1 files changed, 798 insertions, 0 deletions

diff --git a/drivers/infiniband/hw/mlx5/odp.c b/drivers/infiniband/hw/mlx5/odp.c
new file mode 100644
index 000000000000..a2c541c4809a
--- /dev/null
+++ b/drivers/infiniband/hw/mlx5/odp.c
@@ -0,0 +1,798 @@
+/*
+ * 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 <rdma/ib_umem.h>
+#include <rdma/ib_umem_odp.h>
+
+#include "mlx5_ib.h"
+
+#define MAX_PREFETCH_LEN (4*1024*1024U)
+
+/* Timeout in ms to wait for an active mmu notifier to complete when handling
+ * a pagefault. */
+#define MMU_NOTIFIER_TIMEOUT 1000
+
+struct workqueue_struct *mlx5_ib_page_fault_wq;
+
+void mlx5_ib_invalidate_range(struct ib_umem *umem, unsigned long start,
+                              unsigned long end)
+{
+        struct mlx5_ib_mr *mr;
+        const u64 umr_block_mask = (MLX5_UMR_MTT_ALIGNMENT / sizeof(u64)) - 1;
+        u64 idx = 0, blk_start_idx = 0;
+        int in_block = 0;
+        u64 addr;
+
+        if (!umem || !umem->odp_data) {
+                pr_err("invalidation called on NULL umem or non-ODP umem\n");
+                return;
+        }
+
+        mr = umem->odp_data->private;
+
+        if (!mr || !mr->ibmr.pd)
+                return;
+
+        start = max_t(u64, ib_umem_start(umem), start);
+        end = min_t(u64, ib_umem_end(umem), end);
+
+        /*
+         * Iteration one - zap the HW's MTTs. The notifiers_count ensures that
+         * while we are doing the invalidation, no page fault will attempt to
+         * overwrite the same MTTs.  Concurent invalidations might race us,
+         * but they will write 0s as well, so no difference in the end result.
+         */
+
+        for (addr = start; addr < end; addr += (u64)umem->page_size) {
+                idx = (addr - ib_umem_start(umem)) / PAGE_SIZE;
+                /*
+                 * Strive to write the MTTs in chunks, but avoid overwriting
+                 * non-existing MTTs. The huristic here can be improved to
+                 * estimate the cost of another UMR vs. the cost of bigger
+                 * UMR.
+                 */
+                if (umem->odp_data->dma_list[idx] &
+                    (ODP_READ_ALLOWED_BIT | ODP_WRITE_ALLOWED_BIT)) {
+                        if (!in_block) {
+                                blk_start_idx = idx;
+                                in_block = 1;
+                        }
+                } else {
+                        u64 umr_offset = idx & umr_block_mask;
+
+                        if (in_block && umr_offset == 0) {
+                                mlx5_ib_update_mtt(mr, blk_start_idx,
+                                                   idx - blk_start_idx, 1);
+                                in_block = 0;
+                        }
+                }
+        }
+        if (in_block)
+                mlx5_ib_update_mtt(mr, blk_start_idx, idx - blk_start_idx + 1,
+                                   1);
+
+        /*
+         * We are now sure that the device will not access the
+         * memory. We can safely unmap it, and mark it as dirty if
+         * needed.
