1 /*
2 * Copyright (c) 2014 Mellanox Technologies. All rights reserved.
3 *
4 * This software is available to you under a choice of one of two
5 * licenses. You may choose to be licensed under the terms of the GNU
6 * General Public License (GPL) Version 2, available from the file
7 * COPYING in the main directory of this source tree, or the
8 * OpenIB.org BSD license below:
9 *
10 * Redistribution and use in source and binary forms, with or
11 * without modification, are permitted provided that the following
12 * conditions are met:
13 *
14 * - Redistributions of source code must retain the above
15 * copyright notice, this list of conditions and the following
16 * disclaimer.
17 *
18 * - Redistributions in binary form must reproduce the above
19 * copyright notice, this list of conditions and the following
20 * disclaimer in the documentation and/or other materials
21 * provided with the distribution.
22 *
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30 * SOFTWARE.
31 */
32
33 #include <linux/types.h>
34 #include <linux/sched.h>
35 #include <linux/sched/mm.h>
36 #include <linux/sched/task.h>
37 #include <linux/pid.h>
38 #include <linux/slab.h>
39 #include <linux/export.h>
40 #include <linux/vmalloc.h>
41 #include <linux/hugetlb.h>
42 #include <linux/interval_tree_generic.h>
43
44 #include <rdma/ib_verbs.h>
45 #include <rdma/ib_umem.h>
46 #include <rdma/ib_umem_odp.h>
47
48 /*
49 * The ib_umem list keeps track of memory regions for which the HW
50 * device request to receive notification when the related memory
51 * mapping is changed.
52 *
53 * ib_umem_lock protects the list.
54 */
55
node_start(struct umem_odp_node * n)56 static u64 node_start(struct umem_odp_node *n)
57 {
58 struct ib_umem_odp *umem_odp =
59 container_of(n, struct ib_umem_odp, interval_tree);
60
61 return ib_umem_start(umem_odp->umem);
62 }
63
64 /* Note that the representation of the intervals in the interval tree
65 * considers the ending point as contained in the interval, while the
66 * function ib_umem_end returns the first address which is not contained
67 * in the umem.
68 */
node_last(struct umem_odp_node * n)69 static u64 node_last(struct umem_odp_node *n)
70 {
71 struct ib_umem_odp *umem_odp =
72 container_of(n, struct ib_umem_odp, interval_tree);
73
74 return ib_umem_end(umem_odp->umem) - 1;
75 }
76
INTERVAL_TREE_DEFINE(struct umem_odp_node,rb,u64,__subtree_last,node_start,node_last,static,rbt_ib_umem)77 INTERVAL_TREE_DEFINE(struct umem_odp_node, rb, u64, __subtree_last,
78 node_start, node_last, static, rbt_ib_umem)
79
80 static void ib_umem_notifier_start_account(struct ib_umem *item)
81 {
82 mutex_lock(&item->odp_data->umem_mutex);
83
84 /* Only update private counters for this umem if it has them.
85 * Otherwise skip it. All page faults will be delayed for this umem. */
86 if (item->odp_data->mn_counters_active) {
87 int notifiers_count = item->odp_data->notifiers_count++;
88
89 if (notifiers_count == 0)
90 /* Initialize the completion object for waiting on
91 * notifiers. Since notifier_count is zero, no one
92 * should be waiting right now. */
93 reinit_completion(&item->odp_data->notifier_completion);
94 }
95 mutex_unlock(&item->odp_data->umem_mutex);
96 }
97
ib_umem_notifier_end_account(struct ib_umem * item)98 static void ib_umem_notifier_end_account(struct ib_umem *item)
99 {
100 mutex_lock(&item->odp_data->umem_mutex);
101
102 /* Only update private counters for this umem if it has them.
103 * Otherwise skip it. All page faults will be delayed for this umem. */
104 if (item->odp_data->mn_counters_active) {
105 /*
106 * This sequence increase will notify the QP page fault that
107 * the page that is going to be mapped in the spte could have
108 * been freed.
