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d475c634 MW |
1 | /* |
2 | * fs/dax.c - Direct Access filesystem code | |
3 | * Copyright (c) 2013-2014 Intel Corporation | |
4 | * Author: Matthew Wilcox <matthew.r.wilcox@intel.com> | |
5 | * Author: Ross Zwisler <ross.zwisler@linux.intel.com> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify it | |
8 | * under the terms and conditions of the GNU General Public License, | |
9 | * version 2, as published by the Free Software Foundation. | |
10 | * | |
11 | * This program is distributed in the hope it will be useful, but WITHOUT | |
12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
14 | * more details. | |
15 | */ | |
16 | ||
17 | #include <linux/atomic.h> | |
18 | #include <linux/blkdev.h> | |
19 | #include <linux/buffer_head.h> | |
d77e92e2 | 20 | #include <linux/dax.h> |
d475c634 MW |
21 | #include <linux/fs.h> |
22 | #include <linux/genhd.h> | |
f7ca90b1 MW |
23 | #include <linux/highmem.h> |
24 | #include <linux/memcontrol.h> | |
25 | #include <linux/mm.h> | |
d475c634 | 26 | #include <linux/mutex.h> |
9973c98e | 27 | #include <linux/pagevec.h> |
2765cfbb | 28 | #include <linux/pmem.h> |
289c6aed | 29 | #include <linux/sched.h> |
f361bf4a | 30 | #include <linux/sched/signal.h> |
d475c634 | 31 | #include <linux/uio.h> |
f7ca90b1 | 32 | #include <linux/vmstat.h> |
34c0fd54 | 33 | #include <linux/pfn_t.h> |
0e749e54 | 34 | #include <linux/sizes.h> |
4b4bb46d | 35 | #include <linux/mmu_notifier.h> |
a254e568 CH |
36 | #include <linux/iomap.h> |
37 | #include "internal.h" | |
d475c634 | 38 | |
282a8e03 RZ |
39 | #define CREATE_TRACE_POINTS |
40 | #include <trace/events/fs_dax.h> | |
41 | ||
ac401cc7 JK |
42 | /* We choose 4096 entries - same as per-zone page wait tables */ |
43 | #define DAX_WAIT_TABLE_BITS 12 | |
44 | #define DAX_WAIT_TABLE_ENTRIES (1 << DAX_WAIT_TABLE_BITS) | |
45 | ||
ce95ab0f | 46 | static wait_queue_head_t wait_table[DAX_WAIT_TABLE_ENTRIES]; |
ac401cc7 JK |
47 | |
48 | static int __init init_dax_wait_table(void) | |
49 | { | |
50 | int i; | |
51 | ||
52 | for (i = 0; i < DAX_WAIT_TABLE_ENTRIES; i++) | |
53 | init_waitqueue_head(wait_table + i); | |
54 | return 0; | |
55 | } | |
56 | fs_initcall(init_dax_wait_table); | |
57 | ||
642261ac | 58 | static int dax_is_pmd_entry(void *entry) |
d1a5f2b4 | 59 | { |
642261ac | 60 | return (unsigned long)entry & RADIX_DAX_PMD; |
d1a5f2b4 DW |
61 | } |
62 | ||
642261ac | 63 | static int dax_is_pte_entry(void *entry) |
d475c634 | 64 | { |
642261ac | 65 | return !((unsigned long)entry & RADIX_DAX_PMD); |
d475c634 MW |
66 | } |
67 | ||
642261ac | 68 | static int dax_is_zero_entry(void *entry) |
d475c634 | 69 | { |
642261ac | 70 | return (unsigned long)entry & RADIX_DAX_HZP; |
d475c634 MW |
71 | } |
72 | ||
642261ac | 73 | static int dax_is_empty_entry(void *entry) |
b2e0d162 | 74 | { |
642261ac | 75 | return (unsigned long)entry & RADIX_DAX_EMPTY; |
b2e0d162 DW |
76 | } |
77 | ||
ac401cc7 JK |
78 | /* |
79 | * DAX radix tree locking | |
80 | */ | |
81 | struct exceptional_entry_key { | |
82 | struct address_space *mapping; | |
63e95b5c | 83 | pgoff_t entry_start; |
ac401cc7 JK |
84 | }; |
85 | ||
86 | struct wait_exceptional_entry_queue { | |
87 | wait_queue_t wait; | |
88 | struct exceptional_entry_key key; | |
89 | }; | |
90 | ||
63e95b5c RZ |
91 | static wait_queue_head_t *dax_entry_waitqueue(struct address_space *mapping, |
92 | pgoff_t index, void *entry, struct exceptional_entry_key *key) | |
93 | { | |
94 | unsigned long hash; | |
95 | ||
96 | /* | |
97 | * If 'entry' is a PMD, align the 'index' that we use for the wait | |
98 | * queue to the start of that PMD. This ensures that all offsets in | |
99 | * the range covered by the PMD map to the same bit lock. | |
100 | */ | |
642261ac | 101 | if (dax_is_pmd_entry(entry)) |
63e95b5c RZ |
102 | index &= ~((1UL << (PMD_SHIFT - PAGE_SHIFT)) - 1); |
103 | ||
104 | key->mapping = mapping; | |
105 | key->entry_start = index; | |
106 | ||
107 | hash = hash_long((unsigned long)mapping ^ index, DAX_WAIT_TABLE_BITS); | |
108 | return wait_table + hash; | |
109 | } | |
110 | ||
ac401cc7 JK |
111 | static int wake_exceptional_entry_func(wait_queue_t *wait, unsigned int mode, |
112 | int sync, void *keyp) | |
113 | { | |
114 | struct exceptional_entry_key *key = keyp; | |
115 | struct wait_exceptional_entry_queue *ewait = | |
116 | container_of(wait, struct wait_exceptional_entry_queue, wait); | |
117 | ||
118 | if (key->mapping != ewait->key.mapping || | |
63e95b5c | 119 | key->entry_start != ewait->key.entry_start) |
ac401cc7 JK |
120 | return 0; |
121 | return autoremove_wake_function(wait, mode, sync, NULL); | |
122 | } | |
123 | ||
124 | /* | |
125 | * Check whether the given slot is locked. The function must be called with | |
126 | * mapping->tree_lock held | |
127 | */ | |
128 | static inline int slot_locked(struct address_space *mapping, void **slot) | |
129 | { | |
130 | unsigned long entry = (unsigned long) | |
131 | radix_tree_deref_slot_protected(slot, &mapping->tree_lock); | |
132 | return entry & RADIX_DAX_ENTRY_LOCK; | |
133 | } | |
134 | ||
135 | /* | |
136 | * Mark the given slot is locked. The function must be called with | |
137 | * mapping->tree_lock held | |
138 | */ | |
139 | static inline void *lock_slot(struct address_space *mapping, void **slot) | |
140 | { | |
141 | unsigned long entry = (unsigned long) | |
142 | radix_tree_deref_slot_protected(slot, &mapping->tree_lock); | |
143 | ||
144 | entry |= RADIX_DAX_ENTRY_LOCK; | |
6d75f366 | 145 | radix_tree_replace_slot(&mapping->page_tree, slot, (void *)entry); |
ac401cc7 JK |
146 | return (void *)entry; |
147 | } | |
148 | ||
149 | /* | |
150 | * Mark the given slot is unlocked. The function must be called with | |
151 | * mapping->tree_lock held | |
152 | */ | |
153 | static inline void *unlock_slot(struct address_space *mapping, void **slot) | |
154 | { | |
155 | unsigned long entry = (unsigned long) | |
156 | radix_tree_deref_slot_protected(slot, &mapping->tree_lock); | |
157 | ||
158 | entry &= ~(unsigned long)RADIX_DAX_ENTRY_LOCK; | |
6d75f366 | 159 | radix_tree_replace_slot(&mapping->page_tree, slot, (void *)entry); |
ac401cc7 JK |
160 | return (void *)entry; |
161 | } | |
162 | ||
163 | /* | |
164 | * Lookup entry in radix tree, wait for it to become unlocked if it is | |
165 | * exceptional entry and return it. The caller must call | |
166 | * put_unlocked_mapping_entry() when he decided not to lock the entry or | |
167 | * put_locked_mapping_entry() when he locked the entry and now wants to | |
168 | * unlock it. | |
169 | * | |
170 | * The function must be called with mapping->tree_lock held. | |
171 | */ | |
172 | static void *get_unlocked_mapping_entry(struct address_space *mapping, | |
173 | pgoff_t index, void ***slotp) | |
174 | { | |
e3ad61c6 | 175 | void *entry, **slot; |
ac401cc7 | 176 | struct wait_exceptional_entry_queue ewait; |
63e95b5c | 177 | wait_queue_head_t *wq; |
ac401cc7 JK |
178 | |
179 | init_wait(&ewait.wait); | |
180 | ewait.wait.func = wake_exceptional_entry_func; | |
ac401cc7 JK |
181 | |
182 | for (;;) { | |
e3ad61c6 | 183 | entry = __radix_tree_lookup(&mapping->page_tree, index, NULL, |
ac401cc7 | 184 | &slot); |
e3ad61c6 | 185 | if (!entry || !radix_tree_exceptional_entry(entry) || |
ac401cc7 JK |
186 | !slot_locked(mapping, slot)) { |
187 | if (slotp) | |
188 | *slotp = slot; | |
