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5b497af4 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
7b6be844 DW |
2 | /* |
3 | * Copyright(c) 2017 Intel Corporation. All rights reserved. | |
7b6be844 DW |
4 | */ |
5 | #include <linux/pagemap.h> | |
6 | #include <linux/module.h> | |
7 | #include <linux/mount.h> | |
75d4e06f | 8 | #include <linux/pseudo_fs.h> |
7b6be844 | 9 | #include <linux/magic.h> |
ef510424 | 10 | #include <linux/genhd.h> |
569d0365 | 11 | #include <linux/pfn_t.h> |
7b6be844 DW |
12 | #include <linux/cdev.h> |
13 | #include <linux/hash.h> | |
14 | #include <linux/slab.h> | |
7e026c8c | 15 | #include <linux/uio.h> |
6568b08b | 16 | #include <linux/dax.h> |
7b6be844 | 17 | #include <linux/fs.h> |
51cf784c | 18 | #include "dax-private.h" |
7b6be844 | 19 | |
1b764601 CH |
20 | /** |
21 | * struct dax_device - anchor object for dax services | |
22 | * @inode: core vfs | |
23 | * @cdev: optional character interface for "device dax" | |
24 | * @host: optional name for lookups where the device path is not available | |
25 | * @private: dax driver private data | |
26 | * @flags: state and boolean properties | |
27 | */ | |
28 | struct dax_device { | |
29 | struct hlist_node list; | |
30 | struct inode inode; | |
31 | struct cdev cdev; | |
32 | const char *host; | |
33 | void *private; | |
34 | unsigned long flags; | |
35 | const struct dax_operations *ops; | |
36 | }; | |
37 | ||
7b6be844 DW |
38 | static dev_t dax_devt; |
39 | DEFINE_STATIC_SRCU(dax_srcu); | |
40 | static struct vfsmount *dax_mnt; | |
41 | static DEFINE_IDA(dax_minor_ida); | |
42 | static struct kmem_cache *dax_cache __read_mostly; | |
43 | static struct super_block *dax_superblock __read_mostly; | |
44 | ||
72058005 DW |
45 | #define DAX_HASH_SIZE (PAGE_SIZE / sizeof(struct hlist_head)) |
46 | static struct hlist_head dax_host_list[DAX_HASH_SIZE]; | |
47 | static DEFINE_SPINLOCK(dax_host_lock); | |
48 | ||
7b6be844 DW |
49 | int dax_read_lock(void) |
50 | { | |
51 | return srcu_read_lock(&dax_srcu); | |
52 | } | |
53 | EXPORT_SYMBOL_GPL(dax_read_lock); | |
54 | ||
55 | void dax_read_unlock(int id) | |
56 | { | |
57 | srcu_read_unlock(&dax_srcu, id); | |
58 | } | |
59 | EXPORT_SYMBOL_GPL(dax_read_unlock); | |
60 | ||
1b764601 CH |
61 | static int dax_host_hash(const char *host) |
62 | { | |
63 | return hashlen_hash(hashlen_string("DAX", host)) % DAX_HASH_SIZE; | |
64 | } | |
65 | ||
66 | /** | |
67 | * dax_get_by_host() - temporary lookup mechanism for filesystem-dax | |
68 | * @host: alternate name for the device registered by a dax driver | |
69 | */ | |
70 | static struct dax_device *dax_get_by_host(const char *host) | |
71 | { | |
72 | struct dax_device *dax_dev, *found = NULL; | |
73 | int hash, id; | |
74 | ||
75 | if (!host) | |
76 | return NULL; | |
77 | ||
78 | hash = dax_host_hash(host); | |
79 | ||
80 | id = dax_read_lock(); | |
81 | spin_lock(&dax_host_lock); | |
82 | hlist_for_each_entry(dax_dev, &dax_host_list[hash], list) { | |
83 | if (!dax_alive(dax_dev) | |
84 | || strcmp(host, dax_dev->host) != 0) | |
85 | continue; | |
86 | ||
87 | if (igrab(&dax_dev->inode)) | |
88 | found = dax_dev; | |
89 | break; | |
90 | } | |
