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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> | |
8 | #include <linux/magic.h> | |
ef510424 | 9 | #include <linux/genhd.h> |
569d0365 | 10 | #include <linux/pfn_t.h> |
7b6be844 DW |
11 | #include <linux/cdev.h> |
12 | #include <linux/hash.h> | |
13 | #include <linux/slab.h> | |
7e026c8c | 14 | #include <linux/uio.h> |
6568b08b | 15 | #include <linux/dax.h> |
7b6be844 | 16 | #include <linux/fs.h> |
51cf784c | 17 | #include "dax-private.h" |
7b6be844 | 18 | |
7b6be844 DW |
19 | static dev_t dax_devt; |
20 | DEFINE_STATIC_SRCU(dax_srcu); | |
21 | static struct vfsmount *dax_mnt; | |
22 | static DEFINE_IDA(dax_minor_ida); | |
23 | static struct kmem_cache *dax_cache __read_mostly; | |
24 | static struct super_block *dax_superblock __read_mostly; | |
25 | ||
72058005 DW |
26 | #define DAX_HASH_SIZE (PAGE_SIZE / sizeof(struct hlist_head)) |
27 | static struct hlist_head dax_host_list[DAX_HASH_SIZE]; | |
28 | static DEFINE_SPINLOCK(dax_host_lock); | |
29 | ||
7b6be844 DW |
30 | int dax_read_lock(void) |
31 | { | |
32 | return srcu_read_lock(&dax_srcu); | |
33 | } | |
34 | EXPORT_SYMBOL_GPL(dax_read_lock); | |
35 | ||
36 | void dax_read_unlock(int id) | |
37 | { | |
38 | srcu_read_unlock(&dax_srcu, id); | |
39 | } | |
40 | EXPORT_SYMBOL_GPL(dax_read_unlock); | |
41 | ||
9d109081 | 42 | #ifdef CONFIG_BLOCK |
78f35473 DW |
43 | #include <linux/blkdev.h> |
44 | ||
ef510424 DW |
45 | int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size, |
46 | pgoff_t *pgoff) | |
47 | { | |
48 | phys_addr_t phys_off = (get_start_sect(bdev) + sector) * 512; | |
49 | ||
50 | if (pgoff) | |
51 | *pgoff = PHYS_PFN(phys_off); | |
52 | if (phys_off % PAGE_SIZE || size % PAGE_SIZE) | |
53 | return -EINVAL; | |
54 | return 0; | |
55 | } | |
56 | EXPORT_SYMBOL(bdev_dax_pgoff); | |
57 | ||
26f2f4de | 58 | #if IS_ENABLED(CONFIG_FS_DAX) |
78f35473 DW |
59 | struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev) |
60 | { | |
61 | if (!blk_queue_dax(bdev->bd_queue)) | |
62 | return NULL; | |
63 | return fs_dax_get_by_host(bdev->bd_disk->disk_name); | |
64 | } | |
65 | EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev); | |
26f2f4de | 66 | #endif |
78f35473 | 67 | |
7bf7eac8 DW |
68 | bool __generic_fsdax_supported(struct dax_device *dax_dev, |
69 | struct block_device *bdev, int blocksize, sector_t start, | |
70 | sector_t sectors) | |
ef510424 | 71 | { |
e7638488 | 72 | bool dax_enabled = false; |
ad428cdb | 73 | pgoff_t pgoff, pgoff_end; |
ba23cba9 | 74 | char buf[BDEVNAME_SIZE]; |
ad428cdb DW |
75 | void *kaddr, *end_kaddr; |
76 | pfn_t pfn, end_pfn; | |
77 | sector_t last_page; | |
78 | long len, len2; | |
79 | int err, id; | |
ef510424 DW |
80 | |
81 | if (blocksize != PAGE_SIZE) { | |
ba23cba9 DW |
82 | pr_debug("%s: error: unsupported blocksize for dax\n", |
83 | bdevname(bdev, buf)); | |
80660f20 | 84 | return false; |
ef510424 DW |
85 | } |
86 | ||
7bf7eac8 | 87 | err = bdev_dax_pgoff(bdev, start, PAGE_SIZE, &pgoff); |
ef510424 | 88 | if (err) { |
ba23cba9 DW |
