_SRCU(dax_srcu);
22static struct vfsmount *dax_mnt;
23static DEFINE_IDA(dax_minor_ida);
24static struct kmem_cache *dax_cache __read_mostly;
25static struct super_block *dax_superblock __read_mostly;
26
27#define DAX_HASH_SIZE (PAGE_SIZE / sizeof(struct hlist_head))
28static struct hlist_head dax_host_list[DAX_HASH_SIZE];
29static DEFINE_SPINLOCK(dax_host_lock);
30
31int dax_read_lock(void)
32{
33 return srcu_read_lock(&dax_srcu);
34}
35EXPORT_SYMBOL_GPL(dax_read_lock);
36
37void dax_read_unlock(int id)
38{
39 srcu_read_unlock(&dax_srcu, id);
40}
41EXPORT_SYMBOL_GPL(dax_read_unlock);
42
43#ifdef CONFIG_BLOCK
44#include <linux/blkdev.h>
45
46int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size,
47 pgoff_t *pgoff)
48{
49 phys_addr_t phys_off = (get_start_sect(bdev) + sector) * 512;
50
51 if (pgoff)
52 *pgoff = PHYS_PFN(phys_off);
53 if (phys_off % PAGE_SIZE || size % PAGE_SIZE)
54 return -EINVAL;
55 return 0;
56}
57EXPORT_SYMBOL(bdev_dax_pgoff);
58
59#if IS_ENABLED(CONFIG_FS_DAX)
60struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
61{
62 if (!blk_queue_dax(bdev->bd_disk->queue))
63 return NULL;
64 return dax_get_by_host(bdev->bd_disk->disk_name);
65}
66EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev);
67#endif
68
69bool __generic_fsdax_supported(struct dax_device *dax_dev,
70 struct block_device *bdev, int blocksize, sector_t start,
71 sector_t sectors)
72{
73 bool dax_enabled = false;
74 pgoff_t pgoff, pgoff_end;
75 char buf[BDEVNAME_SIZE];
76 void *kaddr, *end_kaddr;
77 pfn_t pfn, end_pfn;
78 sector_t last_page;
79 long len, len2;
80 int err, id;
81
82 if (blocksize != PAGE_SIZE) {
83 pr_info("%s: error: unsupported blocksize for dax\n",
84 bdevname(bdev, buf));
85 return false;
86 }
87
88 if (!dax_dev) {
89 pr_debug("%s: error: dax unsupported by block device\n",
90 bdevname(bdev, buf));
91 return false;
92 }
93
94 err = bdev_dax_pgoff(bdev, start, PAGE_SIZE, &pgoff);
95 if (err) {
96 pr_info("%s: error: unaligned partition for dax\n",
97 bdevname(bdev, buf));
98 return false;
99 }
100
101 last_page = PFN_DOWN((start + sectors - 1) * 512) * PAGE_SIZE / 512;
102 err = bdev_dax_pgoff(bdev, last_page, PAGE_SIZE, &pgoff_end);
103 if (err) {
104 pr_info("%s: error: unaligned partition for dax\n",
105 bdevname(bdev, buf));
106 return false;
107 }
108
109 id = dax_read_lock();
110 len = dax_direct_access(dax_dev, pgoff, 1, &kaddr, &pfn);
111 len2 = dax_direct_access(dax_dev, pgoff_end, 1, &end_kaddr, &end_pfn);
112
113 if (len < 1 || len2 < 1) {
114 pr_info("%s: error: dax access failed (%ld)\n",
115 bdevname(bdev, buf), len < 1 ? len : len2);
116 dax_read_unlock(id);
117 return false;
118 }
119
120 if (IS_ENABLED(CONFIG_FS_DAX_LIMITED) && pfn_t_special(pfn)) {
121 /*
122 * An arch that has enabled the pmem api should also
123 * have its drivers support pfn_t_devmap()
124 *
125 * This is a developer warning and should not trigger in
126 * production. dax_flush() will crash since it depends
127 * on being able to do (page_address(pfn_to_page())).