+         */
+
+        ib_umem_odp_unmap_dma_pages(umem, start, end);
+}
+
+#define COPY_ODP_BIT_MLX_TO_IB(reg, ib_caps, field_name, bit_name) do { \
+        if (be32_to_cpu(reg.field_name) & MLX5_ODP_SUPPORT_##bit_name)  \
+                ib_caps->field_name |= IB_ODP_SUPPORT_##bit_name;       \
+} while (0)
+
+int mlx5_ib_internal_query_odp_caps(struct mlx5_ib_dev *dev)
+{
+        int err;
+        struct mlx5_odp_caps hw_caps;
+        struct ib_odp_caps *caps = &dev->odp_caps;
+
+        memset(caps, 0, sizeof(*caps));
+
+        if (!(dev->mdev->caps.gen.flags & MLX5_DEV_CAP_FLAG_ON_DMND_PG))
+                return 0;
+
+        err = mlx5_query_odp_caps(dev->mdev, &hw_caps);
+        if (err)
+                goto out;
+
+        caps->general_caps = IB_ODP_SUPPORT;
+        COPY_ODP_BIT_MLX_TO_IB(hw_caps, caps, per_transport_caps.ud_odp_caps,
+                               SEND);
+        COPY_ODP_BIT_MLX_TO_IB(hw_caps, caps, per_transport_caps.rc_odp_caps,
+                               SEND);
+        COPY_ODP_BIT_MLX_TO_IB(hw_caps, caps, per_transport_caps.rc_odp_caps,
+                               RECV);
+        COPY_ODP_BIT_MLX_TO_IB(hw_caps, caps, per_transport_caps.rc_odp_caps,
+                               WRITE);
+        COPY_ODP_BIT_MLX_TO_IB(hw_caps, caps, per_transport_caps.rc_odp_caps,
+                               READ);
+
+out:
+        return err;
+}
+
+static struct mlx5_ib_mr *mlx5_ib_odp_find_mr_lkey(struct mlx5_ib_dev *dev,
+                                                   u32 key)
+{
+        u32 base_key = mlx5_base_mkey(key);
+        struct mlx5_core_mr *mmr = __mlx5_mr_lookup(dev->mdev, base_key);
+        struct mlx5_ib_mr *mr = container_of(mmr, struct mlx5_ib_mr, mmr);
+
+        if (!mmr || mmr->key != key || !mr->live)
+                return NULL;
+
+        return container_of(mmr, struct mlx5_ib_mr, mmr);
+}
+
+static void mlx5_ib_page_fault_resume(struct mlx5_ib_qp *qp,
+                                      struct mlx5_ib_pfault *pfault,
+                                      int error) {
+        struct mlx5_ib_dev *dev = to_mdev(qp->ibqp.pd->device);
+        int ret = mlx5_core_page_fault_resume(dev->mdev, qp->mqp.qpn,
+                                              pfault->mpfault.flags,
+                                              error);
+        if (ret)
+                pr_err("Failed to resolve the page fault on QP 0x%x\n",
+                       qp->mqp.qpn);
+}
+
+/*
+ * Handle a single data segment in a page-fault WQE.
+ *
+ * Returns number of pages retrieved on success. The caller will continue to
+ * the next data segment.
+ * Can return the following error codes:
+ * -EAGAIN to designate a temporary error. The caller will abort handling the
+ *  page fault and resolve it.
+ * -EFAULT when there's an error mapping the requested pages. The caller will
+ *  abort the page fault handling and possibly move the QP to an error state.
+ * On other errors the QP should also be closed with an error.
+ */
+static int pagefault_single_data_segment(struct mlx5_ib_qp *qp,
+                                         struct mlx5_ib_pfault *pfault,
+                                         u32 key, u64 io_virt, size_t bcnt,
+                                         u32 *bytes_mapped)
+{
+        struct mlx5_ib_dev *mib_dev = to_mdev(qp->ibqp.pd->device);
+        int srcu_key;
+        unsigned int current_seq;
+        u64 start_idx;
+        int npages = 0, ret = 0;
+        struct mlx5_ib_mr *mr;
+        u64 access_mask = ODP_READ_ALLOWED_BIT;
+
+        srcu_key = srcu_read_lock(&mib_dev->mr_srcu);
+        mr = mlx5_ib_odp_find_mr_lkey(mib_dev, key);
+        /*
+         * If we didn't find the MR, it means the MR was closed while we were
+         * handling the ODP event. In this case we return -EFAULT so that the
+         * QP will be closed.
