Merge tag 'rdma-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband

Pull infiniband updates from Roland Dreier:
 "Main batch of InfiniBand/RDMA changes for 3.19:

   - On-demand paging support in core midlayer and mlx5 driver.  This
     lets userspace create non-pinned memory regions and have the
     adapter HW trigger page faults.
   - iSER and IPoIB updates and fixes.
   - Low-level HW driver updates for cxgb4, mlx4 and ocrdma.
   - Other miscellaneous fixes"

* tag 'rdma-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband: (56 commits)
  IB/mlx5: Implement on demand paging by adding support for MMU notifiers
  IB/mlx5: Add support for RDMA read/write responder page faults
  IB/mlx5: Handle page faults
  IB/mlx5: Page faults handling infrastructure
  IB/mlx5: Add mlx5_ib_update_mtt to update page tables after creation
  IB/mlx5: Changes in memory region creation to support on-demand paging
  IB/mlx5: Implement the ODP capability query verb
  mlx5_core: Add support for page faults events and low level handling
  mlx5_core: Re-add MLX5_DEV_CAP_FLAG_ON_DMND_PG flag
  IB/srp: Allow newline separator for connection string
  IB/core: Implement support for MMU notifiers regarding on demand paging regions
  IB/core: Add support for on demand paging regions
  IB/core: Add flags for on demand paging support
  IB/core: Add support for extended query device caps
  IB/mlx5: Add function to read WQE from user-space
  IB/core: Add umem function to read data from user-space
  IB/core: Replace ib_umem's offset field with a full address
  IB/mlx5: Enhance UMR support to allow partial page table update
  IB/mlx5: Remove per-MR pas and dma pointers
  RDMA/ocrdma: Always resolve destination mac from GRH for UD QPs
  ...

1 files changed, 668 insertions, 0 deletions

diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/infiniband/core/umem_odp.c
new file mode 100644
index 000000000000..6095872549e7
--- /dev/null
+++ b/drivers/infiniband/core/umem_odp.c
@@ -0,0 +1,668 @@
+/*
+ * 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 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)))
+		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;
+
+	mutex_lock(&umem->odp_data->umem_mutex);
+	/*
+	 * 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:
+	mutex_unlock(&umem->odp_data->umem_mutex);
+
+	/* 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(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;
+		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++;
+		}
+
+		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. */
+	for (addr = virt; addr < bound; addr += (u64)umem->page_size) {
+		idx = (addr - ib_umem_start(umem)) / PAGE_SIZE;
+		mutex_lock(&umem->odp_data->umem_mutex);
+		if (umem->odp_data->page_list[idx]) {
+			struct page *page = umem->odp_data->page_list[idx];
+			struct page *head_page = compound_head(page);
+			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)
+				/*
+				 * 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);