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5981690d DW |
1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | /* Copyright(c) 2015 Intel Corporation. All rights reserved. */ | |
7d3dcf26 | 3 | #include <linux/device.h> |
92281dee | 4 | #include <linux/io.h> |
0207df4f | 5 | #include <linux/kasan.h> |
41e94a85 | 6 | #include <linux/memory_hotplug.h> |
bcfa4b72 MW |
7 | #include <linux/mm.h> |
8 | #include <linux/pfn_t.h> | |
5042db43 | 9 | #include <linux/swap.h> |
9ffc1d19 | 10 | #include <linux/mmzone.h> |
5042db43 | 11 | #include <linux/swapops.h> |
bcfa4b72 | 12 | #include <linux/types.h> |
e7638488 | 13 | #include <linux/wait_bit.h> |
bcfa4b72 | 14 | #include <linux/xarray.h> |
92281dee | 15 | |
bcfa4b72 | 16 | static DEFINE_XARRAY(pgmap_array); |
9476df7d | 17 | |
9ffc1d19 DW |
18 | /* |
19 | * The memremap() and memremap_pages() interfaces are alternately used | |
20 | * to map persistent memory namespaces. These interfaces place different | |
21 | * constraints on the alignment and size of the mapping (namespace). | |
22 | * memremap() can map individual PAGE_SIZE pages. memremap_pages() can | |
23 | * only map subsections (2MB), and at least one architecture (PowerPC) | |
24 | * the minimum mapping granularity of memremap_pages() is 16MB. | |
25 | * | |
26 | * The role of memremap_compat_align() is to communicate the minimum | |
27 | * arch supported alignment of a namespace such that it can freely | |
28 | * switch modes without violating the arch constraint. Namely, do not | |
29 | * allow a namespace to be PAGE_SIZE aligned since that namespace may be | |
30 | * reconfigured into a mode that requires SUBSECTION_SIZE alignment. | |
31 | */ | |
32 | #ifndef CONFIG_ARCH_HAS_MEMREMAP_COMPAT_ALIGN | |
33 | unsigned long memremap_compat_align(void) | |
34 | { | |
35 | return SUBSECTION_SIZE; | |
36 | } | |
37 | EXPORT_SYMBOL_GPL(memremap_compat_align); | |
38 | #endif | |
39 | ||
f6a55e1a CH |
40 | #ifdef CONFIG_DEV_PAGEMAP_OPS |
41 | DEFINE_STATIC_KEY_FALSE(devmap_managed_key); | |
42 | EXPORT_SYMBOL(devmap_managed_key); | |
43 | static atomic_t devmap_managed_enable; | |
44 | ||
6f42193f | 45 | static void devmap_managed_enable_put(void) |
f6a55e1a CH |
46 | { |
47 | if (atomic_dec_and_test(&devmap_managed_enable)) | |
48 | static_branch_disable(&devmap_managed_key); | |
49 | } | |
50 | ||
6f42193f | 51 | static int devmap_managed_enable_get(struct dev_pagemap *pgmap) |
f6a55e1a | 52 | { |
429589d6 DW |
53 | if (pgmap->type == MEMORY_DEVICE_PRIVATE && |
54 | (!pgmap->ops || !pgmap->ops->page_free)) { | |
f6a55e1a CH |
55 | WARN(1, "Missing page_free method\n"); |
56 | return -EINVAL; | |
57 | } | |
58 | ||
59 | if (atomic_inc_return(&devmap_managed_enable) == 1) | |
60 | static_branch_enable(&devmap_managed_key); | |
6f42193f | 61 | return 0; |
f6a55e1a CH |
62 | } |
63 | #else | |
6f42193f | 64 | static int devmap_managed_enable_get(struct dev_pagemap *pgmap) |
f6a55e1a CH |
65 | { |
66 | return -EINVAL; | |
67 | } | |
6f42193f CH |
68 | static void devmap_managed_enable_put(void) |
69 | { | |
70 | } | |
f6a55e1a CH |
71 | #endif /* CONFIG_DEV_PAGEMAP_OPS */ |
72 | ||
bcfa4b72 | 73 | static void pgmap_array_delete(struct resource *res) |
ab1b597e | 74 | { |
bcfa4b72 MW |