128 */
129 WARN_ON(IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API));
130 dax_enabled = true;
131 } else if (pfn_t_devmap(pfn) && pfn_t_devmap(end_pfn)) {
132 struct dev_pagemap *pgmap, *end_pgmap;
133
134 pgmap = get_dev_pagemap(pfn_t_to_pfn(pfn), NULL);
135 end_pgmap = get_dev_pagemap(pfn_t_to_pfn(end_pfn), NULL);
136 if (pgmap && pgmap == end_pgmap && pgmap->type == MEMORY_DEVICE_FS_DAX
137 && pfn_t_to_page(pfn)->pgmap == pgmap
138 && pfn_t_to_page(end_pfn)->pgmap == pgmap
139 && pfn_t_to_pfn(pfn) == PHYS_PFN(__pa(kaddr))
140 && pfn_t_to_pfn(end_pfn) == PHYS_PFN(__pa(end_kaddr)))
141 dax_enabled = true;
142 put_dev_pagemap(pgmap);
143 put_dev_pagemap(end_pgmap);
144
145 }
146 dax_read_unlock(id);
147
148 if (!dax_enabled) {
149 pr_info("%s: error: dax support not enabled\n",
150 bdevname(bdev, buf));
151 return false;
152 }
153 return true;
154}
155EXPORT_SYMBOL_GPL(__generic_fsdax_supported);
156
157/**
158 * __bdev_dax_supported() - Check if the device supports dax for filesystem
159 * @bdev: block device to check
160 * @blocksize: The block size of the device
161 *
162 * This is a library function for filesystems to check if the block device
163 * can be mounted with dax option.
164 *
165 * Return: true if supported, false if unsupported
166 */
167bool __bdev_dax_supported(struct block_device *bdev, int blocksize)
168{
169 struct dax_device *dax_dev;
170 struct request_queue *q;
171 char buf[BDEVNAME_SIZE];
172 bool ret;
173 int id;
174
175 q = bdev_get_queue(bdev);
176 if (!q || !blk_queue_dax(q)) {
177 pr_debug("%s: error: request queue doesn't support dax\n",
178 bdevname(bdev, buf));
179 return false;
180 }
181
182 dax_dev = dax_get_by_host(bdev->bd_disk->disk_name);
183 if (!dax_dev) {
184 pr_debug("%s: error: device does not support dax\n",
185 bdevname(bdev, buf));
186 return false;
187 }
188
189 id = dax_read_lock();
190 ret = dax_supported(dax_dev, bdev, blocksize, 0,
191 i_size_read(bdev->bd_inode) / 512);
192 dax_read_unlock(id);
193
194 put_dax(dax_dev);
195
196 return ret;
197}
198EXPORT_SYMBOL_GPL(__bdev_dax_supported);
199#endif
200
201enum dax_device_flags {
202 /* !alive + rcu grace period == no new operations / mappings */
203 DAXDEV_ALIVE,
204 /* gate whether dax_flush() calls the low level flush routine */
205 DAXDEV_WRITE_CACHE,
206 /* flag to check if device supports synchronous flush */
207 DAXDEV_SYNC,
208};
209
210/**
211 * struct dax_device - anchor object for dax services
212 * @inode: core vfs
213 * @cdev: optional character interface for "device dax"
214 * @host: optional name for lookups where the device path is not available
215 * @private: dax driver private data
216 * @flags: state and boolean properties
217 */
218struct dax_device {
219 struct hlist_node list;
220 struct inode inode;
221 struct cdev cdev;
222 const char *host;
223 void *private;
224 unsigned long flags;
225 const struct dax_operations *ops;
226};
227
228static ssize_t write_cache_show(struct device *dev,
229 struct device_attribute *attr, char *buf)
230{
231 struct dax_device *dax_dev = dax_get_by_host(dev_name(dev));
232 ssize_t rc;
233
234 WARN_ON_ONCE(!dax_dev);
235 if (!dax_dev)
236 return -ENXIO;
237
238 rc = sprintf(buf, "%d\n", !!dax_write_cache_enabled(dax_dev));
239 put_dax(dax_dev);
240 return rc;
241}
242
243static ssize_t write_cache_store(struct device *dev,
244 struct device_attribute *attr, const char *buf, size_t len)
