Merge branch 'fb' into devel

[linux-2.6] / drivers / infiniband / hw / mlx4 / qp.c

/*
 * Copyright (c) 2007 Cisco Systems, Inc. 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/log2.h>

#include <rdma/ib_cache.h>
#include <rdma/ib_pack.h>

#include <linux/mlx4/qp.h>

#include "mlx4_ib.h"
#include "user.h"

enum {
        MLX4_IB_ACK_REQ_FREQ    = 8,
};

enum {
        MLX4_IB_DEFAULT_SCHED_QUEUE     = 0x83,
        MLX4_IB_DEFAULT_QP0_SCHED_QUEUE = 0x3f
};

enum {
        /*
         * Largest possible UD header: send with GRH and immediate data.
         */
        MLX4_IB_UD_HEADER_SIZE          = 72
};

struct mlx4_ib_sqp {
        struct mlx4_ib_qp       qp;
        int                     pkey_index;
        u32                     qkey;
        u32                     send_psn;
        struct ib_ud_header     ud_header;
        u8                      header_buf[MLX4_IB_UD_HEADER_SIZE];
};

enum {
        MLX4_IB_MIN_SQ_STRIDE = 6
};

static const __be32 mlx4_ib_opcode[] = {
        [IB_WR_SEND]                    = __constant_cpu_to_be32(MLX4_OPCODE_SEND),
        [IB_WR_LSO]                     = __constant_cpu_to_be32(MLX4_OPCODE_LSO),
        [IB_WR_SEND_WITH_IMM]           = __constant_cpu_to_be32(MLX4_OPCODE_SEND_IMM),
        [IB_WR_RDMA_WRITE]              = __constant_cpu_to_be32(MLX4_OPCODE_RDMA_WRITE),
        [IB_WR_RDMA_WRITE_WITH_IMM]     = __constant_cpu_to_be32(MLX4_OPCODE_RDMA_WRITE_IMM),
        [IB_WR_RDMA_READ]               = __constant_cpu_to_be32(MLX4_OPCODE_RDMA_READ),
        [IB_WR_ATOMIC_CMP_AND_SWP]      = __constant_cpu_to_be32(MLX4_OPCODE_ATOMIC_CS),
        [IB_WR_ATOMIC_FETCH_AND_ADD]    = __constant_cpu_to_be32(MLX4_OPCODE_ATOMIC_FA),
};

static struct mlx4_ib_sqp *to_msqp(struct mlx4_ib_qp *mqp)
{
        return container_of(mqp, struct mlx4_ib_sqp, qp);
}

static int is_sqp(struct mlx4_ib_dev *dev, struct mlx4_ib_qp *qp)
{
        return qp->mqp.qpn >= dev->dev->caps.sqp_start &&
                qp->mqp.qpn <= dev->dev->caps.sqp_start + 3;
}

static int is_qp0(struct mlx4_ib_dev *dev, struct mlx4_ib_qp *qp)
{
        return qp->mqp.qpn >= dev->dev->caps.sqp_start &&
                qp->mqp.qpn <= dev->dev->caps.sqp_start + 1;
}

static void *get_wqe(struct mlx4_ib_qp *qp, int offset)
{
        return mlx4_buf_offset(&qp->buf, offset);
}

static void *get_recv_wqe(struct mlx4_ib_qp *qp, int n)
{
        return get_wqe(qp, qp->rq.offset + (n << qp->rq.wqe_shift));
}

static void *get_send_wqe(struct mlx4_ib_qp *qp, int n)
{
        return get_wqe(qp, qp->sq.offset + (n << qp->sq.wqe_shift));
}

/*
 * Stamp a SQ WQE so that it is invalid if prefetched by marking the
 * first four bytes of every 64 byte chunk with
 *     0x7FFFFFF | (invalid_ownership_value << 31).
 *
 * When the max work request size is less than or equal to the WQE
 * basic block size, as an optimization, we can stamp all WQEs with
 * 0xffffffff, and skip the very first chunk of each WQE.
 */
static void stamp_send_wqe(struct mlx4_ib_qp *qp, int n, int size)
{
        __be32 *wqe;
        int i;
        int s;
        int ind;
        void *buf;
        __be32 stamp;

        s = roundup(size, 1U << qp->sq.wqe_shift);
        if (qp->sq_max_wqes_per_wr > 1) {
                for (i = 0; i < s; i += 64) {
                        ind = (i >> qp->sq.wqe_shift) + n;
                        stamp = ind & qp->sq.wqe_cnt ? cpu_to_be32(0x7fffffff) :
                                                       cpu_to_be32(0xffffffff);
                        buf = get_send_wqe(qp, ind & (qp->sq.wqe_cnt - 1));
                        wqe = buf + (i & ((1 << qp->sq.wqe_shift) - 1));
                        *wqe = stamp;
                }
        } else {
                buf = get_send_wqe(qp, n & (qp->sq.wqe_cnt - 1));
                for (i = 64; i < s; i += 64) {
                        wqe = buf + i;
                        *wqe = cpu_to_be32(0xffffffff);
                }
        }
}

static void post_nop_wqe(struct mlx4_ib_qp *qp, int n, int size)
{
        struct mlx4_wqe_ctrl_seg *ctrl;
        struct mlx4_wqe_inline_seg *inl;
        void *wqe;
        int s;

        ctrl = wqe = get_send_wqe(qp, n & (qp->sq.wqe_cnt - 1));
        s = sizeof(struct mlx4_wqe_ctrl_seg);

        if (qp->ibqp.qp_type == IB_QPT_UD) {
                struct mlx4_wqe_datagram_seg *dgram = wqe + sizeof *ctrl;
                struct mlx4_av *av = (struct mlx4_av *)dgram->av;
                memset(dgram, 0, sizeof *dgram);
                av->port_pd = cpu_to_be32((qp->port << 24) | to_mpd(qp->ibqp.pd)->pdn);
                s += sizeof(struct mlx4_wqe_datagram_seg);
        }

        /* Pad the remainder of the WQE with an inline data segment. */
        if (size > s) {
                inl = wqe + s;
                inl->byte_count = cpu_to_be32(1 << 31 | (size - s - sizeof *inl));
        }
        ctrl->srcrb_flags = 0;
        ctrl->fence_size = size / 16;
        /*
         * Make sure descriptor is fully written before setting ownership bit
         * (because HW can start executing as soon as we do).
         */
        wmb();

        ctrl->owner_opcode = cpu_to_be32(MLX4_OPCODE_NOP | MLX4_WQE_CTRL_NEC) |
                (n & qp->sq.wqe_cnt ? cpu_to_be32(1 << 31) : 0);

        stamp_send_wqe(qp, n + qp->sq_spare_wqes, size);
}

/* Post NOP WQE to prevent wrap-around in the middle of WR */
static inline unsigned pad_wraparound(struct mlx4_ib_qp *qp, int ind)
{
        unsigned s = qp->sq.wqe_cnt - (ind & (qp->sq.wqe_cnt - 1));
        if (unlikely(s < qp->sq_max_wqes_per_wr)) {
                post_nop_wqe(qp, ind, s << qp->sq.wqe_shift);
                ind += s;
        }
        return ind;
}

static void mlx4_ib_qp_event(struct mlx4_qp *qp, enum mlx4_event type)
{
        struct ib_event event;
        struct ib_qp *ibqp = &to_mibqp(qp)->ibqp;

