Linux 4.1.16
[linux/fpc-iii.git] / drivers / infiniband / core / umem_odp.c
blob40becdb3196e07b97c94ade818af5755bfaae4db
1 /*
2 * Copyright (c) 2014 Mellanox Technologies. All rights reserved.
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:
10 * Redistribution and use in source and binary forms, with or
11 * without modification, are permitted provided that the following
12 * conditions are met:
14 * - Redistributions of source code must retain the above
15 * copyright notice, this list of conditions and the following
16 * disclaimer.
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.
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.
33 #include <linux/types.h>
34 #include <linux/sched.h>
35 #include <linux/pid.h>
36 #include <linux/slab.h>
37 #include <linux/export.h>
38 #include <linux/vmalloc.h>
40 #include <rdma/ib_verbs.h>
41 #include <rdma/ib_umem.h>
42 #include <rdma/ib_umem_odp.h>
44 static void ib_umem_notifier_start_account(struct ib_umem *item)
46 mutex_lock(&item->odp_data->umem_mutex);
48 /* Only update private counters for this umem if it has them.
49 * Otherwise skip it. All page faults will be delayed for this umem. */
50 if (item->odp_data->mn_counters_active) {
51 int notifiers_count = item->odp_data->notifiers_count++;
53 if (notifiers_count == 0)
54 /* Initialize the completion object for waiting on
55 * notifiers. Since notifier_count is zero, no one
56 * should be waiting right now. */
57 reinit_completion(&item->odp_data->notifier_completion);
59 mutex_unlock(&item->odp_data->umem_mutex);
62 static void ib_umem_notifier_end_account(struct ib_umem *item)
64 mutex_lock(&item->odp_data->umem_mutex);
66 /* Only update private counters for this umem if it has them.
67 * Otherwise skip it. All page faults will be delayed for this umem. */
68 if (item->odp_data->mn_counters_active) {
70 * This sequence increase will notify the QP page fault that
71 * the page that is going to be mapped in the spte could have
72 * been freed.
74 ++item->odp_data->notifiers_seq;
75 if (--item->odp_data->notifiers_count == 0)
76 complete_all(&item->odp_data->notifier_completion);
78 mutex_unlock(&item->odp_data->umem_mutex);
81 /* Account for a new mmu notifier in an ib_ucontext. */
82 static void ib_ucontext_notifier_start_account(struct ib_ucontext *context)
84 atomic_inc(&context->notifier_count);
87 /* Account for a terminating mmu notifier in an ib_ucontext.
89 * Must be called with the ib_ucontext->umem_rwsem semaphore unlocked, since
90 * the function takes the semaphore itself. */
91 static void ib_ucontext_notifier_end_account(struct ib_ucontext *context)
93 int zero_notifiers = atomic_dec_and_test(&context->notifier_count);
95 if (zero_notifiers &&
96 !list_empty(&context->no_private_counters)) {
97 /* No currently running mmu notifiers. Now is the chance to
98 * add private accounting to all previously added umems. */
99 struct ib_umem_odp *odp_data, *next;
101 /* Prevent concurrent mmu notifiers from working on the
102 * no_private_counters list. */
103 down_write(&context->umem_rwsem);
105 /* Read the notifier_count again, with the umem_rwsem
106 * semaphore taken for write. */
107 if (!atomic_read(&context->notifier_count)) {
108 list_for_each_entry_safe(odp_data, next,
109 &context->no_private_counters,
110 no_private_counters) {
111 mutex_lock(&odp_data->umem_mutex);
112 odp_data->mn_counters_active = true;
113 list_del(&odp_data->no_private_counters);
114 complete_all(&odp_data->notifier_completion);
115 mutex_unlock(&odp_data->umem_mutex);
119 up_write(&context->umem_rwsem);
123 static int ib_umem_notifier_release_trampoline(struct ib_umem *item, u64 start,
124 u64 end, void *cookie) {
126 * Increase the number of notifiers running, to
127 * prevent any further fault handling on this MR.