109 */
110 ++item->odp_data->notifiers_seq;
111 if (--item->odp_data->notifiers_count == 0)
112 complete_all(&item->odp_data->notifier_completion);
113 }
114 mutex_unlock(&item->odp_data->umem_mutex);
115 }
116
117 /* Account for a new mmu notifier in an ib_ucontext. */
ib_ucontext_notifier_start_account(struct ib_ucontext * context)118 static void ib_ucontext_notifier_start_account(struct ib_ucontext *context)
119 {
120 atomic_inc(&context->notifier_count);
121 }
122
123 /* Account for a terminating mmu notifier in an ib_ucontext.
124 *
125 * Must be called with the ib_ucontext->umem_rwsem semaphore unlocked, since
126 * the function takes the semaphore itself. */
ib_ucontext_notifier_end_account(struct ib_ucontext * context)127 static void ib_ucontext_notifier_end_account(struct ib_ucontext *context)
128 {
129 int zero_notifiers = atomic_dec_and_test(&context->notifier_count);
130
131 if (zero_notifiers &&
132 !list_empty(&context->no_private_counters)) {
133 /* No currently running mmu notifiers. Now is the chance to
134 * add private accounting to all previously added umems. */
135 struct ib_umem_odp *odp_data, *next;
136
137 /* Prevent concurrent mmu notifiers from working on the
138 * no_private_counters list. */
139 down_write(&context->umem_rwsem);
140
141 /* Read the notifier_count again, with the umem_rwsem
142 * semaphore taken for write. */
143 if (!atomic_read(&context->notifier_count)) {
144 list_for_each_entry_safe(odp_data, next,
145 &context->no_private_counters,
146 no_private_counters) {
147 mutex_lock(&odp_data->umem_mutex);
148 odp_data->mn_counters_active = true;
149 list_del(&odp_data->no_private_counters);
150 complete_all(&odp_data->notifier_completion);
151 mutex_unlock(&odp_data->umem_mutex);
152 }
153 }
154
155 up_write(&context->umem_rwsem);
156 }
157 }
158
ib_umem_notifier_release_trampoline(struct ib_umem * item,u64 start,u64 end,void * cookie)159 static int ib_umem_notifier_release_trampoline(struct ib_umem *item, u64 start,
160 u64 end, void *cookie) {
161 /*
162 * Increase the number of notifiers running, to
163 * prevent any further fault handling on this MR.
164 */
165 ib_umem_notifier_start_account(item);
166 item->odp_data->dying = 1;
167 /* Make sure that the fact the umem is dying is out before we release
168 * all pending page faults. */
169 smp_wmb();
170 complete_all(&item->odp_data->notifier_completion);
171 item->context->invalidate_range(item, ib_umem_start(item),
172 ib_umem_end(item));
173 return 0;
174 }
175
ib_umem_notifier_release(struct mmu_notifier * mn,struct mm_struct * mm)176 static void ib_umem_notifier_release(struct mmu_notifier *mn,
177 struct mm_struct *mm)
178 {
179 struct ib_ucontext *context = container_of(mn, struct ib_ucontext, mn);
180
181 if (!context->invalidate_range)
182 return;
183
184 ib_ucontext_notifier_start_account(context);
185 down_read(&context->umem_rwsem);
186 rbt_ib_umem_for_each_in_range(&context->umem_tree, 0,
187 ULLONG_MAX,
188 ib_umem_notifier_release_trampoline,
189 true,
190 NULL);
191 up_read(&context->umem_rwsem);
192 }
193
invalidate_page_trampoline(struct ib_umem * item,u64 start,u64 end,void * cookie)194 static int invalidate_page_trampoline(struct ib_umem *item, u64 start,
195 u64 end, void *cookie)
196 {
197 ib_umem_notifier_start_account(item);
198 item->context->invalidate_range(item, start, start + PAGE_SIZE);
199 ib_umem_notifier_end_account(item);
200 return 0;
201 }
202
