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
14 * - Redistributions of source code must retain the above
15 * copyright notice, this list of conditions and the following
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
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.h>
43 #include <linux/pagemap.h>
45 #include <rdma/ib_verbs.h>
46 #include <rdma/ib_umem.h>
47 #include <rdma/ib_umem_odp.h>
51 static inline int ib_init_umem_odp(struct ib_umem_odp *umem_odp,
52 const struct mmu_interval_notifier_ops *ops)
56 umem_odp->umem.is_odp = 1;
57 mutex_init(&umem_odp->umem_mutex);
59 if (!umem_odp->is_implicit_odp) {
60 size_t page_size = 1UL << umem_odp->page_shift;
65 start = ALIGN_DOWN(umem_odp->umem.address, page_size);
66 if (check_add_overflow(umem_odp->umem.address,
67 (unsigned long)umem_odp->umem.length,
70 end = ALIGN(end, page_size);
71 if (unlikely(end < page_size))
74 pages = (end - start) >> umem_odp->page_shift;
78 umem_odp->page_list = kvcalloc(
79 pages, sizeof(*umem_odp->page_list), GFP_KERNEL);
80 if (!umem_odp->page_list)
83 umem_odp->dma_list = kvcalloc(
84 pages, sizeof(*umem_odp->dma_list), GFP_KERNEL);
85 if (!umem_odp->dma_list) {
90 ret = mmu_interval_notifier_insert(&umem_odp->notifier,
91 umem_odp->umem.owning_mm,
92 start, end - start, ops);
100 kvfree(umem_odp->dma_list);
102 kvfree(umem_odp->page_list);
107 * ib_umem_odp_alloc_implicit - Allocate a parent implicit ODP umem
109 * Implicit ODP umems do not have a VA range and do not have any page lists.
110 * They exist only to hold the per_mm reference to help the driver create
113 * @device: IB device to create UMEM
114 * @access: ib_reg_mr access flags
116 struct ib_umem_odp *ib_umem_odp_alloc_implicit(struct ib_device *device,
119 struct ib_umem *umem;
120 struct ib_umem_odp *umem_odp;
123 if (access & IB_ACCESS_HUGETLB)
124 return ERR_PTR(-EINVAL);
126 umem_odp = kzalloc(sizeof(*umem_odp), GFP_KERNEL);
128 return ERR_PTR(-ENOMEM);
129 umem = &umem_odp->umem;
130 umem->ibdev = device;
131 umem->writable = ib_access_writable(access);
132 umem->owning_mm = current->mm;
133 umem_odp->is_implicit_odp = 1;
134 umem_odp->page_shift = PAGE_SHIFT;
136 umem_odp->tgid = get_task_pid(current->group_leader, PIDTYPE_PID);
137 ret = ib_init_umem_odp(umem_odp, NULL);
139 put_pid(umem_odp->tgid);
145 EXPORT_SYMBOL(ib_umem_odp_alloc_implicit);
148 * ib_umem_odp_alloc_child - Allocate a child ODP umem under an implicit
151 * @root: The parent umem enclosing the child. This must be allocated using
152 * ib_alloc_implicit_odp_umem()
153 * @addr: The starting userspace VA
154 * @size: The length of the userspace VA
157 ib_umem_odp_alloc_child(struct ib_umem_odp *root, unsigned long addr,
159 const struct mmu_interval_notifier_ops *ops)
162 * Caller must ensure that root cannot be freed during the call to
165 struct ib_umem_odp *odp_data;
166 struct ib_umem *umem;
169 if (WARN_ON(!root->is_implicit_odp))
170 return ERR_PTR(-EINVAL);
172 odp_data = kzalloc(sizeof(*odp_data), GFP_KERNEL);
174 return ERR_PTR(-ENOMEM);
175 umem = &odp_data->umem;
176 umem->ibdev = root->umem.ibdev;
178 umem->address = addr;
179 umem->writable = root->umem.writable;
180 umem->owning_mm = root->umem.owning_mm;
181 odp_data->page_shift = PAGE_SHIFT;
182 odp_data->notifier.ops = ops;
184 odp_data->tgid = get_pid(root->tgid);
185 ret = ib_init_umem_odp(odp_data, ops);
187 put_pid(odp_data->tgid);
193 EXPORT_SYMBOL(ib_umem_odp_alloc_child);
196 * ib_umem_odp_get - Create a umem_odp for a userspace va
198 * @device: IB device struct to get UMEM
199 * @addr: userspace virtual address to start at
200 * @size: length of region to pin
201 * @access: IB_ACCESS_xxx flags for memory being pinned
203 * The driver should use when the access flags indicate ODP memory. It avoids
204 * pinning, instead, stores the mm for future page fault handling in
205 * conjunction with MMU notifiers.
