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7b6be844 DW |
1 | /* |
2 | * Copyright(c) 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/mount.h> | |
16 | #include <linux/magic.h> | |
ef510424 | 17 | #include <linux/genhd.h> |
3775f646 | 18 | #include <linux/pfn_t.h> |
7b6be844 DW |
19 | #include <linux/cdev.h> |
20 | #include <linux/hash.h> | |
21 | #include <linux/slab.h> | |
7e026c8c | 22 | #include <linux/uio.h> |
6568b08b | 23 | #include <linux/dax.h> |
7b6be844 DW |
24 | #include <linux/fs.h> |
25 | ||
7b6be844 DW |
26 | static dev_t dax_devt; |
27 | DEFINE_STATIC_SRCU(dax_srcu); | |
28 | static struct vfsmount *dax_mnt; | |
29 | static DEFINE_IDA(dax_minor_ida); | |
30 | static struct kmem_cache *dax_cache __read_mostly; | |
31 | static struct super_block *dax_superblock __read_mostly; | |
32 | ||
72058005 DW |
33 | #define DAX_HASH_SIZE (PAGE_SIZE / sizeof(struct hlist_head)) |
34 | static struct hlist_head dax_host_list[DAX_HASH_SIZE]; | |
35 | static DEFINE_SPINLOCK(dax_host_lock); | |
36 | ||
7b6be844 DW |
37 | int dax_read_lock(void) |
38 | { | |
39 | return srcu_read_lock(&dax_srcu); | |
40 | } | |
41 | EXPORT_SYMBOL_GPL(dax_read_lock); | |
42 | ||
43 | void dax_read_unlock(int id) | |
44 | { | |
45 | srcu_read_unlock(&dax_srcu, id); | |
46 | } | |
47 | EXPORT_SYMBOL_GPL(dax_read_unlock); | |
48 | ||
9d109081 | 49 | #ifdef CONFIG_BLOCK |
78f35473 DW |
50 | #include <linux/blkdev.h> |
51 | ||
ef510424 DW |
52 | int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size, |
53 | pgoff_t *pgoff) | |
54 | { | |
55 | phys_addr_t phys_off = (get_start_sect(bdev) + sector) * 512; | |
56 | ||
57 | if (pgoff) | |
58 | *pgoff = PHYS_PFN(phys_off); | |
59 | if (phys_off % PAGE_SIZE || size % PAGE_SIZE) | |
60 | return -EINVAL; | |
61 | return 0; | |
62 | } | |
63 | EXPORT_SYMBOL(bdev_dax_pgoff); | |
64 | ||
26f2f4de | 65 | #if IS_ENABLED(CONFIG_FS_DAX) |
78f35473 DW |
66 | struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev) |
67 | { | |
68 | if (!blk_queue_dax(bdev->bd_queue)) | |
69 | return NULL; | |
70 | return fs_dax_get_by_host(bdev->bd_disk->disk_name); | |
71 | } | |
72 | EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev); | |
26f2f4de | 73 | #endif |
78f35473 | 74 | |
ef510424 DW |
75 | /** |
76 | * __bdev_dax_supported() - Check if the device supports dax for filesystem | |
ca2fad73 | 77 | * @bdev: block device to check |
ef510424 DW |
78 | * @blocksize: The block size of the device |
79 | * | |
80 | * This is a library function for filesystems to check if the block device | |
81 | * can be mounted with dax option. | |
82 | * | |
d8d53b26 | 83 | * Return: true if supported, false if unsupported |
ef510424 | 84 | */ |
d8d53b26 | 85 | bool __bdev_dax_supported(struct block_device *bdev, int blocksize) |
ef510424 | 86 | { |
ef510424 | 87 | struct dax_device *dax_dev; |
02f2d29a | 88 | struct request_queue *q; |
ef510424 DW |
89 | pgoff_t pgoff; |
90 | int err, id; | |
91 | void *kaddr; | |
92 | pfn_t pfn; | |
93 | long len; | |
ca2fad73 | 94 | char buf[BDEVNAME_SIZE]; |
ef510424 DW |