+         */
+        if (!mr || !mr->ibmr.pd) {
+                pr_err("Failed to find relevant mr for lkey=0x%06x, probably the MR was destroyed\n",
+                       key);
+                ret = -EFAULT;
+                goto srcu_unlock;
+        }
+        if (!mr->umem->odp_data) {
+                pr_debug("skipping non ODP MR (lkey=0x%06x) in page fault handler.\n",
+                         key);
+                if (bytes_mapped)
+                        *bytes_mapped +=
+                                (bcnt - pfault->mpfault.bytes_committed);
+                goto srcu_unlock;
+        }
+        if (mr->ibmr.pd != qp->ibqp.pd) {
+                pr_err("Page-fault with different PDs for QP and MR.\n");
+                ret = -EFAULT;
+                goto srcu_unlock;
+        }
+
+        current_seq = ACCESS_ONCE(mr->umem->odp_data->notifiers_seq);
+        /*
+         * Ensure the sequence number is valid for some time before we call
+         * gup.
+         */
+        smp_rmb();
+
+        /*
+         * Avoid branches - this code will perform correctly
+         * in all iterations (in iteration 2 and above,
+         * bytes_committed == 0).
+         */
+        io_virt += pfault->mpfault.bytes_committed;
+        bcnt -= pfault->mpfault.bytes_committed;
+
+        start_idx = (io_virt - (mr->mmr.iova & PAGE_MASK)) >> PAGE_SHIFT;
+
+        if (mr->umem->writable)
+                access_mask |= ODP_WRITE_ALLOWED_BIT;
+        npages = ib_umem_odp_map_dma_pages(mr->umem, io_virt, bcnt,
+                                           access_mask, current_seq);
+        if (npages < 0) {
+                ret = npages;
+                goto srcu_unlock;
+        }
+
+        if (npages > 0) {
+                mutex_lock(&mr->umem->odp_data->umem_mutex);
+                if (!ib_umem_mmu_notifier_retry(mr->umem, current_seq)) {
+                        /*
+                         * No need to check whether the MTTs really belong to
+                         * this MR, since ib_umem_odp_map_dma_pages already
+                         * checks this.
+                         */
+                        ret = mlx5_ib_update_mtt(mr, start_idx, npages, 0);
+                } else {
+                        ret = -EAGAIN;
+                }
+                mutex_unlock(&mr->umem->odp_data->umem_mutex);
+                if (ret < 0) {
+                        if (ret != -EAGAIN)
+                                pr_err("Failed to update mkey page tables\n");
+                        goto srcu_unlock;
+                }
+
+                if (bytes_mapped) {
+                        u32 new_mappings = npages * PAGE_SIZE -
+                                (io_virt - round_down(io_virt, PAGE_SIZE));
+                        *bytes_mapped += min_t(u32, new_mappings, bcnt);
+                }
+        }
+
+srcu_unlock:
+        if (ret == -EAGAIN) {
+                if (!mr->umem->odp_data->dying) {
+                        struct ib_umem_odp *odp_data = mr->umem->odp_data;
+                        unsigned long timeout =
+                                msecs_to_jiffies(MMU_NOTIFIER_TIMEOUT);
+
+                        if (!wait_for_completion_timeout(
+                                        &odp_data->notifier_completion,
+                                        timeout)) {
+                                pr_warn("timeout waiting for mmu notifier completion\n");
+                        }
+                } else {
+                        /* The MR is being killed, kill the QP as well. */
+                        ret = -EFAULT;
+                }
+        }
+        srcu_read_unlock(&mib_dev->mr_srcu, srcu_key);
+        pfault->mpfault.bytes_committed = 0;
+        return ret ? ret : npages;
+}
+
+/**
+ * Parse a series of data segments for page fault handling.
+ *
+ * @qp the QP on which the fault occurred.
+ * @pfault contains page fault information.
+ * @wqe points at the first data segment in the WQE.
+ * @wqe_end points after the end of the WQE.
+ * @bytes_mapped receives the number of bytes that the function was able to
+ *               map. This allows the caller to decide intelligently whether
+ *               enough memory was mapped to resolve the page fault
+ *               successfully (e.g. enough for the next MTU, or the entire
+ *               WQE).
+ * @total_wqe_bytes receives the total data size of this WQE in bytes (minus
+ *                  the committed bytes).
+ *
+ * Returns the number of pages loaded if positive, zero for an empty WQE, or a
+ * negative error code.