91 | spin_unlock(&dax_host_lock); | |
92 | dax_read_unlock(id); | |
93 | ||
94 | return found; | |
95 | } | |
96 | ||
9d109081 | 97 | #ifdef CONFIG_BLOCK |
78f35473 DW |
98 | #include <linux/blkdev.h> |
99 | ||
ef510424 DW |
100 | int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size, |
101 | pgoff_t *pgoff) | |
102 | { | |
1a9d5d40 VG |
103 | sector_t start_sect = bdev ? get_start_sect(bdev) : 0; |
104 | phys_addr_t phys_off = (start_sect + sector) * 512; | |
ef510424 DW |
105 | |
106 | if (pgoff) | |
107 | *pgoff = PHYS_PFN(phys_off); | |
108 | if (phys_off % PAGE_SIZE || size % PAGE_SIZE) | |
109 | return -EINVAL; | |
110 | return 0; | |
111 | } | |
112 | EXPORT_SYMBOL(bdev_dax_pgoff); | |
113 | ||
26f2f4de | 114 | #if IS_ENABLED(CONFIG_FS_DAX) |
78f35473 DW |
115 | struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev) |
116 | { | |
e556f6ba | 117 | if (!blk_queue_dax(bdev->bd_disk->queue)) |
78f35473 | 118 | return NULL; |
f01b16a8 | 119 | return dax_get_by_host(bdev->bd_disk->disk_name); |
78f35473 DW |
120 | } |
121 | EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev); | |
122 | ||
cd93a2a4 | 123 | bool generic_fsdax_supported(struct dax_device *dax_dev, |
7bf7eac8 DW |
124 | struct block_device *bdev, int blocksize, sector_t start, |
125 | sector_t sectors) | |
ef510424 | 126 | { |
e7638488 | 127 | bool dax_enabled = false; |
ad428cdb | 128 | pgoff_t pgoff, pgoff_end; |
ad428cdb DW |
129 | void *kaddr, *end_kaddr; |
130 | pfn_t pfn, end_pfn; | |
131 | sector_t last_page; | |
132 | long len, len2; | |
133 | int err, id; | |
ef510424 DW |
134 | |
135 | if (blocksize != PAGE_SIZE) { | |
39b6389a | 136 | pr_info("%pg: error: unsupported blocksize for dax\n", bdev); |
80660f20 | 137 | return false; |
ef510424 DW |
138 | } |
139 | ||
d4c5da50 | 140 | if (!dax_dev) { |
39b6389a | 141 | pr_debug("%pg: error: dax unsupported by block device\n", bdev); |
d4c5da50 AH |
142 | return false; |
143 | } | |
144 | ||
7bf7eac8 | 145 | err = bdev_dax_pgoff(bdev, start, PAGE_SIZE, &pgoff); |
ef510424 | 146 | if (err) { |
39b6389a | 147 | pr_info("%pg: error: unaligned partition for dax\n", bdev); |
80660f20 | 148 | return false; |
ef510424 DW |
149 | } |
150 | ||
7bf7eac8 | 151 | last_page = PFN_DOWN((start + sectors - 1) * 512) * PAGE_SIZE / 512; |
ad428cdb DW |
152 | err = bdev_dax_pgoff(bdev, last_page, PAGE_SIZE, &pgoff_end); |
153 | if (err) { | |
39b6389a | 154 | pr_info("%pg: error: unaligned partition for dax\n", bdev); |
c2affe92 AH |
155 | return false; |
156 | } | |
157 | ||
ef510424 | 158 | id = dax_read_lock(); |
ad428cdb DW |
159 | len = dax_direct_access(dax_dev, pgoff, 1, &kaddr, &pfn); |
160 | len2 = dax_direct_access(dax_dev, pgoff_end, 1, &end_kaddr, &end_pfn); | |
ef510424 | 161 | |
ad428cdb | 162 | if (len < 1 || len2 < 1) { |
39b6389a CH |
163 | pr_info("%pg: error: dax access failed (%ld)\n", |
164 | bdev, len < 1 ? len : len2); | |
eedfd73d | 165 | dax_read_unlock(id); |
80660f20 | 166 | return false; |
ef510424 DW |
167 | } |
168 | ||
3fe0791c DW |
169 | if (IS_ENABLED(CONFIG_FS_DAX_LIMITED) && pfn_t_special(pfn)) { |
170 | /* | |
171 | * An arch that has enabled the pmem api should also | |