95 | |
96 | if (blocksize != PAGE_SIZE) { | |
ca2fad73 DW |
97 | pr_debug("%s: error: unsupported blocksize for dax\n", |
98 | bdevname(bdev, buf)); | |
d8d53b26 | 99 | return false; |
ef510424 DW |
100 | } |
101 | ||
02f2d29a RZ |
102 | q = bdev_get_queue(bdev); |
103 | if (!q || !blk_queue_dax(q)) { | |
104 | pr_debug("%s: error: request queue doesn't support dax\n", | |
105 | bdevname(bdev, buf)); | |
106 | return false; | |
107 | } | |
108 | ||
ef510424 DW |
109 | err = bdev_dax_pgoff(bdev, 0, PAGE_SIZE, &pgoff); |
110 | if (err) { | |
ca2fad73 DW |
111 | pr_debug("%s: error: unaligned partition for dax\n", |
112 | bdevname(bdev, buf)); | |
d8d53b26 | 113 | return false; |
ef510424 DW |
114 | } |
115 | ||
116 | dax_dev = dax_get_by_host(bdev->bd_disk->disk_name); | |
117 | if (!dax_dev) { | |
ca2fad73 DW |
118 | pr_debug("%s: error: device does not support dax\n", |
119 | bdevname(bdev, buf)); | |
d8d53b26 | 120 | return false; |
ef510424 DW |
121 | } |
122 | ||
123 | id = dax_read_lock(); | |
124 | len = dax_direct_access(dax_dev, pgoff, 1, &kaddr, &pfn); | |
125 | dax_read_unlock(id); | |
126 | ||
127 | put_dax(dax_dev); | |
128 | ||
129 | if (len < 1) { | |
ca2fad73 DW |
130 | pr_debug("%s: error: dax access failed (%ld)\n", |
131 | bdevname(bdev, buf), len); | |
d8d53b26 | 132 | return false; |
ef510424 DW |
133 | } |
134 | ||
3775f646 DW |
135 | if ((IS_ENABLED(CONFIG_FS_DAX_LIMITED) && pfn_t_special(pfn)) |
136 | || pfn_t_devmap(pfn)) | |
137 | /* pass */; | |
138 | else { | |
ca2fad73 DW |
139 | pr_debug("%s: error: dax support not enabled\n", |
140 | bdevname(bdev, buf)); | |
d8d53b26 | 141 | return false; |
3775f646 DW |
142 | } |
143 | ||
d8d53b26 | 144 | return true; |
ef510424 DW |
145 | } |
146 | EXPORT_SYMBOL_GPL(__bdev_dax_supported); | |
9d109081 | 147 | #endif |
ef510424 | 148 | |
9a60c3ef DW |
149 | enum dax_device_flags { |
150 | /* !alive + rcu grace period == no new operations / mappings */ | |
151 | DAXDEV_ALIVE, | |
6e0c90d6 DW |
152 | /* gate whether dax_flush() calls the low level flush routine */ |
153 | DAXDEV_WRITE_CACHE, | |
9a60c3ef DW |
154 | }; |
155 | ||
7b6be844 DW |
156 | /** |
157 | * struct dax_device - anchor object for dax services | |
158 | * @inode: core vfs | |
159 | * @cdev: optional character interface for "device dax" | |
72058005 | 160 | * @host: optional name for lookups where the device path is not available |
7b6be844 | 161 | * @private: dax driver private data |
9a60c3ef | 162 | * @flags: state and boolean properties |
7b6be844 DW |
163 | */ |
164 | struct dax_device { | |
72058005 | 165 | struct hlist_node list; |
7b6be844 DW |
166 | struct inode inode; |
167 | struct cdev cdev; | |
72058005 | 168 | const char *host; |
7b6be844 | 169 | void *private; |
9a60c3ef | 170 | unsigned long flags; |
6568b08b | 171 | const struct dax_operations *ops; |
7b6be844 DW |
172 | }; |
173 | ||
6e0c90d6 DW |
174 | static ssize_t write_cache_show(struct device *dev, |
175 | struct device_attribute *attr, char *buf) | |
176 | { | |
177 | struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); | |