89 | pr_debug("%s: error: unaligned partition for dax\n", |
90 | bdevname(bdev, buf)); | |
80660f20 | 91 | return false; |
ef510424 DW |
92 | } |
93 | ||
7bf7eac8 | 94 | last_page = PFN_DOWN((start + sectors - 1) * 512) * PAGE_SIZE / 512; |
ad428cdb DW |
95 | err = bdev_dax_pgoff(bdev, last_page, PAGE_SIZE, &pgoff_end); |
96 | if (err) { | |
97 | pr_debug("%s: error: unaligned partition for dax\n", | |
98 | bdevname(bdev, buf)); | |
99 | return false; | |
100 | } | |
101 | ||
ef510424 | 102 | id = dax_read_lock(); |
ad428cdb DW |
103 | len = dax_direct_access(dax_dev, pgoff, 1, &kaddr, &pfn); |
104 | len2 = dax_direct_access(dax_dev, pgoff_end, 1, &end_kaddr, &end_pfn); | |
ef510424 DW |
105 | dax_read_unlock(id); |
106 | ||
ad428cdb | 107 | if (len < 1 || len2 < 1) { |
ba23cba9 | 108 | pr_debug("%s: error: dax access failed (%ld)\n", |
ad428cdb | 109 | bdevname(bdev, buf), len < 1 ? len : len2); |
80660f20 | 110 | return false; |
ef510424 DW |
111 | } |
112 | ||
3fe0791c DW |
113 | if (IS_ENABLED(CONFIG_FS_DAX_LIMITED) && pfn_t_special(pfn)) { |
114 | /* | |
115 | * An arch that has enabled the pmem api should also | |
116 | * have its drivers support pfn_t_devmap() | |
117 | * | |
118 | * This is a developer warning and should not trigger in | |
119 | * production. dax_flush() will crash since it depends | |
120 | * on being able to do (page_address(pfn_to_page())). | |
121 | */ | |
122 | WARN_ON(IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API)); | |
e7638488 | 123 | dax_enabled = true; |
ad428cdb DW |
124 | } else if (pfn_t_devmap(pfn) && pfn_t_devmap(end_pfn)) { |
125 | struct dev_pagemap *pgmap, *end_pgmap; | |
e7638488 DW |
126 | |
127 | pgmap = get_dev_pagemap(pfn_t_to_pfn(pfn), NULL); | |
ad428cdb DW |
128 | end_pgmap = get_dev_pagemap(pfn_t_to_pfn(end_pfn), NULL); |
129 | if (pgmap && pgmap == end_pgmap && pgmap->type == MEMORY_DEVICE_FS_DAX | |
130 | && pfn_t_to_page(pfn)->pgmap == pgmap | |
131 | && pfn_t_to_page(end_pfn)->pgmap == pgmap | |
132 | && pfn_t_to_pfn(pfn) == PHYS_PFN(__pa(kaddr)) | |
133 | && pfn_t_to_pfn(end_pfn) == PHYS_PFN(__pa(end_kaddr))) | |
e7638488 DW |
134 | dax_enabled = true; |
135 | put_dev_pagemap(pgmap); | |
ad428cdb DW |
136 | put_dev_pagemap(end_pgmap); |
137 | ||
e7638488 DW |
138 | } |
139 | ||
140 | if (!dax_enabled) { | |
ba23cba9 DW |
141 | pr_debug("%s: error: dax support not enabled\n", |
142 | bdevname(bdev, buf)); | |
80660f20 | 143 | return false; |
569d0365 | 144 | } |
80660f20 | 145 | return true; |
ef510424 | 146 | } |
7bf7eac8 DW |
147 | EXPORT_SYMBOL_GPL(__generic_fsdax_supported); |
148 | ||
149 | /** | |
150 | * __bdev_dax_supported() - Check if the device supports dax for filesystem | |
151 | * @bdev: block device to check | |
152 | * @blocksize: The block size of the device | |
153 | * | |
154 | * This is a library function for filesystems to check if the block device | |
155 | * can be mounted with dax option. | |
156 | * | |
157 | * Return: true if supported, false if unsupported | |
158 | */ | |
159 | bool __bdev_dax_supported(struct block_device *bdev, int blocksize) | |
160 | { | |