        if (type == MLX4_EVENT_TYPE_PATH_MIG)
                to_mibqp(qp)->port = to_mibqp(qp)->alt_port;

        if (ibqp->event_handler) {
                event.device     = ibqp->device;
                event.element.qp = ibqp;
                switch (type) {
                case MLX4_EVENT_TYPE_PATH_MIG:
                        event.event = IB_EVENT_PATH_MIG;
                        break;
                case MLX4_EVENT_TYPE_COMM_EST:
                        event.event = IB_EVENT_COMM_EST;
                        break;
                case MLX4_EVENT_TYPE_SQ_DRAINED:
                        event.event = IB_EVENT_SQ_DRAINED;
                        break;
                case MLX4_EVENT_TYPE_SRQ_QP_LAST_WQE:
                        event.event = IB_EVENT_QP_LAST_WQE_REACHED;
                        break;
                case MLX4_EVENT_TYPE_WQ_CATAS_ERROR:
                        event.event = IB_EVENT_QP_FATAL;
                        break;
                case MLX4_EVENT_TYPE_PATH_MIG_FAILED:
                        event.event = IB_EVENT_PATH_MIG_ERR;
                        break;
                case MLX4_EVENT_TYPE_WQ_INVAL_REQ_ERROR:
                        event.event = IB_EVENT_QP_REQ_ERR;
                        break;
                case MLX4_EVENT_TYPE_WQ_ACCESS_ERROR:
                        event.event = IB_EVENT_QP_ACCESS_ERR;
                        break;
                default:
                        printk(KERN_WARNING "mlx4_ib: Unexpected event type %d "
                               "on QP %06x\n", type, qp->qpn);
                        return;
                }

                ibqp->event_handler(&event, ibqp->qp_context);
        }
}

static int send_wqe_overhead(enum ib_qp_type type, u32 flags)
{
        /*
         * UD WQEs must have a datagram segment.
         * RC and UC WQEs might have a remote address segment.
         * MLX WQEs need two extra inline data segments (for the UD
         * header and space for the ICRC).
         */
        switch (type) {
        case IB_QPT_UD:
                return sizeof (struct mlx4_wqe_ctrl_seg) +
                        sizeof (struct mlx4_wqe_datagram_seg) +
                        ((flags & MLX4_IB_QP_LSO) ? 64 : 0);
        case IB_QPT_UC:
                return sizeof (struct mlx4_wqe_ctrl_seg) +
                        sizeof (struct mlx4_wqe_raddr_seg);
        case IB_QPT_RC:
                return sizeof (struct mlx4_wqe_ctrl_seg) +
                        sizeof (struct mlx4_wqe_atomic_seg) +
                        sizeof (struct mlx4_wqe_raddr_seg);
        case IB_QPT_SMI:
        case IB_QPT_GSI:
                return sizeof (struct mlx4_wqe_ctrl_seg) +
                        ALIGN(MLX4_IB_UD_HEADER_SIZE +
                              DIV_ROUND_UP(MLX4_IB_UD_HEADER_SIZE,
                                           MLX4_INLINE_ALIGN) *
                              sizeof (struct mlx4_wqe_inline_seg),
                              sizeof (struct mlx4_wqe_data_seg)) +
                        ALIGN(4 +
                              sizeof (struct mlx4_wqe_inline_seg),
                              sizeof (struct mlx4_wqe_data_seg));
        default:
                return sizeof (struct mlx4_wqe_ctrl_seg);
        }
}

static int set_rq_size(struct mlx4_ib_dev *dev, struct ib_qp_cap *cap,
                       int is_user, int has_srq, struct mlx4_ib_qp *qp)
{
        /* Sanity check RQ size before proceeding */
        if (cap->max_recv_wr  > dev->dev->caps.max_wqes  ||
            cap->max_recv_sge > dev->dev->caps.max_rq_sg)
                return -EINVAL;

        if (has_srq) {
                /* QPs attached to an SRQ should have no RQ */
                if (cap->max_recv_wr)
                        return -EINVAL;

                qp->rq.wqe_cnt = qp->rq.max_gs = 0;
        } else {
                /* HW requires >= 1 RQ entry with >= 1 gather entry */
                if (is_user && (!cap->max_recv_wr || !cap->max_recv_sge))
                        return -EINVAL;

                qp->rq.wqe_cnt   = roundup_pow_of_two(max(1U, cap->max_recv_wr));
                qp->rq.max_gs    = roundup_pow_of_two(max(1U, cap->max_recv_sge));
                qp->rq.wqe_shift = ilog2(qp->rq.max_gs * sizeof (struct mlx4_wqe_data_seg));
        }

        cap->max_recv_wr  = qp->rq.max_post = qp->rq.wqe_cnt;
        cap->max_recv_sge = qp->rq.max_gs;

        return 0;
}

static int set_kernel_sq_size(struct mlx4_ib_dev *dev, struct ib_qp_cap *cap,
                              enum ib_qp_type type, struct mlx4_ib_qp *qp)
{
        int s;

        /* Sanity check SQ size before proceeding */
        if (cap->max_send_wr     > dev->dev->caps.max_wqes  ||
            cap->max_send_sge    > dev->dev->caps.max_sq_sg ||
            cap->max_inline_data + send_wqe_overhead(type, qp->flags) +
            sizeof (struct mlx4_wqe_inline_seg) > dev->dev->caps.max_sq_desc_sz)
                return -EINVAL;

        /*
         * For MLX transport we need 2 extra S/G entries:
         * one for the header and one for the checksum at the end
         */
        if ((type == IB_QPT_SMI || type == IB_QPT_GSI) &&
            cap->max_send_sge + 2 > dev->dev->caps.max_sq_sg)
                return -EINVAL;

        s = max(cap->max_send_sge * sizeof (struct mlx4_wqe_data_seg),
                cap->max_inline_data + sizeof (struct mlx4_wqe_inline_seg)) +
                send_wqe_overhead(type, qp->flags);

        if (s > dev->dev->caps.max_sq_desc_sz)
                return -EINVAL;

        /*
         * Hermon supports shrinking WQEs, such that a single work
         * request can include multiple units of 1 << wqe_shift.  This
         * way, work requests can differ in size, and do not have to
         * be a power of 2 in size, saving memory and speeding up send
         * WR posting.  Unfortunately, if we do this then the
         * wqe_index field in CQEs can't be used to look up the WR ID
         * anymore, so we do this only if selective signaling is off.
         *
         * Further, on 32-bit platforms, we can't use vmap() to make
         * the QP buffer virtually contigious.  Thus we have to use
         * constant-sized WRs to make sure a WR is always fully within
         * a single page-sized chunk.
         *
         * Finally, we use NOP work requests to pad the end of the
         * work queue, to avoid wrap-around in the middle of WR.  We
         * set NEC bit to avoid getting completions with error for
         * these NOP WRs, but since NEC is only supported starting
         * with firmware 2.2.232, we use constant-sized WRs for older
         * firmware.
         *
         * And, since MLX QPs only support SEND, we use constant-sized
         * WRs in this case.
         *
         * We look for the smallest value of wqe_shift such that the
         * resulting number of wqes does not exceed device
         * capabilities.
         *
         * We set WQE size to at least 64 bytes, this way stamping
         * invalidates each WQE.
         */
        if (dev->dev->caps.fw_ver >= MLX4_FW_VER_WQE_CTRL_NEC &&
            qp->sq_signal_bits && BITS_PER_LONG == 64 &&
            type != IB_QPT_SMI && type != IB_QPT_GSI)
                qp->sq.wqe_shift = ilog2(64);
        else
                qp->sq.wqe_shift = ilog2(roundup_pow_of_two(s));

        for (;;) {
                qp->sq_max_wqes_per_wr = DIV_ROUND_UP(s, 1U << qp->sq.wqe_shift);