e3ad61c6 | 189 | return entry; |
ac401cc7 | 190 | } |
63e95b5c RZ |
191 | |
192 | wq = dax_entry_waitqueue(mapping, index, entry, &ewait.key); | |
ac401cc7 JK |
193 | prepare_to_wait_exclusive(wq, &ewait.wait, |
194 | TASK_UNINTERRUPTIBLE); | |
195 | spin_unlock_irq(&mapping->tree_lock); | |
196 | schedule(); | |
197 | finish_wait(wq, &ewait.wait); | |
198 | spin_lock_irq(&mapping->tree_lock); | |
199 | } | |
200 | } | |
201 | ||
b1aa812b JK |
202 | static void dax_unlock_mapping_entry(struct address_space *mapping, |
203 | pgoff_t index) | |
204 | { | |
205 | void *entry, **slot; | |
206 | ||
207 | spin_lock_irq(&mapping->tree_lock); | |
208 | entry = __radix_tree_lookup(&mapping->page_tree, index, NULL, &slot); | |
209 | if (WARN_ON_ONCE(!entry || !radix_tree_exceptional_entry(entry) || | |
210 | !slot_locked(mapping, slot))) { | |
211 | spin_unlock_irq(&mapping->tree_lock); | |
212 | return; | |
213 | } | |
214 | unlock_slot(mapping, slot); | |
215 | spin_unlock_irq(&mapping->tree_lock); | |
216 | dax_wake_mapping_entry_waiter(mapping, index, entry, false); | |
217 | } | |
218 | ||
422476c4 RZ |
219 | static void put_locked_mapping_entry(struct address_space *mapping, |
220 | pgoff_t index, void *entry) | |
221 | { | |
222 | if (!radix_tree_exceptional_entry(entry)) { | |
223 | unlock_page(entry); | |
224 | put_page(entry); | |
225 | } else { | |
226 | dax_unlock_mapping_entry(mapping, index); | |
227 | } | |
228 | } | |
229 | ||
230 | /* | |
231 | * Called when we are done with radix tree entry we looked up via | |
232 | * get_unlocked_mapping_entry() and which we didn't lock in the end. | |
233 | */ | |
234 | static void put_unlocked_mapping_entry(struct address_space *mapping, | |
235 | pgoff_t index, void *entry) | |
236 | { | |
237 | if (!radix_tree_exceptional_entry(entry)) | |
238 | return; | |
239 | ||
240 | /* We have to wake up next waiter for the radix tree entry lock */ | |
241 | dax_wake_mapping_entry_waiter(mapping, index, entry, false); | |
242 | } | |
243 | ||
ac401cc7 JK |
244 | /* |
245 | * Find radix tree entry at given index. If it points to a page, return with | |
246 | * the page locked. If it points to the exceptional entry, return with the | |
247 | * radix tree entry locked. If the radix tree doesn't contain given index, | |
248 | * create empty exceptional entry for the index and return with it locked. | |
249 | * | |
642261ac RZ |
250 | * When requesting an entry with size RADIX_DAX_PMD, grab_mapping_entry() will |
251 | * either return that locked entry or will return an error. This error will | |
252 | * happen if there are any 4k entries (either zero pages or DAX entries) | |
253 | * within the 2MiB range that we are requesting. | |
254 | * | |
255 | * We always favor 4k entries over 2MiB entries. There isn't a flow where we | |
256 | * evict 4k entries in order to 'upgrade' them to a 2MiB entry. A 2MiB | |
257 | * insertion will fail if it finds any 4k entries already in the tree, and a | |
258 | * 4k insertion will cause an existing 2MiB entry to be unmapped and | |
259 | * downgraded to 4k entries. This happens for both 2MiB huge zero pages as | |
260 | * well as 2MiB empty entries. | |
261 | * | |
262 | * The exception to this downgrade path is for 2MiB DAX PMD entries that have | |
263 | * real storage backing them. We will leave these real 2MiB DAX entries in | |
264 | * the tree, and PTE writes will simply dirty the entire 2MiB DAX entry. | |
265 | * | |
ac401cc7 JK |
266 | * Note: Unlike filemap_fault() we don't honor FAULT_FLAG_RETRY flags. For |
267 | * persistent memory the benefit is doubtful. We can add that later if we can | |
268 | * show it helps. | |
269 | */ | |
642261ac RZ |
270 | static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index, |
271 | unsigned long size_flag) | |
ac401cc7 | 272 | { |
642261ac | 273 | bool pmd_downgrade = false; /* splitting 2MiB entry into 4k entries? */ |
e3ad61c6 | 274 | void *entry, **slot; |
ac401cc7 JK |
275 | |
276 | restart: | |
277 | spin_lock_irq(&mapping->tree_lock); | |
e3ad61c6 | 278 | entry = get_unlocked_mapping_entry(mapping, index, &slot); |
642261ac RZ |
279 | |
280 | if (entry) { | |
281 | if (size_flag & RADIX_DAX_PMD) { | |
282 | if (!radix_tree_exceptional_entry(entry) || | |
283 | dax_is_pte_entry(entry)) { | |
284 | put_unlocked_mapping_entry(mapping, index, | |
285 | entry); | |
286 | entry = ERR_PTR(-EEXIST); | |
287 | goto out_unlock; | |
288 | } | |
289 | } else { /* trying to grab a PTE entry */ | |
290 | if (radix_tree_exceptional_entry(entry) && | |
291 | dax_is_pmd_entry(entry) && | |
292 | (dax_is_zero_entry(entry) || | |
293 | dax_is_empty_entry(entry))) { | |
294 | pmd_downgrade = true; | |
295 | } | |
296 | } | |
297 | } | |
298 | ||
ac401cc7 | 299 | /* No entry for given index? Make sure radix tree is big enough. */ |
642261ac | 300 | if (!entry || pmd_downgrade) { |
ac401cc7 JK |
301 | int err; |
302 | ||
642261ac RZ |
303 | if (pmd_downgrade) { |
304 | /* | |
305 | * Make sure 'entry' remains valid while we drop | |
306 | * mapping->tree_lock. | |
307 | */ | |
308 | entry = lock_slot(mapping, slot); | |
309 | } | |
310 | ||
ac401cc7 | 311 | spin_unlock_irq(&mapping->tree_lock); |
642261ac RZ |
312 | /* |
313 | * Besides huge zero pages the only other thing that gets | |
314 | * downgraded are empty entries which don't need to be | |
315 | * unmapped. | |
316 | */ | |
317 | if (pmd_downgrade && dax_is_zero_entry(entry)) | |
318 | unmap_mapping_range(mapping, | |
319 | (index << PAGE_SHIFT) & PMD_MASK, PMD_SIZE, 0); | |
320 | ||
ac401cc7 JK |
321 | err = radix_tree_preload( |
322 | mapping_gfp_mask(mapping) & ~__GFP_HIGHMEM); | |
0cb80b48 JK |
323 | if (err) { |
324 | if (pmd_downgrade) | |
325 | put_locked_mapping_entry(mapping, index, entry); | |
ac401cc7 | 326 | return ERR_PTR(err); |
0cb80b48 | 327 | } |
ac401cc7 | 328 | spin_lock_irq(&mapping->tree_lock); |
642261ac RZ |
329 | |
330 | if (pmd_downgrade) { | |
331 | radix_tree_delete(&mapping->page_tree, index); | |
332 | mapping->nrexceptional--; | |
333 | dax_wake_mapping_entry_waiter(mapping, index, entry, | |
334 | true); | |
335 | } | |
336 | ||
337 | entry = dax_radix_locked_entry(0, size_flag | RADIX_DAX_EMPTY); | |
338 | ||
339 | err = __radix_tree_insert(&mapping->page_tree, index, | |
340 | dax_radix_order(entry), entry); | |
ac401cc7 JK |
341 | radix_tree_preload_end(); |
342 | if (err) { | |
343 | spin_unlock_irq(&mapping->tree_lock); | |
642261ac RZ |
344 | /* |
345 | * Someone already created the entry? This is a | |
346 | * normal failure when inserting PMDs in a range | |
347 | * that already contains PTEs. In that case we want | |
348 | * to return -EEXIST immediately. | |
349 | */ | |
350 | if (err == -EEXIST && !(size_flag & RADIX_DAX_PMD)) | |
ac401cc7 | 351 | goto restart; |
642261ac RZ |
352 | /* |
353 | * Our insertion of a DAX PMD entry failed, most | |
354 | * likely because it collided with a PTE sized entry | |
355 | * at a different index in the PMD range. We haven't | |
356 | * inserted anything into the radix tree and have no | |
357 | * waiters to wake. | |
358 | */ | |
ac401cc7 JK |
359 | return ERR_PTR(err); |
360 | } | |
361 | /* Good, we have inserted empty locked entry into the tree. */ | |
362 | mapping->nrexceptional++; | |
363 | spin_unlock_irq(&mapping->tree_lock); | |
e3ad61c6 | 364 | return entry; |
ac401cc7 JK |
365 | } |