161 | struct dax_device *dax_dev; | |
162 | struct request_queue *q; | |
163 | char buf[BDEVNAME_SIZE]; | |
164 | bool ret; | |
165 | int id; | |
166 | ||
167 | q = bdev_get_queue(bdev); | |
168 | if (!q || !blk_queue_dax(q)) { | |
169 | pr_debug("%s: error: request queue doesn't support dax\n", | |
170 | bdevname(bdev, buf)); | |
171 | return false; | |
172 | } | |
173 | ||
174 | dax_dev = dax_get_by_host(bdev->bd_disk->disk_name); | |
175 | if (!dax_dev) { | |
176 | pr_debug("%s: error: device does not support dax\n", | |
177 | bdevname(bdev, buf)); | |
178 | return false; | |
179 | } | |
180 | ||
181 | id = dax_read_lock(); | |
182 | ret = dax_supported(dax_dev, bdev, blocksize, 0, | |
183 | i_size_read(bdev->bd_inode) / 512); | |
184 | dax_read_unlock(id); | |
185 | ||
186 | put_dax(dax_dev); | |
187 | ||
188 | return ret; | |
189 | } | |
ef510424 | 190 | EXPORT_SYMBOL_GPL(__bdev_dax_supported); |
9d109081 | 191 | #endif |
ef510424 | 192 | |
9a60c3ef DW |
193 | enum dax_device_flags { |
194 | /* !alive + rcu grace period == no new operations / mappings */ | |
195 | DAXDEV_ALIVE, | |
6e0c90d6 DW |
196 | /* gate whether dax_flush() calls the low level flush routine */ |
197 | DAXDEV_WRITE_CACHE, | |
9a60c3ef DW |
198 | }; |
199 | ||
7b6be844 DW |
200 | /** |
201 | * struct dax_device - anchor object for dax services | |
202 | * @inode: core vfs | |
203 | * @cdev: optional character interface for "device dax" | |
72058005 | 204 | * @host: optional name for lookups where the device path is not available |
7b6be844 | 205 | * @private: dax driver private data |
9a60c3ef | 206 | * @flags: state and boolean properties |
7b6be844 DW |
207 | */ |
208 | struct dax_device { | |
72058005 | 209 | struct hlist_node list; |
7b6be844 DW |
210 | struct inode inode; |
211 | struct cdev cdev; | |
72058005 | 212 | const char *host; |
7b6be844 | 213 | void *private; |
9a60c3ef | 214 | unsigned long flags; |
6568b08b | 215 | const struct dax_operations *ops; |
7b6be844 DW |
216 | }; |
217 | ||
6e0c90d6 DW |
218 | static ssize_t write_cache_show(struct device *dev, |
219 | struct device_attribute *attr, char *buf) | |
220 | { | |
221 | struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); | |
222 | ssize_t rc; | |
223 | ||
224 | WARN_ON_ONCE(!dax_dev); | |
225 | if (!dax_dev) | |
226 | return -ENXIO; | |
227 | ||
808c340b | 228 | rc = sprintf(buf, "%d\n", !!dax_write_cache_enabled(dax_dev)); |
6e0c90d6 DW |
229 | put_dax(dax_dev); |
230 | return rc; | |
231 | } | |
232 | ||
233 | static ssize_t write_cache_store(struct device *dev, | |
234 | struct device_attribute *attr, const char *buf, size_t len) | |
235 | { | |
236 | bool write_cache; | |
237 | int rc = strtobool(buf, &write_cache); | |
238 | struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); | |
239 | ||
240 | WARN_ON_ONCE(!dax_dev); | |
241 | if (!dax_dev) | |
242 | return -ENXIO; | |
243 | ||
244 | if (rc) | |
245 | len = rc; | |
6e0c90d6 | 246 | else |
808c340b | 247 | dax_write_cache(dax_dev, write_cache); |
6e0c90d6 DW |
248 | |
249 | put_dax(dax_dev); | |
250 | return len; | |
251 | } | |
