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- /*
- * 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/sched/mm.h>
- #include <linux/sched/task.h>
- #include <linux/pid.h>
- #include <linux/slab.h>
- #include <linux/export.h>
- #include <linux/vmalloc.h>
- #include <linux/hugetlb.h>
- #include <linux/interval_tree.h>
- #include <linux/hmm.h>
- #include <linux/pagemap.h>
- #include <rdma/ib_verbs.h>
- #include <rdma/ib_umem.h>
- #include <rdma/ib_umem_odp.h>
- #include "uverbs.h"
- static inline int ib_init_umem_odp(struct ib_umem_odp *umem_odp,
- const struct mmu_interval_notifier_ops *ops)
- {
- int ret;
- umem_odp->umem.is_odp = 1;
- mutex_init(&umem_odp->umem_mutex);
- if (!umem_odp->is_implicit_odp) {
- size_t page_size = 1UL << umem_odp->page_shift;
- unsigned long start;
- unsigned long end;
- size_t ndmas, npfns;
- start = ALIGN_DOWN(umem_odp->umem.address, page_size);
- if (check_add_overflow(umem_odp->umem.address,
- (unsigned long)umem_odp->umem.length,
- &end))
- return -EOVERFLOW;
- end = ALIGN(end, page_size);
- if (unlikely(end < page_size))
- return -EOVERFLOW;
- ndmas = (end - start) >> umem_odp->page_shift;
- if (!ndmas)
- return -EINVAL;
- npfns = (end - start) >> PAGE_SHIFT;
- umem_odp->pfn_list = kvcalloc(
- npfns, sizeof(*umem_odp->pfn_list), GFP_KERNEL);
- if (!umem_odp->pfn_list)
- return -ENOMEM;
- umem_odp->dma_list = kvcalloc(
- ndmas, sizeof(*umem_odp->dma_list), GFP_KERNEL);
- if (!umem_odp->dma_list) {
- ret = -ENOMEM;
- goto out_pfn_list;
- }
- ret = mmu_interval_notifier_insert(&umem_odp->notifier,
- umem_odp->umem.owning_mm,
- start, end - start, ops);
- if (ret)
- goto out_dma_list;
- }
- return 0;
- out_dma_list:
- kvfree(umem_odp->dma_list);
- out_pfn_list:
- kvfree(umem_odp->pfn_list);
- return ret;
- }
- /**
- * ib_umem_odp_alloc_implicit - Allocate a parent implicit ODP umem
- *
- * Implicit ODP umems do not have a VA range and do not have any page lists.
- * They exist only to hold the per_mm reference to help the driver create
- * children umems.
- *
- * @device: IB device to create UMEM
- * @access: ib_reg_mr access flags
- */
- struct ib_umem_odp *ib_umem_odp_alloc_implicit(struct ib_device *device,
- int access)
- {
- struct ib_umem *umem;
- struct ib_umem_odp *umem_odp;
- int ret;
- if (access & IB_ACCESS_HUGETLB)
- return ERR_PTR(-EINVAL);
- umem_odp = kzalloc(sizeof(*umem_odp), GFP_KERNEL);
- if (!umem_odp)
- return ERR_PTR(-ENOMEM);
- umem = &umem_odp->umem;
- umem->ibdev = device;
- umem->writable = ib_access_writable(access);
- umem->owning_mm = current->mm;
- umem_odp->is_implicit_odp = 1;
- umem_odp->page_shift = PAGE_SHIFT;
- umem_odp->tgid = get_task_pid(current->group_leader, PIDTYPE_PID);
- ret = ib_init_umem_odp(umem_odp, NULL);
- if (ret) {
- put_pid(umem_odp->tgid);
- kfree(umem_odp);
- return ERR_PTR(ret);
- }
- return umem_odp;
- }
- EXPORT_SYMBOL(ib_umem_odp_alloc_implicit);
- /**
- * ib_umem_odp_alloc_child - Allocate a child ODP umem under an implicit
- * parent ODP umem
- *
- * @root: The parent umem enclosing the child. This must be allocated using
- * ib_alloc_implicit_odp_umem()
- * @addr: The starting userspace VA
- * @size: The length of the userspace VA
- * @ops: MMU interval ops, currently only @invalidate
- */
- struct ib_umem_odp *
- ib_umem_odp_alloc_child(struct ib_umem_odp *root, unsigned long addr,
- size_t size,
- const struct mmu_interval_notifier_ops *ops)
- {
- /*
- * Caller must ensure that root cannot be freed during the call to
- * ib_alloc_odp_umem.