178 | ssize_t rc; | |
179 | ||
180 | WARN_ON_ONCE(!dax_dev); | |
181 | if (!dax_dev) | |
182 | return -ENXIO; | |
183 | ||
184 | rc = sprintf(buf, "%d\n", !!test_bit(DAXDEV_WRITE_CACHE, | |
185 | &dax_dev->flags)); | |
186 | put_dax(dax_dev); | |
187 | return rc; | |
188 | } | |
189 | ||
190 | static ssize_t write_cache_store(struct device *dev, | |
191 | struct device_attribute *attr, const char *buf, size_t len) | |
192 | { | |
193 | bool write_cache; | |
194 | int rc = strtobool(buf, &write_cache); | |
195 | struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); | |
196 | ||
197 | WARN_ON_ONCE(!dax_dev); | |
198 | if (!dax_dev) | |
199 | return -ENXIO; | |
200 | ||
201 | if (rc) | |
202 | len = rc; | |
203 | else if (write_cache) | |
204 | set_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); | |
205 | else | |
206 | clear_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); | |
207 | ||
208 | put_dax(dax_dev); | |
209 | return len; | |
210 | } | |
211 | static DEVICE_ATTR_RW(write_cache); | |
212 | ||
213 | static umode_t dax_visible(struct kobject *kobj, struct attribute *a, int n) | |
214 | { | |
215 | struct device *dev = container_of(kobj, typeof(*dev), kobj); | |
216 | struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); | |
217 | ||
218 | WARN_ON_ONCE(!dax_dev); | |
219 | if (!dax_dev) | |
220 | return 0; | |
221 | ||
c3ca015f MP |
222 | #ifndef CONFIG_ARCH_HAS_PMEM_API |
223 | if (a == &dev_attr_write_cache.attr) | |
6e0c90d6 | 224 | return 0; |
c3ca015f | 225 | #endif |
6e0c90d6 DW |
226 | return a->mode; |
227 | } | |
228 | ||
229 | static struct attribute *dax_attributes[] = { | |
230 | &dev_attr_write_cache.attr, | |
231 | NULL, | |
232 | }; | |
233 | ||
234 | struct attribute_group dax_attribute_group = { | |
235 | .name = "dax", | |
236 | .attrs = dax_attributes, | |
237 | .is_visible = dax_visible, | |
238 | }; | |
239 | EXPORT_SYMBOL_GPL(dax_attribute_group); | |
240 | ||
b0686260 DW |
241 | /** |
242 | * dax_direct_access() - translate a device pgoff to an absolute pfn | |
243 | * @dax_dev: a dax_device instance representing the logical memory range | |
244 | * @pgoff: offset in pages from the start of the device to translate | |
245 | * @nr_pages: number of consecutive pages caller can handle relative to @pfn | |
246 | * @kaddr: output parameter that returns a virtual address mapping of pfn | |
247 | * @pfn: output parameter that returns an absolute pfn translation of @pgoff | |
248 | * | |
249 | * Return: negative errno if an error occurs, otherwise the number of | |
250 | * pages accessible at the device relative @pgoff. | |
251 | */ | |
252 | long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, | |
253 | void **kaddr, pfn_t *pfn) | |
254 | { | |
255 | long avail; | |
256 | ||
257 | /* | |
258 | * The device driver is allowed to sleep, in order to make the | |
259 | * memory directly accessible. | |
260 | */ | |
261 | might_sleep(); | |
262 | ||
263 | if (!dax_dev) | |
264 | return -EOPNOTSUPP; | |
265 | ||
266 | if (!dax_alive(dax_dev)) | |
267 | return -ENXIO; | |
