| /* |
| * Copyright (c) 2014 Mellanox Technologies. All rights reserved. |
| * |
| * This software is available to you under a choice of one of two |
| * licenses. You may choose to be licensed under the terms of the GNU |
| * General Public License (GPL) Version 2, available from the file |
| * COPYING in the main directory of this source tree, or the |
| * OpenIB.org BSD license below: |
| * |
| * Redistribution and use in source and binary forms, with or |
| * without modification, are permitted provided that the following |
| * conditions are met: |
| * |
| * - Redistributions of source code must retain the above |
| * copyright notice, this list of conditions and the following |
| * disclaimer. |
| * |
| * - Redistributions in binary form must reproduce the above |
| * copyright notice, this list of conditions and the following |
| * disclaimer in the documentation and/or other materials |
| * provided with the distribution. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
| * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
| * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
| * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS |
| * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN |
| * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN |
| * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
| * SOFTWARE. |
| */ |
| |
| #include <linux/types.h> |
| #include <linux/sched.h> |
| #include <linux/pid.h> |
| #include <linux/slab.h> |
| #include <linux/export.h> |
| #include <linux/vmalloc.h> |
| |
| #include <rdma/ib_verbs.h> |
| #include <rdma/ib_umem.h> |
| #include <rdma/ib_umem_odp.h> |
| |
| static void ib_umem_notifier_start_account(struct ib_umem *item) |
| { |
| mutex_lock(&item->odp_data->umem_mutex); |
| |
| /* Only update private counters for this umem if it has them. |
| * Otherwise skip it. All page faults will be delayed for this umem. */ |
| if (item->odp_data->mn_counters_active) { |
| int notifiers_count = item->odp_data->notifiers_count++; |
| |
| if (notifiers_count == 0) |
| /* Initialize the completion object for waiting on |
| * notifiers. Since notifier_count is zero, no one |
| * should be waiting right now. */ |
| reinit_completion(&item->odp_data->notifier_completion); |
| } |
| mutex_unlock(&item->odp_data->umem_mutex); |
| } |
| |
| static void ib_umem_notifier_end_account(struct ib_umem *item) |
| { |
| mutex_lock(&item->odp_data->umem_mutex); |
| |
| /* Only update private counters for this umem if it has them. |
| * Otherwise skip it. All page faults will be delayed for this umem. */ |
| if (item->odp_data->mn_counters_active) { |
| /* |
| * This sequence increase will notify the QP page fault that |
| * the page that is going to be mapped in the spte could have |
| * been freed. |
| */ |
| ++item->odp_data->notifiers_seq; |
| if (--item->odp_data->notifiers_count == 0) |
| complete_all(&item->odp_data->notifier_completion); |
| } |
| mutex_unlock(&item->odp_data->umem_mutex); |
| } |
| |
| /* Account for a new mmu notifier in an ib_ucontext. */ |
| static void ib_ucontext_notifier_start_account(struct ib_ucontext *context) |
| { |
| atomic_inc(&context->notifier_count); |
| } |
| |
| /* Account for a terminating mmu notifier in an ib_ucontext. |
| * |
| * Must be called with the ib_ucontext->umem_rwsem semaphore unlocked, since |
| * the function takes the semaphore itself. */ |
| static void ib_ucontext_notifier_end_account(struct ib_ucontext *context) |
| { |
| int zero_notifiers = atomic_dec_and_test(&context->notifier_count); |
| |
| if (zero_notifiers && |