129 ib_umem_notifier_start_account(item);
130 item->odp_data->dying = 1;
131 /* Make sure that the fact the umem is dying is out before we release
132 * all pending page faults. */
133 smp_wmb();
134 complete_all(&item->odp_data->notifier_completion);
135 item->context->invalidate_range(item, ib_umem_start(item),
136 ib_umem_end(item));
137 return 0;
140 static void ib_umem_notifier_release(struct mmu_notifier *mn,
141 struct mm_struct *mm)
143 struct ib_ucontext *context = container_of(mn, struct ib_ucontext, mn);
145 if (!context->invalidate_range)
146 return;
148 ib_ucontext_notifier_start_account(context);
149 down_read(&context->umem_rwsem);
150 rbt_ib_umem_for_each_in_range(&context->umem_tree, 0,
151 ULLONG_MAX,
152 ib_umem_notifier_release_trampoline,
153 NULL);
154 up_read(&context->umem_rwsem);
157 static int invalidate_page_trampoline(struct ib_umem *item, u64 start,
158 u64 end, void *cookie)
160 ib_umem_notifier_start_account(item);
161 item->context->invalidate_range(item, start, start + PAGE_SIZE);
162 ib_umem_notifier_end_account(item);
163 return 0;
166 static void ib_umem_notifier_invalidate_page(struct mmu_notifier *mn,
167 struct mm_struct *mm,
168 unsigned long address)
170 struct ib_ucontext *context = container_of(mn, struct ib_ucontext, mn);
172 if (!context->invalidate_range)
173 return;
175 ib_ucontext_notifier_start_account(context);
176 down_read(&context->umem_rwsem);
177 rbt_ib_umem_for_each_in_range(&context->umem_tree, address,
178 address + PAGE_SIZE,
179 invalidate_page_trampoline, NULL);
180 up_read(&context->umem_rwsem);
181 ib_ucontext_notifier_end_account(context);
184 static int invalidate_range_start_trampoline(struct ib_umem *item, u64 start,
185 u64 end, void *cookie)
187 ib_umem_notifier_start_account(item);
188 item->context->invalidate_range(item, start, end);
189 return 0;
192 static void ib_umem_notifier_invalidate_range_start(struct mmu_notifier *mn,
193 struct mm_struct *mm,
194 unsigned long start,
195 unsigned long end)
197 struct ib_ucontext *context = container_of(mn, struct ib_ucontext, mn);
199 if (!context->invalidate_range)
200 return;
202 ib_ucontext_notifier_start_account(context);
203 down_read(&context->umem_rwsem);
204 rbt_ib_umem_for_each_in_range(&context->umem_tree, start,
205 end,
206 invalidate_range_start_trampoline, NULL);
207 up_read(&context->umem_rwsem);
210 static int invalidate_range_end_trampoline(struct ib_umem *item, u64 start,
211 u64 end, void *cookie)
213 ib_umem_notifier_end_account(item);
214 return 0;
217 static void ib_umem_notifier_invalidate_range_end(struct mmu_notifier *mn,
218 struct mm_struct *mm,
219 unsigned long start,
220 unsigned long end)
222 struct ib_ucontext *context = container_of(mn, struct ib_ucontext, mn);
224 if (!context->invalidate_range)
225 return;
227 down_read(&context->umem_rwsem);
228 rbt_ib_umem_for_each_in_range(&context->umem_tree, start,
229 end,
230 invalidate_range_end_trampoline, NULL);
231 up_read(&context->umem_rwsem);
232 ib_ucontext_notifier_end_account(context);
235 static struct mmu_notifier_ops ib_umem_notifiers = {
236 .release = ib_umem_notifier_release,
237 .invalidate_page = ib_umem_notifier_invalidate_page,
238 .invalidate_range_start = ib_umem_notifier_invalidate_range_start,
239 .invalidate_range_end = ib_umem_notifier_invalidate_range_end,
242 int ib_umem_odp_get(struct ib_ucontext *context, struct ib_umem *umem)
244 int ret_val;
245 struct pid *our_pid;
246 struct mm_struct *mm = get_task_mm(current);
248 if (!mm)
249 return -EINVAL;
251 /* Prevent creating ODP MRs in child processes */
252 rcu_read_lock();
253 our_pid = get_task_pid(current->group_leader, PIDTYPE_PID);
254 rcu_read_unlock();
255 put_pid(our_pid);
256 if (context->tgid != our_pid) {
257 ret_val = -EINVAL;
258 goto out_mm;
261 umem->hugetlb = 0;
262 umem->odp_data = kzalloc(sizeof(*umem->odp_data), GFP_KERNEL);
263 if (!umem->odp_data) {
264 ret_val = -ENOMEM;
265 goto out_mm;
267 umem->odp_data->umem = umem;
269 mutex_init(&umem->odp_data->umem_mutex);
271 init_completion(&umem->odp_data->notifier_completion);
273 umem->odp_data->page_list = vzalloc(ib_umem_num_pages(umem) *
274 sizeof(*umem->odp_data->page_list));
275 if (!umem->odp_data->page_list) {
276 ret_val = -ENOMEM;
277 goto out_odp_data;
280 umem->odp_data->dma_list = vzalloc(ib_umem_num_pages(umem) *
281 sizeof(*umem->odp_data->dma_list));
282 if (!umem->odp_data->dma_list) {
283 ret_val = -ENOMEM;
284 goto out_page_list;
288 * When using MMU notifiers, we will get a
289 * notification before the "current" task (and MM) is
290 * destroyed. We use the umem_rwsem semaphore to synchronize.