75 | xa_store_range(&pgmap_array, PHYS_PFN(res->start), PHYS_PFN(res->end), |
76 | NULL, GFP_KERNEL); | |
ab1b597e | 77 | synchronize_rcu(); |
9476df7d DW |
78 | } |
79 | ||
e7744aa2 | 80 | static unsigned long pfn_first(struct dev_pagemap *pgmap) |
5c2c2587 | 81 | { |
7cc7867f | 82 | return PHYS_PFN(pgmap->res.start) + |
514caf23 | 83 | vmem_altmap_offset(pgmap_altmap(pgmap)); |
5c2c2587 DW |
84 | } |
85 | ||
e7744aa2 | 86 | static unsigned long pfn_end(struct dev_pagemap *pgmap) |
5c2c2587 | 87 | { |
e7744aa2 | 88 | const struct resource *res = &pgmap->res; |
5c2c2587 DW |
89 | |
90 | return (res->start + resource_size(res)) >> PAGE_SHIFT; | |
91 | } | |
92 | ||
949b9325 DW |
93 | static unsigned long pfn_next(unsigned long pfn) |
94 | { | |
95 | if (pfn % 1024 == 0) | |
96 | cond_resched(); | |
97 | return pfn + 1; | |
98 | } | |
99 | ||
5c2c2587 | 100 | #define for_each_device_pfn(pfn, map) \ |
949b9325 | 101 | for (pfn = pfn_first(map); pfn < pfn_end(map); pfn = pfn_next(pfn)) |
5c2c2587 | 102 | |
24917f6b CH |
103 | static void dev_pagemap_kill(struct dev_pagemap *pgmap) |
104 | { | |
105 | if (pgmap->ops && pgmap->ops->kill) | |
106 | pgmap->ops->kill(pgmap); | |
107 | else | |
108 | percpu_ref_kill(pgmap->ref); | |
109 | } | |
110 | ||
111 | static void dev_pagemap_cleanup(struct dev_pagemap *pgmap) | |
112 | { | |
113 | if (pgmap->ops && pgmap->ops->cleanup) { | |
114 | pgmap->ops->cleanup(pgmap); | |
115 | } else { | |
116 | wait_for_completion(&pgmap->done); | |
117 | percpu_ref_exit(pgmap->ref); | |
118 | } | |
06282373 DW |
119 | /* |
120 | * Undo the pgmap ref assignment for the internal case as the | |
121 | * caller may re-enable the same pgmap. | |
122 | */ | |
123 | if (pgmap->ref == &pgmap->internal_ref) | |
124 | pgmap->ref = NULL; | |
24917f6b CH |
125 | } |
126 | ||
6869b7b2 | 127 | void memunmap_pages(struct dev_pagemap *pgmap) |
41e94a85 | 128 | { |
e7744aa2 | 129 | struct resource *res = &pgmap->res; |
77e080e7 | 130 | struct page *first_page; |
71389703 | 131 | unsigned long pfn; |
2c2a5af6 | 132 | int nid; |
71389703 | 133 | |
24917f6b | 134 | dev_pagemap_kill(pgmap); |
e7744aa2 | 135 | for_each_device_pfn(pfn, pgmap) |
71389703 | 136 | put_page(pfn_to_page(pfn)); |
24917f6b | 137 | dev_pagemap_cleanup(pgmap); |
9476df7d | 138 | |
77e080e7 AK |
139 | /* make sure to access a memmap that was actually initialized */ |
140 | first_page = pfn_to_page(pfn_first(pgmap)); | |
141 | ||
41e94a85 | 142 | /* pages are dead and unused, undo the arch mapping */ |
77e080e7 | 143 | nid = page_to_nid(first_page); |
2c2a5af6 | 144 | |
f931ab47 | 145 | mem_hotplug_begin(); |
d33695b1 DH |
146 | remove_pfn_range_from_zone(page_zone(first_page), PHYS_PFN(res->start), |
147 | PHYS_PFN(resource_size(res))); | |
69324b8f | 148 | if (pgmap->type == MEMORY_DEVICE_PRIVATE) { |
feee6b29 | 149 | __remove_pages(PHYS_PFN(res->start), |
77e080e7 | 150 | PHYS_PFN(resource_size(res)), NULL); |
69324b8f | 151 | } else { |
7cc7867f | 152 | arch_remove_memory(nid, res->start, resource_size(res), |
514caf23 | 153 | pgmap_altmap(pgmap)); |
7cc7867f | 154 | kasan_remove_zero_shadow(__va(res->start), resource_size(res)); |
69324b8f | 155 | } |
f931ab47 | 156 | mem_hotplug_done(); |
b5d24fda | 157 | |
