Blame view
mm/mmu_notifier.c
15.8 KB
20c8ccb19 treewide: Replace... |
1 |
// SPDX-License-Identifier: GPL-2.0-only |
cddb8a5c1 mmu-notifiers: core |
2 3 4 5 6 |
/* * linux/mm/mmu_notifier.c * * Copyright (C) 2008 Qumranet, Inc. * Copyright (C) 2008 SGI |
93e205a72 fix Christoph's e... |
7 |
* Christoph Lameter <cl@linux.com> |
cddb8a5c1 mmu-notifiers: core |
8 9 10 11 |
*/ #include <linux/rculist.h> #include <linux/mmu_notifier.h> |
b95f1b31b mm: Map most file... |
12 |
#include <linux/export.h> |
cddb8a5c1 mmu-notifiers: core |
13 14 |
#include <linux/mm.h> #include <linux/err.h> |
21a92735f mm: mmu_notifier:... |
15 |
#include <linux/srcu.h> |
cddb8a5c1 mmu-notifiers: core |
16 17 |
#include <linux/rcupdate.h> #include <linux/sched.h> |
6e84f3152 sched/headers: Pr... |
18 |
#include <linux/sched/mm.h> |
5a0e3ad6a include cleanup: ... |
19 |
#include <linux/slab.h> |
cddb8a5c1 mmu-notifiers: core |
20 |
|
21a92735f mm: mmu_notifier:... |
21 |
/* global SRCU for all MMs */ |
dde8da6cf mm: Use static in... |
22 |
DEFINE_STATIC_SRCU(srcu); |
21a92735f mm: mmu_notifier:... |
23 |
|
23b68395c mm/mmu_notifiers:... |
24 25 26 27 28 |
#ifdef CONFIG_LOCKDEP struct lockdep_map __mmu_notifier_invalidate_range_start_map = { .name = "mmu_notifier_invalidate_range_start" }; #endif |
cddb8a5c1 mmu-notifiers: core |
29 30 31 32 33 34 35 |
/* * This function can't run concurrently against mmu_notifier_register * because mm->mm_users > 0 during mmu_notifier_register and exit_mmap * runs with mm_users == 0. Other tasks may still invoke mmu notifiers * in parallel despite there being no task using this mm any more, * through the vmas outside of the exit_mmap context, such as with * vmtruncate. This serializes against mmu_notifier_unregister with |
21a92735f mm: mmu_notifier:... |
36 37 |
* the mmu_notifier_mm->lock in addition to SRCU and it serializes * against the other mmu notifiers with SRCU. struct mmu_notifier_mm |
cddb8a5c1 mmu-notifiers: core |
38 39 40 41 42 43 |
* can't go away from under us as exit_mmap holds an mm_count pin * itself. */ void __mmu_notifier_release(struct mm_struct *mm) { struct mmu_notifier *mn; |
21a92735f mm: mmu_notifier:... |
44 |
int id; |
3ad3d901b mm: mmu_notifier:... |
45 46 |
/* |
d34883d4e mm: mmu_notifier:... |
47 48 |
* SRCU here will block mmu_notifier_unregister until * ->release returns. |
3ad3d901b mm: mmu_notifier:... |
49 |
*/ |
21a92735f mm: mmu_notifier:... |
50 |
id = srcu_read_lock(&srcu); |
d34883d4e mm: mmu_notifier:... |
51 52 53 54 55 56 57 58 59 |
hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist) /* * If ->release runs before mmu_notifier_unregister it must be * handled, as it's the only way for the driver to flush all * existing sptes and stop the driver from establishing any more * sptes before all the pages in the mm are freed. */ if (mn->ops->release) mn->ops->release(mn, mm); |
d34883d4e mm: mmu_notifier:... |
60 |
|
cddb8a5c1 mmu-notifiers: core |
61 62 63 64 65 66 |
spin_lock(&mm->mmu_notifier_mm->lock); while (unlikely(!hlist_empty(&mm->mmu_notifier_mm->list))) { mn = hlist_entry(mm->mmu_notifier_mm->list.first, struct mmu_notifier, hlist); /* |
d34883d4e mm: mmu_notifier:... |
67 68 69 70 |
* We arrived before mmu_notifier_unregister so * mmu_notifier_unregister will do nothing other than to wait * for ->release to finish and for mmu_notifier_unregister to * return. |