366 | /* Normal page in radix tree? */ | |
e3ad61c6 RZ |
367 | if (!radix_tree_exceptional_entry(entry)) { |
368 | struct page *page = entry; | |
ac401cc7 JK |
369 | |
370 | get_page(page); | |
371 | spin_unlock_irq(&mapping->tree_lock); | |
372 | lock_page(page); | |
373 | /* Page got truncated? Retry... */ | |
374 | if (unlikely(page->mapping != mapping)) { | |
375 | unlock_page(page); | |
376 | put_page(page); | |
377 | goto restart; | |
378 | } | |
379 | return page; | |
380 | } | |
e3ad61c6 | 381 | entry = lock_slot(mapping, slot); |
642261ac | 382 | out_unlock: |
ac401cc7 | 383 | spin_unlock_irq(&mapping->tree_lock); |
e3ad61c6 | 384 | return entry; |
ac401cc7 JK |
385 | } |
386 | ||
63e95b5c RZ |
387 | /* |
388 | * We do not necessarily hold the mapping->tree_lock when we call this | |
389 | * function so it is possible that 'entry' is no longer a valid item in the | |
642261ac RZ |
390 | * radix tree. This is okay because all we really need to do is to find the |
391 | * correct waitqueue where tasks might be waiting for that old 'entry' and | |
392 | * wake them. | |
63e95b5c | 393 | */ |
ac401cc7 | 394 | void dax_wake_mapping_entry_waiter(struct address_space *mapping, |
63e95b5c | 395 | pgoff_t index, void *entry, bool wake_all) |
ac401cc7 | 396 | { |
63e95b5c RZ |
397 | struct exceptional_entry_key key; |
398 | wait_queue_head_t *wq; | |
399 | ||
400 | wq = dax_entry_waitqueue(mapping, index, entry, &key); | |
ac401cc7 JK |
401 | |
402 | /* | |
403 | * Checking for locked entry and prepare_to_wait_exclusive() happens | |
404 | * under mapping->tree_lock, ditto for entry handling in our callers. | |
405 | * So at this point all tasks that could have seen our entry locked | |
406 | * must be in the waitqueue and the following check will see them. | |
407 | */ | |
63e95b5c | 408 | if (waitqueue_active(wq)) |
ac401cc7 | 409 | __wake_up(wq, TASK_NORMAL, wake_all ? 0 : 1, &key); |
ac401cc7 JK |
410 | } |
411 | ||
c6dcf52c JK |
412 | static int __dax_invalidate_mapping_entry(struct address_space *mapping, |
413 | pgoff_t index, bool trunc) | |
414 | { | |
415 | int ret = 0; | |
416 | void *entry; | |
417 | struct radix_tree_root *page_tree = &mapping->page_tree; | |
418 | ||
419 | spin_lock_irq(&mapping->tree_lock); | |
420 | entry = get_unlocked_mapping_entry(mapping, index, NULL); | |
421 | if (!entry || !radix_tree_exceptional_entry(entry)) | |
422 | goto out; | |
423 | if (!trunc && | |
424 | (radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_DIRTY) || | |
425 | radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_TOWRITE))) | |
426 | goto out; | |
427 | radix_tree_delete(page_tree, index); | |
428 | mapping->nrexceptional--; | |
429 | ret = 1; | |
430 | out: | |
431 | put_unlocked_mapping_entry(mapping, index, entry); | |
432 | spin_unlock_irq(&mapping->tree_lock); | |
433 | return ret; | |
434 | } | |
ac401cc7 JK |
435 | /* |
436 | * Delete exceptional DAX entry at @index from @mapping. Wait for radix tree | |
437 | * entry to get unlocked before deleting it. | |
438 | */ | |
439 | int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index) | |
440 | { | |
c6dcf52c | 441 | int ret = __dax_invalidate_mapping_entry(mapping, index, true); |
ac401cc7 | 442 | |
ac401cc7 JK |
443 | /* |
444 | * This gets called from truncate / punch_hole path. As such, the caller | |
445 | * must hold locks protecting against concurrent modifications of the | |
446 | * radix tree (usually fs-private i_mmap_sem for writing). Since the | |
447 | * caller has seen exceptional entry for this index, we better find it | |
448 | * at that index as well... | |
449 | */ | |
c6dcf52c JK |
450 | WARN_ON_ONCE(!ret); |
451 | return ret; | |
452 | } | |
453 | ||
454 | /* | |
455 | * Invalidate exceptional DAX entry if easily possible. This handles DAX | |
456 | * entries for invalidate_inode_pages() so we evict the entry only if we can | |
457 | * do so without blocking. | |
458 | */ | |
459 | int dax_invalidate_mapping_entry(struct address_space *mapping, pgoff_t index) | |
460 | { | |
461 | int ret = 0; | |
462 | void *entry, **slot; | |
463 | struct radix_tree_root *page_tree = &mapping->page_tree; | |
464 | ||
465 | spin_lock_irq(&mapping->tree_lock); | |
466 | entry = __radix_tree_lookup(page_tree, index, NULL, &slot); | |
467 | if (!entry || !radix_tree_exceptional_entry(entry) || | |
468 | slot_locked(mapping, slot)) | |
469 | goto out; | |
470 | if (radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_DIRTY) || | |
471 | radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_TOWRITE)) | |
472 | goto out; | |
473 | radix_tree_delete(page_tree, index); | |
ac401cc7 | 474 | mapping->nrexceptional--; |
c6dcf52c JK |
475 | ret = 1; |
476 | out: | |
ac401cc7 | 477 | spin_unlock_irq(&mapping->tree_lock); |
c6dcf52c JK |
478 | if (ret) |
479 | dax_wake_mapping_entry_waiter(mapping, index, entry, true); | |
480 | return ret; | |
481 | } | |
ac401cc7 | 482 | |
c6dcf52c JK |
483 | /* |
484 | * Invalidate exceptional DAX entry if it is clean. | |
485 | */ | |
486 | int dax_invalidate_mapping_entry_sync(struct address_space *mapping, | |
487 | pgoff_t index) | |
488 | { | |
489 | return __dax_invalidate_mapping_entry(mapping, index, false); | |
ac401cc7 JK |
490 | } |
491 | ||
f7ca90b1 MW |
492 | /* |
493 | * The user has performed a load from a hole in the file. Allocating | |
494 | * a new page in the file would cause excessive storage usage for | |
495 | * workloads with sparse files. We allocate a page cache page instead. | |
496 | * We'll kick it out of the page cache if it's ever written to, | |
497 | * otherwise it will simply fall out of the page cache under memory | |
498 | * pressure without ever having been dirtied. | |
499 | */ | |
f449b936 | 500 | static int dax_load_hole(struct address_space *mapping, void **entry, |
ac401cc7 | 501 | struct vm_fault *vmf) |
f7ca90b1 | 502 | { |
ac401cc7 | 503 | struct page *page; |
f449b936 | 504 | int ret; |
f7ca90b1 | 505 | |
ac401cc7 | 506 | /* Hole page already exists? Return it... */ |
f449b936 JK |
507 | if (!radix_tree_exceptional_entry(*entry)) { |
508 | page = *entry; | |
509 | goto out; | |
ac401cc7 | 510 | } |
f7ca90b1 | 511 | |
ac401cc7 JK |
512 | /* This will replace locked radix tree entry with a hole page */ |
513 | page = find_or_create_page(mapping, vmf->pgoff, | |
514 | vmf->gfp_mask | __GFP_ZERO); | |
b1aa812b | 515 | if (!page) |
ac401cc7 | 516 | return VM_FAULT_OOM; |
f449b936 | 517 | out: |
f7ca90b1 | 518 | vmf->page = page; |
f449b936 JK |
519 | ret = finish_fault(vmf); |
520 | vmf->page = NULL; | |
521 | *entry = page; | |
522 | if (!ret) { | |
523 | /* Grab reference for PTE that is now referencing the page */ | |
524 | get_page(page); | |
525 | return VM_FAULT_NOPAGE; | |
526 | } | |
527 | return ret; | |
f7ca90b1 MW |
528 | } |
529 | ||
cccbce67 DW |
530 | static int copy_user_dax(struct block_device *bdev, struct dax_device *dax_dev, |
531 | sector_t sector, size_t size, struct page *to, | |
532 | unsigned long vaddr) | |
f7ca90b1 | 533 | { |
cccbce67 DW |
534 | void *vto, *kaddr; |
535 | pgoff_t pgoff; | |
536 | pfn_t pfn; | |
537 | long rc; | |
538 | int id; | |
539 | ||
540 | rc = bdev_dax_pgoff(bdev, sector, size, &pgoff); | |
541 | if (rc) | |
542 | return rc; | |
543 | ||
544 | id = dax_read_lock(); | |
545 | rc = dax_direct_access(dax_dev, pgoff, PHYS_PFN(size), &kaddr, &pfn); | |
546 | if (rc < 0) { | |