7cc7867f | 158 | untrack_pfn(NULL, PHYS_PFN(res->start), resource_size(res)); |
bcfa4b72 | 159 | pgmap_array_delete(res); |
fdc029b1 | 160 | WARN_ONCE(pgmap->altmap.alloc, "failed to free all reserved pages\n"); |
6f42193f | 161 | devmap_managed_enable_put(); |
9476df7d | 162 | } |
6869b7b2 CH |
163 | EXPORT_SYMBOL_GPL(memunmap_pages); |
164 | ||
165 | static void devm_memremap_pages_release(void *data) | |
166 | { | |
167 | memunmap_pages(data); | |
168 | } | |
9476df7d | 169 | |
24917f6b CH |
170 | static void dev_pagemap_percpu_release(struct percpu_ref *ref) |
171 | { | |
172 | struct dev_pagemap *pgmap = | |
173 | container_of(ref, struct dev_pagemap, internal_ref); | |
174 | ||
175 | complete(&pgmap->done); | |
176 | } | |
177 | ||
6869b7b2 CH |
178 | /* |
179 | * Not device managed version of dev_memremap_pages, undone by | |
180 | * memunmap_pages(). Please use dev_memremap_pages if you have a struct | |
181 | * device available. | |
4b94ffdc | 182 | */ |
6869b7b2 | 183 | void *memremap_pages(struct dev_pagemap *pgmap, int nid) |
41e94a85 | 184 | { |
949b9325 | 185 | struct resource *res = &pgmap->res; |
966cf44f | 186 | struct dev_pagemap *conflict_pgmap; |
f5637d3b | 187 | struct mhp_params params = { |
940519f0 MH |
188 | /* |
189 | * We do not want any optional features only our own memmap | |
7cc7867f | 190 | */ |
514caf23 | 191 | .altmap = pgmap_altmap(pgmap), |
bfeb022f | 192 | .pgprot = PAGE_KERNEL, |
940519f0 | 193 | }; |
6869b7b2 | 194 | int error, is_ram; |
f6a55e1a | 195 | bool need_devmap_managed = true; |
5f29a77c | 196 | |
3ed2dcdf CH |
197 | switch (pgmap->type) { |
198 | case MEMORY_DEVICE_PRIVATE: | |
199 | if (!IS_ENABLED(CONFIG_DEVICE_PRIVATE)) { | |
200 | WARN(1, "Device private memory not supported\n"); | |
201 | return ERR_PTR(-EINVAL); | |
202 | } | |
897e6365 CH |
203 | if (!pgmap->ops || !pgmap->ops->migrate_to_ram) { |
204 | WARN(1, "Missing migrate_to_ram method\n"); | |
205 | return ERR_PTR(-EINVAL); | |
206 | } | |
f894ddd5 CH |
207 | if (!pgmap->owner) { |
208 | WARN(1, "Missing owner\n"); | |
209 | return ERR_PTR(-EINVAL); | |
210 | } | |
3ed2dcdf CH |
211 | break; |
212 | case MEMORY_DEVICE_FS_DAX: | |
213 | if (!IS_ENABLED(CONFIG_ZONE_DEVICE) || | |
214 | IS_ENABLED(CONFIG_FS_DAX_LIMITED)) { | |
215 | WARN(1, "File system DAX not supported\n"); | |
216 | return ERR_PTR(-EINVAL); | |
217 | } | |
218 | break; | |
4533d3ae | 219 | case MEMORY_DEVICE_GENERIC: |
a50d8d98 LG |
220 | need_devmap_managed = false; |
221 | break; | |
3ed2dcdf | 222 | case MEMORY_DEVICE_PCI_P2PDMA: |
a50d8d98 | 223 | params.pgprot = pgprot_noncached(params.pgprot); |
f6a55e1a | 224 | need_devmap_managed = false; |
3ed2dcdf CH |
225 | break; |
226 | default: | |
227 | WARN(1, "Invalid pgmap type %d\n", pgmap->type); | |
228 | break; | |
229 | } | |
230 | ||
24917f6b CH |
231 | if (!pgmap->ref) { |
232 | if (pgmap->ops && (pgmap->ops->kill || pgmap->ops->cleanup)) | |
233 | return ERR_PTR(-EINVAL); | |
234 | ||
235 | init_completion(&pgmap->done); | |
236 | error = percpu_ref_init(&pgmap->internal_ref, | |
237 | dev_pagemap_percpu_release, 0, GFP_KERNEL); | |
238 | if (error) | |
239 | return ERR_PTR(error); | |
240 | pgmap->ref = &pgmap->internal_ref; | |
241 | } else { | |
242 | if (!pgmap->ops || !pgmap->ops->kill || !pgmap->ops->cleanup) { | |