- */
- struct ib_umem_odp *odp_data;
- struct ib_umem *umem;
- int ret;
- if (WARN_ON(!root->is_implicit_odp))
- return ERR_PTR(-EINVAL);
- odp_data = kzalloc(sizeof(*odp_data), GFP_KERNEL);
- if (!odp_data)
- return ERR_PTR(-ENOMEM);
- umem = &odp_data->umem;
- umem->ibdev = root->umem.ibdev;
- umem->length = size;
- umem->address = addr;
- umem->writable = root->umem.writable;
- umem->owning_mm = root->umem.owning_mm;
- odp_data->page_shift = PAGE_SHIFT;
- odp_data->notifier.ops = ops;
- /*
- * A mmget must be held when registering a notifier, the owming_mm only
- * has a mm_grab at this point.
- */
- if (!mmget_not_zero(umem->owning_mm)) {
- ret = -EFAULT;
- goto out_free;
- }
- odp_data->tgid = get_pid(root->tgid);
- ret = ib_init_umem_odp(odp_data, ops);
- if (ret)
- goto out_tgid;
- mmput(umem->owning_mm);
- return odp_data;
- out_tgid:
- put_pid(odp_data->tgid);
- mmput(umem->owning_mm);
- out_free:
- kfree(odp_data);
- return ERR_PTR(ret);
- }
- EXPORT_SYMBOL(ib_umem_odp_alloc_child);
- /**
- * ib_umem_odp_get - Create a umem_odp for a userspace va
- *
- * @device: IB device struct to get UMEM
- * @addr: userspace virtual address to start at
- * @size: length of region to pin
- * @access: IB_ACCESS_xxx flags for memory being pinned
- * @ops: MMU interval ops, currently only @invalidate
- *
- * The driver should use when the access flags indicate ODP memory. It avoids
- * pinning, instead, stores the mm for future page fault handling in
- * conjunction with MMU notifiers.
- */
- struct ib_umem_odp *ib_umem_odp_get(struct ib_device *device,
- unsigned long addr, size_t size, int access,
- const struct mmu_interval_notifier_ops *ops)
- {
- struct ib_umem_odp *umem_odp;
- struct mm_struct *mm;
- int ret;
- if (WARN_ON_ONCE(!(access & IB_ACCESS_ON_DEMAND)))
- return ERR_PTR(-EINVAL);
- umem_odp = kzalloc(sizeof(struct ib_umem_odp), GFP_KERNEL);
- if (!umem_odp)
- return ERR_PTR(-ENOMEM);
- umem_odp->umem.ibdev = device;
- umem_odp->umem.length = size;
- umem_odp->umem.address = addr;
- umem_odp->umem.writable = ib_access_writable(access);
- umem_odp->umem.owning_mm = mm = current->mm;
- umem_odp->notifier.ops = ops;
- umem_odp->page_shift = PAGE_SHIFT;
- #ifdef CONFIG_HUGETLB_PAGE
- if (access & IB_ACCESS_HUGETLB)
- umem_odp->page_shift = HPAGE_SHIFT;
- #endif
- umem_odp->tgid = get_task_pid(current->group_leader, PIDTYPE_PID);
- ret = ib_init_umem_odp(umem_odp, ops);
- if (ret)
- goto err_put_pid;
- return umem_odp;
- err_put_pid:
- put_pid(umem_odp->tgid);
- kfree(umem_odp);
- return ERR_PTR(ret);
- }
- EXPORT_SYMBOL(ib_umem_odp_get);
- void ib_umem_odp_release(struct ib_umem_odp *umem_odp)
- {
- /*
- * 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.