547 | dax_read_unlock(id); | |
548 | return rc; | |
549 | } | |
f7ca90b1 | 550 | vto = kmap_atomic(to); |
cccbce67 | 551 | copy_user_page(vto, (void __force *)kaddr, vaddr, to); |
f7ca90b1 | 552 | kunmap_atomic(vto); |
cccbce67 | 553 | dax_read_unlock(id); |
f7ca90b1 MW |
554 | return 0; |
555 | } | |
556 | ||
642261ac RZ |
557 | /* |
558 | * By this point grab_mapping_entry() has ensured that we have a locked entry | |
559 | * of the appropriate size so we don't have to worry about downgrading PMDs to | |
560 | * PTEs. If we happen to be trying to insert a PTE and there is a PMD | |
561 | * already in the tree, we will skip the insertion and just dirty the PMD as | |
562 | * appropriate. | |
563 | */ | |
ac401cc7 JK |
564 | static void *dax_insert_mapping_entry(struct address_space *mapping, |
565 | struct vm_fault *vmf, | |
642261ac RZ |
566 | void *entry, sector_t sector, |
567 | unsigned long flags) | |
9973c98e RZ |
568 | { |
569 | struct radix_tree_root *page_tree = &mapping->page_tree; | |
ac401cc7 JK |
570 | int error = 0; |
571 | bool hole_fill = false; | |
572 | void *new_entry; | |
573 | pgoff_t index = vmf->pgoff; | |
9973c98e | 574 | |
ac401cc7 | 575 | if (vmf->flags & FAULT_FLAG_WRITE) |
d2b2a28e | 576 | __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); |
9973c98e | 577 | |
ac401cc7 JK |
578 | /* Replacing hole page with block mapping? */ |
579 | if (!radix_tree_exceptional_entry(entry)) { | |
580 | hole_fill = true; | |
581 | /* | |
582 | * Unmap the page now before we remove it from page cache below. | |
583 | * The page is locked so it cannot be faulted in again. | |
584 | */ | |
585 | unmap_mapping_range(mapping, vmf->pgoff << PAGE_SHIFT, | |
586 | PAGE_SIZE, 0); | |
587 | error = radix_tree_preload(vmf->gfp_mask & ~__GFP_HIGHMEM); | |
588 | if (error) | |
589 | return ERR_PTR(error); | |
642261ac RZ |
590 | } else if (dax_is_zero_entry(entry) && !(flags & RADIX_DAX_HZP)) { |
591 | /* replacing huge zero page with PMD block mapping */ | |
592 | unmap_mapping_range(mapping, | |
593 | (vmf->pgoff << PAGE_SHIFT) & PMD_MASK, PMD_SIZE, 0); | |
9973c98e RZ |
594 | } |
595 | ||
ac401cc7 | 596 | spin_lock_irq(&mapping->tree_lock); |
642261ac RZ |
597 | new_entry = dax_radix_locked_entry(sector, flags); |
598 | ||
ac401cc7 JK |
599 | if (hole_fill) { |
600 | __delete_from_page_cache(entry, NULL); | |
601 | /* Drop pagecache reference */ | |
602 | put_page(entry); | |
642261ac RZ |
603 | error = __radix_tree_insert(page_tree, index, |
604 | dax_radix_order(new_entry), new_entry); | |
ac401cc7 JK |
605 | if (error) { |
606 | new_entry = ERR_PTR(error); | |
9973c98e RZ |
607 | goto unlock; |
608 | } | |
ac401cc7 | 609 | mapping->nrexceptional++; |
642261ac RZ |
610 | } else if (dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) { |
611 | /* | |
612 | * Only swap our new entry into the radix tree if the current | |
613 | * entry is a zero page or an empty entry. If a normal PTE or | |
614 | * PMD entry is already in the tree, we leave it alone. This | |
615 | * means that if we are trying to insert a PTE and the | |
616 | * existing entry is a PMD, we will just leave the PMD in the | |
617 | * tree and dirty it if necessary. | |
618 | */ | |
f7942430 | 619 | struct radix_tree_node *node; |
ac401cc7 JK |
620 | void **slot; |
621 | void *ret; | |
9973c98e | 622 | |
f7942430 | 623 | ret = __radix_tree_lookup(page_tree, index, &node, &slot); |
ac401cc7 | 624 | WARN_ON_ONCE(ret != entry); |
4d693d08 JW |
625 | __radix_tree_replace(page_tree, node, slot, |
626 | new_entry, NULL, NULL); | |
9973c98e | 627 | } |
ac401cc7 | 628 | if (vmf->flags & FAULT_FLAG_WRITE) |
9973c98e RZ |
629 | radix_tree_tag_set(page_tree, index, PAGECACHE_TAG_DIRTY); |
630 | unlock: | |
631 | spin_unlock_irq(&mapping->tree_lock); | |
ac401cc7 JK |
632 | if (hole_fill) { |
633 | radix_tree_preload_end(); | |
634 | /* | |
635 | * We don't need hole page anymore, it has been replaced with | |
636 | * locked radix tree entry now. | |
637 | */ | |
638 | if (mapping->a_ops->freepage) | |
639 | mapping->a_ops->freepage(entry); | |
640 | unlock_page(entry); | |
641 | put_page(entry); | |
642 | } | |
643 | return new_entry; | |
9973c98e RZ |
644 | } |
645 | ||
4b4bb46d JK |
646 | static inline unsigned long |
647 | pgoff_address(pgoff_t pgoff, struct vm_area_struct *vma) | |
648 | { | |
649 | unsigned long address; | |
650 | ||
651 | address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); | |
652 | VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma); | |
653 | return address; | |
654 | } | |
655 | ||
656 | /* Walk all mappings of a given index of a file and writeprotect them */ | |
657 | static void dax_mapping_entry_mkclean(struct address_space *mapping, | |
658 | pgoff_t index, unsigned long pfn) | |
659 | { | |
660 | struct vm_area_struct *vma; | |
f729c8c9 RZ |
661 | pte_t pte, *ptep = NULL; |
662 | pmd_t *pmdp = NULL; | |
4b4bb46d JK |
663 | spinlock_t *ptl; |
664 | bool changed; | |
665 | ||
666 | i_mmap_lock_read(mapping); | |
667 | vma_interval_tree_foreach(vma, &mapping->i_mmap, index, index) { | |
668 | unsigned long address; | |
669 | ||
670 | cond_resched(); | |
671 | ||
672 | if (!(vma->vm_flags & VM_SHARED)) | |
673 | continue; | |
674 | ||
675 | address = pgoff_address(index, vma); | |
676 | changed = false; | |
f729c8c9 | 677 | if (follow_pte_pmd(vma->vm_mm, address, &ptep, &pmdp, &ptl)) |
4b4bb46d | 678 | continue; |
4b4bb46d | 679 | |
f729c8c9 RZ |
680 | if (pmdp) { |
681 | #ifdef CONFIG_FS_DAX_PMD | |
682 | pmd_t pmd; | |
683 | ||
684 | if (pfn != pmd_pfn(*pmdp)) | |
685 | goto unlock_pmd; | |
686 | if (!pmd_dirty(*pmdp) && !pmd_write(*pmdp)) | |
687 | goto unlock_pmd; | |
688 | ||
689 | flush_cache_page(vma, address, pfn); | |
690 | pmd = pmdp_huge_clear_flush(vma, address, pmdp); | |
691 | pmd = pmd_wrprotect(pmd); | |
692 | pmd = pmd_mkclean(pmd); | |
693 | set_pmd_at(vma->vm_mm, address, pmdp, pmd); | |
694 | changed = true; | |
695 | unlock_pmd: | |
696 | spin_unlock(ptl); | |
697 | #endif | |
698 | } else { | |
699 | if (pfn != pte_pfn(*ptep)) | |
700 | goto unlock_pte; | |
701 | if (!pte_dirty(*ptep) && !pte_write(*ptep)) | |
702 | goto unlock_pte; | |
703 | ||
704 | flush_cache_page(vma, address, pfn); | |
705 | pte = ptep_clear_flush(vma, address, ptep); | |
706 | pte = pte_wrprotect(pte); | |
707 | pte = pte_mkclean(pte); | |
708 | set_pte_at(vma->vm_mm, address, ptep, pte); | |
709 | changed = true; | |
710 | unlock_pte: | |
711 | pte_unmap_unlock(ptep, ptl); | |
712 | } | |
4b4bb46d JK |
713 | |
714 | if (changed) | |
715 | mmu_notifier_invalidate_page(vma->vm_mm, address); | |
716 | } | |
717 | i_mmap_unlock_read(mapping); | |
718 | } | |
719 | ||
9973c98e | 720 | static int dax_writeback_one(struct block_device *bdev, |
cccbce67 DW |
721 | struct dax_device *dax_dev, struct address_space *mapping, |
722 | pgoff_t index, void *entry) | |
9973c98e RZ |
723 | { |
724 | struct radix_tree_root *page_tree = &mapping->page_tree; | |
cccbce67 DW |
725 | void *entry2, **slot, *kaddr; |
726 | long ret = 0, id; | |
727 | sector_t sector; | |
728 | pgoff_t pgoff; | |
729 | size_t size; | |
730 | pfn_t pfn; | |
9973c98e | 731 | |
9973c98e | 732 | /* |
a6abc2c0 JK |
733 | * A page got tagged dirty in DAX mapping? Something is seriously |
734 | * wrong. | |
9973c98e | 735 | */ |
a6abc2c0 JK |
736 | if (WARN_ON(!radix_tree_exceptional_entry(entry))) |