252 | static DEVICE_ATTR_RW(write_cache); | |
253 | ||
254 | static umode_t dax_visible(struct kobject *kobj, struct attribute *a, int n) | |
255 | { | |
256 | struct device *dev = container_of(kobj, typeof(*dev), kobj); | |
257 | struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); | |
258 | ||
259 | WARN_ON_ONCE(!dax_dev); | |
260 | if (!dax_dev) | |
261 | return 0; | |
262 | ||
c3ca015f MP |
263 | #ifndef CONFIG_ARCH_HAS_PMEM_API |
264 | if (a == &dev_attr_write_cache.attr) | |
6e0c90d6 | 265 | return 0; |
c3ca015f | 266 | #endif |
6e0c90d6 DW |
267 | return a->mode; |
268 | } | |
269 | ||
270 | static struct attribute *dax_attributes[] = { | |
271 | &dev_attr_write_cache.attr, | |
272 | NULL, | |
273 | }; | |
274 | ||
275 | struct attribute_group dax_attribute_group = { | |
276 | .name = "dax", | |
277 | .attrs = dax_attributes, | |
278 | .is_visible = dax_visible, | |
279 | }; | |
280 | EXPORT_SYMBOL_GPL(dax_attribute_group); | |
281 | ||
b0686260 DW |
282 | /** |
283 | * dax_direct_access() - translate a device pgoff to an absolute pfn | |
284 | * @dax_dev: a dax_device instance representing the logical memory range | |
285 | * @pgoff: offset in pages from the start of the device to translate | |
286 | * @nr_pages: number of consecutive pages caller can handle relative to @pfn | |
287 | * @kaddr: output parameter that returns a virtual address mapping of pfn | |
288 | * @pfn: output parameter that returns an absolute pfn translation of @pgoff | |
289 | * | |
290 | * Return: negative errno if an error occurs, otherwise the number of | |
291 | * pages accessible at the device relative @pgoff. | |
292 | */ | |
293 | long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, | |
294 | void **kaddr, pfn_t *pfn) | |
295 | { | |
296 | long avail; | |
297 | ||
b0686260 DW |
298 | if (!dax_dev) |
299 | return -EOPNOTSUPP; | |
300 | ||
301 | if (!dax_alive(dax_dev)) | |
302 | return -ENXIO; | |
303 | ||
304 | if (nr_pages < 0) | |
305 | return nr_pages; | |
306 | ||
307 | avail = dax_dev->ops->direct_access(dax_dev, pgoff, nr_pages, | |
308 | kaddr, pfn); | |
309 | if (!avail) | |
310 | return -ERANGE; | |
311 | return min(avail, nr_pages); | |
312 | } | |
313 | EXPORT_SYMBOL_GPL(dax_direct_access); | |
314 | ||
7bf7eac8 DW |
315 | bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev, |
316 | int blocksize, sector_t start, sector_t len) | |
317 | { | |
318 | if (!dax_alive(dax_dev)) | |
319 | return false; | |
320 | ||
321 | return dax_dev->ops->dax_supported(dax_dev, bdev, blocksize, start, len); | |
322 | } | |
323 | ||
7e026c8c DW |
324 | size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, |
325 | size_t bytes, struct iov_iter *i) | |
326 | { | |
327 | if (!dax_alive(dax_dev)) | |
328 | return 0; | |
329 | ||
7e026c8c DW |
330 | return dax_dev->ops->copy_from_iter(dax_dev, pgoff, addr, bytes, i); |
331 | } | |
332 | EXPORT_SYMBOL_GPL(dax_copy_from_iter); | |
333 | ||
b3a9a0c3 DW |
334 | size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, |
335 | size_t bytes, struct iov_iter *i) | |
336 | { | |
337 | if (!dax_alive(dax_dev)) | |