| !list_empty(&context->no_private_counters)) { |
| /* No currently running mmu notifiers. Now is the chance to |
| * add private accounting to all previously added umems. */ |
| struct ib_umem_odp *odp_data, *next; |
| |
| /* Prevent concurrent mmu notifiers from working on the |
| * no_private_counters list. */ |
| down_write(&context->umem_rwsem); |
| |
| /* Read the notifier_count again, with the umem_rwsem |
| * semaphore taken for write. */ |
| if (!atomic_read(&context->notifier_count)) { |
| list_for_each_entry_safe(odp_data, next, |
| &context->no_private_counters, |
| no_private_counters) { |
| mutex_lock(&odp_data->umem_mutex); |
| odp_data->mn_counters_active = true; |
| list_del(&odp_data->no_private_counters); |
| complete_all(&odp_data->notifier_completion); |
| mutex_unlock(&odp_data->umem_mutex); |
| } |
| } |
| |
| up_write(&context->umem_rwsem); |
| } |
| } |
| |
| static int ib_umem_notifier_release_trampoline(struct ib_umem *item, u64 start, |
| u64 end, void *cookie) { |
| /* |
| * Increase the number of notifiers running, to |
| * prevent any further fault handling on this MR. |
| */ |
| ib_umem_notifier_start_account(item); |
| item->odp_data->dying = 1; |
| /* Make sure that the fact the umem is dying is out before we release |
| * all pending page faults. */ |
| smp_wmb(); |
| complete_all(&item->odp_data->notifier_completion); |
| item->context->invalidate_range(item, ib_umem_start(item), |
| ib_umem_end(item)); |
| return 0; |
| } |
| |
| static void ib_umem_notifier_release(struct mmu_notifier *mn, |
| struct mm_struct *mm) |
| { |
| struct ib_ucontext *context = container_of(mn, struct ib_ucontext, mn); |
| |
| if (!context->invalidate_range) |
| return; |
| |
| ib_ucontext_notifier_start_account(context); |
| down_read(&context->umem_rwsem); |
| rbt_ib_umem_for_each_in_range(&context->umem_tree, 0, |
| ULLONG_MAX, |
| ib_umem_notifier_release_trampoline, |
| NULL); |
| up_read(&context->umem_rwsem); |
| } |
| |
| static int invalidate_page_trampoline(struct ib_umem *item, u64 start, |
| u64 end, void *cookie) |
| { |
| ib_umem_notifier_start_account(item); |
| item->context->invalidate_range(item, start, start + PAGE_SIZE); |
| ib_umem_notifier_end_account(item); |
| return 0; |
| } |
| |
| static void ib_umem_notifier_invalidate_page(struct mmu_notifier *mn, |
| struct mm_struct *mm, |
| unsigned long address) |
| { |
| struct ib_ucontext *context = container_of(mn, struct ib_ucontext, mn); |
| |
| if (!context->invalidate_range) |
| return; |
| |
| ib_ucontext_notifier_start_account(context); |
| down_read(&context->umem_rwsem); |
| rbt_ib_umem_for_each_in_range(&context->umem_tree, address, |
| address + PAGE_SIZE, |
| invalidate_page_trampoline, NULL); |
| up_read(&context->umem_rwsem); |
| ib_ucontext_notifier_end_account(context); |
| } |
| |
| static int invalidate_range_start_trampoline(struct ib_umem *item, u64 start, |
| u64 end, void *cookie) |
| { |
| ib_umem_notifier_start_account(item); |
| item->context->invalidate_range(item, start, end); |
| return 0; |
| } |
| |
| static void ib_umem_notifier_invalidate_range_start(struct mmu_notifier *mn, |
| struct mm_struct *mm, |
| unsigned long start, |
| unsigned long end) |
| { |
| struct ib_ucontext *context = container_of(mn, struct ib_ucontext, mn); |
| |
| if (!context->invalidate_range) |
| return; |
| |
| ib_ucontext_notifier_start_account(context); |
| down_read(&context->umem_rwsem); |
| rbt_ib_umem_for_each_in_range(&context->umem_tree, start, |
| end, |
| invalidate_range_start_trampoline, NULL); |
| up_read(&context->umem_rwsem); |
| } |
| |