245{
246 bool write_cache;
247 int rc = strtobool(buf, &write_cache);
248 struct dax_device *dax_dev = dax_get_by_host(dev_name(dev));
249
250 WARN_ON_ONCE(!dax_dev);
251 if (!dax_dev)
252 return -ENXIO;
253
254 if (rc)
255 len = rc;
256 else
257 dax_write_cache(dax_dev, write_cache);
258
259 put_dax(dax_dev);
260 return len;
261}
262static DEVICE_ATTR_RW(write_cache);
263
264static umode_t dax_visible(struct kobject *kobj, struct attribute *a, int n)
265{
266 struct device *dev = container_of(kobj, typeof(*dev), kobj);
267 struct dax_device *dax_dev = dax_get_by_host(dev_name(dev));
268
269 WARN_ON_ONCE(!dax_dev);
270 if (!dax_dev)
271 return 0;
272
273#ifndef CONFIG_ARCH_HAS_PMEM_API
274 if (a == &dev_attr_write_cache.attr)
275 return 0;
276#endif
277 return a->mode;
278}
279
280static struct attribute *dax_attributes[] = {
281 &dev_attr_write_cache.attr,
282 NULL,
283};
284
285struct attribute_group dax_attribute_group = {
286 .name = "dax",
287 .attrs = dax_attributes,
288 .is_visible = dax_visible,
289};
290EXPORT_SYMBOL_GPL(dax_attribute_group);
291
292/**
293 * dax_direct_access() - translate a device pgoff to an absolute pfn
294 * @dax_dev: a dax_device instance representing the logical memory range
295 * @pgoff: offset in pages from the start of the device to translate
296 * @nr_pages: number of consecutive pages caller can handle relative to @pfn
297 * @kaddr: output parameter that returns a virtual address mapping of pfn
298 * @pfn: output parameter that returns an absolute pfn translation of @pgoff
299 *
300 * Return: negative errno if an error occurs, otherwise the number of
301 * pages accessible at the device relative @pgoff.
302 */
303long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
304 void **kaddr, pfn_t *pfn)
305{
306 long avail;
307
308 if (!dax_dev)
309 return -EOPNOTSUPP;
310
311 if (!dax_alive(dax_dev))
312 return -ENXIO;
313
314 if (nr_pages < 0)
315 return nr_pages;
316
317 avail = dax_dev->ops->direct_access(dax_dev, pgoff, nr_pages,
318 kaddr, pfn);
319 if (!avail)
320 return -ERANGE;
321 return min(avail, nr_pages);
322}
323EXPORT_SYMBOL_GPL(dax_direct_access);
324
325bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
326 int blocksize, sector_t start, sector_t len)
327{
328 if (!dax_dev)
329 return false;
330
331 if (!dax_alive(dax_dev))
332 return false;
333
334 return dax_dev->ops->dax_supported(dax_dev, bdev, blocksize, start, len);
335}
336EXPORT_SYMBOL_GPL(dax_supported);
337
338size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
339 size_t bytes, struct iov_iter *i)
340{
341 if (!dax_alive(dax_dev))
342 return 0;
343
344 return dax_dev->ops->copy_from_iter(dax_dev, pgoff, addr, bytes, i);
345}
346EXPORT_SYMBOL_GPL(dax_copy_from_iter);
347
348size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
349 size_t bytes, struct iov_iter *i)
350{
351 if (!dax_alive(dax_dev))
352 return 0;
353
354 return dax_dev->ops->copy_to_iter(dax_dev, pgoff, addr, bytes, i);
355}
356EXPORT_SYMBOL_GPL(dax_copy_to_iter);
357
358int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
359 size_t nr_pages)
360{
361 if (!dax_alive(dax_dev))
362 return -ENXIO;
363 /*
364 * There are no callers that want to zero more than one page as of now.
365 * Once users are there, this check can be removed after the
366 * device mapper code has been updated to split ranges across targets.