+ */
+static int pagefault_data_segments(struct mlx5_ib_qp *qp,
+                                   struct mlx5_ib_pfault *pfault, void *wqe,
+                                   void *wqe_end, u32 *bytes_mapped,
+                                   u32 *total_wqe_bytes, int receive_queue)
+{
+        int ret = 0, npages = 0;
+        u64 io_virt;
+        u32 key;
+        u32 byte_count;
+        size_t bcnt;
+        int inline_segment;
+
+        /* Skip SRQ next-WQE segment. */
+        if (receive_queue && qp->ibqp.srq)
+                wqe += sizeof(struct mlx5_wqe_srq_next_seg);
+
+        if (bytes_mapped)
+                *bytes_mapped = 0;
+        if (total_wqe_bytes)
+                *total_wqe_bytes = 0;
+
+        while (wqe < wqe_end) {
+                struct mlx5_wqe_data_seg *dseg = wqe;
+
+                io_virt = be64_to_cpu(dseg->addr);
+                key = be32_to_cpu(dseg->lkey);
+                byte_count = be32_to_cpu(dseg->byte_count);
+                inline_segment = !!(byte_count &  MLX5_INLINE_SEG);
+                bcnt           = byte_count & ~MLX5_INLINE_SEG;
+
+                if (inline_segment) {
+                        bcnt = bcnt & MLX5_WQE_INLINE_SEG_BYTE_COUNT_MASK;
+                        wqe += ALIGN(sizeof(struct mlx5_wqe_inline_seg) + bcnt,
+                                     16);
+                } else {
+                        wqe += sizeof(*dseg);
+                }
+
+                /* receive WQE end of sg list. */
+                if (receive_queue && bcnt == 0 && key == MLX5_INVALID_LKEY &&
+                    io_virt == 0)
+                        break;
+
+                if (!inline_segment && total_wqe_bytes) {
+                        *total_wqe_bytes += bcnt - min_t(size_t, bcnt,
+                                        pfault->mpfault.bytes_committed);
+                }
+
+                /* A zero length data segment designates a length of 2GB. */
+                if (bcnt == 0)
+                        bcnt = 1U << 31;
+
+                if (inline_segment || bcnt <= pfault->mpfault.bytes_committed) {
+                        pfault->mpfault.bytes_committed -=
+                                min_t(size_t, bcnt,
+                                      pfault->mpfault.bytes_committed);
+                        continue;
+                }
+
+                ret = pagefault_single_data_segment(qp, pfault, key, io_virt,
+                                                    bcnt, bytes_mapped);
+                if (ret < 0)
+                        break;
+                npages += ret;
+        }
+
+        return ret < 0 ? ret : npages;
+}
+
+/*
+ * Parse initiator WQE. Advances the wqe pointer to point at the
+ * scatter-gather list, and set wqe_end to the end of the WQE.
+ */
+static int mlx5_ib_mr_initiator_pfault_handler(
+        struct mlx5_ib_qp *qp, struct mlx5_ib_pfault *pfault,
+        void **wqe, void **wqe_end, int wqe_length)
+{
+        struct mlx5_ib_dev *dev = to_mdev(qp->ibqp.pd->device);
+        struct mlx5_wqe_ctrl_seg *ctrl = *wqe;
+        u16 wqe_index = pfault->mpfault.wqe.wqe_index;
+        unsigned ds, opcode;
+#if defined(DEBUG)
+        u32 ctrl_wqe_index, ctrl_qpn;
+#endif
+
+        ds = be32_to_cpu(ctrl->qpn_ds) & MLX5_WQE_CTRL_DS_MASK;
+        if (ds * MLX5_WQE_DS_UNITS > wqe_length) {
+                mlx5_ib_err(dev, "Unable to read the complete WQE. ds = 0x%x, ret = 0x%x\n",
+                            ds, wqe_length);
+                return -EFAULT;
+        }
+
+        if (ds == 0) {