cddb8a5c1 mmu-notifiers: core |
71 72 |
*/ hlist_del_init_rcu(&mn->hlist); |
cddb8a5c1 mmu-notifiers: core |
73 74 |
} spin_unlock(&mm->mmu_notifier_mm->lock); |
b972216e2 mmu_notifier: add... |
75 |
srcu_read_unlock(&srcu, id); |
cddb8a5c1 mmu-notifiers: core |
76 77 |
/* |
d34883d4e mm: mmu_notifier:... |
78 79 80 81 82 83 84 |
* synchronize_srcu here prevents mmu_notifier_release from returning to * exit_mmap (which would proceed with freeing all pages in the mm) * until the ->release method returns, if it was invoked by * mmu_notifier_unregister. * * The mmu_notifier_mm can't go away from under us because one mm_count * is held by exit_mmap. |
cddb8a5c1 mmu-notifiers: core |
85 |
*/ |
21a92735f mm: mmu_notifier:... |
86 |
synchronize_srcu(&srcu); |
cddb8a5c1 mmu-notifiers: core |
87 88 89 90 91 92 93 94 |
} /* * If no young bitflag is supported by the hardware, ->clear_flush_young can * unmap the address and return 1 or 0 depending if the mapping previously * existed or not. */ int __mmu_notifier_clear_flush_young(struct mm_struct *mm, |
571284680 kvm: Fix page age... |
95 96 |
unsigned long start, unsigned long end) |
cddb8a5c1 mmu-notifiers: core |
97 98 |
{ struct mmu_notifier *mn; |
21a92735f mm: mmu_notifier:... |
99 |
int young = 0, id; |
cddb8a5c1 mmu-notifiers: core |
100 |
|
21a92735f mm: mmu_notifier:... |
101 |
id = srcu_read_lock(&srcu); |
b67bfe0d4 hlist: drop the n... |
102 |
hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist) { |
cddb8a5c1 mmu-notifiers: core |
103 |
if (mn->ops->clear_flush_young) |
571284680 kvm: Fix page age... |
104 |
young |= mn->ops->clear_flush_young(mn, mm, start, end); |
cddb8a5c1 mmu-notifiers: core |
105 |
} |
21a92735f mm: mmu_notifier:... |
106 |
srcu_read_unlock(&srcu, id); |
cddb8a5c1 mmu-notifiers: core |
107 108 109 |
return young; } |
1d7715c67 mmu-notifier: add... |
110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 |
int __mmu_notifier_clear_young(struct mm_struct *mm, unsigned long start, unsigned long end) { struct mmu_notifier *mn; int young = 0, id; id = srcu_read_lock(&srcu); hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist) { if (mn->ops->clear_young) young |= mn->ops->clear_young(mn, mm, start, end); } srcu_read_unlock(&srcu, id); return young; } |
8ee53820e thp: mmu_notifier... |
126 127 128 129 |
int __mmu_notifier_test_young(struct mm_struct *mm, unsigned long address) { struct mmu_notifier *mn; |
21a92735f mm: mmu_notifier:... |
130 |
int young = 0, id; |
8ee53820e thp: mmu_notifier... |
131 |
|
21a92735f mm: mmu_notifier:... |
132 |
id = srcu_read_lock(&srcu); |
b67bfe0d4 hlist: drop the n... |
133 |
hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist) { |
8ee53820e thp: mmu_notifier... |
134 135 136 137 138 139 |
if (mn->ops->test_young) { young = mn->ops->test_young(mn, mm, address); if (young) break; } } |
21a92735f mm: mmu_notifier:... |
140 |
srcu_read_unlock(&srcu, id); |
8ee53820e thp: mmu_notifier... |
141 142 143 |
return young; } |
828502d30 ksm: add mmu_noti... |
144 145 146 147 |
void __mmu_notifier_change_pte(struct mm_struct *mm, unsigned long address, pte_t pte) { struct mmu_notifier *mn; |
21a92735f mm: mmu_notifier:... |
148 |
int id; |
828502d30 ksm: add mmu_noti... |
149 |
|