367 */
368 if (nr_pages != 1)
369 return -EIO;
370
371 return dax_dev->ops->zero_page_range(dax_dev, pgoff, nr_pages);
372}
373EXPORT_SYMBOL_GPL(dax_zero_page_range);
374
375#ifdef CONFIG_ARCH_HAS_PMEM_API
376void arch_wb_cache_pmem(void *addr, size_t size);
377void dax_flush(struct dax_device *dax_dev, void *addr, size_t size)
378{
379 if (unlikely(!dax_write_cache_enabled(dax_dev)))
380 return;
381
382 arch_wb_cache_pmem(addr, size);
383}
384#else
385void dax_flush(struct dax_device *dax_dev, void *addr, size_t size)
386{
387}
388#endif
389EXPORT_SYMBOL_GPL(dax_flush);
390
391void dax_write_cache(struct dax_device *dax_dev, bool wc)
392{
393 if (wc)
394 set_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags);
395 else
396 clear_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags);
397}
398EXPORT_SYMBOL_GPL(dax_write_cache);
399
400bool dax_write_cache_enabled(struct dax_device *dax_dev)
401{
402 return test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags);
403}
404EXPORT_SYMBOL_GPL(dax_write_cache_enabled);
405
406bool __dax_synchronous(struct dax_device *dax_dev)
407{
408 return test_bit(DAXDEV_SYNC, &dax_dev->flags);
409}
410EXPORT_SYMBOL_GPL(__dax_synchronous);
411
412void __set_dax_synchronous(struct dax_device *dax_dev)
413{
414 set_bit(DAXDEV_SYNC, &dax_dev->flags);
415}
416EXPORT_SYMBOL_GPL(__set_dax_synchronous);
417
418bool dax_alive(struct dax_device *dax_dev)
419{
420 lockdep_assert_held(&dax_srcu);
421 return test_bit(DAXDEV_ALIVE, &dax_dev->flags);
422}
423EXPORT_SYMBOL_GPL(dax_alive);
424
425static int dax_host_hash(const char *host)
426{
427 return hashlen_hash(hashlen_string("DAX", host)) % DAX_HASH_SIZE;
428}
429
430/*
431 * Note, rcu is not protecting the liveness of dax_dev, rcu is ensuring
432 * that any fault handlers or operations that might have seen
433 * dax_alive(), have completed. Any operations that start after
434 * synchronize_srcu() has run will abort upon seeing !dax_alive().
435 */
436void kill_dax(struct dax_device *dax_dev)
437{
438 if (!dax_dev)
439 return;
440
441 clear_bit(DAXDEV_ALIVE, &dax_dev->flags);
442
443 synchronize_srcu(&dax_srcu);
444
445 spin_lock(&dax_host_lock);
446 hlist_del_init(&dax_dev->list);
447 spin_unlock(&dax_host_lock);
448}
449EXPORT_SYMBOL_GPL(kill_dax);
450
451void run_dax(struct dax_device *dax_dev)
452{
453 set_bit(DAXDEV_ALIVE, &dax_dev->flags);
454}
455EXPORT_SYMBOL_GPL(run_dax);
456
457static struct inode *dax_alloc_inode(struct super_block *sb)
458{
459 struct dax_device *dax_dev;
460 struct inode *inode;
461
462 dax_dev = kmem_cache_alloc(dax_cache, GFP_KERNEL);
463 if (!dax_dev)
464 return NULL;
465
466 inode = &dax_dev->inode;
467 inode->i_rdev = 0;
468 return inode;
469}
470
471static struct dax_device *to_dax_dev(struct inode *inode)
472{
473 return container_of(inode, struct dax_device, inode);
474}
475
476static void dax_free_inode(struct inode *inode)
477{
478 struct dax_device *dax_dev = to_dax_dev(inode);
479 kfree(dax_dev->host);
480 dax_dev->host = NULL;
481 if (inode->i_rdev)
482 ida_simple_remove(&dax_minor_ida, MINOR(inode->i_rdev));
483 kmem_cache_free(dax_cache, dax_dev);
484}
485
486static void dax_destroy_inode(struct inode *inode)
487{
488 struct dax_device *dax_dev = to_dax_dev(inode);