268 | ||
269 | if (nr_pages < 0) | |
270 | return nr_pages; | |
271 | ||
272 | avail = dax_dev->ops->direct_access(dax_dev, pgoff, nr_pages, | |
273 | kaddr, pfn); | |
274 | if (!avail) | |
275 | return -ERANGE; | |
276 | return min(avail, nr_pages); | |
277 | } | |
278 | EXPORT_SYMBOL_GPL(dax_direct_access); | |
279 | ||
7e026c8c DW |
280 | size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, |
281 | size_t bytes, struct iov_iter *i) | |
282 | { | |
283 | if (!dax_alive(dax_dev)) | |
284 | return 0; | |
285 | ||
7e026c8c DW |
286 | return dax_dev->ops->copy_from_iter(dax_dev, pgoff, addr, bytes, i); |
287 | } | |
288 | EXPORT_SYMBOL_GPL(dax_copy_from_iter); | |
289 | ||
c3ca015f MP |
290 | #ifdef CONFIG_ARCH_HAS_PMEM_API |
291 | void arch_wb_cache_pmem(void *addr, size_t size); | |
292 | void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) | |
abebfbe2 | 293 | { |
c3ca015f | 294 | if (unlikely(!test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags))) |
6e0c90d6 DW |
295 | return; |
296 | ||
c3ca015f | 297 | arch_wb_cache_pmem(addr, size); |
abebfbe2 | 298 | } |
c3ca015f MP |
299 | #else |
300 | void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) | |
301 | { | |
302 | } | |
303 | #endif | |
abebfbe2 DW |
304 | EXPORT_SYMBOL_GPL(dax_flush); |
305 | ||
6e0c90d6 DW |
306 | void dax_write_cache(struct dax_device *dax_dev, bool wc) |
307 | { | |
308 | if (wc) | |
309 | set_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); | |
310 | else | |
311 | clear_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); | |
312 | } | |
313 | EXPORT_SYMBOL_GPL(dax_write_cache); | |
314 | ||
273752c9 VG |
315 | bool dax_write_cache_enabled(struct dax_device *dax_dev) |
316 | { | |
317 | return test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); | |
318 | } | |
319 | EXPORT_SYMBOL_GPL(dax_write_cache_enabled); | |
320 | ||
7b6be844 DW |
321 | bool dax_alive(struct dax_device *dax_dev) |
322 | { | |
323 | lockdep_assert_held(&dax_srcu); | |
9a60c3ef | 324 | return test_bit(DAXDEV_ALIVE, &dax_dev->flags); |
7b6be844 DW |
325 | } |
326 | EXPORT_SYMBOL_GPL(dax_alive); | |
327 | ||
72058005 DW |
328 | static int dax_host_hash(const char *host) |
329 | { | |
330 | return hashlen_hash(hashlen_string("DAX", host)) % DAX_HASH_SIZE; | |
331 | } | |
332 | ||
7b6be844 DW |
333 | /* |
334 | * Note, rcu is not protecting the liveness of dax_dev, rcu is ensuring | |
335 | * that any fault handlers or operations that might have seen | |
336 | * dax_alive(), have completed. Any operations that start after | |
337 | * synchronize_srcu() has run will abort upon seeing !dax_alive(). | |
338 | */ | |
339 | void kill_dax(struct dax_device *dax_dev) | |
340 | { | |
341 | if (!dax_dev) | |
342 | return; | |
343 | ||
9a60c3ef | 344 | clear_bit(DAXDEV_ALIVE, &dax_dev->flags); |
72058005 | 345 | |
7b6be844 | 346 | synchronize_srcu(&dax_srcu); |
72058005 DW |
347 | |
348 | spin_lock(&dax_host_lock); | |
349 | hlist_del_init(&dax_dev->list); | |
350 | spin_unlock(&dax_host_lock); | |
351 | ||
7b6be844 DW |
352 | dax_dev->private = NULL; |