21a92735f mm: mmu_notifier:... |
150 |
id = srcu_read_lock(&srcu); |
b67bfe0d4 hlist: drop the n... |
151 |
hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist) { |
828502d30 ksm: add mmu_noti... |
152 153 |
if (mn->ops->change_pte) mn->ops->change_pte(mn, mm, address, pte); |
828502d30 ksm: add mmu_noti... |
154 |
} |
21a92735f mm: mmu_notifier:... |
155 |
srcu_read_unlock(&srcu, id); |
828502d30 ksm: add mmu_noti... |
156 |
} |
ac46d4f3c mm/mmu_notifier: ... |
157 |
int __mmu_notifier_invalidate_range_start(struct mmu_notifier_range *range) |
cddb8a5c1 mmu-notifiers: core |
158 159 |
{ struct mmu_notifier *mn; |
93065ac75 mm, oom: distingu... |
160 |
int ret = 0; |
21a92735f mm: mmu_notifier:... |
161 |
int id; |
cddb8a5c1 mmu-notifiers: core |
162 |
|
21a92735f mm: mmu_notifier:... |
163 |
id = srcu_read_lock(&srcu); |
ac46d4f3c mm/mmu_notifier: ... |
164 |
hlist_for_each_entry_rcu(mn, &range->mm->mmu_notifier_mm->list, hlist) { |
93065ac75 mm, oom: distingu... |
165 |
if (mn->ops->invalidate_range_start) { |
ba170f76b mm, notifier: Cat... |
166 167 168 169 170 171 172 |
int _ret; if (!mmu_notifier_range_blockable(range)) non_block_start(); _ret = mn->ops->invalidate_range_start(mn, range); if (!mmu_notifier_range_blockable(range)) non_block_end(); |
93065ac75 mm, oom: distingu... |
173 174 175 |
if (_ret) { pr_info("%pS callback failed with %d in %sblockable context. ", |
ac46d4f3c mm/mmu_notifier: ... |
176 |
mn->ops->invalidate_range_start, _ret, |
dfcd66604 mm/mmu_notifier: ... |
177 |
!mmu_notifier_range_blockable(range) ? "non-" : ""); |
8402ce61b mm/mmu_notifiers:... |
178 |
WARN_ON(mmu_notifier_range_blockable(range) || |
df2ec7641 mm/mmu_notifiers:... |
179 |
_ret != -EAGAIN); |
93065ac75 mm, oom: distingu... |
180 181 182 |
ret = _ret; } } |
cddb8a5c1 mmu-notifiers: core |
183 |
} |
21a92735f mm: mmu_notifier:... |
184 |
srcu_read_unlock(&srcu, id); |
93065ac75 mm, oom: distingu... |
185 186 |
return ret; |
cddb8a5c1 mmu-notifiers: core |
187 |
} |
ac46d4f3c mm/mmu_notifier: ... |
188 |
void __mmu_notifier_invalidate_range_end(struct mmu_notifier_range *range, |
4645b9fe8 mm/mmu_notifier: ... |
189 |
bool only_end) |
cddb8a5c1 mmu-notifiers: core |
190 191 |
{ struct mmu_notifier *mn; |
21a92735f mm: mmu_notifier:... |
192 |
int id; |
cddb8a5c1 mmu-notifiers: core |
193 |
|
23b68395c mm/mmu_notifiers:... |
194 |
lock_map_acquire(&__mmu_notifier_invalidate_range_start_map); |
21a92735f mm: mmu_notifier:... |
195 |
id = srcu_read_lock(&srcu); |
ac46d4f3c mm/mmu_notifier: ... |
196 |
hlist_for_each_entry_rcu(mn, &range->mm->mmu_notifier_mm->list, hlist) { |
0f0a327fa mmu_notifier: add... |
197 198 199 200 201 202 203 |
/* * Call invalidate_range here too to avoid the need for the * subsystem of having to register an invalidate_range_end * call-back when there is invalidate_range already. Usually a * subsystem registers either invalidate_range_start()/end() or * invalidate_range(), so this will be no additional overhead * (besides the pointer check). |
4645b9fe8 mm/mmu_notifier: ... |
204 205 206 207 208 |
* * We skip call to invalidate_range() if we know it is safe ie * call site use mmu_notifier_invalidate_range_only_end() which * is safe to do when we know that a call to invalidate_range() * already happen under page table lock. |
0f0a327fa mmu_notifier: add... |