172 | * have its drivers support pfn_t_devmap() | |
173 | * | |
174 | * This is a developer warning and should not trigger in | |
175 | * production. dax_flush() will crash since it depends | |
176 | * on being able to do (page_address(pfn_to_page())). | |
177 | */ | |
178 | WARN_ON(IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API)); | |
e7638488 | 179 | dax_enabled = true; |
ad428cdb DW |
180 | } else if (pfn_t_devmap(pfn) && pfn_t_devmap(end_pfn)) { |
181 | struct dev_pagemap *pgmap, *end_pgmap; | |
e7638488 DW |
182 | |
183 | pgmap = get_dev_pagemap(pfn_t_to_pfn(pfn), NULL); | |
ad428cdb DW |
184 | end_pgmap = get_dev_pagemap(pfn_t_to_pfn(end_pfn), NULL); |
185 | if (pgmap && pgmap == end_pgmap && pgmap->type == MEMORY_DEVICE_FS_DAX | |
186 | && pfn_t_to_page(pfn)->pgmap == pgmap | |
187 | && pfn_t_to_page(end_pfn)->pgmap == pgmap | |
188 | && pfn_t_to_pfn(pfn) == PHYS_PFN(__pa(kaddr)) | |
189 | && pfn_t_to_pfn(end_pfn) == PHYS_PFN(__pa(end_kaddr))) | |
e7638488 DW |
190 | dax_enabled = true; |
191 | put_dev_pagemap(pgmap); | |
ad428cdb DW |
192 | put_dev_pagemap(end_pgmap); |
193 | ||
e7638488 | 194 | } |
eedfd73d | 195 | dax_read_unlock(id); |
e7638488 DW |
196 | |
197 | if (!dax_enabled) { | |
39b6389a | 198 | pr_info("%pg: error: dax support not enabled\n", bdev); |
80660f20 | 199 | return false; |
569d0365 | 200 | } |
80660f20 | 201 | return true; |
ef510424 | 202 | } |
cd93a2a4 | 203 | EXPORT_SYMBOL_GPL(generic_fsdax_supported); |
60b8340f CH |
204 | |
205 | bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev, | |
206 | int blocksize, sector_t start, sector_t len) | |
207 | { | |
208 | bool ret = false; | |
209 | int id; | |
210 | ||
211 | if (!dax_dev) | |
212 | return false; | |
213 | ||
214 | id = dax_read_lock(); | |
215 | if (dax_alive(dax_dev) && dax_dev->ops->dax_supported) | |
216 | ret = dax_dev->ops->dax_supported(dax_dev, bdev, blocksize, | |
217 | start, len); | |
218 | dax_read_unlock(id); | |
219 | return ret; | |
220 | } | |
221 | EXPORT_SYMBOL_GPL(dax_supported); | |
cd93a2a4 | 222 | #endif /* CONFIG_FS_DAX */ |
bdd3c50d | 223 | #endif /* CONFIG_BLOCK */ |
ef510424 | 224 | |
9a60c3ef DW |
225 | enum dax_device_flags { |
226 | /* !alive + rcu grace period == no new operations / mappings */ | |
227 | DAXDEV_ALIVE, | |
6e0c90d6 DW |
228 | /* gate whether dax_flush() calls the low level flush routine */ |
229 | DAXDEV_WRITE_CACHE, | |
fefc1d97 PG |
230 | /* flag to check if device supports synchronous flush */ |
231 | DAXDEV_SYNC, | |
9a60c3ef DW |
232 | }; |
233 | ||
6e0c90d6 DW |
234 | static ssize_t write_cache_show(struct device *dev, |
235 | struct device_attribute *attr, char *buf) | |
236 | { | |
237 | struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); | |
238 | ssize_t rc; | |
239 | ||
240 | WARN_ON_ONCE(!dax_dev); | |
241 | if (!dax_dev) | |
242 | return -ENXIO; | |
243 | ||
808c340b | 244 | rc = sprintf(buf, "%d\n", !!dax_write_cache_enabled(dax_dev)); |
6e0c90d6 DW |
245 | put_dax(dax_dev); |
246 | return rc; | |
247 | } | |
248 | ||
249 | static ssize_t write_cache_store(struct device *dev, | |
250 | struct device_attribute *attr, const char *buf, size_t len) | |
251 | { | |