                /*
                 * We need to leave 2 KB + 1 WR of headroom in the SQ to
                 * allow HW to prefetch.
                 */
                qp->sq_spare_wqes = (2048 >> qp->sq.wqe_shift) + qp->sq_max_wqes_per_wr;
                qp->sq.wqe_cnt = roundup_pow_of_two(cap->max_send_wr *
                                                    qp->sq_max_wqes_per_wr +
                                                    qp->sq_spare_wqes);

                if (qp->sq.wqe_cnt <= dev->dev->caps.max_wqes)
                        break;

                if (qp->sq_max_wqes_per_wr <= 1)
                        return -EINVAL;

                ++qp->sq.wqe_shift;
        }

        qp->sq.max_gs = (min(dev->dev->caps.max_sq_desc_sz,
                             (qp->sq_max_wqes_per_wr << qp->sq.wqe_shift)) -
                         send_wqe_overhead(type, qp->flags)) /
                sizeof (struct mlx4_wqe_data_seg);

        qp->buf_size = (qp->rq.wqe_cnt << qp->rq.wqe_shift) +
                (qp->sq.wqe_cnt << qp->sq.wqe_shift);
        if (qp->rq.wqe_shift > qp->sq.wqe_shift) {
                qp->rq.offset = 0;
                qp->sq.offset = qp->rq.wqe_cnt << qp->rq.wqe_shift;
        } else {
                qp->rq.offset = qp->sq.wqe_cnt << qp->sq.wqe_shift;
                qp->sq.offset = 0;
        }

        cap->max_send_wr  = qp->sq.max_post =
                (qp->sq.wqe_cnt - qp->sq_spare_wqes) / qp->sq_max_wqes_per_wr;
        cap->max_send_sge = min(qp->sq.max_gs,
                                min(dev->dev->caps.max_sq_sg,
                                    dev->dev->caps.max_rq_sg));
        /* We don't support inline sends for kernel QPs (yet) */
        cap->max_inline_data = 0;

        return 0;
}

static int set_user_sq_size(struct mlx4_ib_dev *dev,
                            struct mlx4_ib_qp *qp,
                            struct mlx4_ib_create_qp *ucmd)
{
        /* Sanity check SQ size before proceeding */
        if ((1 << ucmd->log_sq_bb_count) > dev->dev->caps.max_wqes       ||
            ucmd->log_sq_stride >
                ilog2(roundup_pow_of_two(dev->dev->caps.max_sq_desc_sz)) ||
            ucmd->log_sq_stride < MLX4_IB_MIN_SQ_STRIDE)
                return -EINVAL;

        qp->sq.wqe_cnt   = 1 << ucmd->log_sq_bb_count;
        qp->sq.wqe_shift = ucmd->log_sq_stride;

        qp->buf_size = (qp->rq.wqe_cnt << qp->rq.wqe_shift) +
                (qp->sq.wqe_cnt << qp->sq.wqe_shift);

        return 0;
}

static int create_qp_common(struct mlx4_ib_dev *dev, struct ib_pd *pd,
                            struct ib_qp_init_attr *init_attr,
                            struct ib_udata *udata, int sqpn, struct mlx4_ib_qp *qp)
{
        int err;

        mutex_init(&qp->mutex);
        spin_lock_init(&qp->sq.lock);
        spin_lock_init(&qp->rq.lock);

        qp->state        = IB_QPS_RESET;
        qp->atomic_rd_en = 0;
        qp->resp_depth   = 0;

        qp->rq.head         = 0;
        qp->rq.tail         = 0;
        qp->sq.head         = 0;
        qp->sq.tail         = 0;
        qp->sq_next_wqe     = 0;

        if (init_attr->sq_sig_type == IB_SIGNAL_ALL_WR)
                qp->sq_signal_bits = cpu_to_be32(MLX4_WQE_CTRL_CQ_UPDATE);
        else
                qp->sq_signal_bits = 0;

        err = set_rq_size(dev, &init_attr->cap, !!pd->uobject, !!init_attr->srq, qp);
        if (err)
                goto err;

        if (pd->uobject) {
                struct mlx4_ib_create_qp ucmd;

                if (ib_copy_from_udata(&ucmd, udata, sizeof ucmd)) {
                        err = -EFAULT;
                        goto err;
                }

                qp->sq_no_prefetch = ucmd.sq_no_prefetch;

                err = set_user_sq_size(dev, qp, &ucmd);
                if (err)
                        goto err;

                qp->umem = ib_umem_get(pd->uobject->context, ucmd.buf_addr,
                                       qp->buf_size, 0, 0);
                if (IS_ERR(qp->umem)) {
                        err = PTR_ERR(qp->umem);
                        goto err;
                }

                err = mlx4_mtt_init(dev->dev, ib_umem_page_count(qp->umem),
                                    ilog2(qp->umem->page_size), &qp->mtt);
                if (err)
                        goto err_buf;

                err = mlx4_ib_umem_write_mtt(dev, &qp->mtt, qp->umem);
                if (err)
                        goto err_mtt;

                if (!init_attr->srq) {
                        err = mlx4_ib_db_map_user(to_mucontext(pd->uobject->context),
                                                  ucmd.db_addr, &qp->db);
                        if (err)
                                goto err_mtt;
                }
        } else {
                qp->sq_no_prefetch = 0;

                if (init_attr->create_flags & IB_QP_CREATE_IPOIB_UD_LSO)
                        qp->flags |= MLX4_IB_QP_LSO;

                err = set_kernel_sq_size(dev, &init_attr->cap, init_attr->qp_type, qp);
                if (err)
                        goto err;

                if (!init_attr->srq) {
                        err = mlx4_db_alloc(dev->dev, &qp->db, 0);
                        if (err)
                                goto err;

                        *qp->db.db = 0;
                }

                if (mlx4_buf_alloc(dev->dev, qp->buf_size, PAGE_SIZE * 2, &qp->buf)) {
                        err = -ENOMEM;
                        goto err_db;
                }

                err = mlx4_mtt_init(dev->dev, qp->buf.npages, qp->buf.page_shift,
                                    &qp->mtt);
                if (err)
                        goto err_buf;

                err = mlx4_buf_write_mtt(dev->dev, &qp->mtt, &qp->buf);
                if (err)
                        goto err_mtt;

                qp->sq.wrid  = kmalloc(qp->sq.wqe_cnt * sizeof (u64), GFP_KERNEL);
                qp->rq.wrid  = kmalloc(qp->rq.wqe_cnt * sizeof (u64), GFP_KERNEL);

                if (!qp->sq.wrid || !qp->rq.wrid) {
                        err = -ENOMEM;
                        goto err_wrid;
                }
        }

        err = mlx4_qp_alloc(dev->dev, sqpn, &qp->mqp);
        if (err)
                goto err_wrid;