209 |
*/ |
4645b9fe8 mm/mmu_notifier: ... |
210 |
if (!only_end && mn->ops->invalidate_range) |
ac46d4f3c mm/mmu_notifier: ... |
211 212 213 |
mn->ops->invalidate_range(mn, range->mm, range->start, range->end); |
ba170f76b mm, notifier: Cat... |
214 215 216 |
if (mn->ops->invalidate_range_end) { if (!mmu_notifier_range_blockable(range)) non_block_start(); |
5d6527a78 mm/mmu_notifier: ... |
217 |
mn->ops->invalidate_range_end(mn, range); |
ba170f76b mm, notifier: Cat... |
218 219 220 |
if (!mmu_notifier_range_blockable(range)) non_block_end(); } |
cddb8a5c1 mmu-notifiers: core |
221 |
} |
21a92735f mm: mmu_notifier:... |
222 |
srcu_read_unlock(&srcu, id); |
23b68395c mm/mmu_notifiers:... |
223 |
lock_map_release(&__mmu_notifier_invalidate_range_start_map); |
cddb8a5c1 mmu-notifiers: core |
224 |
} |
0f0a327fa mmu_notifier: add... |
225 226 227 228 229 230 231 232 233 234 235 236 237 |
void __mmu_notifier_invalidate_range(struct mm_struct *mm, unsigned long start, unsigned long end) { struct mmu_notifier *mn; int id; id = srcu_read_lock(&srcu); hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist) { if (mn->ops->invalidate_range) mn->ops->invalidate_range(mn, mm, start, end); } srcu_read_unlock(&srcu, id); } |
0f0a327fa mmu_notifier: add... |
238 |
|
56c57103d mm/mmu_notifiers:... |
239 240 241 242 243 |
/* * Same as mmu_notifier_register but here the caller must hold the * mmap_sem in write mode. */ int __mmu_notifier_register(struct mmu_notifier *mn, struct mm_struct *mm) |
cddb8a5c1 mmu-notifiers: core |
244 |
{ |
70df291bf mm/mmu_notifiers:... |
245 |
struct mmu_notifier_mm *mmu_notifier_mm = NULL; |
cddb8a5c1 mmu-notifiers: core |
246 |
int ret; |
56c57103d mm/mmu_notifiers:... |
247 |
lockdep_assert_held_write(&mm->mmap_sem); |
cddb8a5c1 mmu-notifiers: core |
248 |
BUG_ON(atomic_read(&mm->mm_users) <= 0); |
66204f1d2 mm/mmu_notifiers:... |
249 250 251 252 253 254 |
if (IS_ENABLED(CONFIG_LOCKDEP)) { fs_reclaim_acquire(GFP_KERNEL); lock_map_acquire(&__mmu_notifier_invalidate_range_start_map); lock_map_release(&__mmu_notifier_invalidate_range_start_map); fs_reclaim_release(GFP_KERNEL); } |
2c7933f53 mm/mmu_notifiers:... |
255 256 |
mn->mm = mm; mn->users = 1; |
70df291bf mm/mmu_notifiers:... |
257 258 259 260 261 262 263 264 265 266 267 268 269 270 |
if (!mm->mmu_notifier_mm) { /* * kmalloc cannot be called under mm_take_all_locks(), but we * know that mm->mmu_notifier_mm can't change while we hold * the write side of the mmap_sem. */ mmu_notifier_mm = kmalloc(sizeof(struct mmu_notifier_mm), GFP_KERNEL); if (!mmu_notifier_mm) return -ENOMEM; INIT_HLIST_HEAD(&mmu_notifier_mm->list); spin_lock_init(&mmu_notifier_mm->lock); } |
35cfa2b0b mm/mmu_notifier: ... |
271 |
|
cddb8a5c1 mmu-notifiers: core |
272 273 |
ret = mm_take_all_locks(mm); if (unlikely(ret)) |
35cfa2b0b mm/mmu_notifier: ... |
274 |
goto out_clean; |
cddb8a5c1 mmu-notifiers: core |
275 |
|
70df291bf mm/mmu_notifiers:... |
276 |
/* Pairs with the mmdrop in mmu_notifier_unregister_* */ |
f1f100764 mm: add new mmgra... |
277 |
mmgrab(mm); |
cddb8a5c1 mmu-notifiers: core |
278 279 280 281 282 283 284 285 286 |
/* * Serialize the update against mmu_notifier_unregister. A * side note: mmu_notifier_release can't run concurrently with * us because we hold the mm_users pin (either implicitly as * current->mm or explicitly with get_task_mm() or similar). * We can't race against any other mmu notifier method either * thanks to mm_take_all_locks(). */ |