+                mlx5_ib_err(dev, "Got WQE with zero DS. wqe_index=%x, qpn=%x\n",
+                            wqe_index, qp->mqp.qpn);
+                return -EFAULT;
+        }
+
+#if defined(DEBUG)
+        ctrl_wqe_index = (be32_to_cpu(ctrl->opmod_idx_opcode) &
+                        MLX5_WQE_CTRL_WQE_INDEX_MASK) >>
+                        MLX5_WQE_CTRL_WQE_INDEX_SHIFT;
+        if (wqe_index != ctrl_wqe_index) {
+                mlx5_ib_err(dev, "Got WQE with invalid wqe_index. wqe_index=0x%x, qpn=0x%x ctrl->wqe_index=0x%x\n",
+                            wqe_index, qp->mqp.qpn,
+                            ctrl_wqe_index);
+                return -EFAULT;
+        }
+
+        ctrl_qpn = (be32_to_cpu(ctrl->qpn_ds) & MLX5_WQE_CTRL_QPN_MASK) >>
+                MLX5_WQE_CTRL_QPN_SHIFT;
+        if (qp->mqp.qpn != ctrl_qpn) {
+                mlx5_ib_err(dev, "Got WQE with incorrect QP number. wqe_index=0x%x, qpn=0x%x ctrl->qpn=0x%x\n",
+                            wqe_index, qp->mqp.qpn,
+                            ctrl_qpn);
+                return -EFAULT;
+        }
+#endif /* DEBUG */
+
+        *wqe_end = *wqe + ds * MLX5_WQE_DS_UNITS;
+        *wqe += sizeof(*ctrl);
+
+        opcode = be32_to_cpu(ctrl->opmod_idx_opcode) &
+                 MLX5_WQE_CTRL_OPCODE_MASK;
+        switch (qp->ibqp.qp_type) {
+        case IB_QPT_RC:
+                switch (opcode) {
+                case MLX5_OPCODE_SEND:
+                case MLX5_OPCODE_SEND_IMM:
+                case MLX5_OPCODE_SEND_INVAL:
+                        if (!(dev->odp_caps.per_transport_caps.rc_odp_caps &
+                              IB_ODP_SUPPORT_SEND))
+                                goto invalid_transport_or_opcode;
+                        break;
+                case MLX5_OPCODE_RDMA_WRITE:
+                case MLX5_OPCODE_RDMA_WRITE_IMM:
+                        if (!(dev->odp_caps.per_transport_caps.rc_odp_caps &
+                              IB_ODP_SUPPORT_WRITE))
+                                goto invalid_transport_or_opcode;
+                        *wqe += sizeof(struct mlx5_wqe_raddr_seg);
+                        break;
+                case MLX5_OPCODE_RDMA_READ:
+                        if (!(dev->odp_caps.per_transport_caps.rc_odp_caps &
+                              IB_ODP_SUPPORT_READ))
+                                goto invalid_transport_or_opcode;
+                        *wqe += sizeof(struct mlx5_wqe_raddr_seg);
+                        break;
+                default:
+                        goto invalid_transport_or_opcode;
+                }
+                break;
+        case IB_QPT_UD:
+                switch (opcode) {
+                case MLX5_OPCODE_SEND:
+                case MLX5_OPCODE_SEND_IMM:
+                        if (!(dev->odp_caps.per_transport_caps.ud_odp_caps &
+                              IB_ODP_SUPPORT_SEND))
+                                goto invalid_transport_or_opcode;
+                        *wqe += sizeof(struct mlx5_wqe_datagram_seg);
+                        break;
+                default:
+                        goto invalid_transport_or_opcode;
+                }
+                break;
+        default:
+invalid_transport_or_opcode:
+                mlx5_ib_err(dev, "ODP fault on QP of an unsupported opcode or transport. transport: 0x%x opcode: 0x%x.\n",
+                            qp->ibqp.qp_type, opcode);
+                return -EFAULT;
+        }
+
+        return 0;
+}
+
+/*
+ * Parse responder WQE. Advances the wqe pointer to point at the
+ * scatter-gather list, and set wqe_end to the end of the WQE.