292 down_write(&context->umem_rwsem);
293 context->odp_mrs_count++;
294 if (likely(ib_umem_start(umem) != ib_umem_end(umem)))
295 rbt_ib_umem_insert(&umem->odp_data->interval_tree,
296 &context->umem_tree);
297 if (likely(!atomic_read(&context->notifier_count)) ||
298 context->odp_mrs_count == 1)
299 umem->odp_data->mn_counters_active = true;
300 else
301 list_add(&umem->odp_data->no_private_counters,
302 &context->no_private_counters);
303 downgrade_write(&context->umem_rwsem);
305 if (context->odp_mrs_count == 1) {
307 * Note that at this point, no MMU notifier is running
308 * for this context!
310 atomic_set(&context->notifier_count, 0);
311 INIT_HLIST_NODE(&context->mn.hlist);
312 context->mn.ops = &ib_umem_notifiers;
314 * Lock-dep detects a false positive for mmap_sem vs.
315 * umem_rwsem, due to not grasping downgrade_write correctly.
317 lockdep_off();
318 ret_val = mmu_notifier_register(&context->mn, mm);
319 lockdep_on();
320 if (ret_val) {
321 pr_err("Failed to register mmu_notifier %d\n", ret_val);
322 ret_val = -EBUSY;
323 goto out_mutex;
327 up_read(&context->umem_rwsem);
330 * Note that doing an mmput can cause a notifier for the relevant mm.
331 * If the notifier is called while we hold the umem_rwsem, this will
332 * cause a deadlock. Therefore, we release the reference only after we
333 * released the semaphore.
335 mmput(mm);
336 return 0;
338 out_mutex:
339 up_read(&context->umem_rwsem);
340 vfree(umem->odp_data->dma_list);
341 out_page_list:
342 vfree(umem->odp_data->page_list);
343 out_odp_data:
344 kfree(umem->odp_data);
345 out_mm:
346 mmput(mm);
347 return ret_val;
350 void ib_umem_odp_release(struct ib_umem *umem)
352 struct ib_ucontext *context = umem->context;
355 * Ensure that no more pages are mapped in the umem.
357 * It is the driver's responsibility to ensure, before calling us,
358 * that the hardware will not attempt to access the MR any more.
360 ib_umem_odp_unmap_dma_pages(umem, ib_umem_start(umem),
361 ib_umem_end(umem));
363 down_write(&context->umem_rwsem);
364 if (likely(ib_umem_start(umem) != ib_umem_end(umem)))
365 rbt_ib_umem_remove(&umem->odp_data->interval_tree,
366 &context->umem_tree);
367 context->odp_mrs_count--;
368 if (!umem->odp_data->mn_counters_active) {
369 list_del(&umem->odp_data->no_private_counters);
370 complete_all(&umem->odp_data->notifier_completion);
374 * Downgrade the lock to a read lock. This ensures that the notifiers
375 * (who lock the mutex for reading) will be able to finish, and we
376 * will be able to enventually obtain the mmu notifiers SRCU. Note
377 * that since we are doing it atomically, no other user could register
378 * and unregister while we do the check.
380 downgrade_write(&context->umem_rwsem);
381 if (!context->odp_mrs_count) {
382 struct task_struct *owning_process = NULL;
383 struct mm_struct *owning_mm = NULL;
385 owning_process = get_pid_task(context->tgid,
386 PIDTYPE_PID);
387 if (owning_process == NULL)
389 * The process is already dead, notifier were removed
390 * already.
392 goto out;
394 owning_mm = get_task_mm(owning_process);
395 if (owning_mm == NULL)
397 * The process' mm is already dead, notifier were
398 * removed already.
400 goto out_put_task;
401 mmu_notifier_unregister(&context->mn, owning_mm);
403 mmput(owning_mm);
405 out_put_task:
406 put_task_struct(owning_process);
408 out:
409 up_read(&context->umem_rwsem);
411 vfree(umem->odp_data->dma_list);
412 vfree(umem->odp_data->page_list);
413 kfree(umem->odp_data);
414 kfree(umem);
418 * Map for DMA and insert a single page into the on-demand paging page tables.
420 * @umem: the umem to insert the page to.
421 * @page_index: index in the umem to add the page to.