737 | return -EIO; | |
9973c98e | 738 | |
a6abc2c0 JK |
739 | spin_lock_irq(&mapping->tree_lock); |
740 | entry2 = get_unlocked_mapping_entry(mapping, index, &slot); | |
741 | /* Entry got punched out / reallocated? */ | |
742 | if (!entry2 || !radix_tree_exceptional_entry(entry2)) | |
743 | goto put_unlocked; | |
744 | /* | |
745 | * Entry got reallocated elsewhere? No need to writeback. We have to | |
746 | * compare sectors as we must not bail out due to difference in lockbit | |
747 | * or entry type. | |
748 | */ | |
749 | if (dax_radix_sector(entry2) != dax_radix_sector(entry)) | |
750 | goto put_unlocked; | |
642261ac RZ |
751 | if (WARN_ON_ONCE(dax_is_empty_entry(entry) || |
752 | dax_is_zero_entry(entry))) { | |
9973c98e | 753 | ret = -EIO; |
a6abc2c0 | 754 | goto put_unlocked; |
9973c98e RZ |
755 | } |
756 | ||
a6abc2c0 JK |
757 | /* Another fsync thread may have already written back this entry */ |
758 | if (!radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_TOWRITE)) | |
759 | goto put_unlocked; | |
760 | /* Lock the entry to serialize with page faults */ | |
761 | entry = lock_slot(mapping, slot); | |
762 | /* | |
763 | * We can clear the tag now but we have to be careful so that concurrent | |
764 | * dax_writeback_one() calls for the same index cannot finish before we | |
765 | * actually flush the caches. This is achieved as the calls will look | |
766 | * at the entry only under tree_lock and once they do that they will | |
767 | * see the entry locked and wait for it to unlock. | |
768 | */ | |
769 | radix_tree_tag_clear(page_tree, index, PAGECACHE_TAG_TOWRITE); | |
770 | spin_unlock_irq(&mapping->tree_lock); | |
771 | ||
642261ac RZ |
772 | /* |
773 | * Even if dax_writeback_mapping_range() was given a wbc->range_start | |
774 | * in the middle of a PMD, the 'index' we are given will be aligned to | |
775 | * the start index of the PMD, as will the sector we pull from | |
776 | * 'entry'. This allows us to flush for PMD_SIZE and not have to | |
777 | * worry about partial PMD writebacks. | |
778 | */ | |
cccbce67 DW |
779 | sector = dax_radix_sector(entry); |
780 | size = PAGE_SIZE << dax_radix_order(entry); | |
781 | ||
782 | id = dax_read_lock(); | |
783 | ret = bdev_dax_pgoff(bdev, sector, size, &pgoff); | |
784 | if (ret) | |
785 | goto dax_unlock; | |
9973c98e RZ |
786 | |
787 | /* | |
cccbce67 DW |
788 | * dax_direct_access() may sleep, so cannot hold tree_lock over |
789 | * its invocation. | |
9973c98e | 790 | */ |
cccbce67 DW |
791 | ret = dax_direct_access(dax_dev, pgoff, size / PAGE_SIZE, &kaddr, &pfn); |
792 | if (ret < 0) | |
793 | goto dax_unlock; | |
9973c98e | 794 | |
cccbce67 | 795 | if (WARN_ON_ONCE(ret < size / PAGE_SIZE)) { |
9973c98e | 796 | ret = -EIO; |
cccbce67 | 797 | goto dax_unlock; |
9973c98e RZ |
798 | } |
799 | ||
cccbce67 DW |
800 | dax_mapping_entry_mkclean(mapping, index, pfn_t_to_pfn(pfn)); |
801 | wb_cache_pmem(kaddr, size); | |
4b4bb46d JK |
802 | /* |
803 | * After we have flushed the cache, we can clear the dirty tag. There | |
804 | * cannot be new dirty data in the pfn after the flush has completed as | |
805 | * the pfn mappings are writeprotected and fault waits for mapping | |
806 | * entry lock. | |
807 | */ | |
808 | spin_lock_irq(&mapping->tree_lock); | |
809 | radix_tree_tag_clear(page_tree, index, PAGECACHE_TAG_DIRTY); | |
810 | spin_unlock_irq(&mapping->tree_lock); | |
cccbce67 DW |
811 | dax_unlock: |
812 | dax_read_unlock(id); | |
a6abc2c0 | 813 | put_locked_mapping_entry(mapping, index, entry); |
9973c98e RZ |
814 | return ret; |
815 | ||
a6abc2c0 JK |
816 | put_unlocked: |
817 | put_unlocked_mapping_entry(mapping, index, entry2); | |
9973c98e RZ |
818 | spin_unlock_irq(&mapping->tree_lock); |
819 | return ret; | |
820 | } | |
821 | ||
822 | /* | |
823 | * Flush the mapping to the persistent domain within the byte range of [start, | |
824 | * end]. This is required by data integrity operations to ensure file data is | |
825 | * on persistent storage prior to completion of the operation. | |
826 | */ | |
7f6d5b52 RZ |
827 | int dax_writeback_mapping_range(struct address_space *mapping, |
828 | struct block_device *bdev, struct writeback_control *wbc) | |
9973c98e RZ |
829 | { |
830 | struct inode *inode = mapping->host; | |
642261ac | 831 | pgoff_t start_index, end_index; |
9973c98e | 832 | pgoff_t indices[PAGEVEC_SIZE]; |
cccbce67 | 833 | struct dax_device *dax_dev; |
9973c98e RZ |
834 | struct pagevec pvec; |
835 | bool done = false; | |
836 | int i, ret = 0; | |
9973c98e RZ |
837 | |
838 | if (WARN_ON_ONCE(inode->i_blkbits != PAGE_SHIFT)) | |
839 | return -EIO; | |
840 | ||
7f6d5b52 RZ |
841 | if (!mapping->nrexceptional || wbc->sync_mode != WB_SYNC_ALL) |
842 | return 0; | |
843 | ||
cccbce67 DW |
844 | dax_dev = dax_get_by_host(bdev->bd_disk->disk_name); |
845 | if (!dax_dev) | |
846 | return -EIO; | |
847 | ||
09cbfeaf KS |
848 | start_index = wbc->range_start >> PAGE_SHIFT; |
849 | end_index = wbc->range_end >> PAGE_SHIFT; | |
9973c98e RZ |
850 | |
851 | tag_pages_for_writeback(mapping, start_index, end_index); | |
852 | ||
853 | pagevec_init(&pvec, 0); | |
854 | while (!done) { | |
855 | pvec.nr = find_get_entries_tag(mapping, start_index, | |
856 | PAGECACHE_TAG_TOWRITE, PAGEVEC_SIZE, | |
857 | pvec.pages, indices); | |
858 | ||
859 | if (pvec.nr == 0) | |
860 | break; | |
861 | ||
862 | for (i = 0; i < pvec.nr; i++) { | |
863 | if (indices[i] > end_index) { | |
864 | done = true; | |
865 | break; | |
866 | } | |
867 | ||
cccbce67 DW |
868 | ret = dax_writeback_one(bdev, dax_dev, mapping, |
869 | indices[i], pvec.pages[i]); | |
870 | if (ret < 0) { | |
871 | put_dax(dax_dev); | |
9973c98e | 872 | return ret; |
cccbce67 | 873 | } |
9973c98e RZ |
874 | } |
875 | } | |
cccbce67 | 876 | put_dax(dax_dev); |
9973c98e RZ |
877 | return 0; |
878 | } | |
879 | EXPORT_SYMBOL_GPL(dax_writeback_mapping_range); | |
880 | ||
ac401cc7 | 881 | static int dax_insert_mapping(struct address_space *mapping, |
cccbce67 DW |
882 | struct block_device *bdev, struct dax_device *dax_dev, |
883 | sector_t sector, size_t size, void **entryp, | |
884 | struct vm_area_struct *vma, struct vm_fault *vmf) | |
f7ca90b1 | 885 | { |
1a29d85e | 886 | unsigned long vaddr = vmf->address; |
ac401cc7 | 887 | void *entry = *entryp; |
cccbce67 DW |
888 | void *ret, *kaddr; |
889 | pgoff_t pgoff; | |
890 | int id, rc; | |
891 | pfn_t pfn; | |
f7ca90b1 | 892 | |
cccbce67 DW |
893 | rc = bdev_dax_pgoff(bdev, sector, size, &pgoff); |
894 | if (rc) | |
895 | return rc; | |
f7ca90b1 | 896 | |
cccbce67 DW |
897 | id = dax_read_lock(); |
898 | rc = dax_direct_access(dax_dev, pgoff, PHYS_PFN(size), &kaddr, &pfn); | |
899 | if (rc < 0) { | |
900 | dax_read_unlock(id); | |
901 | return rc; | |
902 | } | |
903 | dax_read_unlock(id); | |
904 | ||
905 | ret = dax_insert_mapping_entry(mapping, vmf, entry, sector, 0); | |
4d9a2c87 JK |
906 | if (IS_ERR(ret)) |
907 | return PTR_ERR(ret); | |
ac401cc7 | 908 | *entryp = ret; |
9973c98e | 909 | |
cccbce67 | 910 | return vm_insert_mixed(vma, vaddr, pfn); |
f7ca90b1 MW |
911 | } |
912 | ||
0e3b210c BH |
913 | /** |
914 | * dax_pfn_mkwrite - handle first write to DAX page | |
0e3b210c | 915 | * @vmf: The description of the fault |
0e3b210c | 916 | */ |
11bac800 | 917 | int dax_pfn_mkwrite(struct vm_fault *vmf) |
0e3b210c | 918 | { |
11bac800 | 919 | struct file *file = vmf->vma->vm_file; |