70df291bf mm/mmu_notifiers:... |
287 288 |
if (mmu_notifier_mm) mm->mmu_notifier_mm = mmu_notifier_mm; |
cddb8a5c1 mmu-notifiers: core |
289 |
spin_lock(&mm->mmu_notifier_mm->lock); |
543bdb2d8 mm/mmu_notifier: ... |
290 |
hlist_add_head_rcu(&mn->hlist, &mm->mmu_notifier_mm->list); |
cddb8a5c1 mmu-notifiers: core |
291 292 293 |
spin_unlock(&mm->mmu_notifier_mm->lock); mm_drop_all_locks(mm); |
70df291bf mm/mmu_notifiers:... |
294 295 |
BUG_ON(atomic_read(&mm->mm_users) <= 0); return 0; |
35cfa2b0b mm/mmu_notifier: ... |
296 |
out_clean: |
35cfa2b0b mm/mmu_notifier: ... |
297 |
kfree(mmu_notifier_mm); |
cddb8a5c1 mmu-notifiers: core |
298 299 |
return ret; } |
56c57103d mm/mmu_notifiers:... |
300 |
EXPORT_SYMBOL_GPL(__mmu_notifier_register); |
cddb8a5c1 mmu-notifiers: core |
301 |
|
2c7933f53 mm/mmu_notifiers:... |
302 303 304 305 306 |
/** * mmu_notifier_register - Register a notifier on a mm * @mn: The notifier to attach * @mm: The mm to attach the notifier to * |
cddb8a5c1 mmu-notifiers: core |
307 308 309 310 311 312 |
* Must not hold mmap_sem nor any other VM related lock when calling * this registration function. Must also ensure mm_users can't go down * to zero while this runs to avoid races with mmu_notifier_release, * so mm has to be current->mm or the mm should be pinned safely such * as with get_task_mm(). If the mm is not current->mm, the mm_users * pin should be released by calling mmput after mmu_notifier_register |
2c7933f53 mm/mmu_notifiers:... |
313 314 315 316 317 318 319 |
* returns. * * mmu_notifier_unregister() or mmu_notifier_put() must be always called to * unregister the notifier. * * While the caller has a mmu_notifier get the mn->mm pointer will remain * valid, and can be converted to an active mm pointer via mmget_not_zero(). |
cddb8a5c1 mmu-notifiers: core |
320 321 322 |
*/ int mmu_notifier_register(struct mmu_notifier *mn, struct mm_struct *mm) { |
56c57103d mm/mmu_notifiers:... |
323 |
int ret; |
cddb8a5c1 mmu-notifiers: core |
324 |
|
56c57103d mm/mmu_notifiers:... |
325 326 327 328 |
down_write(&mm->mmap_sem); ret = __mmu_notifier_register(mn, mm); up_write(&mm->mmap_sem); return ret; |
cddb8a5c1 mmu-notifiers: core |
329 |
} |
56c57103d mm/mmu_notifiers:... |
330 |
EXPORT_SYMBOL_GPL(mmu_notifier_register); |
cddb8a5c1 mmu-notifiers: core |
331 |
|
2c7933f53 mm/mmu_notifiers:... |
332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 |
static struct mmu_notifier * find_get_mmu_notifier(struct mm_struct *mm, const struct mmu_notifier_ops *ops) { struct mmu_notifier *mn; spin_lock(&mm->mmu_notifier_mm->lock); hlist_for_each_entry_rcu (mn, &mm->mmu_notifier_mm->list, hlist) { if (mn->ops != ops) continue; if (likely(mn->users != UINT_MAX)) mn->users++; else mn = ERR_PTR(-EOVERFLOW); spin_unlock(&mm->mmu_notifier_mm->lock); return mn; } spin_unlock(&mm->mmu_notifier_mm->lock); return NULL; } /** * mmu_notifier_get_locked - Return the single struct mmu_notifier for * the mm & ops * @ops: The operations struct being subscribe with * @mm : The mm to attach notifiers too * * This function either allocates a new mmu_notifier via * ops->alloc_notifier(), or returns an