207 struct ib_umem_odp *ib_umem_odp_get(struct ib_device *device,
208 unsigned long addr, size_t size, int access,
209 const struct mmu_interval_notifier_ops *ops)
211 struct ib_umem_odp *umem_odp;
212 struct mm_struct *mm;
215 if (WARN_ON_ONCE(!(access & IB_ACCESS_ON_DEMAND)))
216 return ERR_PTR(-EINVAL);
218 umem_odp = kzalloc(sizeof(struct ib_umem_odp), GFP_KERNEL);
220 return ERR_PTR(-ENOMEM);
222 umem_odp->umem.ibdev = device;
223 umem_odp->umem.length = size;
224 umem_odp->umem.address = addr;
225 umem_odp->umem.writable = ib_access_writable(access);
226 umem_odp->umem.owning_mm = mm = current->mm;
227 umem_odp->notifier.ops = ops;
229 umem_odp->page_shift = PAGE_SHIFT;
230 if (access & IB_ACCESS_HUGETLB) {
231 struct vm_area_struct *vma;
234 down_read(&mm->mmap_sem);
235 vma = find_vma(mm, ib_umem_start(umem_odp));
236 if (!vma || !is_vm_hugetlb_page(vma)) {
237 up_read(&mm->mmap_sem);
242 umem_odp->page_shift = huge_page_shift(h);
243 up_read(&mm->mmap_sem);
246 umem_odp->tgid = get_task_pid(current->group_leader, PIDTYPE_PID);
247 ret = ib_init_umem_odp(umem_odp, ops);
253 put_pid(umem_odp->tgid);
258 EXPORT_SYMBOL(ib_umem_odp_get);
260 void ib_umem_odp_release(struct ib_umem_odp *umem_odp)
263 * Ensure that no more pages are mapped in the umem.
265 * It is the driver's responsibility to ensure, before calling us,
266 * that the hardware will not attempt to access the MR any more.
268 if (!umem_odp->is_implicit_odp) {
269 mutex_lock(&umem_odp->umem_mutex);
270 ib_umem_odp_unmap_dma_pages(umem_odp, ib_umem_start(umem_odp),
271 ib_umem_end(umem_odp));
272 mutex_unlock(&umem_odp->umem_mutex);
273 mmu_interval_notifier_remove(&umem_odp->notifier);
274 kvfree(umem_odp->dma_list);
275 kvfree(umem_odp->page_list);
276 put_pid(umem_odp->tgid);
280 EXPORT_SYMBOL(ib_umem_odp_release);
283 * Map for DMA and insert a single page into the on-demand paging page tables.
285 * @umem: the umem to insert the page to.
286 * @page_index: index in the umem to add the page to.
287 * @page: the page struct to map and add.
288 * @access_mask: access permissions needed for this page.
289 * @current_seq: sequence number for synchronization with invalidations.
290 * the sequence number is taken from
291 * umem_odp->notifiers_seq.
293 * The function returns -EFAULT if the DMA mapping operation fails. It returns
294 * -EAGAIN if a concurrent invalidation prevents us from updating the page.