+ */
+static int mlx5_ib_mr_responder_pfault_handler(
+        struct mlx5_ib_qp *qp, struct mlx5_ib_pfault *pfault,
+        void **wqe, void **wqe_end, int wqe_length)
+{
+        struct mlx5_ib_dev *dev = to_mdev(qp->ibqp.pd->device);
+        struct mlx5_ib_wq *wq = &qp->rq;
+        int wqe_size = 1 << wq->wqe_shift;
+
+        if (qp->ibqp.srq) {
+                mlx5_ib_err(dev, "ODP fault on SRQ is not supported\n");
+                return -EFAULT;
+        }
+
+        if (qp->wq_sig) {
+                mlx5_ib_err(dev, "ODP fault with WQE signatures is not supported\n");
+                return -EFAULT;
+        }
+
+        if (wqe_size > wqe_length) {
+                mlx5_ib_err(dev, "Couldn't read all of the receive WQE's content\n");
+                return -EFAULT;
+        }
+
+        switch (qp->ibqp.qp_type) {
+        case IB_QPT_RC:
+                if (!(dev->odp_caps.per_transport_caps.rc_odp_caps &
+                      IB_ODP_SUPPORT_RECV))
+                        goto invalid_transport_or_opcode;
+                break;
+        default:
+invalid_transport_or_opcode:
+                mlx5_ib_err(dev, "ODP fault on QP of an unsupported transport. transport: 0x%x\n",
+                            qp->ibqp.qp_type);
+                return -EFAULT;
+        }
+
+        *wqe_end = *wqe + wqe_size;
+
+        return 0;
+}
+
+static void mlx5_ib_mr_wqe_pfault_handler(struct mlx5_ib_qp *qp,
+                                          struct mlx5_ib_pfault *pfault)
+{
+        struct mlx5_ib_dev *dev = to_mdev(qp->ibqp.pd->device);
+        int ret;
+        void *wqe, *wqe_end;
+        u32 bytes_mapped, total_wqe_bytes;
+        char *buffer = NULL;
+        int resume_with_error = 0;
+        u16 wqe_index = pfault->mpfault.wqe.wqe_index;
+        int requestor = pfault->mpfault.flags & MLX5_PFAULT_REQUESTOR;
+
+        buffer = (char *)__get_free_page(GFP_KERNEL);
+        if (!buffer) {
+                mlx5_ib_err(dev, "Error allocating memory for IO page fault handling.\n");
+                resume_with_error = 1;
+                goto resolve_page_fault;
+        }
+
+        ret = mlx5_ib_read_user_wqe(qp, requestor, wqe_index, buffer,
+                                    PAGE_SIZE);
+        if (ret < 0) {
+                mlx5_ib_err(dev, "Failed reading a WQE following page fault, error=%x, wqe_index=%x, qpn=%x\n",
+                            -ret, wqe_index, qp->mqp.qpn);
+                resume_with_error = 1;
+                goto resolve_page_fault;
+        }
+
+        wqe = buffer;
+        if (requestor)
+                ret = mlx5_ib_mr_initiator_pfault_handler(qp, pfault, &wqe,
+                                                          &wqe_end, ret);
+        else
+                ret = mlx5_ib_mr_responder_pfault_handler(qp, pfault, &wqe,
+                                                          &wqe_end, ret);
+        if (ret < 0) {
+                resume_with_error = 1;
+                goto resolve_page_fault;
+        }
+
+        if (wqe >= wqe_end) {
+                mlx5_ib_err(dev, "ODP fault on invalid WQE.\n");
+                resume_with_error = 1;
+                goto resolve_page_fault;
+        }
+
+        ret = pagefault_data_segments(qp, pfault, wqe, wqe_end, &bytes_mapped,
+                                      &total_wqe_bytes, !requestor);
+        if (ret == -EAGAIN) {
+                goto resolve_page_fault;
+        } else if (ret < 0 || total_wqe_bytes > bytes_mapped) {
+                mlx5_ib_err(dev, "Error getting user pages for page fault. Error: 0x%x\n",
+                            -ret);
+                resume_with_error = 1;
+                goto resolve_page_fault;
+        }
+
+resolve_page_fault:
+        mlx5_ib_page_fault_resume(qp, pfault, resume_with_error);
+        mlx5_ib_dbg(dev, "PAGE FAULT completed. QP 0x%x resume_with_error=%d, flags: 0x%x\n",
+                    qp->mqp.qpn, resume_with_error, pfault->mpfault.flags);
+
+        free_page((unsigned long)buffer);
+}
+
+static int pages_in_range(u64 address, u32 length)
+{
+        return (ALIGN(address + length, PAGE_SIZE) -
+                (address & PAGE_MASK)) >> PAGE_SHIFT;
+}
+
+static void mlx5_ib_mr_rdma_pfault_handler(struct mlx5_ib_qp *qp,
+                                           struct mlx5_ib_pfault *pfault)
+{
+        struct mlx5_pagefault *mpfault = &pfault->mpfault;
+        u64 address;
+        u32 length;
+        u32 prefetch_len = mpfault->bytes_committed;
+        int prefetch_activated = 0;
+        u32 rkey = mpfault->rdma.r_key;
+        int ret;
+
+        /* The RDMA responder handler handles the page fault in two parts.