338 | return 0; | |
339 | ||
340 | return dax_dev->ops->copy_to_iter(dax_dev, pgoff, addr, bytes, i); | |
341 | } | |
342 | EXPORT_SYMBOL_GPL(dax_copy_to_iter); | |
343 | ||
c3ca015f MP |
344 | #ifdef CONFIG_ARCH_HAS_PMEM_API |
345 | void arch_wb_cache_pmem(void *addr, size_t size); | |
346 | void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) | |
abebfbe2 | 347 | { |
808c340b | 348 | if (unlikely(!dax_write_cache_enabled(dax_dev))) |
6e0c90d6 DW |
349 | return; |
350 | ||
c3ca015f | 351 | arch_wb_cache_pmem(addr, size); |
abebfbe2 | 352 | } |
c3ca015f MP |
353 | #else |
354 | void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) | |
355 | { | |
356 | } | |
357 | #endif | |
abebfbe2 DW |
358 | EXPORT_SYMBOL_GPL(dax_flush); |
359 | ||
6e0c90d6 DW |
360 | void dax_write_cache(struct dax_device *dax_dev, bool wc) |
361 | { | |
362 | if (wc) | |
363 | set_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); | |
364 | else | |
365 | clear_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); | |
366 | } | |
367 | EXPORT_SYMBOL_GPL(dax_write_cache); | |
368 | ||
273752c9 VG |
369 | bool dax_write_cache_enabled(struct dax_device *dax_dev) |
370 | { | |
371 | return test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); | |
372 | } | |
373 | EXPORT_SYMBOL_GPL(dax_write_cache_enabled); | |
374 | ||
7b6be844 DW |
375 | bool dax_alive(struct dax_device *dax_dev) |
376 | { | |
377 | lockdep_assert_held(&dax_srcu); | |
9a60c3ef | 378 | return test_bit(DAXDEV_ALIVE, &dax_dev->flags); |
7b6be844 DW |
379 | } |
380 | EXPORT_SYMBOL_GPL(dax_alive); | |
381 | ||
72058005 DW |
382 | static int dax_host_hash(const char *host) |
383 | { | |
384 | return hashlen_hash(hashlen_string("DAX", host)) % DAX_HASH_SIZE; | |
385 | } | |
386 | ||
7b6be844 DW |
387 | /* |
388 | * Note, rcu is not protecting the liveness of dax_dev, rcu is ensuring | |
389 | * that any fault handlers or operations that might have seen | |
390 | * dax_alive(), have completed. Any operations that start after | |
391 | * synchronize_srcu() has run will abort upon seeing !dax_alive(). | |
392 | */ | |
393 | void kill_dax(struct dax_device *dax_dev) | |
394 | { | |
395 | if (!dax_dev) | |
396 | return; | |
397 | ||
9a60c3ef | 398 | clear_bit(DAXDEV_ALIVE, &dax_dev->flags); |
72058005 | 399 | |
7b6be844 | 400 | synchronize_srcu(&dax_srcu); |
72058005 DW |
401 | |
402 | spin_lock(&dax_host_lock); | |
403 | hlist_del_init(&dax_dev->list); | |
404 | spin_unlock(&dax_host_lock); | |
7b6be844 DW |
405 | } |
406 | EXPORT_SYMBOL_GPL(kill_dax); | |
407 | ||
9567da0b DW |
408 | void run_dax(struct dax_device *dax_dev) |
409 | { | |
410 | set_bit(DAXDEV_ALIVE, &dax_dev->flags); | |
411 | } | |
412 | EXPORT_SYMBOL_GPL(run_dax); | |
413 | ||
7b6be844 DW |
414 | static struct inode *dax_alloc_inode(struct super_block *sb) |
415 | { | |
416 | struct dax_device *dax_dev; | |
b9d39d17 | 417 | struct inode *inode; |
7b6be844 DW |
418 | |
419 | dax_dev = kmem_cache_alloc(dax_cache, GFP_KERNEL); | |
9f586fff MP |
420 | if (!dax_dev) |
421 | return NULL; | |
422 | ||
b9d39d17 DW |