489 WARN_ONCE(test_bit(DAXDEV_ALIVE, &dax_dev->flags),
490 "kill_dax() must be called before final iput()\n");
491}
492
493static const struct super_operations dax_sops = {
494 .statfs = simple_statfs,
495 .alloc_inode = dax_alloc_inode,
496 .destroy_inode = dax_destroy_inode,
497 .free_inode = dax_free_inode,
498 .drop_inode = generic_delete_inode,
499};
500
501static int dax_init_fs_context(struct fs_context *fc)
502{
503 struct pseudo_fs_context *ctx = init_pseudo(fc, DAXFS_MAGIC);
504 if (!ctx)
505 return -ENOMEM;
506 ctx->ops = &dax_sops;
507 return 0;
508}
509
510static struct file_system_type dax_fs_type = {
511 .name = "dax",
512 .init_fs_context = dax_init_fs_context,
513 .kill_sb = kill_anon_super,
514};
515
516static int dax_test(struct inode *inode, void *data)
517{
518 dev_t devt = *(dev_t *) data;
519
520 return inode->i_rdev == devt;
521}
522
523static int dax_set(struct inode *inode, void *data)
524{
525 dev_t devt = *(dev_t *) data;
526
527 inode->i_rdev = devt;
528 return 0;
529}
530
531static struct dax_device *dax_dev_get(dev_t devt)
532{
533 struct dax_device *dax_dev;
534 struct inode *inode;
535
536 inode = iget5_locked(dax_superblock, hash_32(devt + DAXFS_MAGIC, 31),
537 dax_test, dax_set, &devt);
538
539 if (!inode)
540 return NULL;
541
542 dax_dev = to_dax_dev(inode);
543 if (inode->i_state & I_NEW) {
544 set_bit(DAXDEV_ALIVE, &dax_dev->flags);
545 inode->i_cdev = &dax_dev->cdev;
546 inode->i_mode = S_IFCHR;
547 inode->i_flags = S_DAX;
548 mapping_set_gfp_mask(&inode->i_data, GFP_USER);
549 unlock_new_inode(inode);
550 }
551
552 return dax_dev;
553}
554
555static void dax_add_host(struct dax_device *dax_dev, const char *host)
556{
557 int hash;
558
559 /*
560 * Unconditionally init dax_dev since it's coming from a
561 * non-zeroed slab cache
562 */
563 INIT_HLIST_NODE(&dax_dev->list);
564 dax_dev->host = host;
565 if (!host)
566 return;
567
568 hash = dax_host_hash(host);
569 spin_lock(&dax_host_lock);
570 hlist_add_head(&dax_dev->list, &dax_host_list[hash]);
571 spin_unlock(&dax_host_lock);
572}
573
574struct dax_device *alloc_dax(void *private, const char *__host,
575 const struct dax_operations *ops, unsigned long flags)
576{
577 struct dax_device *dax_dev;
578 const char *host;
579 dev_t devt;
580 int minor;
581
582 if (ops && !ops->zero_page_range) {
583 pr_debug("%s: error: device does not provide dax"
584 " operation zero_page_range()\n",
585 __host ? __host : "Unknown");
586 return ERR_PTR(-EINVAL);
587 }
588
589 host = kstrdup(__host, GFP_KERNEL);
590 if (__host && !host)
591 return ERR_PTR(-ENOMEM);
592
593 minor = ida_simple_get(&dax_minor_ida, 0, MINORMASK+1, GFP_KERNEL);
594 if (minor < 0)
595 goto err_minor;
596
597 devt = MKDEV(MAJOR(dax_devt), minor);
598 dax_dev = dax_dev_get(devt);
599 if (!dax_dev)
600 goto err_dev;
601
602 dax_add_host(dax_dev, host);
603 dax_dev->ops = ops;
604 dax_dev->private = private;
605 if (flags & DAXDEV_F_SYNC)
606 set_dax_synchronous(dax_dev);
607
608 return dax_dev;
609
610 err_dev:
611 ida_simple_remove(&dax_minor_ida, minor);
612 err_minor:
613 kfree(host);
614 return ERR_PTR(-ENOMEM);
615}
616EXPORT_SYMBOL_GPL(alloc_dax);
617
618void put_dax(struct dax_device *dax_dev)
619{