+         * First it brings the necessary pages for the current packet
+         * (and uses the pfault context), and then (after resuming the QP)
+         * prefetches more pages. The second operation cannot use the pfault
+         * context and therefore uses the dummy_pfault context allocated on
+         * the stack */
+        struct mlx5_ib_pfault dummy_pfault = {};
+
+        dummy_pfault.mpfault.bytes_committed = 0;
+
+        mpfault->rdma.rdma_va += mpfault->bytes_committed;
+        mpfault->rdma.rdma_op_len -= min(mpfault->bytes_committed,
+                                         mpfault->rdma.rdma_op_len);
+        mpfault->bytes_committed = 0;
+
+        address = mpfault->rdma.rdma_va;
+        length  = mpfault->rdma.rdma_op_len;
+
+        /* For some operations, the hardware cannot tell the exact message
+         * length, and in those cases it reports zero. Use prefetch
+         * logic. */
+        if (length == 0) {
+                prefetch_activated = 1;
+                length = mpfault->rdma.packet_size;
+                prefetch_len = min(MAX_PREFETCH_LEN, prefetch_len);
+        }
+
+        ret = pagefault_single_data_segment(qp, pfault, rkey, address, length,
+                                            NULL);
+        if (ret == -EAGAIN) {
+                /* We're racing with an invalidation, don't prefetch */
+                prefetch_activated = 0;
+        } else if (ret < 0 || pages_in_range(address, length) > ret) {
+                mlx5_ib_page_fault_resume(qp, pfault, 1);
+                return;
+        }
+
+        mlx5_ib_page_fault_resume(qp, pfault, 0);
+
+        /* At this point, there might be a new pagefault already arriving in
+         * the eq, switch to the dummy pagefault for the rest of the
+         * processing. We're still OK with the objects being alive as the
+         * work-queue is being fenced. */
+
+        if (prefetch_activated) {
+                ret = pagefault_single_data_segment(qp, &dummy_pfault, rkey,
+                                                    address,
+                                                    prefetch_len,
+                                                    NULL);
+                if (ret < 0) {
+                        pr_warn("Prefetch failed (ret = %d, prefetch_activated = %d) for QPN %d, address: 0x%.16llx, length = 0x%.16x\n",
+                                ret, prefetch_activated,
+                                qp->ibqp.qp_num, address, prefetch_len);
+                }
+        }
+}
+
+void mlx5_ib_mr_pfault_handler(struct mlx5_ib_qp *qp,
+                               struct mlx5_ib_pfault *pfault)
+{
+        u8 event_subtype = pfault->mpfault.event_subtype;
+
+        switch (event_subtype) {
+        case MLX5_PFAULT_SUBTYPE_WQE:
+                mlx5_ib_mr_wqe_pfault_handler(qp, pfault);
+                break;
+        case MLX5_PFAULT_SUBTYPE_RDMA:
+                mlx5_ib_mr_rdma_pfault_handler(qp, pfault);
+                break;
+        default:
+                pr_warn("Invalid page fault event subtype: 0x%x\n",
+                        event_subtype);
+                mlx5_ib_page_fault_resume(qp, pfault, 1);
+                break;
+        }
+}
+
+static void mlx5_ib_qp_pfault_action(struct work_struct *work)
+{
+        struct mlx5_ib_pfault *pfault = container_of(work,
+                                                     struct mlx5_ib_pfault,
+                                                     work);
+        enum mlx5_ib_pagefault_context context =
+                mlx5_ib_get_pagefault_context(&pfault->mpfault);
+        struct mlx5_ib_qp *qp = container_of(pfault, struct mlx5_ib_qp,
+                                             pagefaults[context]);
+        mlx5_ib_mr_pfault_handler(qp, pfault);
+}
+
+void mlx5_ib_qp_disable_pagefaults(struct mlx5_ib_qp *qp)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave(&qp->disable_page_faults_lock, flags);
+        qp->disable_page_faults = 1;
+        spin_unlock_irqrestore(&qp->disable_page_faults_lock, flags);
+
+        /*
+         * Note that at this point, we are guarenteed that no more
+         * work queue elements will be posted to the work queue with
+         * the QP we are closing.