        /*
         * Hardware wants QPN written in big-endian order (after
         * shifting) for send doorbell.  Precompute this value to save
         * a little bit when posting sends.
         */
        qp->doorbell_qpn = swab32(qp->mqp.qpn << 8);

        qp->mqp.event = mlx4_ib_qp_event;

        return 0;

err_wrid:
        if (pd->uobject) {
                if (!init_attr->srq)
                        mlx4_ib_db_unmap_user(to_mucontext(pd->uobject->context),
                                              &qp->db);
        } else {
                kfree(qp->sq.wrid);
                kfree(qp->rq.wrid);
        }

err_mtt:
        mlx4_mtt_cleanup(dev->dev, &qp->mtt);

err_buf:
        if (pd->uobject)
                ib_umem_release(qp->umem);
        else
                mlx4_buf_free(dev->dev, qp->buf_size, &qp->buf);

err_db:
        if (!pd->uobject && !init_attr->srq)
                mlx4_db_free(dev->dev, &qp->db);

err:
        return err;
}

static enum mlx4_qp_state to_mlx4_state(enum ib_qp_state state)
{
        switch (state) {
        case IB_QPS_RESET:      return MLX4_QP_STATE_RST;
        case IB_QPS_INIT:       return MLX4_QP_STATE_INIT;
        case IB_QPS_RTR:        return MLX4_QP_STATE_RTR;
        case IB_QPS_RTS:        return MLX4_QP_STATE_RTS;
        case IB_QPS_SQD:        return MLX4_QP_STATE_SQD;
        case IB_QPS_SQE:        return MLX4_QP_STATE_SQER;
        case IB_QPS_ERR:        return MLX4_QP_STATE_ERR;
        default:                return -1;
        }
}

static void mlx4_ib_lock_cqs(struct mlx4_ib_cq *send_cq, struct mlx4_ib_cq *recv_cq)
{
        if (send_cq == recv_cq)
                spin_lock_irq(&send_cq->lock);
        else if (send_cq->mcq.cqn < recv_cq->mcq.cqn) {
                spin_lock_irq(&send_cq->lock);
                spin_lock_nested(&recv_cq->lock, SINGLE_DEPTH_NESTING);
        } else {
                spin_lock_irq(&recv_cq->lock);
                spin_lock_nested(&send_cq->lock, SINGLE_DEPTH_NESTING);
        }
}

static void mlx4_ib_unlock_cqs(struct mlx4_ib_cq *send_cq, struct mlx4_ib_cq *recv_cq)
{
        if (send_cq == recv_cq)
                spin_unlock_irq(&send_cq->lock);
        else if (send_cq->mcq.cqn < recv_cq->mcq.cqn) {
                spin_unlock(&recv_cq->lock);
                spin_unlock_irq(&send_cq->lock);
        } else {
                spin_unlock(&send_cq->lock);
                spin_unlock_irq(&recv_cq->lock);
        }
}

static void destroy_qp_common(struct mlx4_ib_dev *dev, struct mlx4_ib_qp *qp,
                              int is_user)
{
        struct mlx4_ib_cq *send_cq, *recv_cq;

        if (qp->state != IB_QPS_RESET)
                if (mlx4_qp_modify(dev->dev, NULL, to_mlx4_state(qp->state),
                                   MLX4_QP_STATE_RST, NULL, 0, 0, &qp->mqp))
                        printk(KERN_WARNING "mlx4_ib: modify QP %06x to RESET failed.\n",
                               qp->mqp.qpn);

        send_cq = to_mcq(qp->ibqp.send_cq);
        recv_cq = to_mcq(qp->ibqp.recv_cq);

        mlx4_ib_lock_cqs(send_cq, recv_cq);

        if (!is_user) {
                __mlx4_ib_cq_clean(recv_cq, qp->mqp.qpn,
                                 qp->ibqp.srq ? to_msrq(qp->ibqp.srq): NULL);
                if (send_cq != recv_cq)
                        __mlx4_ib_cq_clean(send_cq, qp->mqp.qpn, NULL);
        }

        mlx4_qp_remove(dev->dev, &qp->mqp);

        mlx4_ib_unlock_cqs(send_cq, recv_cq);

        mlx4_qp_free(dev->dev, &qp->mqp);
        mlx4_mtt_cleanup(dev->dev, &qp->mtt);

        if (is_user) {
                if (!qp->ibqp.srq)
                        mlx4_ib_db_unmap_user(to_mucontext(qp->ibqp.uobject->context),
                                              &qp->db);
                ib_umem_release(qp->umem);
        } else {
                kfree(qp->sq.wrid);
                kfree(qp->rq.wrid);
                mlx4_buf_free(dev->dev, qp->buf_size, &qp->buf);
                if (!qp->ibqp.srq)
                        mlx4_db_free(dev->dev, &qp->db);
        }
}

struct ib_qp *mlx4_ib_create_qp(struct ib_pd *pd,
                                struct ib_qp_init_attr *init_attr,
                                struct ib_udata *udata)
{
        struct mlx4_ib_dev *dev = to_mdev(pd->device);
        struct mlx4_ib_sqp *sqp;
        struct mlx4_ib_qp *qp;
        int err;

        /* We only support LSO, and only for kernel UD QPs. */
        if (init_attr->create_flags & ~IB_QP_CREATE_IPOIB_UD_LSO)
                return ERR_PTR(-EINVAL);
        if (init_attr->create_flags & IB_QP_CREATE_IPOIB_UD_LSO &&
            (pd->uobject || init_attr->qp_type != IB_QPT_UD))
                return ERR_PTR(-EINVAL);

        switch (init_attr->qp_type) {
        case IB_QPT_RC:
        case IB_QPT_UC:
        case IB_QPT_UD:
        {
                qp = kmalloc(sizeof *qp, GFP_KERNEL);
                if (!qp)
                        return ERR_PTR(-ENOMEM);

                err = create_qp_common(dev, pd, init_attr, udata, 0, qp);
                if (err) {
                        kfree(qp);
                        return ERR_PTR(err);
                }

                qp->ibqp.qp_num = qp->mqp.qpn;

                break;
        }
        case IB_QPT_SMI:
        case IB_QPT_GSI:
        {
                /* Userspace is not allowed to create special QPs: */
                if (pd->uobject)
                        return ERR_PTR(-EINVAL);

                sqp = kmalloc(sizeof *sqp, GFP_KERNEL);
                if (!sqp)
                        return ERR_PTR(-ENOMEM);

                qp = &sqp->qp;

                err = create_qp_common(dev, pd, init_attr, udata,
                                       dev->dev->caps.sqp_start +
                                       (init_attr->qp_type == IB_QPT_SMI ? 0 : 2) +
                                       init_attr->port_num - 1,
                                       qp);
                if (err) {
                        kfree(sqp);
                        return ERR_PTR(err);
                }

                qp->port        = init_attr->port_num;
                qp->ibqp.qp_num = init_attr->qp_type == IB_QPT_SMI ? 0 : 1;

                break;
        }
        default:
                /* Don't support raw QPs */
                return ERR_PTR(-EINVAL);
        }

        return &qp->ibqp;
}

int mlx4_ib_destroy_qp(struct ib_qp *qp)
{
        struct mlx4_ib_dev *dev = to_mdev(qp->device);
        struct mlx4_ib_qp *mqp = to_mqp(qp);

        if (is_qp0(dev, mqp))
                mlx4_CLOSE_PORT(dev->dev, mqp->port);

        destroy_qp_common(dev, mqp, !!qp->pd->uobject);

        if (is_sqp(dev, mqp))
                kfree(to_msqp(mqp));
        else
                kfree(mqp);