252 | bool write_cache; | |
253 | int rc = strtobool(buf, &write_cache); | |
254 | struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); | |
255 | ||
256 | WARN_ON_ONCE(!dax_dev); | |
257 | if (!dax_dev) | |
258 | return -ENXIO; | |
259 | ||
260 | if (rc) | |
261 | len = rc; | |
6e0c90d6 | 262 | else |
808c340b | 263 | dax_write_cache(dax_dev, write_cache); |
6e0c90d6 DW |
264 | |
265 | put_dax(dax_dev); | |
266 | return len; | |
267 | } | |
268 | static DEVICE_ATTR_RW(write_cache); | |
269 | ||
270 | static umode_t dax_visible(struct kobject *kobj, struct attribute *a, int n) | |
271 | { | |
272 | struct device *dev = container_of(kobj, typeof(*dev), kobj); | |
273 | struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); | |
274 | ||
275 | WARN_ON_ONCE(!dax_dev); | |
276 | if (!dax_dev) | |
277 | return 0; | |
278 | ||
c3ca015f MP |
279 | #ifndef CONFIG_ARCH_HAS_PMEM_API |
280 | if (a == &dev_attr_write_cache.attr) | |
6e0c90d6 | 281 | return 0; |
c3ca015f | 282 | #endif |
6e0c90d6 DW |
283 | return a->mode; |
284 | } | |
285 | ||
286 | static struct attribute *dax_attributes[] = { | |
287 | &dev_attr_write_cache.attr, | |
288 | NULL, | |
289 | }; | |
290 | ||
291 | struct attribute_group dax_attribute_group = { | |
292 | .name = "dax", | |
293 | .attrs = dax_attributes, | |
294 | .is_visible = dax_visible, | |
295 | }; | |
296 | EXPORT_SYMBOL_GPL(dax_attribute_group); | |
297 | ||
b0686260 DW |
298 | /** |
299 | * dax_direct_access() - translate a device pgoff to an absolute pfn | |
300 | * @dax_dev: a dax_device instance representing the logical memory range | |
301 | * @pgoff: offset in pages from the start of the device to translate | |
302 | * @nr_pages: number of consecutive pages caller can handle relative to @pfn | |
303 | * @kaddr: output parameter that returns a virtual address mapping of pfn | |
304 | * @pfn: output parameter that returns an absolute pfn translation of @pgoff | |
305 | * | |
306 | * Return: negative errno if an error occurs, otherwise the number of | |
307 | * pages accessible at the device relative @pgoff. | |
308 | */ | |
309 | long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, | |
310 | void **kaddr, pfn_t *pfn) | |
311 | { | |
312 | long avail; | |
313 | ||
b0686260 DW |
314 | if (!dax_dev) |
315 | return -EOPNOTSUPP; | |
316 | ||
317 | if (!dax_alive(dax_dev)) | |
318 | return -ENXIO; | |
319 | ||
320 | if (nr_pages < 0) | |
b05d4c57 | 321 | return -EINVAL; |
b0686260 DW |
322 | |
323 | avail = dax_dev->ops->direct_access(dax_dev, pgoff, nr_pages, | |
324 | kaddr, pfn); | |
325 | if (!avail) | |
326 | return -ERANGE; | |
327 | return min(avail, nr_pages); | |
328 | } | |
329 | EXPORT_SYMBOL_GPL(dax_direct_access); | |
330 | ||
7e026c8c DW |
331 | size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, |
332 | size_t bytes, struct iov_iter *i) | |
333 | { | |
334 | if (!dax_alive(dax_dev)) | |
335 | return 0; | |
336 | ||
7e026c8c DW |
337 | return dax_dev->ops->copy_from_iter(dax_dev, pgoff, addr, bytes, i); |
338 | } | |
339 | EXPORT_SYMBOL_GPL(dax_copy_from_iter); | |
340 | ||
b3a9a0c3 DW |
341 | size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, |
342 | size_t bytes, struct iov_iter *i) | |