620 if (!dax_dev)
621 return;
622 iput(&dax_dev->inode);
623}
624EXPORT_SYMBOL_GPL(put_dax);
625
626/**
627 * dax_get_by_host() - temporary lookup mechanism for filesystem-dax
628 * @host: alternate name for the device registered by a dax driver
629 */
630struct dax_device *dax_get_by_host(const char *host)
631{
632 struct dax_device *dax_dev, *found = NULL;
633 int hash, id;
634
635 if (!host)
636 return NULL;
637
638 hash = dax_host_hash(host);
639
640 id = dax_read_lock();
641 spin_lock(&dax_host_lock);
642 hlist_for_each_entry(dax_dev, &dax_host_list[hash], list) {
643 if (!dax_alive(dax_dev)
644 || strcmp(host, dax_dev->host) != 0)
645 continue;
646
647 if (igrab(&dax_dev->inode))
648 found = dax_dev;
649 break;
650 }
651 spin_unlock(&dax_host_lock);
652 dax_read_unlock(id);
653
654 return found;
655}
656EXPORT_SYMBOL_GPL(dax_get_by_host);
657
658/**
659 * inode_dax: convert a public inode into its dax_dev
660 * @inode: An inode with i_cdev pointing to a dax_dev
661 *
662 * Note this is not equivalent to to_dax_dev() which is for private
663 * internal use where we know the inode filesystem type == dax_fs_type.
664 */
665struct dax_device *inode_dax(struct inode *inode)
666{
667 struct cdev *cdev = inode->i_cdev;
668
669 return container_of(cdev, struct dax_device, cdev);
670}
671EXPORT_SYMBOL_GPL(inode_dax);
672
673struct inode *dax_inode(struct dax_device *dax_dev)
674{
675 return &dax_dev->inode;
676}
677EXPORT_SYMBOL_GPL(dax_inode);
678
679void *dax_get_private(struct dax_device *dax_dev)
680{
681 if (!test_bit(DAXDEV_ALIVE, &dax_dev->flags))
682 return NULL;
683 return dax_dev->private;
684}
685EXPORT_SYMBOL_GPL(dax_get_private);
686
687static void init_once(void *_dax_dev)
688{
689 struct dax_device *dax_dev = _dax_dev;
690 struct inode *inode = &dax_dev->inode;
691
692 memset(dax_dev, 0, sizeof(*dax_dev));
693 inode_init_once(inode);
694}
695
696static int dax_fs_init(void)
697{
698 int rc;
699
700 dax_cache = kmem_cache_create("dax_cache", sizeof(struct dax_device), 0,
701 (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
702 SLAB_MEM_SPREAD|SLAB_ACCOUNT),
703 init_once);
704 if (!dax_cache)
705 return -ENOMEM;
706
707 dax_mnt = kern_mount(&dax_fs_type);
708 if (IS_ERR(dax_mnt)) {
709 rc = PTR_ERR(dax_mnt);
710 goto err_mount;
711 }
712 dax_superblock = dax_mnt->mnt_sb;
713
714 return 0;
715
716 err_mount:
717 kmem_cache_destroy(dax_cache);
718
719 return rc;
720}
721
722static void dax_fs_exit(void)
723{
724 kern_unmount(dax_mnt);
725 kmem_cache_destroy(dax_cache);
726}
727
728static int __init dax_core_init(void)
729{
730 int rc;
731
732 rc = dax_fs_init();
733 if (rc)
734 return rc;
735
736 rc = alloc_chrdev_region(&dax_devt, 0, MINORMASK+1, "dax");
737 if (rc)
738 goto err_chrdev;
739
740 rc = dax_bus_init();
741 if (rc)
742 goto err_bus;
743 return 0;
744
745err_bus:
746 unregister_chrdev_region(dax_devt, MINORMASK+1);
747err_chrdev:
748 dax_fs_exit();
749 return 0;
750}
751
752static void __exit dax_core_exit(void)
753{
754 unregister_chrdev_region(dax_devt, MINORMASK+1);
755 ida_destroy(&dax_minor_ida);
756 dax_fs_exit();
757}
758
759MODULE_AUTHOR("Intel Corporation");
760MODULE_LICENSE("GPL v2");
761subsys_initcall(dax_core_init);
762module_exit(dax_core_exit);