        return 0;
}

static int to_mlx4_st(enum ib_qp_type type)
{
        switch (type) {
        case IB_QPT_RC:         return MLX4_QP_ST_RC;
        case IB_QPT_UC:         return MLX4_QP_ST_UC;
        case IB_QPT_UD:         return MLX4_QP_ST_UD;
        case IB_QPT_SMI:
        case IB_QPT_GSI:        return MLX4_QP_ST_MLX;
        default:                return -1;
        }
}

static __be32 to_mlx4_access_flags(struct mlx4_ib_qp *qp, const struct ib_qp_attr *attr,
                                   int attr_mask)
{
        u8 dest_rd_atomic;
        u32 access_flags;
        u32 hw_access_flags = 0;

        if (attr_mask & IB_QP_MAX_DEST_RD_ATOMIC)
                dest_rd_atomic = attr->max_dest_rd_atomic;
        else
                dest_rd_atomic = qp->resp_depth;

        if (attr_mask & IB_QP_ACCESS_FLAGS)
                access_flags = attr->qp_access_flags;
        else
                access_flags = qp->atomic_rd_en;

        if (!dest_rd_atomic)
                access_flags &= IB_ACCESS_REMOTE_WRITE;

        if (access_flags & IB_ACCESS_REMOTE_READ)
                hw_access_flags |= MLX4_QP_BIT_RRE;
        if (access_flags & IB_ACCESS_REMOTE_ATOMIC)
                hw_access_flags |= MLX4_QP_BIT_RAE;
        if (access_flags & IB_ACCESS_REMOTE_WRITE)
                hw_access_flags |= MLX4_QP_BIT_RWE;

        return cpu_to_be32(hw_access_flags);
}

static void store_sqp_attrs(struct mlx4_ib_sqp *sqp, const struct ib_qp_attr *attr,
                            int attr_mask)
{
        if (attr_mask & IB_QP_PKEY_INDEX)
                sqp->pkey_index = attr->pkey_index;
        if (attr_mask & IB_QP_QKEY)
                sqp->qkey = attr->qkey;
        if (attr_mask & IB_QP_SQ_PSN)
                sqp->send_psn = attr->sq_psn;
}

static void mlx4_set_sched(struct mlx4_qp_path *path, u8 port)
{
        path->sched_queue = (path->sched_queue & 0xbf) | ((port - 1) << 6);
}

static int mlx4_set_path(struct mlx4_ib_dev *dev, const struct ib_ah_attr *ah,
                         struct mlx4_qp_path *path, u8 port)
{
        path->grh_mylmc     = ah->src_path_bits & 0x7f;
        path->rlid          = cpu_to_be16(ah->dlid);
        if (ah->static_rate) {
                path->static_rate = ah->static_rate + MLX4_STAT_RATE_OFFSET;
                while (path->static_rate > IB_RATE_2_5_GBPS + MLX4_STAT_RATE_OFFSET &&
                       !(1 << path->static_rate & dev->dev->caps.stat_rate_support))
                        --path->static_rate;
        } else
                path->static_rate = 0;
        path->counter_index = 0xff;

        if (ah->ah_flags & IB_AH_GRH) {
                if (ah->grh.sgid_index >= dev->dev->caps.gid_table_len[port]) {
                        printk(KERN_ERR "sgid_index (%u) too large. max is %d\n",
                               ah->grh.sgid_index, dev->dev->caps.gid_table_len[port] - 1);
                        return -1;
                }

                path->grh_mylmc |= 1 << 7;
                path->mgid_index = ah->grh.sgid_index;
                path->hop_limit  = ah->grh.hop_limit;
                path->tclass_flowlabel =
                        cpu_to_be32((ah->grh.traffic_class << 20) |
                                    (ah->grh.flow_label));
                memcpy(path->rgid, ah->grh.dgid.raw, 16);
        }

        path->sched_queue = MLX4_IB_DEFAULT_SCHED_QUEUE |
                ((port - 1) << 6) | ((ah->sl & 0xf) << 2);

        return 0;
}

static int __mlx4_ib_modify_qp(struct ib_qp *ibqp,
                               const struct ib_qp_attr *attr, int attr_mask,
                               enum ib_qp_state cur_state, enum ib_qp_state new_state)
{
        struct mlx4_ib_dev *dev = to_mdev(ibqp->device);
        struct mlx4_ib_qp *qp = to_mqp(ibqp);
        struct mlx4_qp_context *context;
        enum mlx4_qp_optpar optpar = 0;
        int sqd_event;
        int err = -EINVAL;

        context = kzalloc(sizeof *context, GFP_KERNEL);
        if (!context)
                return -ENOMEM;

        context->flags = cpu_to_be32((to_mlx4_state(new_state) << 28) |
                                     (to_mlx4_st(ibqp->qp_type) << 16));
        context->flags     |= cpu_to_be32(1 << 8); /* DE? */

        if (!(attr_mask & IB_QP_PATH_MIG_STATE))
                context->flags |= cpu_to_be32(MLX4_QP_PM_MIGRATED << 11);
        else {
                optpar |= MLX4_QP_OPTPAR_PM_STATE;
                switch (attr->path_mig_state) {
                case IB_MIG_MIGRATED:
                        context->flags |= cpu_to_be32(MLX4_QP_PM_MIGRATED << 11);
                        break;
                case IB_MIG_REARM:
                        context->flags |= cpu_to_be32(MLX4_QP_PM_REARM << 11);
                        break;
                case IB_MIG_ARMED:
                        context->flags |= cpu_to_be32(MLX4_QP_PM_ARMED << 11);
                        break;
                }
        }

        if (ibqp->qp_type == IB_QPT_GSI || ibqp->qp_type == IB_QPT_SMI)
                context->mtu_msgmax = (IB_MTU_4096 << 5) | 11;
        else if (ibqp->qp_type == IB_QPT_UD) {
                if (qp->flags & MLX4_IB_QP_LSO)
                        context->mtu_msgmax = (IB_MTU_4096 << 5) |
                                              ilog2(dev->dev->caps.max_gso_sz);
                else
                        context->mtu_msgmax = (IB_MTU_4096 << 5) | 11;
        } else if (attr_mask & IB_QP_PATH_MTU) {
                if (attr->path_mtu < IB_MTU_256 || attr->path_mtu > IB_MTU_4096) {
                        printk(KERN_ERR "path MTU (%u) is invalid\n",
                               attr->path_mtu);
                        goto out;
                }
                context->mtu_msgmax = (attr->path_mtu << 5) | 31;
        }

        if (qp->rq.wqe_cnt)
                context->rq_size_stride = ilog2(qp->rq.wqe_cnt) << 3;
        context->rq_size_stride |= qp->rq.wqe_shift - 4;

        if (qp->sq.wqe_cnt)
                context->sq_size_stride = ilog2(qp->sq.wqe_cnt) << 3;
        context->sq_size_stride |= qp->sq.wqe_shift - 4;

        if (cur_state == IB_QPS_RESET && new_state == IB_QPS_INIT)
                context->sq_size_stride |= !!qp->sq_no_prefetch << 7;

        if (qp->ibqp.uobject)
                context->usr_page = cpu_to_be32(to_mucontext(ibqp->uobject->context)->uar.index);
        else
                context->usr_page = cpu_to_be32(dev->priv_uar.index);