343 | { | |
344 | if (!dax_alive(dax_dev)) | |
345 | return 0; | |
346 | ||
347 | return dax_dev->ops->copy_to_iter(dax_dev, pgoff, addr, bytes, i); | |
348 | } | |
349 | EXPORT_SYMBOL_GPL(dax_copy_to_iter); | |
350 | ||
f605a263 VG |
351 | int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, |
352 | size_t nr_pages) | |
353 | { | |
354 | if (!dax_alive(dax_dev)) | |
355 | return -ENXIO; | |
f605a263 VG |
356 | /* |
357 | * There are no callers that want to zero more than one page as of now. | |
358 | * Once users are there, this check can be removed after the | |
359 | * device mapper code has been updated to split ranges across targets. | |
360 | */ | |
361 | if (nr_pages != 1) | |
362 | return -EIO; | |
363 | ||
364 | return dax_dev->ops->zero_page_range(dax_dev, pgoff, nr_pages); | |
365 | } | |
366 | EXPORT_SYMBOL_GPL(dax_zero_page_range); | |
367 | ||
c3ca015f MP |
368 | #ifdef CONFIG_ARCH_HAS_PMEM_API |
369 | void arch_wb_cache_pmem(void *addr, size_t size); | |
370 | void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) | |
abebfbe2 | 371 | { |
808c340b | 372 | if (unlikely(!dax_write_cache_enabled(dax_dev))) |
6e0c90d6 DW |
373 | return; |
374 | ||
c3ca015f | 375 | arch_wb_cache_pmem(addr, size); |
abebfbe2 | 376 | } |
c3ca015f MP |
377 | #else |
378 | void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) | |
379 | { | |
380 | } | |
381 | #endif | |
abebfbe2 DW |
382 | EXPORT_SYMBOL_GPL(dax_flush); |
383 | ||
6e0c90d6 DW |
384 | void dax_write_cache(struct dax_device *dax_dev, bool wc) |
385 | { | |
386 | if (wc) | |
387 | set_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); | |
388 | else | |
389 | clear_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); | |
390 | } | |
391 | EXPORT_SYMBOL_GPL(dax_write_cache); | |
392 | ||
273752c9 VG |
393 | bool dax_write_cache_enabled(struct dax_device *dax_dev) |
394 | { | |
395 | return test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); | |
396 | } | |
397 | EXPORT_SYMBOL_GPL(dax_write_cache_enabled); | |
398 | ||
fefc1d97 PG |
399 | bool __dax_synchronous(struct dax_device *dax_dev) |
400 | { | |
401 | return test_bit(DAXDEV_SYNC, &dax_dev->flags); | |
402 | } | |
403 | EXPORT_SYMBOL_GPL(__dax_synchronous); | |
404 | ||
405 | void __set_dax_synchronous(struct dax_device *dax_dev) | |
406 | { | |
407 | set_bit(DAXDEV_SYNC, &dax_dev->flags); | |
408 | } | |
409 | EXPORT_SYMBOL_GPL(__set_dax_synchronous); | |
410 | ||
7b6be844 DW |
411 | bool dax_alive(struct dax_device *dax_dev) |
412 | { | |
413 | lockdep_assert_held(&dax_srcu); | |
9a60c3ef | 414 | return test_bit(DAXDEV_ALIVE, &dax_dev->flags); |
7b6be844 DW |
415 | } |
416 | EXPORT_SYMBOL_GPL(dax_alive); | |
417 | ||
418 | /* | |
419 | * Note, rcu is not protecting the liveness of dax_dev, rcu is ensuring | |
420 | * that any fault handlers or operations that might have seen | |
421 | * dax_alive(), have completed. Any operations that start after | |
422 | * synchronize_srcu() has run will abort upon seeing !dax_alive(). | |
423 | */ | |
424 | void kill_dax(struct dax_device *dax_dev) | |
425 | { | |
426 | if (!dax_dev) | |
427 | return; | |
428 | ||
9a60c3ef | 429 | clear_bit(DAXDEV_ALIVE, &dax_dev->flags); |