296 * The page is released via put_user_page even if the operation failed. For
297 * on-demand pinning, the page is released whenever it isn't stored in the
300 static int ib_umem_odp_map_dma_single_page(
301 struct ib_umem_odp *umem_odp,
302 unsigned int page_index,
305 unsigned long current_seq)
307 struct ib_device *dev = umem_odp->umem.ibdev;
311 if (mmu_interval_check_retry(&umem_odp->notifier, current_seq)) {
315 if (!(umem_odp->dma_list[page_index])) {
317 ib_dma_map_page(dev, page, 0, BIT(umem_odp->page_shift),
319 if (ib_dma_mapping_error(dev, dma_addr)) {
323 umem_odp->dma_list[page_index] = dma_addr | access_mask;
324 umem_odp->page_list[page_index] = page;
326 } else if (umem_odp->page_list[page_index] == page) {
327 umem_odp->dma_list[page_index] |= access_mask;
330 * This is a race here where we could have done:
336 * mutex_lock(umem_mutex)
337 * page from GUP != page in ODP
339 * It should be prevented by the retry test above as reading
340 * the seq number should be reliable under the
341 * umem_mutex. Thus something is really not working right if
345 "Got different pages in IB device and from get_user_pages. IB device page: %p, gup page: %p\n",
346 umem_odp->page_list[page_index], page);
356 * ib_umem_odp_map_dma_pages - Pin and DMA map userspace memory in an ODP MR.
358 * Pins the range of pages passed in the argument, and maps them to
359 * DMA addresses. The DMA addresses of the mapped pages is updated in
360 * umem_odp->dma_list.
362 * Returns the number of pages mapped in success, negative error code
364 * An -EAGAIN error code is returned when a concurrent mmu notifier prevents
365 * the function from completing its task.
366 * An -ENOENT error code indicates that userspace process is being terminated
367 * and mm was already destroyed.
368 * @umem_odp: the umem to map and pin
369 * @user_virt: the address from which we need to map.
370 * @bcnt: the minimal number of bytes to pin and map. The mapping might be
371 * bigger due to alignment, and may also be smaller in case of an error
372 * pinning or mapping a page. The actual pages mapped is returned in
374 * @access_mask: bit mask of the requested access permissions for the given
376 * @current_seq: the MMU notifiers sequance value for synchronization with
377 * invalidations. the sequance number is read from
378 * umem_odp->notifiers_seq before calling this function
380 int ib_umem_odp_map_dma_pages(struct ib_umem_odp *umem_odp, u64 user_virt,
381 u64 bcnt, u64 access_mask,
382 unsigned long current_seq)
384 struct task_struct *owning_process = NULL;
385 struct mm_struct *owning_mm = umem_odp->umem.owning_mm;
386 struct page **local_page_list = NULL;
388 int j, k, ret = 0, start_idx, npages = 0;
389 unsigned int flags = 0, page_shift;
392 if (access_mask == 0)
395 if (user_virt < ib_umem_start(umem_odp) ||
396 user_virt + bcnt > ib_umem_end(umem_odp))
399 local_page_list = (struct page **)__get_free_page(GFP_KERNEL);
400 if (!local_page_list)
403 page_shift = umem_odp->page_shift;
404 page_mask = ~(BIT(page_shift) - 1);
405 off = user_virt & (~page_mask);
406 user_virt = user_virt & page_mask;
407 bcnt += off; /* Charge for the first page offset as well. */
410 * owning_process is allowed to be NULL, this means somehow the mm is
411 * existing beyond the lifetime of the originating process.. Presumably
412 * mmget_not_zero will fail in this case.