423 | inode = &dax_dev->inode; |
424 | inode->i_rdev = 0; | |
425 | return inode; | |
7b6be844 DW |
426 | } |
427 | ||
428 | static struct dax_device *to_dax_dev(struct inode *inode) | |
429 | { | |
430 | return container_of(inode, struct dax_device, inode); | |
431 | } | |
432 | ||
53e22829 | 433 | static void dax_free_inode(struct inode *inode) |
7b6be844 | 434 | { |
7b6be844 | 435 | struct dax_device *dax_dev = to_dax_dev(inode); |
72058005 DW |
436 | kfree(dax_dev->host); |
437 | dax_dev->host = NULL; | |
b9d39d17 DW |
438 | if (inode->i_rdev) |
439 | ida_simple_remove(&dax_minor_ida, MINOR(inode->i_rdev)); | |
7b6be844 DW |
440 | kmem_cache_free(dax_cache, dax_dev); |
441 | } | |
442 | ||
443 | static void dax_destroy_inode(struct inode *inode) | |
444 | { | |
445 | struct dax_device *dax_dev = to_dax_dev(inode); | |
9a60c3ef | 446 | WARN_ONCE(test_bit(DAXDEV_ALIVE, &dax_dev->flags), |
7b6be844 | 447 | "kill_dax() must be called before final iput()\n"); |
7b6be844 DW |
448 | } |
449 | ||
450 | static const struct super_operations dax_sops = { | |
451 | .statfs = simple_statfs, | |
452 | .alloc_inode = dax_alloc_inode, | |
453 | .destroy_inode = dax_destroy_inode, | |
53e22829 | 454 | .free_inode = dax_free_inode, |
7b6be844 DW |
455 | .drop_inode = generic_delete_inode, |
456 | }; | |
457 | ||
458 | static struct dentry *dax_mount(struct file_system_type *fs_type, | |
459 | int flags, const char *dev_name, void *data) | |
460 | { | |
461 | return mount_pseudo(fs_type, "dax:", &dax_sops, NULL, DAXFS_MAGIC); | |
462 | } | |
463 | ||
464 | static struct file_system_type dax_fs_type = { | |
465 | .name = "dax", | |
466 | .mount = dax_mount, | |
467 | .kill_sb = kill_anon_super, | |
468 | }; | |
469 | ||
470 | static int dax_test(struct inode *inode, void *data) | |
471 | { | |
472 | dev_t devt = *(dev_t *) data; | |
473 | ||
474 | return inode->i_rdev == devt; | |
475 | } | |
476 | ||
477 | static int dax_set(struct inode *inode, void *data) | |
478 | { | |
479 | dev_t devt = *(dev_t *) data; | |
480 | ||
481 | inode->i_rdev = devt; | |
482 | return 0; | |
483 | } | |
484 | ||
485 | static struct dax_device *dax_dev_get(dev_t devt) | |
486 | { | |
487 | struct dax_device *dax_dev; | |
488 | struct inode *inode; | |
489 | ||
490 | inode = iget5_locked(dax_superblock, hash_32(devt + DAXFS_MAGIC, 31), | |
491 | dax_test, dax_set, &devt); | |
492 | ||
493 | if (!inode) | |
494 | return NULL; | |
495 | ||
496 | dax_dev = to_dax_dev(inode); | |
497 | if (inode->i_state & I_NEW) { | |
9a60c3ef | 498 | set_bit(DAXDEV_ALIVE, &dax_dev->flags); |
7b6be844 DW |
499 | inode->i_cdev = &dax_dev->cdev; |
500 | inode->i_mode = S_IFCHR; | |
501 | inode->i_flags = S_DAX; | |
502 | mapping_set_gfp_mask(&inode->i_data, GFP_USER); | |
503 | unlock_new_inode(inode); | |
504 | } | |
505 | ||
506 | return dax_dev; | |
507 | } | |
508 | ||
72058005 DW |
509 | static void dax_add_host(struct dax_device *dax_dev, const char *host) |
510 | { | |
511 | int hash; | |
512 | ||
513 | /* | |
514 | * Unconditionally init dax_dev since it's coming from a | |
515 | * non-zeroed slab cache | |