ac401cc7 | 920 | struct address_space *mapping = file->f_mapping; |
2f89dc12 | 921 | void *entry, **slot; |
ac401cc7 | 922 | pgoff_t index = vmf->pgoff; |
30f471fd | 923 | |
ac401cc7 | 924 | spin_lock_irq(&mapping->tree_lock); |
2f89dc12 JK |
925 | entry = get_unlocked_mapping_entry(mapping, index, &slot); |
926 | if (!entry || !radix_tree_exceptional_entry(entry)) { | |
927 | if (entry) | |
928 | put_unlocked_mapping_entry(mapping, index, entry); | |
929 | spin_unlock_irq(&mapping->tree_lock); | |
930 | return VM_FAULT_NOPAGE; | |
931 | } | |
ac401cc7 | 932 | radix_tree_tag_set(&mapping->page_tree, index, PAGECACHE_TAG_DIRTY); |
2f89dc12 | 933 | entry = lock_slot(mapping, slot); |
ac401cc7 | 934 | spin_unlock_irq(&mapping->tree_lock); |
2f89dc12 JK |
935 | /* |
936 | * If we race with somebody updating the PTE and finish_mkwrite_fault() | |
937 | * fails, we don't care. We need to return VM_FAULT_NOPAGE and retry | |
938 | * the fault in either case. | |
939 | */ | |
940 | finish_mkwrite_fault(vmf); | |
941 | put_locked_mapping_entry(mapping, index, entry); | |
0e3b210c BH |
942 | return VM_FAULT_NOPAGE; |
943 | } | |
944 | EXPORT_SYMBOL_GPL(dax_pfn_mkwrite); | |
945 | ||
4b0228fa VV |
946 | static bool dax_range_is_aligned(struct block_device *bdev, |
947 | unsigned int offset, unsigned int length) | |
948 | { | |
949 | unsigned short sector_size = bdev_logical_block_size(bdev); | |
950 | ||
951 | if (!IS_ALIGNED(offset, sector_size)) | |
952 | return false; | |
953 | if (!IS_ALIGNED(length, sector_size)) | |
954 | return false; | |
955 | ||
956 | return true; | |
957 | } | |
958 | ||
cccbce67 DW |
959 | int __dax_zero_page_range(struct block_device *bdev, |
960 | struct dax_device *dax_dev, sector_t sector, | |
961 | unsigned int offset, unsigned int size) | |
679c8bd3 | 962 | { |
cccbce67 DW |
963 | if (dax_range_is_aligned(bdev, offset, size)) { |
964 | sector_t start_sector = sector + (offset >> 9); | |
4b0228fa VV |
965 | |
966 | return blkdev_issue_zeroout(bdev, start_sector, | |
cccbce67 | 967 | size >> 9, GFP_NOFS, true); |
4b0228fa | 968 | } else { |
cccbce67 DW |
969 | pgoff_t pgoff; |
970 | long rc, id; | |
971 | void *kaddr; | |
972 | pfn_t pfn; | |
973 | ||
974 | rc = bdev_dax_pgoff(bdev, sector, size, &pgoff); | |
975 | if (rc) | |
976 | return rc; | |
977 | ||
978 | id = dax_read_lock(); | |
979 | rc = dax_direct_access(dax_dev, pgoff, PHYS_PFN(size), &kaddr, | |
980 | &pfn); | |
981 | if (rc < 0) { | |
982 | dax_read_unlock(id); | |
983 | return rc; | |
984 | } | |
985 | clear_pmem(kaddr + offset, size); | |
986 | dax_read_unlock(id); | |
4b0228fa | 987 | } |
679c8bd3 CH |
988 | return 0; |
989 | } | |
990 | EXPORT_SYMBOL_GPL(__dax_zero_page_range); | |
991 | ||
333ccc97 | 992 | static sector_t dax_iomap_sector(struct iomap *iomap, loff_t pos) |
25726bc1 | 993 | { |
333ccc97 | 994 | return iomap->blkno + (((pos & PAGE_MASK) - iomap->offset) >> 9); |
25726bc1 | 995 | } |
a254e568 | 996 | |
a254e568 | 997 | static loff_t |
11c59c92 | 998 | dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data, |
a254e568 CH |
999 | struct iomap *iomap) |
1000 | { | |
cccbce67 DW |
1001 | struct block_device *bdev = iomap->bdev; |
1002 | struct dax_device *dax_dev = iomap->dax_dev; | |
a254e568 CH |
1003 | struct iov_iter *iter = data; |
1004 | loff_t end = pos + length, done = 0; | |
1005 | ssize_t ret = 0; | |
cccbce67 | 1006 | int id; |
a254e568 CH |
1007 | |
1008 | if (iov_iter_rw(iter) == READ) { | |
1009 | end = min(end, i_size_read(inode)); | |
1010 | if (pos >= end) | |
1011 | return 0; | |
1012 | ||
1013 | if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN) | |
1014 | return iov_iter_zero(min(length, end - pos), iter); | |
1015 | } | |
1016 | ||
1017 | if (WARN_ON_ONCE(iomap->type != IOMAP_MAPPED)) | |
1018 | return -EIO; | |
1019 | ||
e3fce68c JK |
1020 | /* |
1021 | * Write can allocate block for an area which has a hole page mapped | |
1022 | * into page tables. We have to tear down these mappings so that data | |
1023 | * written by write(2) is visible in mmap. | |
1024 | */ | |
1025 | if ((iomap->flags & IOMAP_F_NEW) && inode->i_mapping->nrpages) { | |
1026 | invalidate_inode_pages2_range(inode->i_mapping, | |
1027 | pos >> PAGE_SHIFT, | |
1028 | (end - 1) >> PAGE_SHIFT); | |
1029 | } | |
1030 | ||
cccbce67 | 1031 | id = dax_read_lock(); |
a254e568 CH |
1032 | while (pos < end) { |
1033 | unsigned offset = pos & (PAGE_SIZE - 1); | |
cccbce67 DW |
1034 | const size_t size = ALIGN(length + offset, PAGE_SIZE); |
1035 | const sector_t sector = dax_iomap_sector(iomap, pos); | |
a254e568 | 1036 | ssize_t map_len; |
cccbce67 DW |
1037 | pgoff_t pgoff; |
1038 | void *kaddr; | |
1039 | pfn_t pfn; | |
a254e568 | 1040 | |
d1908f52 MH |
1041 | if (fatal_signal_pending(current)) { |
1042 | ret = -EINTR; | |
1043 | break; | |
1044 | } | |
1045 | ||
cccbce67 DW |
1046 | ret = bdev_dax_pgoff(bdev, sector, size, &pgoff); |
1047 | if (ret) | |
1048 | break; | |
1049 | ||
1050 | map_len = dax_direct_access(dax_dev, pgoff, PHYS_PFN(size), | |
1051 | &kaddr, &pfn); | |
a254e568 CH |
1052 | if (map_len < 0) { |
1053 | ret = map_len; | |
1054 | break; | |
1055 | } | |
1056 | ||
cccbce67 DW |
1057 | map_len = PFN_PHYS(map_len); |
1058 | kaddr += offset; | |
a254e568 CH |
1059 | map_len -= offset; |
1060 | if (map_len > end - pos) | |
1061 | map_len = end - pos; | |
1062 | ||
1063 | if (iov_iter_rw(iter) == WRITE) | |
cccbce67 | 1064 | map_len = copy_from_iter_pmem(kaddr, map_len, iter); |
a254e568 | 1065 | else |
cccbce67 | 1066 | map_len = copy_to_iter(kaddr, map_len, iter); |
a254e568 CH |
1067 | if (map_len <= 0) { |
1068 | ret = map_len ? map_len : -EFAULT; | |
1069 | break; | |
1070 | } | |
1071 | ||
1072 | pos += map_len; | |
1073 | length -= map_len; | |
1074 | done += map_len; | |
1075 | } | |
cccbce67 | 1076 | dax_read_unlock(id); |
a254e568 CH |
1077 | |
1078 | return done ? done : ret; | |
1079 | } | |
1080 | ||
1081 | /** | |
11c59c92 | 1082 | * dax_iomap_rw - Perform I/O to a DAX file |
a254e568 CH |
1083 | * @iocb: The control block for this I/O |
1084 | * @iter: The addresses to do I/O from or to | |
1085 | * @ops: iomap ops passed from the file system | |
1086 | * | |
1087 | * This function performs read and write operations to directly mapped | |
1088 | * persistent memory. The callers needs to take care of read/write exclusion | |
1089 | * and evicting any page cache pages in the region under I/O. | |
1090 | */ | |
1091 | ssize_t | |
11c59c92 | 1092 | dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, |
8ff6daa1 | 1093 | const struct iomap_ops *ops) |
a254e568 CH |
1094 | { |
1095 | struct address_space *mapping = iocb->ki_filp->f_mapping; | |
1096 | struct inode *inode = mapping->host; | |
1097 | loff_t pos = iocb->ki_pos, ret = 0, done = 0; | |
1098 | unsigned flags = 0; | |
1099 | ||
168316db CH |
1100 | if (iov_iter_rw(iter) == WRITE) { |
1101 | lockdep_assert_held_exclusive(&inode->i_rwsem); | |
a254e568 | 1102 | flags |= IOMAP_WRITE; |
168316db CH |
1103 | } else { |
1104 | lockdep_assert_held(&inode->i_rwsem); | |
1105 | } | |
a254e568 | 1106 | |
a254e568 CH |
1107 | while (iov_iter_count(iter)) { |
1108 | ret = iomap_apply(inode, pos, iov_iter_count(iter), flags, ops, | |
11c59c92 | 1109 | iter, dax_iomap_actor); |
a254e568 CH |
1110 | if (ret <= 0) |
1111 | break; | |
1112 | pos += ret; | |
1113 | done += ret; | |