353 | } | |
354 | EXPORT_SYMBOL_GPL(kill_dax); | |
355 | ||
356 | static struct inode *dax_alloc_inode(struct super_block *sb) | |
357 | { | |
358 | struct dax_device *dax_dev; | |
b9d39d17 | 359 | struct inode *inode; |
7b6be844 DW |
360 | |
361 | dax_dev = kmem_cache_alloc(dax_cache, GFP_KERNEL); | |
9f586fff MP |
362 | if (!dax_dev) |
363 | return NULL; | |
364 | ||
b9d39d17 DW |
365 | inode = &dax_dev->inode; |
366 | inode->i_rdev = 0; | |
367 | return inode; | |
7b6be844 DW |
368 | } |
369 | ||
370 | static struct dax_device *to_dax_dev(struct inode *inode) | |
371 | { | |
372 | return container_of(inode, struct dax_device, inode); | |
373 | } | |
374 | ||
375 | static void dax_i_callback(struct rcu_head *head) | |
376 | { | |
377 | struct inode *inode = container_of(head, struct inode, i_rcu); | |
378 | struct dax_device *dax_dev = to_dax_dev(inode); | |
379 | ||
72058005 DW |
380 | kfree(dax_dev->host); |
381 | dax_dev->host = NULL; | |
b9d39d17 DW |
382 | if (inode->i_rdev) |
383 | ida_simple_remove(&dax_minor_ida, MINOR(inode->i_rdev)); | |
7b6be844 DW |
384 | kmem_cache_free(dax_cache, dax_dev); |
385 | } | |
386 | ||
387 | static void dax_destroy_inode(struct inode *inode) | |
388 | { | |
389 | struct dax_device *dax_dev = to_dax_dev(inode); | |
390 | ||
9a60c3ef | 391 | WARN_ONCE(test_bit(DAXDEV_ALIVE, &dax_dev->flags), |
7b6be844 DW |
392 | "kill_dax() must be called before final iput()\n"); |
393 | call_rcu(&inode->i_rcu, dax_i_callback); | |
394 | } | |
395 | ||
396 | static const struct super_operations dax_sops = { | |
397 | .statfs = simple_statfs, | |
398 | .alloc_inode = dax_alloc_inode, | |
399 | .destroy_inode = dax_destroy_inode, | |
400 | .drop_inode = generic_delete_inode, | |
401 | }; | |
402 | ||
403 | static struct dentry *dax_mount(struct file_system_type *fs_type, | |
404 | int flags, const char *dev_name, void *data) | |
405 | { | |
406 | return mount_pseudo(fs_type, "dax:", &dax_sops, NULL, DAXFS_MAGIC); | |
407 | } | |
408 | ||
409 | static struct file_system_type dax_fs_type = { | |
410 | .name = "dax", | |
411 | .mount = dax_mount, | |
412 | .kill_sb = kill_anon_super, | |
413 | }; | |
414 | ||
415 | static int dax_test(struct inode *inode, void *data) | |
416 | { | |
417 | dev_t devt = *(dev_t *) data; | |
418 | ||
419 | return inode->i_rdev == devt; | |
420 | } | |
421 | ||
422 | static int dax_set(struct inode *inode, void *data) | |
423 | { | |
424 | dev_t devt = *(dev_t *) data; | |
425 | ||
426 | inode->i_rdev = devt; | |
427 | return 0; | |
428 | } | |
429 | ||
430 | static struct dax_device *dax_dev_get(dev_t devt) | |
431 | { | |
432 | struct dax_device *dax_dev; | |
433 | struct inode *inode; | |
434 | ||
435 | inode = iget5_locked(dax_superblock, hash_32(devt + DAXFS_MAGIC, 31), | |
436 | dax_test, dax_set, &devt); | |
437 | ||
438 | if (!inode) | |
439 | return NULL; | |
440 | ||
441 | dax_dev = to_dax_dev(inode); | |
442 | if (inode->i_state & I_NEW) { | |
9a60c3ef | 443 | set_bit(DAXDEV_ALIVE, &dax_dev->flags); |
7b6be844 DW |
444 | inode->i_cdev = &dax_dev->cdev; |