516 | */ | |
517 | INIT_HLIST_NODE(&dax_dev->list); | |
518 | dax_dev->host = host; | |
519 | if (!host) | |
520 | return; | |
521 | ||
522 | hash = dax_host_hash(host); | |
523 | spin_lock(&dax_host_lock); | |
524 | hlist_add_head(&dax_dev->list, &dax_host_list[hash]); | |
525 | spin_unlock(&dax_host_lock); | |
526 | } | |
527 | ||
6568b08b DW |
528 | struct dax_device *alloc_dax(void *private, const char *__host, |
529 | const struct dax_operations *ops) | |
7b6be844 DW |
530 | { |
531 | struct dax_device *dax_dev; | |
72058005 | 532 | const char *host; |
7b6be844 DW |
533 | dev_t devt; |
534 | int minor; | |
535 | ||
72058005 DW |
536 | host = kstrdup(__host, GFP_KERNEL); |
537 | if (__host && !host) | |
538 | return NULL; | |
539 | ||
cf1e2289 | 540 | minor = ida_simple_get(&dax_minor_ida, 0, MINORMASK+1, GFP_KERNEL); |
7b6be844 | 541 | if (minor < 0) |
72058005 | 542 | goto err_minor; |
7b6be844 DW |
543 | |
544 | devt = MKDEV(MAJOR(dax_devt), minor); | |
545 | dax_dev = dax_dev_get(devt); | |
546 | if (!dax_dev) | |
72058005 | 547 | goto err_dev; |
7b6be844 | 548 | |
72058005 | 549 | dax_add_host(dax_dev, host); |
6568b08b | 550 | dax_dev->ops = ops; |
7b6be844 DW |
551 | dax_dev->private = private; |
552 | return dax_dev; | |
553 | ||
72058005 | 554 | err_dev: |
7b6be844 | 555 | ida_simple_remove(&dax_minor_ida, minor); |
72058005 DW |
556 | err_minor: |
557 | kfree(host); | |
7b6be844 DW |
558 | return NULL; |
559 | } | |
560 | EXPORT_SYMBOL_GPL(alloc_dax); | |
561 | ||
562 | void put_dax(struct dax_device *dax_dev) | |
563 | { | |
564 | if (!dax_dev) | |
565 | return; | |
566 | iput(&dax_dev->inode); | |
567 | } | |
568 | EXPORT_SYMBOL_GPL(put_dax); | |
569 | ||
72058005 DW |
570 | /** |
571 | * dax_get_by_host() - temporary lookup mechanism for filesystem-dax | |
572 | * @host: alternate name for the device registered by a dax driver | |
573 | */ | |
574 | struct dax_device *dax_get_by_host(const char *host) | |
575 | { | |
576 | struct dax_device *dax_dev, *found = NULL; | |
577 | int hash, id; | |
578 | ||
579 | if (!host) | |
580 | return NULL; | |
581 | ||
582 | hash = dax_host_hash(host); | |
583 | ||
584 | id = dax_read_lock(); | |
585 | spin_lock(&dax_host_lock); | |
586 | hlist_for_each_entry(dax_dev, &dax_host_list[hash], list) { | |
587 | if (!dax_alive(dax_dev) | |
588 | || strcmp(host, dax_dev->host) != 0) | |
589 | continue; | |
590 | ||
591 | if (igrab(&dax_dev->inode)) | |
592 | found = dax_dev; | |
593 | break; | |
594 | } | |
595 | spin_unlock(&dax_host_lock); | |
596 | dax_read_unlock(id); | |
597 | ||
598 | return found; | |
599 | } | |
600 | EXPORT_SYMBOL_GPL(dax_get_by_host); | |
601 | ||
7b6be844 DW |
602 | /** |
603 | * inode_dax: convert a public inode into its dax_dev | |
604 | * @inode: An inode with i_cdev pointing to a dax_dev | |
605 | * | |
606 | * Note this is not equivalent to to_dax_dev() which is for private | |
607 | * internal use where we know the inode filesystem type == dax_fs_type. | |
608 | */ | |
609 | struct dax_device *inode_dax(struct inode *inode) | |
610 | { | |