invalidate_range_start_trampoline(struct ib_umem * item,u64 start,u64 end,void * cookie)203 static int invalidate_range_start_trampoline(struct ib_umem *item, u64 start,
204 u64 end, void *cookie)
205 {
206 ib_umem_notifier_start_account(item);
207 item->context->invalidate_range(item, start, end);
208 return 0;
209 }
210
ib_umem_notifier_invalidate_range_start(struct mmu_notifier * mn,struct mm_struct * mm,unsigned long start,unsigned long end,bool blockable)211 static int ib_umem_notifier_invalidate_range_start(struct mmu_notifier *mn,
212 struct mm_struct *mm,
213 unsigned long start,
214 unsigned long end,
215 bool blockable)
216 {
217 struct ib_ucontext *context = container_of(mn, struct ib_ucontext, mn);
218 int ret;
219
220 if (!context->invalidate_range)
221 return 0;
222
223 if (blockable)
224 down_read(&context->umem_rwsem);
225 else if (!down_read_trylock(&context->umem_rwsem))
226 return -EAGAIN;
227
228 ib_ucontext_notifier_start_account(context);
229 ret = rbt_ib_umem_for_each_in_range(&context->umem_tree, start,
230 end,
231 invalidate_range_start_trampoline,
232 blockable, NULL);
233 up_read(&context->umem_rwsem);
234
235 return ret;
236 }
237
invalidate_range_end_trampoline(struct ib_umem * item,u64 start,u64 end,void * cookie)238 static int invalidate_range_end_trampoline(struct ib_umem *item, u64 start,
239 u64 end, void *cookie)
240 {
241 ib_umem_notifier_end_account(item);
242 return 0;
243 }
244
ib_umem_notifier_invalidate_range_end(struct mmu_notifier * mn,struct mm_struct * mm,unsigned long start,unsigned long end)245 static void ib_umem_notifier_invalidate_range_end(struct mmu_notifier *mn,
246 struct mm_struct *mm,
247 unsigned long start,
248 unsigned long end)
249 {
250 struct ib_ucontext *context = container_of(mn, struct ib_ucontext, mn);
251
252 if (!context->invalidate_range)
253 return;
254
255 /*
256 * TODO: we currently bail out if there is any sleepable work to be done
257 * in ib_umem_notifier_invalidate_range_start so we shouldn't really block
258 * here. But this is ugly and fragile.
259 */
260 down_read(&context->umem_rwsem);
261 rbt_ib_umem_for_each_in_range(&context->umem_tree, start,
262 end,
263 invalidate_range_end_trampoline, true, NULL);
264 up_read(&context->umem_rwsem);
265 ib_ucontext_notifier_end_account(context);
266 }
267
268 static const struct mmu_notifier_ops ib_umem_notifiers = {
269 .release = ib_umem_notifier_release,
270 .invalidate_range_start = ib_umem_notifier_invalidate_range_start,
271 .invalidate_range_end = ib_umem_notifier_invalidate_range_end,
272 };
273
ib_alloc_odp_umem(struct ib_ucontext * context,unsigned long addr,size_t size)274 struct ib_umem *ib_alloc_odp_umem(struct ib_ucontext *context,
275 unsigned long addr,
276 size_t size)
277 {
278 struct ib_umem *umem;
279 struct ib_umem_odp *odp_data;
280 int pages = size >> PAGE_SHIFT;
281 int ret;
282
283 umem = kzalloc(sizeof(*umem), GFP_KERNEL);
284 if (!umem)
285 return ERR_PTR(-ENOMEM);
286
287 umem->context = context;
288 umem->length = size;
289 umem->address = addr;
290 umem->page_shift = PAGE_SHIFT;
291 umem->writable = 1;
292
293 odp_data = kzalloc(sizeof(*odp_data), GFP_KERNEL);
294 if (!odp_data) {
295 ret = -ENOMEM;
296 goto out_umem;
297 }
298 odp_data->umem = umem;
299
300 mutex_init(&odp_data->umem_mutex);
301 init_completion(&odp_data->notifier_completion);
302
303 odp_data->page_list =
304 vzalloc(array_size(pages, sizeof(*odp_data->page_list)));