422 * @page: the page struct to map and add.
423 * @access_mask: access permissions needed for this page.
424 * @current_seq: sequence number for synchronization with invalidations.
425 * the sequence number is taken from
426 * umem->odp_data->notifiers_seq.
428 * The function returns -EFAULT if the DMA mapping operation fails. It returns
429 * -EAGAIN if a concurrent invalidation prevents us from updating the page.
431 * The page is released via put_page even if the operation failed. For
432 * on-demand pinning, the page is released whenever it isn't stored in the
433 * umem.
435 static int ib_umem_odp_map_dma_single_page(
436 struct ib_umem *umem,
437 int page_index,
438 u64 base_virt_addr,
439 struct page *page,
440 u64 access_mask,
441 unsigned long current_seq)
443 struct ib_device *dev = umem->context->device;
444 dma_addr_t dma_addr;
445 int stored_page = 0;
446 int remove_existing_mapping = 0;
447 int ret = 0;
450 * Note: we avoid writing if seq is different from the initial seq, to
451 * handle case of a racing notifier. This check also allows us to bail
452 * early if we have a notifier running in parallel with us.
454 if (ib_umem_mmu_notifier_retry(umem, current_seq)) {
455 ret = -EAGAIN;
456 goto out;
458 if (!(umem->odp_data->dma_list[page_index])) {
459 dma_addr = ib_dma_map_page(dev,
460 page,
461 0, PAGE_SIZE,
462 DMA_BIDIRECTIONAL);
463 if (ib_dma_mapping_error(dev, dma_addr)) {
464 ret = -EFAULT;
465 goto out;
467 umem->odp_data->dma_list[page_index] = dma_addr | access_mask;
468 umem->odp_data->page_list[page_index] = page;
469 stored_page = 1;
470 } else if (umem->odp_data->page_list[page_index] == page) {
471 umem->odp_data->dma_list[page_index] |= access_mask;
472 } else {
473 pr_err("error: got different pages in IB device and from get_user_pages. IB device page: %p, gup page: %p\n",
474 umem->odp_data->page_list[page_index], page);
475 /* Better remove the mapping now, to prevent any further
476 * damage. */
477 remove_existing_mapping = 1;
480 out:
481 /* On Demand Paging - avoid pinning the page */
482 if (umem->context->invalidate_range || !stored_page)
483 put_page(page);
485 if (remove_existing_mapping && umem->context->invalidate_range) {
486 invalidate_page_trampoline(
487 umem,
488 base_virt_addr + (page_index * PAGE_SIZE),
489 base_virt_addr + ((page_index+1)*PAGE_SIZE),
490 NULL);
491 ret = -EAGAIN;
494 return ret;
498 * ib_umem_odp_map_dma_pages - Pin and DMA map userspace memory in an ODP MR.
500 * Pins the range of pages passed in the argument, and maps them to
501 * DMA addresses. The DMA addresses of the mapped pages is updated in
502 * umem->odp_data->dma_list.
504 * Returns the number of pages mapped in success, negative error code
505 * for failure.
506 * An -EAGAIN error code is returned when a concurrent mmu notifier prevents
507 * the function from completing its task.
509 * @umem: the umem to map and pin
510 * @user_virt: the address from which we need to map.
511 * @bcnt: the minimal number of bytes to pin and map. The mapping might be
512 * bigger due to alignment, and may also be smaller in case of an error
513 * pinning or mapping a page. The actual pages mapped is returned in
514 * the return value.
515 * @access_mask: bit mask of the requested access permissions for the given
516 * range.