243 | WARN(1, "Missing reference count teardown definition\n"); | |
244 | return ERR_PTR(-EINVAL); | |
245 | } | |
50f44ee7 | 246 | } |
a95c90f1 | 247 | |
f6a55e1a | 248 | if (need_devmap_managed) { |
6f42193f | 249 | error = devmap_managed_enable_get(pgmap); |
f6a55e1a CH |
250 | if (error) |
251 | return ERR_PTR(error); | |
252 | } | |
253 | ||
7cc7867f | 254 | conflict_pgmap = get_dev_pagemap(PHYS_PFN(res->start), NULL); |
15d36fec | 255 | if (conflict_pgmap) { |
6869b7b2 | 256 | WARN(1, "Conflicting mapping in same section\n"); |
15d36fec | 257 | put_dev_pagemap(conflict_pgmap); |
50f44ee7 DW |
258 | error = -ENOMEM; |
259 | goto err_array; | |
15d36fec DJ |
260 | } |
261 | ||
7cc7867f | 262 | conflict_pgmap = get_dev_pagemap(PHYS_PFN(res->end), NULL); |
15d36fec | 263 | if (conflict_pgmap) { |
6869b7b2 | 264 | WARN(1, "Conflicting mapping in same section\n"); |
15d36fec | 265 | put_dev_pagemap(conflict_pgmap); |
50f44ee7 DW |
266 | error = -ENOMEM; |
267 | goto err_array; | |
15d36fec DJ |
268 | } |
269 | ||
7cc7867f | 270 | is_ram = region_intersects(res->start, resource_size(res), |
d37a14bb | 271 | IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE); |
41e94a85 | 272 | |
06489cfb DW |
273 | if (is_ram != REGION_DISJOINT) { |
274 | WARN_ONCE(1, "%s attempted on %s region %pr\n", __func__, | |
275 | is_ram == REGION_MIXED ? "mixed" : "ram", res); | |
a95c90f1 DW |
276 | error = -ENXIO; |
277 | goto err_array; | |
41e94a85 CH |
278 | } |
279 | ||
bcfa4b72 MW |
280 | error = xa_err(xa_store_range(&pgmap_array, PHYS_PFN(res->start), |
281 | PHYS_PFN(res->end), pgmap, GFP_KERNEL)); | |
9476df7d | 282 | if (error) |
bcfa4b72 | 283 | goto err_array; |
9476df7d | 284 | |
41e94a85 | 285 | if (nid < 0) |
7eff93b7 | 286 | nid = numa_mem_id(); |
41e94a85 | 287 | |
bfeb022f LG |
288 | error = track_pfn_remap(NULL, ¶ms.pgprot, PHYS_PFN(res->start), |
289 | 0, resource_size(res)); | |
9049771f DW |
290 | if (error) |
291 | goto err_pfn_remap; | |
292 | ||
f931ab47 | 293 | mem_hotplug_begin(); |
69324b8f DW |
294 | |
295 | /* | |
296 | * For device private memory we call add_pages() as we only need to | |
297 | * allocate and initialize struct page for the device memory. More- | |
298 | * over the device memory is un-accessible thus we do not want to | |
299 | * create a linear mapping for the memory like arch_add_memory() | |
300 | * would do. | |
301 | * | |
302 | * For all other device memory types, which are accessible by | |
303 | * the CPU, we do want the linear mapping and thus use | |
304 | * arch_add_memory(). | |
305 | */ | |
306 | if (pgmap->type == MEMORY_DEVICE_PRIVATE) { | |
7cc7867f | 307 | error = add_pages(nid, PHYS_PFN(res->start), |
f5637d3b | 308 | PHYS_PFN(resource_size(res)), ¶ms); |
69324b8f | 309 | } else { |
7cc7867f | 310 | error = kasan_add_zero_shadow(__va(res->start), resource_size(res)); |
69324b8f DW |
311 | if (error) { |
312 | mem_hotplug_done(); | |
313 | goto err_kasan; | |
314 | } | |
315 | ||
7cc7867f | 316 | error = arch_add_memory(nid, res->start, resource_size(res), |
f5637d3b | 317 | ¶ms); |
69324b8f DW |
318 | } |
319 | ||
320 | if (!error) { | |
321 | struct zone *zone; | |
322 | ||
323 | zone = &NODE_DATA(nid)->node_zones[ZONE_DEVICE]; | |