305 if (!odp_data->page_list) {
306 ret = -ENOMEM;
307 goto out_odp_data;
308 }
309
310 odp_data->dma_list =
311 vzalloc(array_size(pages, sizeof(*odp_data->dma_list)));
312 if (!odp_data->dma_list) {
313 ret = -ENOMEM;
314 goto out_page_list;
315 }
316
317 down_write(&context->umem_rwsem);
318 context->odp_mrs_count++;
319 rbt_ib_umem_insert(&odp_data->interval_tree, &context->umem_tree);
320 if (likely(!atomic_read(&context->notifier_count)))
321 odp_data->mn_counters_active = true;
322 else
323 list_add(&odp_data->no_private_counters,
324 &context->no_private_counters);
325 up_write(&context->umem_rwsem);
326
327 umem->odp_data = odp_data;
328
329 return umem;
330
331 out_page_list:
332 vfree(odp_data->page_list);
333 out_odp_data:
334 kfree(odp_data);
335 out_umem:
336 kfree(umem);
337 return ERR_PTR(ret);
338 }
339 EXPORT_SYMBOL(ib_alloc_odp_umem);
340
ib_umem_odp_get(struct ib_ucontext * context,struct ib_umem * umem,int access)341 int ib_umem_odp_get(struct ib_ucontext *context, struct ib_umem *umem,
342 int access)
343 {
344 int ret_val;
345 struct pid *our_pid;
346 struct mm_struct *mm = get_task_mm(current);
347
348 if (!mm)
349 return -EINVAL;
350
351 if (access & IB_ACCESS_HUGETLB) {
352 struct vm_area_struct *vma;
353 struct hstate *h;
354
355 down_read(&mm->mmap_sem);
356 vma = find_vma(mm, ib_umem_start(umem));
357 if (!vma || !is_vm_hugetlb_page(vma)) {
358 up_read(&mm->mmap_sem);
359 return -EINVAL;
360 }
361 h = hstate_vma(vma);
362 umem->page_shift = huge_page_shift(h);
363 up_read(&mm->mmap_sem);
364 umem->hugetlb = 1;
365 } else {
366 umem->hugetlb = 0;
367 }
368
369 /* Prevent creating ODP MRs in child processes */
370 rcu_read_lock();
371 our_pid = get_task_pid(current->group_leader, PIDTYPE_PID);
372 rcu_read_unlock();
373 put_pid(our_pid);
374 if (context->tgid != our_pid) {
375 ret_val = -EINVAL;
376 goto out_mm;
377 }
378
379 umem->odp_data = kzalloc(sizeof(*umem->odp_data), GFP_KERNEL);
380 if (!umem->odp_data) {
381 ret_val = -ENOMEM;
382 goto out_mm;
383 }
384 umem->odp_data->umem = umem;
385
386 mutex_init(&umem->odp_data->umem_mutex);
387
388 init_completion(&umem->odp_data->notifier_completion);
389
390 if (ib_umem_num_pages(umem)) {
391 umem->odp_data->page_list =
392 vzalloc(array_size(sizeof(*umem->odp_data->page_list),
393 ib_umem_num_pages(umem)));
394 if (!umem->odp_data->page_list) {
395 ret_val = -ENOMEM;
396 goto out_odp_data;
397 }
398
399 umem->odp_data->dma_list =
400 vzalloc(array_size(sizeof(*umem->odp_data->dma_list),
401 ib_umem_num_pages(umem)));
402 if (!umem->odp_data->dma_list) {
403 ret_val = -ENOMEM;
404 goto out_page_list;
405 }
406 }
407
408 /*
409 * When using MMU notifiers, we will get a
410 * notification before the "current" task (and MM) is
411 * destroyed. We use the umem_rwsem semaphore to synchronize.
412 */
413 down_write(&context->umem_rwsem);
414 context->odp_mrs_count++;
415 if (likely(ib_umem_start(umem) != ib_umem_end(umem)))
416 rbt_ib_umem_insert(&umem->odp_data->interval_tree,
417 &context->umem_tree);
418 if (likely(!atomic_read(&context->notifier_count)) ||
419 context->odp_mrs_count == 1)
420 umem->odp_data->mn_counters_active = true;
421 else
422 list_add(&umem->odp_data->no_private_counters,
423 &context->no_private_counters);
424 downgrade_write(&context->umem_rwsem);
425
426 if (context->odp_mrs_count == 1) {
427 /*
428 * Note that at this point, no MMU notifier is running
429 * for this context!