445 | inode->i_mode = S_IFCHR; | |
446 | inode->i_flags = S_DAX; | |
447 | mapping_set_gfp_mask(&inode->i_data, GFP_USER); | |
448 | unlock_new_inode(inode); | |
449 | } | |
450 | ||
451 | return dax_dev; | |
452 | } | |
453 | ||
72058005 DW |
454 | static void dax_add_host(struct dax_device *dax_dev, const char *host) |
455 | { | |
456 | int hash; | |
457 | ||
458 | /* | |
459 | * Unconditionally init dax_dev since it's coming from a | |
460 | * non-zeroed slab cache | |
461 | */ | |
462 | INIT_HLIST_NODE(&dax_dev->list); | |
463 | dax_dev->host = host; | |
464 | if (!host) | |
465 | return; | |
466 | ||
467 | hash = dax_host_hash(host); | |
468 | spin_lock(&dax_host_lock); | |
469 | hlist_add_head(&dax_dev->list, &dax_host_list[hash]); | |
470 | spin_unlock(&dax_host_lock); | |
471 | } | |
472 | ||
6568b08b DW |
473 | struct dax_device *alloc_dax(void *private, const char *__host, |
474 | const struct dax_operations *ops) | |
7b6be844 DW |
475 | { |
476 | struct dax_device *dax_dev; | |
72058005 | 477 | const char *host; |
7b6be844 DW |
478 | dev_t devt; |
479 | int minor; | |
480 | ||
72058005 DW |
481 | host = kstrdup(__host, GFP_KERNEL); |
482 | if (__host && !host) | |
483 | return NULL; | |
484 | ||
cf1e2289 | 485 | minor = ida_simple_get(&dax_minor_ida, 0, MINORMASK+1, GFP_KERNEL); |
7b6be844 | 486 | if (minor < 0) |
72058005 | 487 | goto err_minor; |
7b6be844 DW |
488 | |
489 | devt = MKDEV(MAJOR(dax_devt), minor); | |
490 | dax_dev = dax_dev_get(devt); | |
491 | if (!dax_dev) | |
72058005 | 492 | goto err_dev; |
7b6be844 | 493 | |
72058005 | 494 | dax_add_host(dax_dev, host); |
6568b08b | 495 | dax_dev->ops = ops; |
7b6be844 DW |
496 | dax_dev->private = private; |
497 | return dax_dev; | |
498 | ||
72058005 | 499 | err_dev: |
7b6be844 | 500 | ida_simple_remove(&dax_minor_ida, minor); |
72058005 DW |
501 | err_minor: |
502 | kfree(host); | |
7b6be844 DW |
503 | return NULL; |
504 | } | |
505 | EXPORT_SYMBOL_GPL(alloc_dax); | |
506 | ||
507 | void put_dax(struct dax_device *dax_dev) | |
508 | { | |
509 | if (!dax_dev) | |
510 | return; | |
511 | iput(&dax_dev->inode); | |
512 | } | |
513 | EXPORT_SYMBOL_GPL(put_dax); | |
514 | ||
72058005 DW |
515 | /** |
516 | * dax_get_by_host() - temporary lookup mechanism for filesystem-dax | |
517 | * @host: alternate name for the device registered by a dax driver | |
518 | */ | |
519 | struct dax_device *dax_get_by_host(const char *host) | |
520 | { | |
521 | struct dax_device *dax_dev, *found = NULL; | |
522 | int hash, id; | |
523 | ||
524 | if (!host) | |
525 | return NULL; | |
526 | ||
527 | hash = dax_host_hash(host); | |
528 | ||
529 | id = dax_read_lock(); | |
530 | spin_lock(&dax_host_lock); | |
531 | hlist_for_each_entry(dax_dev, &dax_host_list[hash], list) { | |
532 | if (!dax_alive(dax_dev) | |
533 | || strcmp(host, dax_dev->host) != 0) | |
534 | continue; | |
535 | ||
536 | if (igrab(&dax_dev->inode)) | |
537 | found = dax_dev; | |
538 | break; | |
539 | } | |
540 | spin_unlock(&dax_host_lock); | |
541 | dax_read_unlock(id); | |
542 | ||
543 | return found; | |
544 | } | |