        if (attr_mask & IB_QP_DEST_QPN)
                context->remote_qpn = cpu_to_be32(attr->dest_qp_num);

        if (attr_mask & IB_QP_PORT) {
                if (cur_state == IB_QPS_SQD && new_state == IB_QPS_SQD &&
                    !(attr_mask & IB_QP_AV)) {
                        mlx4_set_sched(&context->pri_path, attr->port_num);
                        optpar |= MLX4_QP_OPTPAR_SCHED_QUEUE;
                }
        }

        if (attr_mask & IB_QP_PKEY_INDEX) {
                context->pri_path.pkey_index = attr->pkey_index;
                optpar |= MLX4_QP_OPTPAR_PKEY_INDEX;
        }

        if (attr_mask & IB_QP_AV) {
                if (mlx4_set_path(dev, &attr->ah_attr, &context->pri_path,
                                  attr_mask & IB_QP_PORT ? attr->port_num : qp->port))
                        goto out;

                optpar |= (MLX4_QP_OPTPAR_PRIMARY_ADDR_PATH |
                           MLX4_QP_OPTPAR_SCHED_QUEUE);
        }

        if (attr_mask & IB_QP_TIMEOUT) {
                context->pri_path.ackto = attr->timeout << 3;
                optpar |= MLX4_QP_OPTPAR_ACK_TIMEOUT;
        }

        if (attr_mask & IB_QP_ALT_PATH) {
                if (attr->alt_port_num == 0 ||
                    attr->alt_port_num > dev->dev->caps.num_ports)
                        goto out;

                if (attr->alt_pkey_index >=
                    dev->dev->caps.pkey_table_len[attr->alt_port_num])
                        goto out;

                if (mlx4_set_path(dev, &attr->alt_ah_attr, &context->alt_path,
                                  attr->alt_port_num))
                        goto out;

                context->alt_path.pkey_index = attr->alt_pkey_index;
                context->alt_path.ackto = attr->alt_timeout << 3;
                optpar |= MLX4_QP_OPTPAR_ALT_ADDR_PATH;
        }

        context->pd         = cpu_to_be32(to_mpd(ibqp->pd)->pdn);
        context->params1    = cpu_to_be32(MLX4_IB_ACK_REQ_FREQ << 28);

        if (attr_mask & IB_QP_RNR_RETRY) {
                context->params1 |= cpu_to_be32(attr->rnr_retry << 13);
                optpar |= MLX4_QP_OPTPAR_RNR_RETRY;
        }

        if (attr_mask & IB_QP_RETRY_CNT) {
                context->params1 |= cpu_to_be32(attr->retry_cnt << 16);
                optpar |= MLX4_QP_OPTPAR_RETRY_COUNT;
        }

        if (attr_mask & IB_QP_MAX_QP_RD_ATOMIC) {
                if (attr->max_rd_atomic)
                        context->params1 |=
                                cpu_to_be32(fls(attr->max_rd_atomic - 1) << 21);
                optpar |= MLX4_QP_OPTPAR_SRA_MAX;
        }

        if (attr_mask & IB_QP_SQ_PSN)
                context->next_send_psn = cpu_to_be32(attr->sq_psn);

        context->cqn_send = cpu_to_be32(to_mcq(ibqp->send_cq)->mcq.cqn);

        if (attr_mask & IB_QP_MAX_DEST_RD_ATOMIC) {
                if (attr->max_dest_rd_atomic)
                        context->params2 |=
                                cpu_to_be32(fls(attr->max_dest_rd_atomic - 1) << 21);
                optpar |= MLX4_QP_OPTPAR_RRA_MAX;
        }

        if (attr_mask & (IB_QP_ACCESS_FLAGS | IB_QP_MAX_DEST_RD_ATOMIC)) {
                context->params2 |= to_mlx4_access_flags(qp, attr, attr_mask);
                optpar |= MLX4_QP_OPTPAR_RWE | MLX4_QP_OPTPAR_RRE | MLX4_QP_OPTPAR_RAE;
        }

        if (ibqp->srq)
                context->params2 |= cpu_to_be32(MLX4_QP_BIT_RIC);

        if (attr_mask & IB_QP_MIN_RNR_TIMER) {
                context->rnr_nextrecvpsn |= cpu_to_be32(attr->min_rnr_timer << 24);
                optpar |= MLX4_QP_OPTPAR_RNR_TIMEOUT;
        }
        if (attr_mask & IB_QP_RQ_PSN)
                context->rnr_nextrecvpsn |= cpu_to_be32(attr->rq_psn);

        context->cqn_recv = cpu_to_be32(to_mcq(ibqp->recv_cq)->mcq.cqn);

        if (attr_mask & IB_QP_QKEY) {
                context->qkey = cpu_to_be32(attr->qkey);
                optpar |= MLX4_QP_OPTPAR_Q_KEY;
        }

        if (ibqp->srq)
                context->srqn = cpu_to_be32(1 << 24 | to_msrq(ibqp->srq)->msrq.srqn);

        if (!ibqp->srq && cur_state == IB_QPS_RESET && new_state == IB_QPS_INIT)
                context->db_rec_addr = cpu_to_be64(qp->db.dma);

        if (cur_state == IB_QPS_INIT &&
            new_state == IB_QPS_RTR  &&
            (ibqp->qp_type == IB_QPT_GSI || ibqp->qp_type == IB_QPT_SMI ||
             ibqp->qp_type == IB_QPT_UD)) {
                context->pri_path.sched_queue = (qp->port - 1) << 6;
                if (is_qp0(dev, qp))
                        context->pri_path.sched_queue |= MLX4_IB_DEFAULT_QP0_SCHED_QUEUE;
                else
                        context->pri_path.sched_queue |= MLX4_IB_DEFAULT_SCHED_QUEUE;
        }

        if (cur_state == IB_QPS_RTS && new_state == IB_QPS_SQD  &&
            attr_mask & IB_QP_EN_SQD_ASYNC_NOTIFY && attr->en_sqd_async_notify)
                sqd_event = 1;
        else
                sqd_event = 0;

        /*
         * Before passing a kernel QP to the HW, make sure that the
         * ownership bits of the send queue are set and the SQ
         * headroom is stamped so that the hardware doesn't start
         * processing stale work requests.
         */
        if (!ibqp->uobject && cur_state == IB_QPS_RESET && new_state == IB_QPS_INIT) {
                struct mlx4_wqe_ctrl_seg *ctrl;
                int i;

                for (i = 0; i < qp->sq.wqe_cnt; ++i) {
                        ctrl = get_send_wqe(qp, i);
                        ctrl->owner_opcode = cpu_to_be32(1 << 31);

                        stamp_send_wqe(qp, i, 1 << qp->sq.wqe_shift);
                }
        }

        err = mlx4_qp_modify(dev->dev, &qp->mtt, to_mlx4_state(cur_state),
                             to_mlx4_state(new_state), context, optpar,
                             sqd_event, &qp->mqp);
        if (err)
                goto out;

        qp->state = new_state;

        if (attr_mask & IB_QP_ACCESS_FLAGS)
                qp->atomic_rd_en = attr->qp_access_flags;
        if (attr_mask & IB_QP_MAX_DEST_RD_ATOMIC)
                qp->resp_depth = attr->max_dest_rd_atomic;
        if (attr_mask & IB_QP_PORT)
                qp->port = attr->port_num;
        if (attr_mask & IB_QP_ALT_PATH)
                qp->alt_port = attr->alt_port_num;

        if (is_sqp(dev, qp))
                store_sqp_attrs(to_msqp(qp), attr, attr_mask);