- */
- if (!umem_odp->is_implicit_odp) {
- mutex_lock(&umem_odp->umem_mutex);
- ib_umem_odp_unmap_dma_pages(umem_odp, ib_umem_start(umem_odp),
- ib_umem_end(umem_odp));
- mutex_unlock(&umem_odp->umem_mutex);
- mmu_interval_notifier_remove(&umem_odp->notifier);
- kvfree(umem_odp->dma_list);
- kvfree(umem_odp->pfn_list);
- }
- put_pid(umem_odp->tgid);
- kfree(umem_odp);
- }
- EXPORT_SYMBOL(ib_umem_odp_release);
- /*
- * Map for DMA and insert a single page into the on-demand paging page tables.
- *
- * @umem: the umem to insert the page to.
- * @dma_index: index in the umem to add the dma 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->notifiers_seq.
- *
- * The function returns -EFAULT if the DMA mapping operation fails.
- *
- */
- static int ib_umem_odp_map_dma_single_page(
- struct ib_umem_odp *umem_odp,
- unsigned int dma_index,
- struct page *page,
- u64 access_mask)
- {
- struct ib_device *dev = umem_odp->umem.ibdev;
- dma_addr_t *dma_addr = &umem_odp->dma_list[dma_index];
- if (*dma_addr) {
- /*
- * If the page is already dma mapped it means it went through
- * a non-invalidating trasition, like read-only to writable.
- * Resync the flags.
- */
- *dma_addr = (*dma_addr & ODP_DMA_ADDR_MASK) | access_mask;
- return 0;
- }
- *dma_addr = ib_dma_map_page(dev, page, 0, 1 << umem_odp->page_shift,
- DMA_BIDIRECTIONAL);
- if (ib_dma_mapping_error(dev, *dma_addr)) {
- *dma_addr = 0;
- return -EFAULT;
- }
- umem_odp->npages++;
- *dma_addr |= access_mask;
- return 0;
- }
- /**
- * ib_umem_odp_map_dma_and_lock - DMA map userspace memory in an ODP MR and lock it.
- *
- * Maps the range passed in the argument to DMA addresses.
- * The DMA addresses of the mapped pages is updated in umem_odp->dma_list.
- * Upon success the ODP MR will be locked to let caller complete its device
- * page table update.
- *
- * Returns the number of pages mapped in success, negative error code
- * for failure.
- * @umem_odp: 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.
- * @fault: is faulting required for the given range
- */
- int ib_umem_odp_map_dma_and_lock(struct ib_umem_odp *umem_odp, u64 user_virt,
- u64 bcnt, u64 access_mask, bool fault)
- __acquires(&umem_odp->umem_mutex)
- {
- struct task_struct *owning_process = NULL;
- struct mm_struct *owning_mm = umem_odp->umem.owning_mm;
- int pfn_index, dma_index, ret = 0, start_idx;
- unsigned int page_shift, hmm_order, pfn_start_idx;
- unsigned long num_pfns, current_seq;
- struct hmm_range range = {};
- unsigned long timeout;
- if (access_mask == 0)
- return -EINVAL;
- if (user_virt < ib_umem_start(umem_odp) ||
- user_virt + bcnt > ib_umem_end(umem_odp))
- return -EFAULT;
- page_shift = umem_odp->page_shift;
- /*
- * owning_process is allowed to be NULL, this means somehow the mm is
- * existing beyond the lifetime of the originating process.. Presumably
- * mmget_not_zero will fail in this case.
- */
- owning_process = get_pid_task(umem_odp->tgid, PIDTYPE_PID);
- if (!owning_process || !mmget_not_zero(owning_mm)) {
- ret = -EINVAL;
- goto out_put_task;
- }
- range.notifier = &umem_odp->notifier;
- range.start = ALIGN_DOWN(user_virt, 1UL << page_shift);
- range.end = ALIGN(user_virt + bcnt, 1UL << page_shift);
- pfn_start_idx = (range.start - ib_umem_start(umem_odp)) >> PAGE_SHIFT;
- num_pfns = (range.end - range.start) >> PAGE_SHIFT;
- if (fault) {
- range.default_flags = HMM_PFN_REQ_FAULT;
- if (access_mask & ODP_WRITE_ALLOWED_BIT)
- range.default_flags |= HMM_PFN_REQ_WRITE;
- }
- range.hmm_pfns = &(umem_odp->pfn_list[pfn_start_idx]);
- timeout = jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
- retry:
- current_seq = range.notifier_seq =
- mmu_interval_read_begin(&umem_odp->notifier);
- mmap_read_lock(owning_mm);
- ret = hmm_range_fault(&range);
- mmap_read_unlock(owning_mm);
- if (unlikely(ret)) {
- if (ret == -EBUSY && !time_after(jiffies, timeout))
- goto retry;
- goto out_put_mm;
- }
- start_idx = (range.start - ib_umem_start(umem_odp)) >> page_shift;
- dma_index = start_idx;
- mutex_lock(&umem_odp->umem_mutex);
- if (mmu_interval_read_retry(&umem_odp->notifier, current_seq)) {
- mutex_unlock(&umem_odp->umem_mutex);
- goto retry;
- }
- for (pfn_index = 0; pfn_index < num_pfns;
- pfn_index += 1 << (page_shift - PAGE_SHIFT), dma_index++) {
- if (fault) {
- /*
- * Since we asked for hmm_range_fault() to populate
- * pages it shouldn't return an error entry on success.