545 | EXPORT_SYMBOL_GPL(dax_get_by_host); | |
546 | ||
7b6be844 DW |
547 | /** |
548 | * inode_dax: convert a public inode into its dax_dev | |
549 | * @inode: An inode with i_cdev pointing to a dax_dev | |
550 | * | |
551 | * Note this is not equivalent to to_dax_dev() which is for private | |
552 | * internal use where we know the inode filesystem type == dax_fs_type. | |
553 | */ | |
554 | struct dax_device *inode_dax(struct inode *inode) | |
555 | { | |
556 | struct cdev *cdev = inode->i_cdev; | |
557 | ||
558 | return container_of(cdev, struct dax_device, cdev); | |
559 | } | |
560 | EXPORT_SYMBOL_GPL(inode_dax); | |
561 | ||
562 | struct inode *dax_inode(struct dax_device *dax_dev) | |
563 | { | |
564 | return &dax_dev->inode; | |
565 | } | |
566 | EXPORT_SYMBOL_GPL(dax_inode); | |
567 | ||
568 | void *dax_get_private(struct dax_device *dax_dev) | |
569 | { | |
570 | return dax_dev->private; | |
571 | } | |
572 | EXPORT_SYMBOL_GPL(dax_get_private); | |
573 | ||
574 | static void init_once(void *_dax_dev) | |
575 | { | |
576 | struct dax_device *dax_dev = _dax_dev; | |
577 | struct inode *inode = &dax_dev->inode; | |
578 | ||
b9d39d17 | 579 | memset(dax_dev, 0, sizeof(*dax_dev)); |
7b6be844 DW |
580 | inode_init_once(inode); |
581 | } | |
582 | ||
583 | static int __dax_fs_init(void) | |
584 | { | |
585 | int rc; | |
586 | ||
587 | dax_cache = kmem_cache_create("dax_cache", sizeof(struct dax_device), 0, | |
588 | (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| | |
589 | SLAB_MEM_SPREAD|SLAB_ACCOUNT), | |
590 | init_once); | |
591 | if (!dax_cache) | |
592 | return -ENOMEM; | |
593 | ||
594 | rc = register_filesystem(&dax_fs_type); | |
595 | if (rc) | |
596 | goto err_register_fs; | |
597 | ||
598 | dax_mnt = kern_mount(&dax_fs_type); | |
599 | if (IS_ERR(dax_mnt)) { | |
600 | rc = PTR_ERR(dax_mnt); | |
601 | goto err_mount; | |
602 | } | |
603 | dax_superblock = dax_mnt->mnt_sb; | |
604 | ||
605 | return 0; | |
606 | ||
607 | err_mount: | |
608 | unregister_filesystem(&dax_fs_type); | |
609 | err_register_fs: | |
610 | kmem_cache_destroy(dax_cache); | |
611 | ||
612 | return rc; | |
613 | } | |
614 | ||
615 | static void __dax_fs_exit(void) | |
616 | { | |
617 | kern_unmount(dax_mnt); | |
618 | unregister_filesystem(&dax_fs_type); | |
619 | kmem_cache_destroy(dax_cache); | |
620 | } | |
621 | ||
622 | static int __init dax_fs_init(void) | |
623 | { | |
624 | int rc; | |
625 | ||
626 | rc = __dax_fs_init(); | |
627 | if (rc) | |
628 | return rc; | |
629 | ||
cf1e2289 | 630 | rc = alloc_chrdev_region(&dax_devt, 0, MINORMASK+1, "dax"); |
7b6be844 DW |
631 | if (rc) |
632 | __dax_fs_exit(); | |
633 | return rc; | |
634 | } | |
635 | ||
636 | static void __exit dax_fs_exit(void) | |
637 | { | |
cf1e2289 | 638 | unregister_chrdev_region(dax_devt, MINORMASK+1); |
7b6be844 DW |
639 | ida_destroy(&dax_minor_ida); |
640 | __dax_fs_exit(); | |
641 | } | |
642 | ||
643 | MODULE_AUTHOR("Intel Corporation"); | |
644 | MODULE_LICENSE("GPL v2"); | |
645 | subsys_initcall(dax_fs_init); | |
646 | module_exit(dax_fs_exit); |