72058005 | 430 | |
7b6be844 | 431 | synchronize_srcu(&dax_srcu); |
72058005 DW |
432 | |
433 | spin_lock(&dax_host_lock); | |
434 | hlist_del_init(&dax_dev->list); | |
435 | spin_unlock(&dax_host_lock); | |
7b6be844 DW |
436 | } |
437 | EXPORT_SYMBOL_GPL(kill_dax); | |
438 | ||
9567da0b DW |
439 | void run_dax(struct dax_device *dax_dev) |
440 | { | |
441 | set_bit(DAXDEV_ALIVE, &dax_dev->flags); | |
442 | } | |
443 | EXPORT_SYMBOL_GPL(run_dax); | |
444 | ||
7b6be844 DW |
445 | static struct inode *dax_alloc_inode(struct super_block *sb) |
446 | { | |
447 | struct dax_device *dax_dev; | |
b9d39d17 | 448 | struct inode *inode; |
7b6be844 DW |
449 | |
450 | dax_dev = kmem_cache_alloc(dax_cache, GFP_KERNEL); | |
9f586fff MP |
451 | if (!dax_dev) |
452 | return NULL; | |
453 | ||
b9d39d17 DW |
454 | inode = &dax_dev->inode; |
455 | inode->i_rdev = 0; | |
456 | return inode; | |
7b6be844 DW |
457 | } |
458 | ||
459 | static struct dax_device *to_dax_dev(struct inode *inode) | |
460 | { | |
461 | return container_of(inode, struct dax_device, inode); | |
462 | } | |
463 | ||
53e22829 | 464 | static void dax_free_inode(struct inode *inode) |
7b6be844 | 465 | { |
7b6be844 | 466 | struct dax_device *dax_dev = to_dax_dev(inode); |
72058005 DW |
467 | kfree(dax_dev->host); |
468 | dax_dev->host = NULL; | |
b9d39d17 | 469 | if (inode->i_rdev) |
6f24784f | 470 | ida_simple_remove(&dax_minor_ida, iminor(inode)); |
7b6be844 DW |
471 | kmem_cache_free(dax_cache, dax_dev); |
472 | } | |
473 | ||
474 | static void dax_destroy_inode(struct inode *inode) | |
475 | { | |
476 | struct dax_device *dax_dev = to_dax_dev(inode); | |
9a60c3ef | 477 | WARN_ONCE(test_bit(DAXDEV_ALIVE, &dax_dev->flags), |
7b6be844 | 478 | "kill_dax() must be called before final iput()\n"); |
7b6be844 DW |
479 | } |
480 | ||
481 | static const struct super_operations dax_sops = { | |
482 | .statfs = simple_statfs, | |
483 | .alloc_inode = dax_alloc_inode, | |
484 | .destroy_inode = dax_destroy_inode, | |
53e22829 | 485 | .free_inode = dax_free_inode, |
7b6be844 DW |
486 | .drop_inode = generic_delete_inode, |
487 | }; | |
488 | ||
75d4e06f | 489 | static int dax_init_fs_context(struct fs_context *fc) |
7b6be844 | 490 | { |
75d4e06f DH |
491 | struct pseudo_fs_context *ctx = init_pseudo(fc, DAXFS_MAGIC); |
492 | if (!ctx) | |
493 | return -ENOMEM; | |
494 | ctx->ops = &dax_sops; | |
495 | return 0; | |
7b6be844 DW |
496 | } |
497 | ||
498 | static struct file_system_type dax_fs_type = { | |
75d4e06f DH |
499 | .name = "dax", |
500 | .init_fs_context = dax_init_fs_context, | |
501 | .kill_sb = kill_anon_super, | |
7b6be844 DW |
502 | }; |
503 | ||
504 | static int dax_test(struct inode *inode, void *data) | |
505 | { | |
506 | dev_t devt = *(dev_t *) data; | |
507 | ||
508 | return inode->i_rdev == devt; | |
509 | } | |
510 | ||
511 | static int dax_set(struct inode *inode, void *data) | |
512 | { | |
513 | dev_t devt = *(dev_t *) data; | |
514 | ||
515 | inode->i_rdev = devt; | |
516 | return 0; | |
517 | } | |
518 | ||
519 | static struct dax_device *dax_dev_get(dev_t devt) | |
520 | { | |
521 | struct dax_device *dax_dev; | |
522 | struct inode *inode; | |