1114 | } | |
1115 | ||
1116 | iocb->ki_pos += done; | |
1117 | return done ? done : ret; | |
1118 | } | |
11c59c92 | 1119 | EXPORT_SYMBOL_GPL(dax_iomap_rw); |
a7d73fe6 | 1120 | |
9f141d6e JK |
1121 | static int dax_fault_return(int error) |
1122 | { | |
1123 | if (error == 0) | |
1124 | return VM_FAULT_NOPAGE; | |
1125 | if (error == -ENOMEM) | |
1126 | return VM_FAULT_OOM; | |
1127 | return VM_FAULT_SIGBUS; | |
1128 | } | |
1129 | ||
a2d58167 DJ |
1130 | static int dax_iomap_pte_fault(struct vm_fault *vmf, |
1131 | const struct iomap_ops *ops) | |
a7d73fe6 | 1132 | { |
11bac800 | 1133 | struct address_space *mapping = vmf->vma->vm_file->f_mapping; |
a7d73fe6 | 1134 | struct inode *inode = mapping->host; |
1a29d85e | 1135 | unsigned long vaddr = vmf->address; |
a7d73fe6 CH |
1136 | loff_t pos = (loff_t)vmf->pgoff << PAGE_SHIFT; |
1137 | sector_t sector; | |
1138 | struct iomap iomap = { 0 }; | |
9484ab1b | 1139 | unsigned flags = IOMAP_FAULT; |
a7d73fe6 | 1140 | int error, major = 0; |
b1aa812b | 1141 | int vmf_ret = 0; |
a7d73fe6 CH |
1142 | void *entry; |
1143 | ||
1144 | /* | |
1145 | * Check whether offset isn't beyond end of file now. Caller is supposed | |
1146 | * to hold locks serializing us with truncate / punch hole so this is | |
1147 | * a reliable test. | |
1148 | */ | |
1149 | if (pos >= i_size_read(inode)) | |
1150 | return VM_FAULT_SIGBUS; | |
1151 | ||
a7d73fe6 CH |
1152 | if ((vmf->flags & FAULT_FLAG_WRITE) && !vmf->cow_page) |
1153 | flags |= IOMAP_WRITE; | |
1154 | ||
1155 | /* | |
1156 | * Note that we don't bother to use iomap_apply here: DAX required | |
1157 | * the file system block size to be equal the page size, which means | |
1158 | * that we never have to deal with more than a single extent here. | |
1159 | */ | |
1160 | error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap); | |
1161 | if (error) | |
9f141d6e | 1162 | return dax_fault_return(error); |
a7d73fe6 | 1163 | if (WARN_ON_ONCE(iomap.offset + iomap.length < pos + PAGE_SIZE)) { |
9f141d6e JK |
1164 | vmf_ret = dax_fault_return(-EIO); /* fs corruption? */ |
1165 | goto finish_iomap; | |
1166 | } | |
1167 | ||
1168 | entry = grab_mapping_entry(mapping, vmf->pgoff, 0); | |
1169 | if (IS_ERR(entry)) { | |
1170 | vmf_ret = dax_fault_return(PTR_ERR(entry)); | |
1550290b | 1171 | goto finish_iomap; |
a7d73fe6 CH |
1172 | } |
1173 | ||
333ccc97 | 1174 | sector = dax_iomap_sector(&iomap, pos); |
a7d73fe6 CH |
1175 | |
1176 | if (vmf->cow_page) { | |
1177 | switch (iomap.type) { | |
1178 | case IOMAP_HOLE: | |
1179 | case IOMAP_UNWRITTEN: | |
1180 | clear_user_highpage(vmf->cow_page, vaddr); | |
1181 | break; | |
1182 | case IOMAP_MAPPED: | |
cccbce67 DW |
1183 | error = copy_user_dax(iomap.bdev, iomap.dax_dev, |
1184 | sector, PAGE_SIZE, vmf->cow_page, vaddr); | |
a7d73fe6 CH |
1185 | break; |
1186 | default: | |
1187 | WARN_ON_ONCE(1); | |
1188 | error = -EIO; | |
1189 | break; | |
1190 | } | |
1191 | ||
1192 | if (error) | |
9f141d6e | 1193 | goto error_unlock_entry; |
b1aa812b JK |
1194 | |
1195 | __SetPageUptodate(vmf->cow_page); | |
1196 | vmf_ret = finish_fault(vmf); | |
1197 | if (!vmf_ret) | |
1198 | vmf_ret = VM_FAULT_DONE_COW; | |
9f141d6e | 1199 | goto unlock_entry; |
a7d73fe6 CH |
1200 | } |
1201 | ||
1202 | switch (iomap.type) { | |
1203 | case IOMAP_MAPPED: | |
1204 | if (iomap.flags & IOMAP_F_NEW) { | |
1205 | count_vm_event(PGMAJFAULT); | |
11bac800 | 1206 | mem_cgroup_count_vm_event(vmf->vma->vm_mm, PGMAJFAULT); |
a7d73fe6 CH |
1207 | major = VM_FAULT_MAJOR; |
1208 | } | |
cccbce67 DW |
1209 | error = dax_insert_mapping(mapping, iomap.bdev, iomap.dax_dev, |
1210 | sector, PAGE_SIZE, &entry, vmf->vma, vmf); | |
9f141d6e JK |
1211 | /* -EBUSY is fine, somebody else faulted on the same PTE */ |
1212 | if (error == -EBUSY) | |
1213 | error = 0; | |
a7d73fe6 CH |
1214 | break; |
1215 | case IOMAP_UNWRITTEN: | |
1216 | case IOMAP_HOLE: | |
1550290b | 1217 | if (!(vmf->flags & FAULT_FLAG_WRITE)) { |
f449b936 | 1218 | vmf_ret = dax_load_hole(mapping, &entry, vmf); |
9f141d6e | 1219 | goto unlock_entry; |
1550290b | 1220 | } |
a7d73fe6 CH |
1221 | /*FALLTHRU*/ |
1222 | default: | |
1223 | WARN_ON_ONCE(1); | |
1224 | error = -EIO; | |
1225 | break; | |
1226 | } | |
1227 | ||
9f141d6e JK |
1228 | error_unlock_entry: |
1229 | vmf_ret = dax_fault_return(error) | major; | |
a7d73fe6 | 1230 | unlock_entry: |
f449b936 | 1231 | put_locked_mapping_entry(mapping, vmf->pgoff, entry); |
9f141d6e JK |
1232 | finish_iomap: |
1233 | if (ops->iomap_end) { | |
1234 | int copied = PAGE_SIZE; | |
1235 | ||
1236 | if (vmf_ret & VM_FAULT_ERROR) | |
1237 | copied = 0; | |
1238 | /* | |
1239 | * The fault is done by now and there's no way back (other | |
1240 | * thread may be already happily using PTE we have installed). | |
1241 | * Just ignore error from ->iomap_end since we cannot do much | |
1242 | * with it. | |
1243 | */ | |
1244 | ops->iomap_end(inode, pos, PAGE_SIZE, copied, flags, &iomap); | |
1550290b | 1245 | } |
9f141d6e | 1246 | return vmf_ret; |
a7d73fe6 | 1247 | } |
642261ac RZ |
1248 | |
1249 | #ifdef CONFIG_FS_DAX_PMD | |
1250 | /* | |
1251 | * The 'colour' (ie low bits) within a PMD of a page offset. This comes up | |
1252 | * more often than one might expect in the below functions. | |
1253 | */ | |
1254 | #define PG_PMD_COLOUR ((PMD_SIZE >> PAGE_SHIFT) - 1) | |
1255 | ||
f4200391 DJ |
1256 | static int dax_pmd_insert_mapping(struct vm_fault *vmf, struct iomap *iomap, |
1257 | loff_t pos, void **entryp) | |
642261ac | 1258 | { |
f4200391 | 1259 | struct address_space *mapping = vmf->vma->vm_file->f_mapping; |
cccbce67 DW |
1260 | const sector_t sector = dax_iomap_sector(iomap, pos); |
1261 | struct dax_device *dax_dev = iomap->dax_dev; | |
642261ac | 1262 | struct block_device *bdev = iomap->bdev; |
27a7ffac | 1263 | struct inode *inode = mapping->host; |
cccbce67 DW |
1264 | const size_t size = PMD_SIZE; |
1265 | void *ret = NULL, *kaddr; | |
1266 | long length = 0; | |
1267 | pgoff_t pgoff; | |
1268 | pfn_t pfn; | |
1269 | int id; | |
1270 | ||
1271 | if (bdev_dax_pgoff(bdev, sector, size, &pgoff) != 0) | |
27a7ffac | 1272 | goto fallback; |
642261ac | 1273 | |
cccbce67 DW |
1274 | id = dax_read_lock(); |
1275 | length = dax_direct_access(dax_dev, pgoff, PHYS_PFN(size), &kaddr, &pfn); | |
1276 | if (length < 0) | |
1277 | goto unlock_fallback; | |
1278 | length = PFN_PHYS(length); | |
1279 | ||
1280 | if (length < size) | |
1281 | goto unlock_fallback; | |
1282 | if (pfn_t_to_pfn(pfn) & PG_PMD_COLOUR) | |
1283 | goto unlock_fallback; | |
1284 | if (!pfn_t_devmap(pfn)) | |
1285 | goto unlock_fallback; | |
1286 | dax_read_unlock(id); | |
1287 | ||
1288 | ret = dax_insert_mapping_entry(mapping, vmf, *entryp, sector, | |
642261ac RZ |
1289 | RADIX_DAX_PMD); |
1290 | if (IS_ERR(ret)) | |
27a7ffac | 1291 | goto fallback; |
642261ac RZ |
1292 | *entryp = ret; |
1293 | ||
cccbce67 | 1294 | trace_dax_pmd_insert_mapping(inode, vmf, length, pfn, ret); |
f4200391 | 1295 | return vmf_insert_pfn_pmd(vmf->vma, vmf->address, vmf->pmd, |
cccbce67 | 1296 | pfn, vmf->flags & FAULT_FLAG_WRITE); |
642261ac | 1297 | |
cccbce67 DW |
1298 | unlock_fallback: |
1299 | dax_read_unlock(id); | |
27a7ffac | 1300 | fallback: |
cccbce67 | 1301 | trace_dax_pmd_insert_mapping_fallback(inode, vmf, length, pfn, ret); |
642261ac RZ |
1302 | return VM_FAULT_FALLBACK; |
1303 | } | |
1304 | ||
f4200391 DJ |