| static int invalidate_range_end_trampoline(struct ib_umem *item, u64 start, |
| u64 end, void *cookie) |
| { |
| ib_umem_notifier_end_account(item); |
| return 0; |
| } |
| |
| static void ib_umem_notifier_invalidate_range_end(struct mmu_notifier *mn, |
| struct mm_struct *mm, |
| unsigned long start, |
| unsigned long end) |
| { |
| struct ib_ucontext *context = container_of(mn, struct ib_ucontext, mn); |
| |
| if (!context->invalidate_range) |
| return; |
| |
| down_read(&context->umem_rwsem); |
| rbt_ib_umem_for_each_in_range(&context->umem_tree, start, |
| end, |
| invalidate_range_end_trampoline, NULL); |
| up_read(&context->umem_rwsem); |
| ib_ucontext_notifier_end_account(context); |
| } |
| |
| static const struct mmu_notifier_ops ib_umem_notifiers = { |
| .release = ib_umem_notifier_release, |
| .invalidate_page = ib_umem_notifier_invalidate_page, |
| .invalidate_range_start = ib_umem_notifier_invalidate_range_start, |
| .invalidate_range_end = ib_umem_notifier_invalidate_range_end, |
| }; |
| |
| int ib_umem_odp_get(struct ib_ucontext *context, struct ib_umem *umem) |
| { |
| int ret_val; |
| struct pid *our_pid; |
| struct mm_struct *mm = get_task_mm(current); |
| |
| if (!mm) |
| return -EINVAL; |
| |
| /* Prevent creating ODP MRs in child processes */ |
| rcu_read_lock(); |
| our_pid = get_task_pid(current->group_leader, PIDTYPE_PID); |
| rcu_read_unlock(); |
| put_pid(our_pid); |
| if (context->tgid != our_pid) { |
| ret_val = -EINVAL; |
| goto out_mm; |
| } |
| |
| umem->hugetlb = 0; |
| umem->odp_data = kzalloc(sizeof(*umem->odp_data), GFP_KERNEL); |
| if (!umem->odp_data) { |
| ret_val = -ENOMEM; |
| goto out_mm; |
| } |
| umem->odp_data->umem = umem; |
| |
| mutex_init(&umem->odp_data->umem_mutex); |
| |
| init_completion(&umem->odp_data->notifier_completion); |
| |
| umem->odp_data->page_list = vzalloc(ib_umem_num_pages(umem) * |
| sizeof(*umem->odp_data->page_list)); |
| if (!umem->odp_data->page_list) { |
| ret_val = -ENOMEM; |
| goto out_odp_data; |
| } |
| |
| umem->odp_data->dma_list = vzalloc(ib_umem_num_pages(umem) * |
| sizeof(*umem->odp_data->dma_list)); |
| if (!umem->odp_data->dma_list) { |
| ret_val = -ENOMEM; |
| goto out_page_list; |
| } |
| |
| /* |
| * When using MMU notifiers, we will get a |
| * notification before the "current" task (and MM) is |
| * destroyed. We use the umem_rwsem semaphore to synchronize. |
| */ |
| down_write(&context->umem_rwsem); |
| context->odp_mrs_count++; |
| if (likely(ib_umem_start(umem) != ib_umem_end(umem))) |
| rbt_ib_umem_insert(&umem->odp_data->interval_tree, |
| &context->umem_tree); |
| if (likely(!atomic_read(&context->notifier_count)) || |
| context->odp_mrs_count == 1) |
| umem->odp_data->mn_counters_active = true; |
| else |
| list_add(&umem->odp_data->no_private_counters, |
| &context->no_private_counters); |
| downgrade_write(&context->umem_rwsem); |
| |
| if (context->odp_mrs_count == 1) { |
| /* |
| * Note that at this point, no MMU notifier is running |
| * for this context! |
| */ |
| atomic_set(&context->notifier_count, 0); |
| INIT_HLIST_NODE(&context->mn.hlist); |
| context->mn.ops = &ib_umem_notifiers; |
| /* |
| * Lock-dep detects a false positive for mmap_sem vs. |
| * umem_rwsem, due to not grasping downgrade_write correctly. |
| */ |
| lockdep_off(); |
| ret_val = mmu_notifier_register(&context->mn, mm); |
| lockdep_on(); |
| if (ret_val) { |
| pr_err("Failed to register mmu_notifier %d\n", ret_val); |
| ret_val = -EBUSY; |
| goto out_mutex; |
| } |
| } |
| |
| up_read(&context->umem_rwsem); |
| |
| /* |
| * Note that doing an mmput can cause a notifier for the relevant mm. |