523 | ||
524 | inode = iget5_locked(dax_superblock, hash_32(devt + DAXFS_MAGIC, 31), | |
525 | dax_test, dax_set, &devt); | |
526 | ||
527 | if (!inode) | |
528 | return NULL; | |
529 | ||
530 | dax_dev = to_dax_dev(inode); | |
531 | if (inode->i_state & I_NEW) { | |
9a60c3ef | 532 | set_bit(DAXDEV_ALIVE, &dax_dev->flags); |
7b6be844 DW |
533 | inode->i_cdev = &dax_dev->cdev; |
534 | inode->i_mode = S_IFCHR; | |
535 | inode->i_flags = S_DAX; | |
536 | mapping_set_gfp_mask(&inode->i_data, GFP_USER); | |
537 | unlock_new_inode(inode); | |
538 | } | |
539 | ||
540 | return dax_dev; | |
541 | } | |
542 | ||
72058005 DW |
543 | static void dax_add_host(struct dax_device *dax_dev, const char *host) |
544 | { | |
545 | int hash; | |
546 | ||
547 | /* | |
548 | * Unconditionally init dax_dev since it's coming from a | |
549 | * non-zeroed slab cache | |
550 | */ | |
551 | INIT_HLIST_NODE(&dax_dev->list); | |
552 | dax_dev->host = host; | |
553 | if (!host) | |
554 | return; | |
555 | ||
556 | hash = dax_host_hash(host); | |
557 | spin_lock(&dax_host_lock); | |
558 | hlist_add_head(&dax_dev->list, &dax_host_list[hash]); | |
559 | spin_unlock(&dax_host_lock); | |
560 | } | |
561 | ||
6568b08b | 562 | struct dax_device *alloc_dax(void *private, const char *__host, |
fefc1d97 | 563 | const struct dax_operations *ops, unsigned long flags) |
7b6be844 DW |
564 | { |
565 | struct dax_device *dax_dev; | |
72058005 | 566 | const char *host; |
7b6be844 DW |
567 | dev_t devt; |
568 | int minor; | |
569 | ||
4e4ced93 VG |
570 | if (ops && !ops->zero_page_range) { |
571 | pr_debug("%s: error: device does not provide dax" | |
572 | " operation zero_page_range()\n", | |
573 | __host ? __host : "Unknown"); | |
574 | return ERR_PTR(-EINVAL); | |
575 | } | |
576 | ||
72058005 DW |
577 | host = kstrdup(__host, GFP_KERNEL); |
578 | if (__host && !host) | |
4e4ced93 | 579 | return ERR_PTR(-ENOMEM); |
72058005 | 580 | |
cf1e2289 | 581 | minor = ida_simple_get(&dax_minor_ida, 0, MINORMASK+1, GFP_KERNEL); |
7b6be844 | 582 | if (minor < 0) |
72058005 | 583 | goto err_minor; |
7b6be844 DW |
584 | |
585 | devt = MKDEV(MAJOR(dax_devt), minor); | |
586 | dax_dev = dax_dev_get(devt); | |
587 | if (!dax_dev) | |
72058005 | 588 | goto err_dev; |
7b6be844 | 589 | |
72058005 | 590 | dax_add_host(dax_dev, host); |
6568b08b | 591 | dax_dev->ops = ops; |
7b6be844 | 592 | dax_dev->private = private; |
fefc1d97 PG |
593 | if (flags & DAXDEV_F_SYNC) |
594 | set_dax_synchronous(dax_dev); | |
595 | ||
7b6be844 DW |
596 | return dax_dev; |
597 | ||
72058005 | 598 | err_dev: |
7b6be844 | 599 | ida_simple_remove(&dax_minor_ida, minor); |
72058005 DW |
600 | err_minor: |
601 | kfree(host); | |
4e4ced93 | 602 | return ERR_PTR(-ENOMEM); |
7b6be844 DW |
603 | } |
604 | EXPORT_SYMBOL_GPL(alloc_dax); | |
605 | ||
606 | void put_dax(struct dax_device *dax_dev) | |
607 | { | |
608 | if (!dax_dev) | |
609 | return; | |
610 | iput(&dax_dev->inode); | |
611 | } | |
612 | EXPORT_SYMBOL_GPL(put_dax); | |
613 | ||
614 | /** | |
615 | * inode_dax: convert a public inode into its dax_dev | |
616 | * @inode: An inode with i_cdev pointing to a dax_dev | |
617 | * | |