+         */
+        flush_workqueue(mlx5_ib_page_fault_wq);
+}
+
+void mlx5_ib_qp_enable_pagefaults(struct mlx5_ib_qp *qp)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave(&qp->disable_page_faults_lock, flags);
+        qp->disable_page_faults = 0;
+        spin_unlock_irqrestore(&qp->disable_page_faults_lock, flags);
+}
+
+static void mlx5_ib_pfault_handler(struct mlx5_core_qp *qp,
+                                   struct mlx5_pagefault *pfault)
+{
+        /*
+         * Note that we will only get one fault event per QP per context
+         * (responder/initiator, read/write), until we resolve the page fault
+         * with the mlx5_ib_page_fault_resume command. Since this function is
+         * called from within the work element, there is no risk of missing
+         * events.
+         */
+        struct mlx5_ib_qp *mibqp = to_mibqp(qp);
+        enum mlx5_ib_pagefault_context context =
+                mlx5_ib_get_pagefault_context(pfault);
+        struct mlx5_ib_pfault *qp_pfault = &mibqp->pagefaults[context];
+
+        qp_pfault->mpfault = *pfault;
+
+        /* No need to stop interrupts here since we are in an interrupt */
+        spin_lock(&mibqp->disable_page_faults_lock);
+        if (!mibqp->disable_page_faults)
+                queue_work(mlx5_ib_page_fault_wq, &qp_pfault->work);
+        spin_unlock(&mibqp->disable_page_faults_lock);
+}
+
+void mlx5_ib_odp_create_qp(struct mlx5_ib_qp *qp)
+{
+        int i;
+
+        qp->disable_page_faults = 1;
+        spin_lock_init(&qp->disable_page_faults_lock);
+
+        qp->mqp.pfault_handler  = mlx5_ib_pfault_handler;
+
+        for (i = 0; i < MLX5_IB_PAGEFAULT_CONTEXTS; ++i)
+                INIT_WORK(&qp->pagefaults[i].work, mlx5_ib_qp_pfault_action);
+}
+
+int mlx5_ib_odp_init_one(struct mlx5_ib_dev *ibdev)
+{
+        int ret;
+
+        ret = init_srcu_struct(&ibdev->mr_srcu);
+        if (ret)
+                return ret;
+
+        return 0;
+}
+
+void mlx5_ib_odp_remove_one(struct mlx5_ib_dev *ibdev)
+{
+        cleanup_srcu_struct(&ibdev->mr_srcu);
+}
+
+int __init mlx5_ib_odp_init(void)
+{
+        mlx5_ib_page_fault_wq =
+                create_singlethread_workqueue("mlx5_ib_page_faults");
+        if (!mlx5_ib_page_fault_wq)
+                return -ENOMEM;
+
+        return 0;
+}
+
+void mlx5_ib_odp_cleanup(void)
+{
+        destroy_workqueue(mlx5_ib_page_fault_wq);
+}