611 | struct cdev *cdev = inode->i_cdev; | |
612 | ||
613 | return container_of(cdev, struct dax_device, cdev); | |
614 | } | |
615 | EXPORT_SYMBOL_GPL(inode_dax); | |
616 | ||
617 | struct inode *dax_inode(struct dax_device *dax_dev) | |
618 | { | |
619 | return &dax_dev->inode; | |
620 | } | |
621 | EXPORT_SYMBOL_GPL(dax_inode); | |
622 | ||
623 | void *dax_get_private(struct dax_device *dax_dev) | |
624 | { | |
9567da0b DW |
625 | if (!test_bit(DAXDEV_ALIVE, &dax_dev->flags)) |
626 | return NULL; | |
7b6be844 DW |
627 | return dax_dev->private; |
628 | } | |
629 | EXPORT_SYMBOL_GPL(dax_get_private); | |
630 | ||
631 | static void init_once(void *_dax_dev) | |
632 | { | |
633 | struct dax_device *dax_dev = _dax_dev; | |
634 | struct inode *inode = &dax_dev->inode; | |
635 | ||
b9d39d17 | 636 | memset(dax_dev, 0, sizeof(*dax_dev)); |
7b6be844 DW |
637 | inode_init_once(inode); |
638 | } | |
639 | ||
9567da0b | 640 | static int dax_fs_init(void) |
7b6be844 DW |
641 | { |
642 | int rc; | |
643 | ||
644 | dax_cache = kmem_cache_create("dax_cache", sizeof(struct dax_device), 0, | |
645 | (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| | |
646 | SLAB_MEM_SPREAD|SLAB_ACCOUNT), | |
647 | init_once); | |
648 | if (!dax_cache) | |
649 | return -ENOMEM; | |
650 | ||
651 | rc = register_filesystem(&dax_fs_type); | |
652 | if (rc) | |
653 | goto err_register_fs; | |
654 | ||
655 | dax_mnt = kern_mount(&dax_fs_type); | |
656 | if (IS_ERR(dax_mnt)) { | |
657 | rc = PTR_ERR(dax_mnt); | |
658 | goto err_mount; | |
659 | } | |
660 | dax_superblock = dax_mnt->mnt_sb; | |
661 | ||
662 | return 0; | |
663 | ||
664 | err_mount: | |
665 | unregister_filesystem(&dax_fs_type); | |
666 | err_register_fs: | |
667 | kmem_cache_destroy(dax_cache); | |
668 | ||
669 | return rc; | |
670 | } | |
671 | ||
9567da0b | 672 | static void dax_fs_exit(void) |
7b6be844 DW |
673 | { |
674 | kern_unmount(dax_mnt); | |
675 | unregister_filesystem(&dax_fs_type); | |
676 | kmem_cache_destroy(dax_cache); | |
677 | } | |
678 | ||
9567da0b | 679 | static int __init dax_core_init(void) |
7b6be844 DW |
680 | { |
681 | int rc; | |
682 | ||
9567da0b | 683 | rc = dax_fs_init(); |
7b6be844 DW |
684 | if (rc) |
685 | return rc; | |
686 | ||
cf1e2289 | 687 | rc = alloc_chrdev_region(&dax_devt, 0, MINORMASK+1, "dax"); |
7b6be844 | 688 | if (rc) |
9567da0b DW |
689 | goto err_chrdev; |
690 | ||
691 | rc = dax_bus_init(); | |
692 | if (rc) | |
693 | goto err_bus; | |
694 | return 0; | |
695 | ||
696 | err_bus: | |
697 | unregister_chrdev_region(dax_devt, MINORMASK+1); | |
698 | err_chrdev: | |
699 | dax_fs_exit(); | |
700 | return 0; | |
7b6be844 DW |
701 | } |
702 | ||
9567da0b | 703 | static void __exit dax_core_exit(void) |
7b6be844 | 704 | { |
cf1e2289 | 705 | unregister_chrdev_region(dax_devt, MINORMASK+1); |
7b6be844 | 706 | ida_destroy(&dax_minor_ida); |
9567da0b | 707 | dax_fs_exit(); |
7b6be844 DW |
708 | } |
709 | ||
710 | MODULE_AUTHOR("Intel Corporation"); | |
711 | MODULE_LICENSE("GPL v2"); | |
9567da0b DW |
712 | subsys_initcall(dax_core_init); |
713 | module_exit(dax_core_exit); |