7cc7867f | 324 | move_pfn_range_to_zone(zone, PHYS_PFN(res->start), |
f5637d3b | 325 | PHYS_PFN(resource_size(res)), params.altmap); |
0207df4f AR |
326 | } |
327 | ||
f931ab47 | 328 | mem_hotplug_done(); |
9476df7d DW |
329 | if (error) |
330 | goto err_add_memory; | |
41e94a85 | 331 | |
966cf44f AD |
332 | /* |
333 | * Initialization of the pages has been deferred until now in order | |
334 | * to allow us to do the work while not holding the hotplug lock. | |
335 | */ | |
336 | memmap_init_zone_device(&NODE_DATA(nid)->node_zones[ZONE_DEVICE], | |
7cc7867f DW |
337 | PHYS_PFN(res->start), |
338 | PHYS_PFN(resource_size(res)), pgmap); | |
966cf44f | 339 | percpu_ref_get_many(pgmap->ref, pfn_end(pgmap) - pfn_first(pgmap)); |
41e94a85 | 340 | return __va(res->start); |
9476df7d DW |
341 | |
342 | err_add_memory: | |
7cc7867f | 343 | kasan_remove_zero_shadow(__va(res->start), resource_size(res)); |
0207df4f | 344 | err_kasan: |
7cc7867f | 345 | untrack_pfn(NULL, PHYS_PFN(res->start), resource_size(res)); |
9049771f | 346 | err_pfn_remap: |
bcfa4b72 MW |
347 | pgmap_array_delete(res); |
348 | err_array: | |
24917f6b CH |
349 | dev_pagemap_kill(pgmap); |
350 | dev_pagemap_cleanup(pgmap); | |
6f42193f | 351 | devmap_managed_enable_put(); |
9476df7d | 352 | return ERR_PTR(error); |
41e94a85 | 353 | } |
6869b7b2 CH |
354 | EXPORT_SYMBOL_GPL(memremap_pages); |
355 | ||
356 | /** | |
357 | * devm_memremap_pages - remap and provide memmap backing for the given resource | |
358 | * @dev: hosting device for @res | |
359 | * @pgmap: pointer to a struct dev_pagemap | |
360 | * | |
361 | * Notes: | |
362 | * 1/ At a minimum the res and type members of @pgmap must be initialized | |
363 | * by the caller before passing it to this function | |
364 | * | |
365 | * 2/ The altmap field may optionally be initialized, in which case | |
366 | * PGMAP_ALTMAP_VALID must be set in pgmap->flags. | |
367 | * | |
368 | * 3/ The ref field may optionally be provided, in which pgmap->ref must be | |
369 | * 'live' on entry and will be killed and reaped at | |
370 | * devm_memremap_pages_release() time, or if this routine fails. | |
371 | * | |
372 | * 4/ res is expected to be a host memory range that could feasibly be | |
373 | * treated as a "System RAM" range, i.e. not a device mmio range, but | |
374 | * this is not enforced. | |
375 | */ | |
376 | void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) | |
377 | { | |
378 | int error; | |
379 | void *ret; | |
380 | ||
381 | ret = memremap_pages(pgmap, dev_to_node(dev)); | |
382 | if (IS_ERR(ret)) | |
383 | return ret; | |
384 | ||
385 | error = devm_add_action_or_reset(dev, devm_memremap_pages_release, | |
386 | pgmap); | |
387 | if (error) | |
388 | return ERR_PTR(error); | |
389 | return ret; | |
390 | } | |
808153e1 | 391 | EXPORT_SYMBOL_GPL(devm_memremap_pages); |
4b94ffdc | 392 | |
2e3f139e DW |
393 | void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap) |
394 | { | |
395 | devm_release_action(dev, devm_memremap_pages_release, pgmap); | |
396 | } | |
397 | EXPORT_SYMBOL_GPL(devm_memunmap_pages); | |
398 | ||
4b94ffdc DW |
399 | unsigned long vmem_altmap_offset(struct vmem_altmap *altmap) |
400 | { | |
401 | /* number of pfns from base where pfn_to_page() is valid */ | |
514caf23 CH |