        /*
         * If we moved QP0 to RTR, bring the IB link up; if we moved
         * QP0 to RESET or ERROR, bring the link back down.
         */
        if (is_qp0(dev, qp)) {
                if (cur_state != IB_QPS_RTR && new_state == IB_QPS_RTR)
                        if (mlx4_INIT_PORT(dev->dev, qp->port))
                                printk(KERN_WARNING "INIT_PORT failed for port %d\n",
                                       qp->port);

                if (cur_state != IB_QPS_RESET && cur_state != IB_QPS_ERR &&
                    (new_state == IB_QPS_RESET || new_state == IB_QPS_ERR))
                        mlx4_CLOSE_PORT(dev->dev, qp->port);
        }

        /*
         * If we moved a kernel QP to RESET, clean up all old CQ
         * entries and reinitialize the QP.
         */
        if (new_state == IB_QPS_RESET && !ibqp->uobject) {
                mlx4_ib_cq_clean(to_mcq(ibqp->recv_cq), qp->mqp.qpn,
                                 ibqp->srq ? to_msrq(ibqp->srq): NULL);
                if (ibqp->send_cq != ibqp->recv_cq)
                        mlx4_ib_cq_clean(to_mcq(ibqp->send_cq), qp->mqp.qpn, NULL);

                qp->rq.head = 0;
                qp->rq.tail = 0;
                qp->sq.head = 0;
                qp->sq.tail = 0;
                qp->sq_next_wqe = 0;
                if (!ibqp->srq)
                        *qp->db.db  = 0;
        }

out:
        kfree(context);
        return err;
}

static const struct ib_qp_attr mlx4_ib_qp_attr = { .port_num = 1 };
static const int mlx4_ib_qp_attr_mask_table[IB_QPT_UD + 1] = {
                [IB_QPT_UD]  = (IB_QP_PKEY_INDEX                |
                                IB_QP_PORT                      |
                                IB_QP_QKEY),
                [IB_QPT_UC]  = (IB_QP_PKEY_INDEX                |
                                IB_QP_PORT                      |
                                IB_QP_ACCESS_FLAGS),
                [IB_QPT_RC]  = (IB_QP_PKEY_INDEX                |
                                IB_QP_PORT                      |
                                IB_QP_ACCESS_FLAGS),
                [IB_QPT_SMI] = (IB_QP_PKEY_INDEX                |
                                IB_QP_QKEY),
                [IB_QPT_GSI] = (IB_QP_PKEY_INDEX                |
                                IB_QP_QKEY),
};

int mlx4_ib_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr,
                      int attr_mask, struct ib_udata *udata)
{
        struct mlx4_ib_dev *dev = to_mdev(ibqp->device);
        struct mlx4_ib_qp *qp = to_mqp(ibqp);
        enum ib_qp_state cur_state, new_state;
        int err = -EINVAL;

        mutex_lock(&qp->mutex);

        cur_state = attr_mask & IB_QP_CUR_STATE ? attr->cur_qp_state : qp->state;
        new_state = attr_mask & IB_QP_STATE ? attr->qp_state : cur_state;

        if (!ib_modify_qp_is_ok(cur_state, new_state, ibqp->qp_type, attr_mask))
                goto out;

        if ((attr_mask & IB_QP_PORT) &&
            (attr->port_num == 0 || attr->port_num > dev->dev->caps.num_ports)) {
                goto out;
        }

        if (attr_mask & IB_QP_PKEY_INDEX) {
                int p = attr_mask & IB_QP_PORT ? attr->port_num : qp->port;
                if (attr->pkey_index >= dev->dev->caps.pkey_table_len[p])
                        goto out;
        }

        if (attr_mask & IB_QP_MAX_QP_RD_ATOMIC &&
            attr->max_rd_atomic > dev->dev->caps.max_qp_init_rdma) {
                goto out;
        }

        if (attr_mask & IB_QP_MAX_DEST_RD_ATOMIC &&
            attr->max_dest_rd_atomic > dev->dev->caps.max_qp_dest_rdma) {
                goto out;
        }

        if (cur_state == new_state && cur_state == IB_QPS_RESET) {
                err = 0;
                goto out;
        }

        if (cur_state == IB_QPS_RESET && new_state == IB_QPS_ERR) {
                err = __mlx4_ib_modify_qp(ibqp, &mlx4_ib_qp_attr,
                                          mlx4_ib_qp_attr_mask_table[ibqp->qp_type],
                                          IB_QPS_RESET, IB_QPS_INIT);
                if (err)
                        goto out;
                cur_state = IB_QPS_INIT;
        }

        err = __mlx4_ib_modify_qp(ibqp, attr, attr_mask, cur_state, new_state);

out:
        mutex_unlock(&qp->mutex);
        return err;
}

static int build_mlx_header(struct mlx4_ib_sqp *sqp, struct ib_send_wr *wr,
                            void *wqe, unsigned *mlx_seg_len)
{
        struct ib_device *ib_dev = &to_mdev(sqp->qp.ibqp.device)->ib_dev;
        struct mlx4_wqe_mlx_seg *mlx = wqe;
        struct mlx4_wqe_inline_seg *inl = wqe + sizeof *mlx;
        struct mlx4_ib_ah *ah = to_mah(wr->wr.ud.ah);
        u16 pkey;
        int send_size;
        int header_size;
        int spc;
        int i;

        send_size = 0;
        for (i = 0; i < wr->num_sge; ++i)
                send_size += wr->sg_list[i].length;

        ib_ud_header_init(send_size, mlx4_ib_ah_grh_present(ah), &sqp->ud_header);

        sqp->ud_header.lrh.service_level   =
                be32_to_cpu(ah->av.sl_tclass_flowlabel) >> 28;
        sqp->ud_header.lrh.destination_lid = ah->av.dlid;
        sqp->ud_header.lrh.source_lid      = cpu_to_be16(ah->av.g_slid & 0x7f);
        if (mlx4_ib_ah_grh_present(ah)) {
                sqp->ud_header.grh.traffic_class =
                        (be32_to_cpu(ah->av.sl_tclass_flowlabel) >> 20) & 0xff;
                sqp->ud_header.grh.flow_label    =
                        ah->av.sl_tclass_flowlabel & cpu_to_be32(0xfffff);
                sqp->ud_header.grh.hop_limit     = ah->av.hop_limit;
                ib_get_cached_gid(ib_dev, be32_to_cpu(ah->av.port_pd) >> 24,
                                  ah->av.gid_index, &sqp->ud_header.grh.source_gid);
                memcpy(sqp->ud_header.grh.destination_gid.raw,
                       ah->av.dgid, 16);
        }

        mlx->flags &= cpu_to_be32(MLX4_WQE_CTRL_CQ_UPDATE);
        mlx->flags |= cpu_to_be32((!sqp->qp.ibqp.qp_num ? MLX4_WQE_MLX_VL15 : 0) |
                                  (sqp->ud_header.lrh.destination_lid ==
                                   IB_LID_PERMISSIVE ? MLX4_WQE_MLX_SLR : 0) |
                                  (sqp->ud_header.lrh.service_level << 8));
        mlx->rlid   = sqp->ud_header.lrh.destination_lid;