1305 | static int dax_pmd_load_hole(struct vm_fault *vmf, struct iomap *iomap, |
1306 | void **entryp) | |
642261ac | 1307 | { |
f4200391 DJ |
1308 | struct address_space *mapping = vmf->vma->vm_file->f_mapping; |
1309 | unsigned long pmd_addr = vmf->address & PMD_MASK; | |
653b2ea3 | 1310 | struct inode *inode = mapping->host; |
642261ac | 1311 | struct page *zero_page; |
653b2ea3 | 1312 | void *ret = NULL; |
642261ac RZ |
1313 | spinlock_t *ptl; |
1314 | pmd_t pmd_entry; | |
642261ac | 1315 | |
f4200391 | 1316 | zero_page = mm_get_huge_zero_page(vmf->vma->vm_mm); |
642261ac RZ |
1317 | |
1318 | if (unlikely(!zero_page)) | |
653b2ea3 | 1319 | goto fallback; |
642261ac RZ |
1320 | |
1321 | ret = dax_insert_mapping_entry(mapping, vmf, *entryp, 0, | |
1322 | RADIX_DAX_PMD | RADIX_DAX_HZP); | |
1323 | if (IS_ERR(ret)) | |
653b2ea3 | 1324 | goto fallback; |
642261ac RZ |
1325 | *entryp = ret; |
1326 | ||
f4200391 DJ |
1327 | ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); |
1328 | if (!pmd_none(*(vmf->pmd))) { | |
642261ac | 1329 | spin_unlock(ptl); |
653b2ea3 | 1330 | goto fallback; |
642261ac RZ |
1331 | } |
1332 | ||
f4200391 | 1333 | pmd_entry = mk_pmd(zero_page, vmf->vma->vm_page_prot); |
642261ac | 1334 | pmd_entry = pmd_mkhuge(pmd_entry); |
f4200391 | 1335 | set_pmd_at(vmf->vma->vm_mm, pmd_addr, vmf->pmd, pmd_entry); |
642261ac | 1336 | spin_unlock(ptl); |
f4200391 | 1337 | trace_dax_pmd_load_hole(inode, vmf, zero_page, ret); |
642261ac | 1338 | return VM_FAULT_NOPAGE; |
653b2ea3 RZ |
1339 | |
1340 | fallback: | |
f4200391 | 1341 | trace_dax_pmd_load_hole_fallback(inode, vmf, zero_page, ret); |
653b2ea3 | 1342 | return VM_FAULT_FALLBACK; |
642261ac RZ |
1343 | } |
1344 | ||
a2d58167 DJ |
1345 | static int dax_iomap_pmd_fault(struct vm_fault *vmf, |
1346 | const struct iomap_ops *ops) | |
642261ac | 1347 | { |
f4200391 | 1348 | struct vm_area_struct *vma = vmf->vma; |
642261ac | 1349 | struct address_space *mapping = vma->vm_file->f_mapping; |
d8a849e1 DJ |
1350 | unsigned long pmd_addr = vmf->address & PMD_MASK; |
1351 | bool write = vmf->flags & FAULT_FLAG_WRITE; | |
9484ab1b | 1352 | unsigned int iomap_flags = (write ? IOMAP_WRITE : 0) | IOMAP_FAULT; |
642261ac RZ |
1353 | struct inode *inode = mapping->host; |
1354 | int result = VM_FAULT_FALLBACK; | |
1355 | struct iomap iomap = { 0 }; | |
1356 | pgoff_t max_pgoff, pgoff; | |
642261ac RZ |
1357 | void *entry; |
1358 | loff_t pos; | |
1359 | int error; | |
1360 | ||
282a8e03 RZ |
1361 | /* |
1362 | * Check whether offset isn't beyond end of file now. Caller is | |
1363 | * supposed to hold locks serializing us with truncate / punch hole so | |
1364 | * this is a reliable test. | |
1365 | */ | |
1366 | pgoff = linear_page_index(vma, pmd_addr); | |
1367 | max_pgoff = (i_size_read(inode) - 1) >> PAGE_SHIFT; | |
1368 | ||
f4200391 | 1369 | trace_dax_pmd_fault(inode, vmf, max_pgoff, 0); |
282a8e03 | 1370 | |
642261ac RZ |
1371 | /* Fall back to PTEs if we're going to COW */ |
1372 | if (write && !(vma->vm_flags & VM_SHARED)) | |
1373 | goto fallback; | |
1374 | ||
1375 | /* If the PMD would extend outside the VMA */ | |
1376 | if (pmd_addr < vma->vm_start) | |
1377 | goto fallback; | |
1378 | if ((pmd_addr + PMD_SIZE) > vma->vm_end) | |
1379 | goto fallback; | |
1380 | ||
282a8e03 RZ |
1381 | if (pgoff > max_pgoff) { |
1382 | result = VM_FAULT_SIGBUS; | |
1383 | goto out; | |
1384 | } | |
642261ac RZ |
1385 | |
1386 | /* If the PMD would extend beyond the file size */ | |
1387 | if ((pgoff | PG_PMD_COLOUR) > max_pgoff) | |
1388 | goto fallback; | |
1389 | ||
642261ac RZ |
1390 | /* |
1391 | * Note that we don't use iomap_apply here. We aren't doing I/O, only | |
1392 | * setting up a mapping, so really we're using iomap_begin() as a way | |
1393 | * to look up our filesystem block. | |
1394 | */ | |
1395 | pos = (loff_t)pgoff << PAGE_SHIFT; | |
1396 | error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap); | |
1397 | if (error) | |
9f141d6e JK |
1398 | goto fallback; |
1399 | ||
642261ac RZ |
1400 | if (iomap.offset + iomap.length < pos + PMD_SIZE) |
1401 | goto finish_iomap; | |
1402 | ||
9f141d6e JK |
1403 | /* |
1404 | * grab_mapping_entry() will make sure we get a 2M empty entry, a DAX | |
1405 | * PMD or a HZP entry. If it can't (because a 4k page is already in | |
1406 | * the tree, for instance), it will return -EEXIST and we just fall | |
1407 | * back to 4k entries. | |
1408 | */ | |
1409 | entry = grab_mapping_entry(mapping, pgoff, RADIX_DAX_PMD); | |
1410 | if (IS_ERR(entry)) | |
1411 | goto finish_iomap; | |
1412 | ||
642261ac RZ |
1413 | switch (iomap.type) { |
1414 | case IOMAP_MAPPED: | |
f4200391 | 1415 | result = dax_pmd_insert_mapping(vmf, &iomap, pos, &entry); |
642261ac RZ |
1416 | break; |
1417 | case IOMAP_UNWRITTEN: | |
1418 | case IOMAP_HOLE: | |
1419 | if (WARN_ON_ONCE(write)) | |
9f141d6e | 1420 | goto unlock_entry; |
f4200391 | 1421 | result = dax_pmd_load_hole(vmf, &iomap, &entry); |
642261ac RZ |
1422 | break; |
1423 | default: | |
1424 | WARN_ON_ONCE(1); | |
1425 | break; | |
1426 | } | |
1427 | ||
9f141d6e JK |
1428 | unlock_entry: |
1429 | put_locked_mapping_entry(mapping, pgoff, entry); | |
642261ac RZ |
1430 | finish_iomap: |
1431 | if (ops->iomap_end) { | |
9f141d6e JK |
1432 | int copied = PMD_SIZE; |
1433 | ||
1434 | if (result == VM_FAULT_FALLBACK) | |
1435 | copied = 0; | |
1436 | /* | |
1437 | * The fault is done by now and there's no way back (other | |
1438 | * thread may be already happily using PMD we have installed). | |
1439 | * Just ignore error from ->iomap_end since we cannot do much | |
1440 | * with it. | |
1441 | */ | |
1442 | ops->iomap_end(inode, pos, PMD_SIZE, copied, iomap_flags, | |
1443 | &iomap); | |
642261ac | 1444 | } |
642261ac RZ |
1445 | fallback: |
1446 | if (result == VM_FAULT_FALLBACK) { | |
d8a849e1 | 1447 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
642261ac RZ |
1448 | count_vm_event(THP_FAULT_FALLBACK); |
1449 | } | |
282a8e03 | 1450 | out: |
f4200391 | 1451 | trace_dax_pmd_fault_done(inode, vmf, max_pgoff, result); |
642261ac RZ |
1452 | return result; |
1453 | } | |
a2d58167 | 1454 | #else |
01cddfe9 AB |
1455 | static int dax_iomap_pmd_fault(struct vm_fault *vmf, |
1456 | const struct iomap_ops *ops) | |
a2d58167 DJ |
1457 | { |
1458 | return VM_FAULT_FALLBACK; | |
1459 | } | |
642261ac | 1460 | #endif /* CONFIG_FS_DAX_PMD */ |
a2d58167 DJ |
1461 | |
1462 | /** | |
1463 | * dax_iomap_fault - handle a page fault on a DAX file | |
1464 | * @vmf: The description of the fault | |
1465 | * @ops: iomap ops passed from the file system | |
1466 | * | |
1467 | * When a page fault occurs, filesystems may call this helper in | |
1468 | * their fault handler for DAX files. dax_iomap_fault() assumes the caller | |
1469 | * has done all the necessary locking for page fault to proceed | |
1470 | * successfully. | |
1471 | */ | |
c791ace1 DJ |
1472 | int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size, |
1473 | const struct iomap_ops *ops) | |
a2d58167 | 1474 | { |
c791ace1 DJ |
1475 | switch (pe_size) { |
1476 | case PE_SIZE_PTE: | |
a2d58167 | 1477 | return dax_iomap_pte_fault(vmf, ops); |
c791ace1 | 1478 | case PE_SIZE_PMD: |
a2d58167 DJ |
1479 | return dax_iomap_pmd_fault(vmf, ops); |
1480 | default: | |
1481 | return VM_FAULT_FALLBACK; | |
1482 | } | |
1483 | } | |
1484 | EXPORT_SYMBOL_GPL(dax_iomap_fault); |