517 * @current_seq: the MMU notifiers sequance value for synchronization with
518 * invalidations. the sequance number is read from
519 * umem->odp_data->notifiers_seq before calling this function
521 int ib_umem_odp_map_dma_pages(struct ib_umem *umem, u64 user_virt, u64 bcnt,
522 u64 access_mask, unsigned long current_seq)
524 struct task_struct *owning_process = NULL;
525 struct mm_struct *owning_mm = NULL;
526 struct page **local_page_list = NULL;
527 u64 off;
528 int j, k, ret = 0, start_idx, npages = 0;
529 u64 base_virt_addr;
531 if (access_mask == 0)
532 return -EINVAL;
534 if (user_virt < ib_umem_start(umem) ||
535 user_virt + bcnt > ib_umem_end(umem))
536 return -EFAULT;
538 local_page_list = (struct page **)__get_free_page(GFP_KERNEL);
539 if (!local_page_list)
540 return -ENOMEM;
542 off = user_virt & (~PAGE_MASK);
543 user_virt = user_virt & PAGE_MASK;
544 base_virt_addr = user_virt;
545 bcnt += off; /* Charge for the first page offset as well. */
547 owning_process = get_pid_task(umem->context->tgid, PIDTYPE_PID);
548 if (owning_process == NULL) {
549 ret = -EINVAL;
550 goto out_no_task;
553 owning_mm = get_task_mm(owning_process);
554 if (owning_mm == NULL) {
555 ret = -EINVAL;
556 goto out_put_task;
559 start_idx = (user_virt - ib_umem_start(umem)) >> PAGE_SHIFT;
560 k = start_idx;
562 while (bcnt > 0) {
563 const size_t gup_num_pages =
564 min_t(size_t, ALIGN(bcnt, PAGE_SIZE) / PAGE_SIZE,
565 PAGE_SIZE / sizeof(struct page *));
567 down_read(&owning_mm->mmap_sem);
569 * Note: this might result in redundent page getting. We can
570 * avoid this by checking dma_list to be 0 before calling
571 * get_user_pages. However, this make the code much more
572 * complex (and doesn't gain us much performance in most use
573 * cases).
575 npages = get_user_pages(owning_process, owning_mm, user_virt,
576 gup_num_pages,
577 access_mask & ODP_WRITE_ALLOWED_BIT, 0,
578 local_page_list, NULL);
579 up_read(&owning_mm->mmap_sem);
581 if (npages < 0)
582 break;
584 bcnt -= min_t(size_t, npages << PAGE_SHIFT, bcnt);
585 user_virt += npages << PAGE_SHIFT;
586 mutex_lock(&umem->odp_data->umem_mutex);
587 for (j = 0; j < npages; ++j) {
588 ret = ib_umem_odp_map_dma_single_page(
589 umem, k, base_virt_addr, local_page_list[j],
590 access_mask, current_seq);
591 if (ret < 0)
592 break;
593 k++;
595 mutex_unlock(&umem->odp_data->umem_mutex);
597 if (ret < 0) {
598 /* Release left over pages when handling errors. */
599 for (++j; j < npages; ++j)
600 put_page(local_page_list[j]);
601 break;
605 if (ret >= 0) {
606 if (npages < 0 && k == start_idx)
607 ret = npages;
608 else
609 ret = k - start_idx;
612 mmput(owning_mm);
613 out_put_task:
614 put_task_struct(owning_process);
615 out_no_task:
616 free_page((unsigned long)local_page_list);
617 return ret;
619 EXPORT_SYMBOL(ib_umem_odp_map_dma_pages);
621 void ib_umem_odp_unmap_dma_pages(struct ib_umem *umem, u64 virt,
622 u64 bound)
624 int idx;
625 u64 addr;
626 struct ib_device *dev = umem->context->device;
628 virt = max_t(u64, virt, ib_umem_start(umem));
629 bound = min_t(u64, bound, ib_umem_end(umem));
630 /* Note that during the run of this function, the
631 * notifiers_count of the MR is > 0, preventing any racing
632 * faults from completion. We might be racing with other
633 * invalidations, so we must make sure we free each page only
634 * once. */
635 mutex_lock(&umem->odp_data->umem_mutex);
636 for (addr = virt; addr < bound; addr += (u64)umem->page_size) {
637 idx = (addr - ib_umem_start(umem)) / PAGE_SIZE;
638 if (umem->odp_data->page_list[idx]) {
639 struct page *page = umem->odp_data->page_list[idx];
640 dma_addr_t dma = umem->odp_data->dma_list[idx];
641 dma_addr_t dma_addr = dma & ODP_DMA_ADDR_MASK;
643 WARN_ON(!dma_addr);
645 ib_dma_unmap_page(dev, dma_addr, PAGE_SIZE,
646 DMA_BIDIRECTIONAL);
647 if (dma & ODP_WRITE_ALLOWED_BIT) {
648 struct page *head_page = compound_head(page);
650 * set_page_dirty prefers being called with
651 * the page lock. However, MMU notifiers are
652 * called sometimes with and sometimes without
653 * the lock. We rely on the umem_mutex instead
654 * to prevent other mmu notifiers from
655 * continuing and allowing the page mapping to
656 * be removed.
658 set_page_dirty(head_page);
660 /* on demand pinning support */
661 if (!umem->context->invalidate_range)
662 put_page(page);
663 umem->odp_data->page_list[idx] = NULL;
664 umem->odp_data->dma_list[idx] = 0;
667 mutex_unlock(&umem->odp_data->umem_mutex);
669 EXPORT_SYMBOL(ib_umem_odp_unmap_dma_pages);