already existing notifier on the * list. The value of the ops pointer is used to determine when two notifiers * are the same. * * Each call to mmu_notifier_get() must be paired with a call to * mmu_notifier_put(). The caller must hold the write side of mm->mmap_sem. * * While the caller has a mmu_notifier get the mm pointer will remain valid, * and can be converted to an active mm pointer via mmget_not_zero(). */ struct mmu_notifier *mmu_notifier_get_locked(const struct mmu_notifier_ops *ops, struct mm_struct *mm) { struct mmu_notifier *mn; int ret; lockdep_assert_held_write(&mm->mmap_sem); if (mm->mmu_notifier_mm) { mn = find_get_mmu_notifier(mm, ops); if (mn) return mn; } mn = ops->alloc_notifier(mm); if (IS_ERR(mn)) return mn; mn->ops = ops; ret = __mmu_notifier_register(mn, mm); if (ret) goto out_free; return mn; out_free: mn->ops->free_notifier(mn); return ERR_PTR(ret); } EXPORT_SYMBOL_GPL(mmu_notifier_get_locked); |
cddb8a5c1 mmu-notifiers: core |
397 398 399 400 401 402 403 404 405 406 407 |
/* this is called after the last mmu_notifier_unregister() returned */ void __mmu_notifier_mm_destroy(struct mm_struct *mm) { BUG_ON(!hlist_empty(&mm->mmu_notifier_mm->list)); kfree(mm->mmu_notifier_mm); mm->mmu_notifier_mm = LIST_POISON1; /* debug */ } /* * This releases the mm_count pin automatically and frees the mm * structure if it was the last user of it. It serializes against |
21a92735f mm: mmu_notifier:... |
408 409 |
* running mmu notifiers with SRCU and against mmu_notifier_unregister * with the unregister lock + SRCU. All sptes must be dropped before |
cddb8a5c1 mmu-notifiers: core |
410 411 412 413 414 415 416 417 |
* calling mmu_notifier_unregister. ->release or any other notifier * method may be invoked concurrently with mmu_notifier_unregister, * and only after mmu_notifier_unregister returned we're guaranteed * that ->release or any other method can't run anymore. */ void mmu_notifier_unregister(struct mmu_notifier *mn, struct mm_struct *mm) { BUG_ON(atomic_read(&mm->mm_count) <= 0); |
cddb8a5c1 mmu-notifiers: core |
418 |
if (!hlist_unhashed(&mn->hlist)) { |
d34883d4e mm: mmu_notifier:... |
419 420 421 422 |
/* * SRCU here will force exit_mmap to wait for ->release to * finish before freeing the pages. */ |
21a92735f mm: mmu_notifier:... |
423 |
int id; |
3ad3d901b mm: mmu_notifier:... |
424 |
|
d34883d4e mm: mmu_notifier:... |
425 |
id = srcu_read_lock(&srcu); |
cddb8a5c1 mmu-notifiers: core |
426 |
/* |
d34883d4e mm: mmu_notifier:... |
427 428 |
* exit_mmap will block in mmu_notifier_release to guarantee * that ->release is called before freeing the pages. |
cddb8a5c1 mmu-notifiers: core |
429 430 431 |
*/ if (mn->ops->release) mn->ops->release(mn, mm); |
d34883d4e mm: mmu_notifier:... |
432 |
srcu_read_unlock(&srcu, id); |
3ad3d901b mm: mmu_notifier:... |
433 |
|
d34883d4e mm: mmu_notifier:... |
434 |
spin_lock(&mm->mmu_notifier_mm->lock); |
751efd861 mmu_notifier_unre... |
435 |
/* |
d34883d4e mm: mmu_notifier:... |
436 437 |
* Can not use list_del_rcu() since __mmu_notifier_release * can delete it before we hold the lock. |
751efd861 mmu_notifier_unre... |
438 |
*/ |
d34883d4e mm: mmu_notifier:... |
439 |
hlist_del_init_rcu(&mn->hlist); |
cddb8a5c1 mmu-notifiers: core |
440 |
spin_unlock(&mm->mmu_notifier_mm->lock); |
d34883d4e mm: mmu_notifier:... |