414 owning_process = get_pid_task(umem_odp->tgid, PIDTYPE_PID);
415 if (!owning_process || !mmget_not_zero(owning_mm)) {
420 if (access_mask & ODP_WRITE_ALLOWED_BIT)
423 start_idx = (user_virt - ib_umem_start(umem_odp)) >> page_shift;
427 const size_t gup_num_pages = min_t(size_t,
428 (bcnt + BIT(page_shift) - 1) >> page_shift,
429 PAGE_SIZE / sizeof(struct page *));
431 down_read(&owning_mm->mmap_sem);
433 * Note: this might result in redundent page getting. We can
434 * avoid this by checking dma_list to be 0 before calling
435 * get_user_pages. However, this make the code much more
436 * complex (and doesn't gain us much performance in most use
439 npages = get_user_pages_remote(owning_process, owning_mm,
440 user_virt, gup_num_pages,
441 flags, local_page_list, NULL, NULL);
442 up_read(&owning_mm->mmap_sem);
445 if (npages != -EAGAIN)
446 pr_warn("fail to get %zu user pages with error %d\n", gup_num_pages, npages);
448 pr_debug("fail to get %zu user pages with error %d\n", gup_num_pages, npages);
452 bcnt -= min_t(size_t, npages << PAGE_SHIFT, bcnt);
453 mutex_lock(&umem_odp->umem_mutex);
454 for (j = 0; j < npages; j++, user_virt += PAGE_SIZE) {
455 if (user_virt & ~page_mask) {
457 if (page_to_phys(local_page_list[j]) != p) {
461 put_user_page(local_page_list[j]);
465 ret = ib_umem_odp_map_dma_single_page(
466 umem_odp, k, local_page_list[j],
467 access_mask, current_seq);
470 pr_warn("ib_umem_odp_map_dma_single_page failed with error %d\n", ret);
472 pr_debug("ib_umem_odp_map_dma_single_page failed with error %d\n", ret);
476 p = page_to_phys(local_page_list[j]);
479 mutex_unlock(&umem_odp->umem_mutex);
483 * Release pages, remembering that the first page
484 * to hit an error was already released by
485 * ib_umem_odp_map_dma_single_page().
487 if (npages - (j + 1) > 0)
488 put_user_pages(&local_page_list[j+1],
495 if (npages < 0 && k == start_idx)
504 put_task_struct(owning_process);
505 free_page((unsigned long)local_page_list);
508 EXPORT_SYMBOL(ib_umem_odp_map_dma_pages);
510 void ib_umem_odp_unmap_dma_pages(struct ib_umem_odp *umem_odp, u64 virt,
515 struct ib_device *dev = umem_odp->umem.ibdev;
517 lockdep_assert_held(&umem_odp->umem_mutex);
519 virt = max_t(u64, virt, ib_umem_start(umem_odp));
520 bound = min_t(u64, bound, ib_umem_end(umem_odp));
521 /* Note that during the run of this function, the
522 * notifiers_count of the MR is > 0, preventing any racing
523 * faults from completion. We might be racing with other
524 * invalidations, so we must make sure we free each page only
526 for (addr = virt; addr < bound; addr += BIT(umem_odp->page_shift)) {
527 idx = (addr - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
528 if (umem_odp->page_list[idx]) {
529 struct page *page = umem_odp->page_list[idx];
530 dma_addr_t dma = umem_odp->dma_list[idx];
531 dma_addr_t dma_addr = dma & ODP_DMA_ADDR_MASK;
535 ib_dma_unmap_page(dev, dma_addr,
536 BIT(umem_odp->page_shift),
538 if (dma & ODP_WRITE_ALLOWED_BIT) {
539 struct page *head_page = compound_head(page);
541 * set_page_dirty prefers being called with
542 * the page lock. However, MMU notifiers are
543 * called sometimes with and sometimes without
544 * the lock. We rely on the umem_mutex instead
545 * to prevent other mmu notifiers from
546 * continuing and allowing the page mapping to
549 set_page_dirty(head_page);
551 umem_odp->page_list[idx] = NULL;
552 umem_odp->dma_list[idx] = 0;
557 EXPORT_SYMBOL(ib_umem_odp_unmap_dma_pages);