618 | * Note this is not equivalent to to_dax_dev() which is for private | |
619 | * internal use where we know the inode filesystem type == dax_fs_type. | |
620 | */ | |
621 | struct dax_device *inode_dax(struct inode *inode) | |
622 | { | |
623 | struct cdev *cdev = inode->i_cdev; | |
624 | ||
625 | return container_of(cdev, struct dax_device, cdev); | |
626 | } | |
627 | EXPORT_SYMBOL_GPL(inode_dax); | |
628 | ||
629 | struct inode *dax_inode(struct dax_device *dax_dev) | |
630 | { | |
631 | return &dax_dev->inode; | |
632 | } | |
633 | EXPORT_SYMBOL_GPL(dax_inode); | |
634 | ||
635 | void *dax_get_private(struct dax_device *dax_dev) | |
636 | { | |
9567da0b DW |
637 | if (!test_bit(DAXDEV_ALIVE, &dax_dev->flags)) |
638 | return NULL; | |
7b6be844 DW |
639 | return dax_dev->private; |
640 | } | |
641 | EXPORT_SYMBOL_GPL(dax_get_private); | |
642 | ||
643 | static void init_once(void *_dax_dev) | |
644 | { | |
645 | struct dax_device *dax_dev = _dax_dev; | |
646 | struct inode *inode = &dax_dev->inode; | |
647 | ||
b9d39d17 | 648 | memset(dax_dev, 0, sizeof(*dax_dev)); |
7b6be844 DW |
649 | inode_init_once(inode); |
650 | } | |
651 | ||
9567da0b | 652 | static int dax_fs_init(void) |
7b6be844 DW |
653 | { |
654 | int rc; | |
655 | ||
656 | dax_cache = kmem_cache_create("dax_cache", sizeof(struct dax_device), 0, | |
657 | (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| | |
658 | SLAB_MEM_SPREAD|SLAB_ACCOUNT), | |
659 | init_once); | |
660 | if (!dax_cache) | |
661 | return -ENOMEM; | |
662 | ||
7b6be844 DW |
663 | dax_mnt = kern_mount(&dax_fs_type); |
664 | if (IS_ERR(dax_mnt)) { | |
665 | rc = PTR_ERR(dax_mnt); | |
666 | goto err_mount; | |
667 | } | |
668 | dax_superblock = dax_mnt->mnt_sb; | |
669 | ||
670 | return 0; | |
671 | ||
672 | err_mount: | |
7b6be844 DW |
673 | kmem_cache_destroy(dax_cache); |
674 | ||
675 | return rc; | |
676 | } | |
677 | ||
9567da0b | 678 | static void dax_fs_exit(void) |
7b6be844 DW |
679 | { |
680 | kern_unmount(dax_mnt); | |
2566ff04 | 681 | rcu_barrier(); |
7b6be844 DW |
682 | kmem_cache_destroy(dax_cache); |
683 | } | |
684 | ||
9567da0b | 685 | static int __init dax_core_init(void) |
7b6be844 DW |
686 | { |
687 | int rc; | |
688 | ||
9567da0b | 689 | rc = dax_fs_init(); |
7b6be844 DW |
690 | if (rc) |
691 | return rc; | |
692 | ||
cf1e2289 | 693 | rc = alloc_chrdev_region(&dax_devt, 0, MINORMASK+1, "dax"); |
7b6be844 | 694 | if (rc) |
9567da0b DW |
695 | goto err_chrdev; |
696 | ||
697 | rc = dax_bus_init(); | |
698 | if (rc) | |
699 | goto err_bus; | |
700 | return 0; | |
701 | ||
702 | err_bus: | |
703 | unregister_chrdev_region(dax_devt, MINORMASK+1); | |
704 | err_chrdev: | |
705 | dax_fs_exit(); | |
706 | return 0; | |
7b6be844 DW |
707 | } |
708 | ||
9567da0b | 709 | static void __exit dax_core_exit(void) |
7b6be844 | 710 | { |
1aa57431 | 711 | dax_bus_exit(); |
cf1e2289 | 712 | unregister_chrdev_region(dax_devt, MINORMASK+1); |
7b6be844 | 713 | ida_destroy(&dax_minor_ida); |
9567da0b | 714 | dax_fs_exit(); |
7b6be844 DW |
715 | } |
716 | ||
717 | MODULE_AUTHOR("Intel Corporation"); | |
718 | MODULE_LICENSE("GPL v2"); | |
9567da0b DW |
719 | subsys_initcall(dax_core_init); |
720 | module_exit(dax_core_exit); |