441 |
} |
cddb8a5c1 mmu-notifiers: core |
442 443 |
/* |
d34883d4e mm: mmu_notifier:... |
444 |
* Wait for any running method to finish, of course including |
83a35e360 treewide: relase ... |
445 |
* ->release if it was run by mmu_notifier_release instead of us. |
cddb8a5c1 mmu-notifiers: core |
446 |
*/ |
21a92735f mm: mmu_notifier:... |
447 |
synchronize_srcu(&srcu); |
cddb8a5c1 mmu-notifiers: core |
448 449 450 451 452 453 |
BUG_ON(atomic_read(&mm->mm_count) <= 0); mmdrop(mm); } EXPORT_SYMBOL_GPL(mmu_notifier_unregister); |
21a92735f mm: mmu_notifier:... |
454 |
|
2c7933f53 mm/mmu_notifiers:... |
455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 |
static void mmu_notifier_free_rcu(struct rcu_head *rcu) { struct mmu_notifier *mn = container_of(rcu, struct mmu_notifier, rcu); struct mm_struct *mm = mn->mm; mn->ops->free_notifier(mn); /* Pairs with the get in __mmu_notifier_register() */ mmdrop(mm); } /** * mmu_notifier_put - Release the reference on the notifier * @mn: The notifier to act on * * This function must be paired with each mmu_notifier_get(), it releases the * reference obtained by the get. If this is the last reference then process * to free the notifier will be run asynchronously. * * Unlike mmu_notifier_unregister() the get/put flow only calls ops->release * when the mm_struct is destroyed. Instead free_notifier is always called to * release any resources held by the user. * * As ops->release is not guaranteed to be called, the user must ensure that * all sptes are dropped, and no new sptes can be established before * mmu_notifier_put() is called. * * This function can be called from the ops->release callback, however the * caller must still ensure it is called pairwise with mmu_notifier_get(). * * Modules calling this function must call mmu_notifier_synchronize() in * their __exit functions to ensure the async work is completed. */ void mmu_notifier_put(struct mmu_notifier *mn) { struct mm_struct *mm = mn->mm; spin_lock(&mm->mmu_notifier_mm->lock); if (WARN_ON(!mn->users) || --mn->users) goto out_unlock; hlist_del_init_rcu(&mn->hlist); spin_unlock(&mm->mmu_notifier_mm->lock); call_srcu(&srcu, &mn->rcu, mmu_notifier_free_rcu); return; out_unlock: spin_unlock(&mm->mmu_notifier_mm->lock); } EXPORT_SYMBOL_GPL(mmu_notifier_put); /** * mmu_notifier_synchronize - Ensure all mmu_notifiers are freed * * This function ensures that all outstanding async SRU work from * mmu_notifier_put() is completed. After it returns any mmu_notifier_ops * associated with an unused mmu_notifier will no longer be called. * * Before using the caller must ensure that all of its mmu_notifiers have been * fully released via mmu_notifier_put(). * * Modules using the mmu_notifier_put() API should call this in their __exit * function to avoid module unloading races. */ void mmu_notifier_synchronize(void) { synchronize_srcu(&srcu); } EXPORT_SYMBOL_GPL(mmu_notifier_synchronize); |
c6d23413f mm/mmu_notifier: ... |
523 524 525 526 527 528 529 530 531 |
bool mmu_notifier_range_update_to_read_only(const struct mmu_notifier_range *range) { if (!range->vma || range->event != MMU_NOTIFY_PROTECTION_VMA) return false; /* Return true if the vma still have the read flag set. */ return range->vma->vm_flags & VM_READ; } EXPORT_SYMBOL_GPL(mmu_notifier_range_update_to_read_only); |