| * If the notifier is called while we hold the umem_rwsem, this will |
| * cause a deadlock. Therefore, we release the reference only after we |
| * released the semaphore. |
| */ |
| mmput(mm); |
| return 0; |
| |
| out_mutex: |
| up_read(&context->umem_rwsem); |
| vfree(umem->odp_data->dma_list); |
| out_page_list: |
| vfree(umem->odp_data->page_list); |
| out_odp_data: |
| kfree(umem->odp_data); |
| out_mm: |
| mmput(mm); |
| return ret_val; |
| } |
| |
| void ib_umem_odp_release(struct ib_umem *umem) |
| { |
| struct ib_ucontext *context = umem->context; |
| |
| /* |
| * Ensure that no more pages are mapped in the umem. |
| * |
| * It is the driver's responsibility to ensure, before calling us, |
| * that the hardware will not attempt to access the MR any more. |
| */ |
| ib_umem_odp_unmap_dma_pages(umem, ib_umem_start(umem), |
| ib_umem_end(umem)); |
| |
| down_write(&context->umem_rwsem); |
| if (likely(ib_umem_start(umem) != ib_umem_end(umem))) |
| rbt_ib_umem_remove(&umem->odp_data->interval_tree, |
| &context->umem_tree); |
| context->odp_mrs_count--; |
| if (!umem->odp_data->mn_counters_active) { |
| list_del(&umem->odp_data->no_private_counters); |
| complete_all(&umem->odp_data->notifier_completion); |
| } |
| |
| /* |
| * Downgrade the lock to a read lock. This ensures that the notifiers |
| * (who lock the mutex for reading) will be able to finish, and we |
| * will be able to enventually obtain the mmu notifiers SRCU. Note |
| * that since we are doing it atomically, no other user could register |
| * and unregister while we do the check. |
| */ |
| downgrade_write(&context->umem_rwsem); |
| if (!context->odp_mrs_count) { |
| struct task_struct *owning_process = NULL; |
| struct mm_struct *owning_mm = NULL; |
| |
| owning_process = get_pid_task(context->tgid, |
| PIDTYPE_PID); |
| if (owning_process == NULL) |
| /* |
| * The process is already dead, notifier were removed |
| * already. |
| */ |
| goto out; |
| |
| owning_mm = get_task_mm(owning_process); |
| if (owning_mm == NULL) |
| /* |
| * The process' mm is already dead, notifier were |
| * removed already. |
| */ |
| goto out_put_task; |
| mmu_notifier_unregister(&context->mn, owning_mm); |
| |
| mmput(owning_mm); |
| |
| out_put_task: |
| put_task_struct(owning_process); |
| } |
| out: |
| up_read(&context->umem_rwsem); |
| |
| vfree(umem->odp_data->dma_list); |
| vfree(umem->odp_data->page_list); |
| kfree(umem->odp_data); |
| kfree(umem); |
| } |
| |
| /* |
| * Map for DMA and insert a single page into the on-demand paging page tables. |
| * |
| * @umem: the umem to insert the page to. |
| * @page_index: index in the umem to add the page to. |
| * @page: the page struct to map and add. |
| * @access_mask: access permissions needed for this page. |
| * @current_seq: sequence number for synchronization with invalidations. |
| * the sequence number is taken from |
| * umem->odp_data->notifiers_seq. |
| * |
| * The function returns -EFAULT if the DMA mapping operation fails. It returns |
| * -EAGAIN if a concurrent invalidation prevents us from updating the page. |
| * |
| * The page is released via put_page even if the operation failed. For |
| * on-demand pinning, the page is released whenever it isn't stored in the |
| * umem. |
| */ |
| static int ib_umem_odp_map_dma_single_page( |
| struct ib_umem *umem, |
| int page_index, |
| u64 base_virt_addr, |
| struct page *page, |
| u64 access_mask, |
| unsigned long current_seq) |
| { |
| struct ib_device *dev = umem->context->device; |
| dma_addr_t dma_addr; |
| int stored_page = 0; |