430 */
431 atomic_set(&context->notifier_count, 0);
432 INIT_HLIST_NODE(&context->mn.hlist);
433 context->mn.ops = &ib_umem_notifiers;
434 /*
435 * Lock-dep detects a false positive for mmap_sem vs.
436 * umem_rwsem, due to not grasping downgrade_write correctly.
437 */
438 lockdep_off();
439 ret_val = mmu_notifier_register(&context->mn, mm);
440 lockdep_on();
441 if (ret_val) {
442 pr_err("Failed to register mmu_notifier %d\n", ret_val);
443 ret_val = -EBUSY;
444 goto out_mutex;
445 }
446 }
447
448 up_read(&context->umem_rwsem);
449
450 /*
451 * Note that doing an mmput can cause a notifier for the relevant mm.
452 * If the notifier is called while we hold the umem_rwsem, this will
453 * cause a deadlock. Therefore, we release the reference only after we
454 * released the semaphore.
455 */
456 mmput(mm);
457 return 0;
458
459 out_mutex:
460 up_read(&context->umem_rwsem);
461 vfree(umem->odp_data->dma_list);
462 out_page_list:
463 vfree(umem->odp_data->page_list);
464 out_odp_data:
465 kfree(umem->odp_data);
466 out_mm:
467 mmput(mm);
468 return ret_val;
469 }
470
ib_umem_odp_release(struct ib_umem * umem)471 void ib_umem_odp_release(struct ib_umem *umem)
472 {
473 struct ib_ucontext *context = umem->context;
474
475 /*
476 * Ensure that no more pages are mapped in the umem.
477 *
478 * It is the driver's responsibility to ensure, before calling us,
479 * that the hardware will not attempt to access the MR any more.
480 */
481 ib_umem_odp_unmap_dma_pages(umem, ib_umem_start(umem),
482 ib_umem_end(umem));
483
484 down_write(&context->umem_rwsem);
485 if (likely(ib_umem_start(umem) != ib_umem_end(umem)))
486 rbt_ib_umem_remove(&umem->odp_data->interval_tree,
487 &context->umem_tree);
488 context->odp_mrs_count--;
489 if (!umem->odp_data->mn_counters_active) {
490 list_del(&umem->odp_data->no_private_counters);
491 complete_all(&umem->odp_data->notifier_completion);
492 }
493
494 /*
495 * Downgrade the lock to a read lock. This ensures that the notifiers
496 * (who lock the mutex for reading) will be able to finish, and we
497 * will be able to enventually obtain the mmu notifiers SRCU. Note
498 * that since we are doing it atomically, no other user could register
499 * and unregister while we do the check.
500 */
501 downgrade_write(&context->umem_rwsem);
502 if (!context->odp_mrs_count) {
503 struct task_struct *owning_process = NULL;
504 struct mm_struct *owning_mm = NULL;
505
506 owning_process = get_pid_task(context->tgid,
507 PIDTYPE_PID);
508 if (owning_process == NULL)
509 /*
510 * The process is already dead, notifier were removed
511 * already.
512 */
513 goto out;
514
515 owning_mm = get_task_mm(owning_process);
516 if (owning_mm == NULL)
517 /*
518 * The process' mm is already dead, notifier were
519 * removed already.
520 */
521 goto out_put_task;
522 mmu_notifier_unregister(&context->mn, owning_mm);
523
524 mmput(owning_mm);
525
526 out_put_task:
527 put_task_struct(owning_process);
528 }
529 out:
530 up_read(&context->umem_rwsem);
531
532 vfree(umem->odp_data->dma_list);
533 vfree(umem->odp_data->page_list);
534 kfree(umem->odp_data);
535 kfree(umem);
536 }
537
538 /*
539 * Map for DMA and insert a single page into the on-demand paging page tables.
540 *
541 * @umem: the umem to insert the page to.
542 * @page_index: index in the umem to add the page to.
543 * @page: the page struct to map and add.