- */
- WARN_ON(range.hmm_pfns[pfn_index] & HMM_PFN_ERROR);
- WARN_ON(!(range.hmm_pfns[pfn_index] & HMM_PFN_VALID));
- } else {
- if (!(range.hmm_pfns[pfn_index] & HMM_PFN_VALID)) {
- WARN_ON(umem_odp->dma_list[dma_index]);
- continue;
- }
- access_mask = ODP_READ_ALLOWED_BIT;
- if (range.hmm_pfns[pfn_index] & HMM_PFN_WRITE)
- access_mask |= ODP_WRITE_ALLOWED_BIT;
- }
- hmm_order = hmm_pfn_to_map_order(range.hmm_pfns[pfn_index]);
- /* If a hugepage was detected and ODP wasn't set for, the umem
- * page_shift will be used, the opposite case is an error.
- */
- if (hmm_order + PAGE_SHIFT < page_shift) {
- ret = -EINVAL;
- ibdev_dbg(umem_odp->umem.ibdev,
- "%s: un-expected hmm_order %d, page_shift %d\n",
- __func__, hmm_order, page_shift);
- break;
- }
- ret = ib_umem_odp_map_dma_single_page(
- umem_odp, dma_index, hmm_pfn_to_page(range.hmm_pfns[pfn_index]),
- access_mask);
- if (ret < 0) {
- ibdev_dbg(umem_odp->umem.ibdev,
- "ib_umem_odp_map_dma_single_page failed with error %d\n", ret);
- break;
- }
- }
- /* upon sucesss lock should stay on hold for the callee */
- if (!ret)
- ret = dma_index - start_idx;
- else
- mutex_unlock(&umem_odp->umem_mutex);
- out_put_mm:
- mmput(owning_mm);
- out_put_task:
- if (owning_process)
- put_task_struct(owning_process);
- return ret;
- }
- EXPORT_SYMBOL(ib_umem_odp_map_dma_and_lock);
- void ib_umem_odp_unmap_dma_pages(struct ib_umem_odp *umem_odp, u64 virt,
- u64 bound)
- {
- dma_addr_t dma_addr;
- dma_addr_t dma;
- int idx;
- u64 addr;
- struct ib_device *dev = umem_odp->umem.ibdev;
- lockdep_assert_held(&umem_odp->umem_mutex);
- virt = max_t(u64, virt, ib_umem_start(umem_odp));
- bound = min_t(u64, bound, ib_umem_end(umem_odp));
- for (addr = virt; addr < bound; addr += BIT(umem_odp->page_shift)) {
- idx = (addr - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
- dma = umem_odp->dma_list[idx];
- /* The access flags guaranteed a valid DMA address in case was NULL */
- if (dma) {
- unsigned long pfn_idx = (addr - ib_umem_start(umem_odp)) >> PAGE_SHIFT;
- struct page *page = hmm_pfn_to_page(umem_odp->pfn_list[pfn_idx]);
- dma_addr = dma & ODP_DMA_ADDR_MASK;
- ib_dma_unmap_page(dev, dma_addr,
- BIT(umem_odp->page_shift),
- 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);
- }
- umem_odp->dma_list[idx] = 0;
- umem_odp->npages--;
- }
- }
- }
- EXPORT_SYMBOL(ib_umem_odp_unmap_dma_pages);
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