| int remove_existing_mapping = 0; |
| int ret = 0; |
| |
| /* |
| * Note: we avoid writing if seq is different from the initial seq, to |
| * handle case of a racing notifier. This check also allows us to bail |
| * early if we have a notifier running in parallel with us. |
| */ |
| if (ib_umem_mmu_notifier_retry(umem, current_seq)) { |
| ret = -EAGAIN; |
| goto out; |
| } |
| if (!(umem->odp_data->dma_list[page_index])) { |
| dma_addr = ib_dma_map_page(dev, |
| page, |
| 0, PAGE_SIZE, |
| DMA_BIDIRECTIONAL); |
| if (ib_dma_mapping_error(dev, dma_addr)) { |
| ret = -EFAULT; |
| goto out; |
| } |
| umem->odp_data->dma_list[page_index] = dma_addr | access_mask; |
| umem->odp_data->page_list[page_index] = page; |
| stored_page = 1; |
| } else if (umem->odp_data->page_list[page_index] == page) { |
| umem->odp_data->dma_list[page_index] |= access_mask; |
| } else { |
| pr_err("error: got different pages in IB device and from get_user_pages. IB device page: %p, gup page: %p\n", |
| umem->odp_data->page_list[page_index], page); |
| /* Better remove the mapping now, to prevent any further |
| * damage. */ |
| remove_existing_mapping = 1; |
| } |
| |
| out: |
| /* On Demand Paging - avoid pinning the page */ |
| if (umem->context->invalidate_range || !stored_page) |
| put_page(page); |
| |
| if (remove_existing_mapping && umem->context->invalidate_range) { |
| invalidate_page_trampoline( |
| umem, |
| base_virt_addr + (page_index * PAGE_SIZE), |
| base_virt_addr + ((page_index+1)*PAGE_SIZE), |
| NULL); |
| ret = -EAGAIN; |
| } |
| |
| return ret; |
| } |
| |
| /** |
| * ib_umem_odp_map_dma_pages - Pin and DMA map userspace memory in an ODP MR. |
| * |
| * Pins the range of pages passed in the argument, and maps them to |
| * DMA addresses. The DMA addresses of the mapped pages is updated in |
| * umem->odp_data->dma_list. |
| * |
| * Returns the number of pages mapped in success, negative error code |
| * for failure. |
| * An -EAGAIN error code is returned when a concurrent mmu notifier prevents |
| * the function from completing its task. |
| * |
| * @umem: the umem to map and pin |
| * @user_virt: the address from which we need to map. |
| * @bcnt: the minimal number of bytes to pin and map. The mapping might be |
| * bigger due to alignment, and may also be smaller in case of an error |
| * pinning or mapping a page. The actual pages mapped is returned in |
| * the return value. |
| * @access_mask: bit mask of the requested access permissions for the given |
| * range. |
| * @current_seq: the MMU notifiers sequance value for synchronization with |
| * invalidations. the sequance number is read from |
| * umem->odp_data->notifiers_seq before calling this function |
| */ |
| int ib_umem_odp_map_dma_pages(struct ib_umem *umem, u64 user_virt, u64 bcnt, |
| u64 access_mask, unsigned long current_seq) |
| { |
| struct task_struct *owning_process = NULL; |
| struct mm_struct *owning_mm = NULL; |
| struct page **local_page_list = NULL; |
| u64 off; |
| int j, k, ret = 0, start_idx, npages = 0; |
| u64 base_virt_addr; |
| |
| if (access_mask == 0) |
| return -EINVAL; |
| |
| if (user_virt < ib_umem_start(umem) || |
| user_virt + bcnt > ib_umem_end(umem)) |
| return -EFAULT; |
| |
| local_page_list = (struct page **)__get_free_page(GFP_KERNEL); |
| if (!local_page_list) |
| return -ENOMEM; |
| |
| off = user_virt & (~PAGE_MASK); |
| user_virt = user_virt & PAGE_MASK; |
| base_virt_addr = user_virt; |
| bcnt += off; /* Charge for the first page offset as well. */ |
| |
| owning_process = get_pid_task(umem->context->tgid, PIDTYPE_PID); |
| if (owning_process == NULL) { |