544 * @access_mask: access permissions needed for this page.
545 * @current_seq: sequence number for synchronization with invalidations.
546 * the sequence number is taken from
547 * umem->odp_data->notifiers_seq.
548 *
549 * The function returns -EFAULT if the DMA mapping operation fails. It returns
550 * -EAGAIN if a concurrent invalidation prevents us from updating the page.
551 *
552 * The page is released via put_page even if the operation failed. For
553 * on-demand pinning, the page is released whenever it isn't stored in the
554 * umem.
555 */
ib_umem_odp_map_dma_single_page(struct ib_umem * umem,int page_index,struct page * page,u64 access_mask,unsigned long current_seq)556 static int ib_umem_odp_map_dma_single_page(
557 struct ib_umem *umem,
558 int page_index,
559 struct page *page,
560 u64 access_mask,
561 unsigned long current_seq)
562 {
563 struct ib_device *dev = umem->context->device;
564 dma_addr_t dma_addr;
565 int stored_page = 0;
566 int remove_existing_mapping = 0;
567 int ret = 0;
568
569 /*
570 * Note: we avoid writing if seq is different from the initial seq, to
571 * handle case of a racing notifier. This check also allows us to bail
572 * early if we have a notifier running in parallel with us.
573 */
574 if (ib_umem_mmu_notifier_retry(umem, current_seq)) {
575 ret = -EAGAIN;
576 goto out;
577 }
578 if (!(umem->odp_data->dma_list[page_index])) {
579 dma_addr = ib_dma_map_page(dev,
580 page,
581 0, BIT(umem->page_shift),
582 DMA_BIDIRECTIONAL);
583 if (ib_dma_mapping_error(dev, dma_addr)) {
584 ret = -EFAULT;
585 goto out;
586 }
587 umem->odp_data->dma_list[page_index] = dma_addr | access_mask;
588 umem->odp_data->page_list[page_index] = page;
589 umem->npages++;
590 stored_page = 1;
591 } else if (umem->odp_data->page_list[page_index] == page) {
592 umem->odp_data->dma_list[page_index] |= access_mask;
593 } else {
594 pr_err("error: got different pages in IB device and from get_user_pages. IB device page: %p, gup page: %p\n",
595 umem->odp_data->page_list[page_index], page);
596 /* Better remove the mapping now, to prevent any further
597 * damage. */
598 remove_existing_mapping = 1;
599 }
600
601 out:
602 /* On Demand Paging - avoid pinning the page */
603 if (umem->context->invalidate_range || !stored_page)
604 put_page(page);
605
606 if (remove_existing_mapping && umem->context->invalidate_range) {
607 invalidate_page_trampoline(
608 umem,
609 ib_umem_start(umem) + (page_index >> umem->page_shift),
610 ib_umem_start(umem) + ((page_index + 1) >>
611 umem->page_shift),
612 NULL);
613 ret = -EAGAIN;
614 }
615
616 return ret;
617 }
618
619 /**
620 * ib_umem_odp_map_dma_pages - Pin and DMA map userspace memory in an ODP MR.
621 *
622 * Pins the range of pages passed in the argument, and maps them to
623 * DMA addresses. The DMA addresses of the mapped pages is updated in
624 * umem->odp_data->dma_list.
625 *
626 * Returns the number of pages mapped in success, negative error code
627 * for failure.
628 * An -EAGAIN error code is returned when a concurrent mmu notifier prevents
629 * the function from completing its task.
630 * An -ENOENT error code indicates that userspace process is being terminated
631 * and mm was already destroyed.
632 * @umem: the umem to map and pin
633 * @user_virt: the address from which we need to map.
634 * @bcnt: the minimal number of bytes to pin and map. The mapping might be
635 * bigger due to alignment, and may also be smaller in case of an error
636 * pinning or mapping a page. The actual pages mapped is returned in
637 * the return value.
638 * @access_mask: bit mask of the requested access permissions for the given
639 * range.