402 | if (altmap) |
403 | return altmap->reserve + altmap->free; | |
404 | return 0; | |
4b94ffdc DW |
405 | } |
406 | ||
407 | void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns) | |
408 | { | |
409 | altmap->alloc -= nr_pfns; | |
410 | } | |
411 | ||
0822acb8 CH |
412 | /** |
413 | * get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn | |
414 | * @pfn: page frame number to lookup page_map | |
415 | * @pgmap: optional known pgmap that already has a reference | |
416 | * | |
832d7aa0 CH |
417 | * If @pgmap is non-NULL and covers @pfn it will be returned as-is. If @pgmap |
418 | * is non-NULL but does not cover @pfn the reference to it will be released. | |
0822acb8 CH |
419 | */ |
420 | struct dev_pagemap *get_dev_pagemap(unsigned long pfn, | |
421 | struct dev_pagemap *pgmap) | |
422 | { | |
0822acb8 CH |
423 | resource_size_t phys = PFN_PHYS(pfn); |
424 | ||
425 | /* | |
832d7aa0 | 426 | * In the cached case we're already holding a live reference. |
0822acb8 | 427 | */ |
832d7aa0 | 428 | if (pgmap) { |
e7744aa2 | 429 | if (phys >= pgmap->res.start && phys <= pgmap->res.end) |
832d7aa0 CH |
430 | return pgmap; |
431 | put_dev_pagemap(pgmap); | |
0822acb8 CH |
432 | } |
433 | ||
434 | /* fall back to slow path lookup */ | |
435 | rcu_read_lock(); | |
bcfa4b72 | 436 | pgmap = xa_load(&pgmap_array, PHYS_PFN(phys)); |
0822acb8 CH |
437 | if (pgmap && !percpu_ref_tryget_live(pgmap->ref)) |
438 | pgmap = NULL; | |
439 | rcu_read_unlock(); | |
440 | ||
441 | return pgmap; | |
442 | } | |
e7638488 | 443 | EXPORT_SYMBOL_GPL(get_dev_pagemap); |
7b2d55d2 | 444 | |
e7638488 | 445 | #ifdef CONFIG_DEV_PAGEMAP_OPS |
07d80269 | 446 | void free_devmap_managed_page(struct page *page) |
7b2d55d2 | 447 | { |
429589d6 DW |
448 | /* notify page idle for dax */ |
449 | if (!is_device_private_page(page)) { | |
450 | wake_up_var(&page->_refcount); | |
451 | return; | |
452 | } | |
7ab0ad0e | 453 | |
429589d6 DW |
454 | /* Clear Active bit in case of parallel mark_page_accessed */ |
455 | __ClearPageActive(page); | |
456 | __ClearPageWaiters(page); | |
457 | ||
458 | mem_cgroup_uncharge(page); | |
459 | ||
460 | /* | |
461 | * When a device_private page is freed, the page->mapping field | |
462 | * may still contain a (stale) mapping value. For example, the | |
463 | * lower bits of page->mapping may still identify the page as an | |
464 | * anonymous page. Ultimately, this entire field is just stale | |
465 | * and wrong, and it will cause errors if not cleared. One | |
466 | * example is: | |
467 | * | |
468 | * migrate_vma_pages() | |
469 | * migrate_vma_insert_page() | |
470 | * page_add_new_anon_rmap() | |
471 | * __page_set_anon_rmap() | |
472 | * ...checks page->mapping, via PageAnon(page) call, | |
473 | * and incorrectly concludes that the page is an | |
474 | * anonymous page. Therefore, it incorrectly, | |
475 | * silently fails to set up the new anon rmap. | |
476 | * | |
477 | * For other types of ZONE_DEVICE pages, migration is either | |
478 | * handled differently or not done at all, so there is no need | |
479 | * to clear page->mapping. | |
480 | */ | |
481 | page->mapping = NULL; | |
482 | page->pgmap->ops->page_free(page); | |
7b2d55d2 | 483 | } |
e7638488 | 484 | #endif /* CONFIG_DEV_PAGEMAP_OPS */ |