| ret = -EINVAL; |
| goto out_no_task; |
| } |
| |
| owning_mm = get_task_mm(owning_process); |
| if (owning_mm == NULL) { |
| ret = -EINVAL; |
| goto out_put_task; |
| } |
| |
| start_idx = (user_virt - ib_umem_start(umem)) >> PAGE_SHIFT; |
| k = start_idx; |
| |
| while (bcnt > 0) { |
| const size_t gup_num_pages = |
| min_t(size_t, ALIGN(bcnt, PAGE_SIZE) / PAGE_SIZE, |
| PAGE_SIZE / sizeof(struct page *)); |
| |
| down_read(&owning_mm->mmap_sem); |
| /* |
| * Note: this might result in redundent page getting. We can |
| * avoid this by checking dma_list to be 0 before calling |
| * get_user_pages. However, this make the code much more |
| * complex (and doesn't gain us much performance in most use |
| * cases). |
| */ |
| npages = get_user_pages_remote(owning_process, owning_mm, |
| user_virt, gup_num_pages, |
| access_mask & ODP_WRITE_ALLOWED_BIT, |
| 0, local_page_list, NULL); |
| up_read(&owning_mm->mmap_sem); |
| |
| if (npages < 0) |
| break; |
| |
| bcnt -= min_t(size_t, npages << PAGE_SHIFT, bcnt); |
| user_virt += npages << PAGE_SHIFT; |
| mutex_lock(&umem->odp_data->umem_mutex); |
| for (j = 0; j < npages; ++j) { |
| ret = ib_umem_odp_map_dma_single_page( |
| umem, k, base_virt_addr, local_page_list[j], |
| access_mask, current_seq); |
| if (ret < 0) |
| break; |
| k++; |
| } |
| mutex_unlock(&umem->odp_data->umem_mutex); |
| |
| if (ret < 0) { |
| /* Release left over pages when handling errors. */ |
| for (++j; j < npages; ++j) |
| put_page(local_page_list[j]); |
| break; |
| } |
| } |
| |
| if (ret >= 0) { |
| if (npages < 0 && k == start_idx) |
| ret = npages; |
| else |
| ret = k - start_idx; |
| } |
| |
| mmput(owning_mm); |
| out_put_task: |
| put_task_struct(owning_process); |
| out_no_task: |
| free_page((unsigned long)local_page_list); |
| return ret; |
| } |
| EXPORT_SYMBOL(ib_umem_odp_map_dma_pages); |
| |
| void ib_umem_odp_unmap_dma_pages(struct ib_umem *umem, u64 virt, |
| u64 bound) |
| { |
| int idx; |
| u64 addr; |
| struct ib_device *dev = umem->context->device; |
| |
| virt = max_t(u64, virt, ib_umem_start(umem)); |
| bound = min_t(u64, bound, ib_umem_end(umem)); |
| /* Note that during the run of this function, the |
| * notifiers_count of the MR is > 0, preventing any racing |
| * faults from completion. We might be racing with other |
| * invalidations, so we must make sure we free each page only |
| * once. */ |
| mutex_lock(&umem->odp_data->umem_mutex); |
| for (addr = virt; addr < bound; addr += (u64)umem->page_size) { |
| idx = (addr - ib_umem_start(umem)) / PAGE_SIZE; |
| if (umem->odp_data->page_list[idx]) { |
| struct page *page = umem->odp_data->page_list[idx]; |
| dma_addr_t dma = umem->odp_data->dma_list[idx]; |
| dma_addr_t dma_addr = dma & ODP_DMA_ADDR_MASK; |
| |
| WARN_ON(!dma_addr); |
| |
| ib_dma_unmap_page(dev, dma_addr, PAGE_SIZE, |
| DMA_BIDIRECTIONAL); |
| if (dma & ODP_WRITE_ALLOWED_BIT) { |
| struct page *head_page = compound_head(page); |
| /* |
| * set_page_dirty prefers being called with |
| * the page lock. However, MMU notifiers are |
| * called sometimes with and sometimes without |
| * the lock. We rely on the umem_mutex instead |
| * to prevent other mmu notifiers from |
| * continuing and allowing the page mapping to |
| * be removed. |
| */ |
| set_page_dirty(head_page); |
| } |
| /* on demand pinning support */ |
| if (!umem->context->invalidate_range) |
| put_page(page); |
| umem->odp_data->page_list[idx] = NULL; |
| umem->odp_data->dma_list[idx] = 0; |
| } |
| } |
| mutex_unlock(&umem->odp_data->umem_mutex); |
| } |
| EXPORT_SYMBOL(ib_umem_odp_unmap_dma_pages); |