640 * @current_seq: the MMU notifiers sequance value for synchronization with
641 * invalidations. the sequance number is read from
642 * umem->odp_data->notifiers_seq before calling this function
643 */
ib_umem_odp_map_dma_pages(struct ib_umem * umem,u64 user_virt,u64 bcnt,u64 access_mask,unsigned long current_seq)644 int ib_umem_odp_map_dma_pages(struct ib_umem *umem, u64 user_virt, u64 bcnt,
645 u64 access_mask, unsigned long current_seq)
646 {
647 struct task_struct *owning_process = NULL;
648 struct mm_struct *owning_mm = NULL;
649 struct page **local_page_list = NULL;
650 u64 page_mask, off;
651 int j, k, ret = 0, start_idx, npages = 0, page_shift;
652 unsigned int flags = 0;
653 phys_addr_t p = 0;
654
655 if (access_mask == 0)
656 return -EINVAL;
657
658 if (user_virt < ib_umem_start(umem) ||
659 user_virt + bcnt > ib_umem_end(umem))
660 return -EFAULT;
661
662 local_page_list = (struct page **)__get_free_page(GFP_KERNEL);
663 if (!local_page_list)
664 return -ENOMEM;
665
666 page_shift = umem->page_shift;
667 page_mask = ~(BIT(page_shift) - 1);
668 off = user_virt & (~page_mask);
669 user_virt = user_virt & page_mask;
670 bcnt += off; /* Charge for the first page offset as well. */
671
672 owning_process = get_pid_task(umem->context->tgid, PIDTYPE_PID);
673 if (owning_process == NULL) {
674 ret = -EINVAL;
675 goto out_no_task;
676 }
677
678 owning_mm = get_task_mm(owning_process);
679 if (owning_mm == NULL) {
680 ret = -ENOENT;
681 goto out_put_task;
682 }
683
684 if (access_mask & ODP_WRITE_ALLOWED_BIT)
685 flags |= FOLL_WRITE;
686
687 start_idx = (user_virt - ib_umem_start(umem)) >> page_shift;
688 k = start_idx;
689
690 while (bcnt > 0) {
691 const size_t gup_num_pages = min_t(size_t,
692 (bcnt + BIT(page_shift) - 1) >> page_shift,
693 PAGE_SIZE / sizeof(struct page *));
694
695 down_read(&owning_mm->mmap_sem);
696 /*
697 * Note: this might result in redundent page getting. We can
698 * avoid this by checking dma_list to be 0 before calling
699 * get_user_pages. However, this make the code much more
700 * complex (and doesn't gain us much performance in most use
701 * cases).
702 */
703 npages = get_user_pages_remote(owning_process, owning_mm,
704 user_virt, gup_num_pages,
705 flags, local_page_list, NULL, NULL);
706 up_read(&owning_mm->mmap_sem);
707
708 if (npages < 0)
709 break;
710
711 bcnt -= min_t(size_t, npages << PAGE_SHIFT, bcnt);
712 mutex_lock(&umem->odp_data->umem_mutex);
713 for (j = 0; j < npages; j++, user_virt += PAGE_SIZE) {
714 if (user_virt & ~page_mask) {
715 p += PAGE_SIZE;
716 if (page_to_phys(local_page_list[j]) != p) {
717 ret = -EFAULT;
718 break;
719 }
720 put_page(local_page_list[j]);
721 continue;
722 }
723
724 ret = ib_umem_odp_map_dma_single_page(
725 umem, k, local_page_list[j],
726 access_mask, current_seq);
727 if (ret < 0)
728 break;
729
730 p = page_to_phys(local_page_list[j]);
731 k++;
732 }
733 mutex_unlock(&umem->odp_data->umem_mutex);
734
735 if (ret < 0) {
736 /* Release left over pages when handling errors. */
737 for (++j; j < npages; ++j)
738 put_page(local_page_list[j]);
739 break;
740 }
741 }
742
743 if (ret >= 0) {
744 if (npages < 0 && k == start_idx)
745 ret = npages;
746 else
747 ret = k - start_idx;
748 }
749
750 mmput(owning_mm);
751 out_put_task:
752 put_task_struct(owning_process);
753 out_no_task:
754 free_page((unsigned long)local_page_list);
755 return ret;
756 }
757 EXPORT_SYMBOL(ib_umem_odp_map_dma_pages);
758
ib_umem_odp_unmap_dma_pages(struct ib_umem * umem,u64 virt,u64 bound)759 void ib_umem_odp_unmap_dma_pages(struct ib_umem *umem, u64 virt,
760 u64 bound)
761 {
762 int idx;
763 u64 addr;
764 struct ib_device *dev = umem->context->device;
765
766 virt = max_t(u64, virt, ib_umem_start(umem));
767 bound = min_t(u64, bound, ib_umem_end(umem));
768 /* Note that during the run of this function, the
769 * notifiers_count of the MR is > 0, preventing any racing
770 * faults from completion. We might be racing with other
771 * invalidations, so we must make sure we free each page only
772 * once. */
773 mutex_lock(&umem->odp_data->umem_mutex);
774 for (addr = virt; addr < bound; addr += BIT(umem->page_shift)) {
775 idx = (addr - ib_umem_start(umem)) >> umem->page_shift;
776 if (umem->odp_data->page_list[idx]) {
777 struct page *page = umem->odp_data->page_list[idx];
778 dma_addr_t dma = umem->odp_data->dma_list[idx];
779 dma_addr_t dma_addr = dma & ODP_DMA_ADDR_MASK;
780
781 WARN_ON(!dma_addr);
782
783 ib_dma_unmap_page(dev, dma_addr, PAGE_SIZE,
784 DMA_BIDIRECTIONAL);
785 if (dma & ODP_WRITE_ALLOWED_BIT) {
786 struct page *head_page = compound_head(page);
787 /*
788 * set_page_dirty prefers being called with
789 * the page lock. However, MMU notifiers are
790 * called sometimes with and sometimes without
791 * the lock. We rely on the umem_mutex instead
792 * to prevent other mmu notifiers from
793 * continuing and allowing the page mapping to
794 * be removed.
795 */
796 set_page_dirty(head_page);
797 }
798 /* on demand pinning support */
799 if (!umem->context->invalidate_range)
800 put_page(page);
801 umem->odp_data->page_list[idx] = NULL;
802 umem->odp_data->dma_list[idx] = 0;
803 umem->npages--;
804 }
805 }
806 mutex_unlock(&umem->odp_data->umem_mutex);
807 }
808 EXPORT_SYMBOL(ib_umem_odp_unmap_dma_pages);
809
810 /* @last is not a part of the interval. See comment for function
811 * node_last.
812 */
rbt_ib_umem_for_each_in_range(struct rb_root_cached * root,u64 start,u64 last,umem_call_back cb,bool blockable,void * cookie)813 int rbt_ib_umem_for_each_in_range(struct rb_root_cached *root,
814 u64 start, u64 last,
815 umem_call_back cb,
816 bool blockable,
817 void *cookie)
818 {
819 int ret_val = 0;
820 struct umem_odp_node *node, *next;
821 struct ib_umem_odp *umem;
822
823 if (unlikely(start == last))
824 return ret_val;
825
826 for (node = rbt_ib_umem_iter_first(root, start, last - 1);
827 node; node = next) {
828 /* TODO move the blockable decision up to the callback */
829 if (!blockable)
830 return -EAGAIN;
831 next = rbt_ib_umem_iter_next(node, start, last - 1);
832 umem = container_of(node, struct ib_umem_odp, interval_tree);
833 ret_val = cb(umem->umem, start, last, cookie) || ret_val;
834 }
835
836 return ret_val;
837 }
838 EXPORT_SYMBOL(rbt_ib_umem_for_each_in_range);
839
rbt_ib_umem_lookup(struct rb_root_cached * root,u64 addr,u64 length)840 struct ib_umem_odp *rbt_ib_umem_lookup(struct rb_root_cached *root,
841 u64 addr, u64 length)
842 {
843 struct umem_odp_node *node;
844
845 node = rbt_ib_umem_iter_first(root, addr, addr + length - 1);
846 if (node)
847 return container_of(node, struct ib_umem_odp, interval_tree);
848 return NULL;
849
850 }
851 EXPORT_SYMBOL(rbt_ib_umem_lookup);
852