        switch (wr->opcode) {
        case IB_WR_SEND:
                sqp->ud_header.bth.opcode        = IB_OPCODE_UD_SEND_ONLY;
                sqp->ud_header.immediate_present = 0;
                break;
        case IB_WR_SEND_WITH_IMM:
                sqp->ud_header.bth.opcode        = IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE;
                sqp->ud_header.immediate_present = 1;
                sqp->ud_header.immediate_data    = wr->ex.imm_data;
                break;
        default:
                return -EINVAL;
        }

        sqp->ud_header.lrh.virtual_lane    = !sqp->qp.ibqp.qp_num ? 15 : 0;
        if (sqp->ud_header.lrh.destination_lid == IB_LID_PERMISSIVE)
                sqp->ud_header.lrh.source_lid = IB_LID_PERMISSIVE;
        sqp->ud_header.bth.solicited_event = !!(wr->send_flags & IB_SEND_SOLICITED);
        if (!sqp->qp.ibqp.qp_num)
                ib_get_cached_pkey(ib_dev, sqp->qp.port, sqp->pkey_index, &pkey);
        else
                ib_get_cached_pkey(ib_dev, sqp->qp.port, wr->wr.ud.pkey_index, &pkey);
        sqp->ud_header.bth.pkey = cpu_to_be16(pkey);
        sqp->ud_header.bth.destination_qpn = cpu_to_be32(wr->wr.ud.remote_qpn);
        sqp->ud_header.bth.psn = cpu_to_be32((sqp->send_psn++) & ((1 << 24) - 1));
        sqp->ud_header.deth.qkey = cpu_to_be32(wr->wr.ud.remote_qkey & 0x80000000 ?
                                               sqp->qkey : wr->wr.ud.remote_qkey);
        sqp->ud_header.deth.source_qpn = cpu_to_be32(sqp->qp.ibqp.qp_num);

        header_size = ib_ud_header_pack(&sqp->ud_header, sqp->header_buf);

        if (0) {
                printk(KERN_ERR "built UD header of size %d:\n", header_size);
                for (i = 0; i < header_size / 4; ++i) {
                        if (i % 8 == 0)
                                printk("  [%02x] ", i * 4);
                        printk(" %08x",
                               be32_to_cpu(((__be32 *) sqp->header_buf)[i]));
                        if ((i + 1) % 8 == 0)
                                printk("\n");
                }
                printk("\n");
        }

        /*
         * Inline data segments may not cross a 64 byte boundary.  If
         * our UD header is bigger than the space available up to the
         * next 64 byte boundary in the WQE, use two inline data
         * segments to hold the UD header.
         */
        spc = MLX4_INLINE_ALIGN -
                ((unsigned long) (inl + 1) & (MLX4_INLINE_ALIGN - 1));
        if (header_size <= spc) {
                inl->byte_count = cpu_to_be32(1 << 31 | header_size);
                memcpy(inl + 1, sqp->header_buf, header_size);
                i = 1;
        } else {
                inl->byte_count = cpu_to_be32(1 << 31 | spc);
                memcpy(inl + 1, sqp->header_buf, spc);

                inl = (void *) (inl + 1) + spc;
                memcpy(inl + 1, sqp->header_buf + spc, header_size - spc);
                /*
                 * Need a barrier here to make sure all the data is
                 * visible before the byte_count field is set.
                 * Otherwise the HCA prefetcher could grab the 64-byte
                 * chunk with this inline segment and get a valid (!=
                 * 0xffffffff) byte count but stale data, and end up
                 * generating a packet with bad headers.
                 *
                 * The first inline segment's byte_count field doesn't
                 * need a barrier, because it comes after a
                 * control/MLX segment and therefore is at an offset
                 * of 16 mod 64.
                 */
                wmb();
                inl->byte_count = cpu_to_be32(1 << 31 | (header_size - spc));
                i = 2;
        }

        *mlx_seg_len =
                ALIGN(i * sizeof (struct mlx4_wqe_inline_seg) + header_size, 16);
        return 0;
}

static int mlx4_wq_overflow(struct mlx4_ib_wq *wq, int nreq, struct ib_cq *ib_cq)
{
        unsigned cur;
        struct mlx4_ib_cq *cq;

        cur = wq->head - wq->tail;
        if (likely(cur + nreq < wq->max_post))
                return 0;

        cq = to_mcq(ib_cq);
        spin_lock(&cq->lock);
        cur = wq->head - wq->tail;
        spin_unlock(&cq->lock);

        return cur + nreq >= wq->max_post;
}

static __always_inline void set_raddr_seg(struct mlx4_wqe_raddr_seg *rseg,
                                          u64 remote_addr, u32 rkey)
{
        rseg->raddr    = cpu_to_be64(remote_addr);
        rseg->rkey     = cpu_to_be32(rkey);
        rseg->reserved = 0;
}

static void set_atomic_seg(struct mlx4_wqe_atomic_seg *aseg, struct ib_send_wr *wr)
{
        if (wr->opcode == IB_WR_ATOMIC_CMP_AND_SWP) {
                aseg->swap_add = cpu_to_be64(wr->wr.atomic.swap);
                aseg->compare  = cpu_to_be64(wr->wr.atomic.compare_add);
        } else {
                aseg->swap_add = cpu_to_be64(wr->wr.atomic.compare_add);
                aseg->compare  = 0;
        }

}

static void set_datagram_seg(struct mlx4_wqe_datagram_seg *dseg,
                             struct ib_send_wr *wr)
{
        memcpy(dseg->av, &to_mah(wr->wr.ud.ah)->av, sizeof (struct mlx4_av));
        dseg->dqpn = cpu_to_be32(wr->wr.ud.remote_qpn);
        dseg->qkey = cpu_to_be32(wr->wr.ud.remote_qkey);
}

static void set_mlx_icrc_seg(void *dseg)
{
        u32 *t = dseg;
        struct mlx4_wqe_inline_seg *iseg = dseg;

        t[1] = 0;

        /*
         * Need a barrier here before writing the byte_count field to
         * make sure that all the data is visible before the
         * byte_count field is set.  Otherwise, if the segment begins
         * a new cacheline, the HCA prefetcher could grab the 64-byte
         * chunk and get a valid (!= * 0xffffffff) byte count but
         * stale data, and end up sending the wrong data.
         */
        wmb();

        iseg->byte_count = cpu_to_be32((1 << 31) | 4);
}

static void set_data_seg(struct mlx4_wqe_data_seg *dseg, struct ib_sge *sg)
{
        dseg->lkey       = cpu_to_be32(sg->lkey);
        dseg->addr       = cpu_to_be64(sg->addr);

        /*
         * Need a barrier here before writing the byte_count field to
         * make sure that all the data is visible before the
         * byte_count field is set.  Otherwise, if the segment begins
         * a new cacheline, the HCA prefetcher could grab the 64-byte
         * chunk and get a valid (!= * 0xffffffff) byte count but
         * stale data, and end up sending the wrong data.
         */
        wmb();

        dseg->byte_count = cpu_to_be32(sg->length);
}

static void __set_data_seg(struct mlx4_wqe_data_seg *dseg, struct ib_sge *sg)
{
        dseg->byte_count = cpu_to_be32(sg->length);
        dseg->lkey       = cpu_to_be32(sg->lkey);
        dseg->addr       = cpu_to_be64(sg->addr);
}

static int build_lso_seg(struct mlx4_lso_seg *wqe, struct ib_send_wr *wr,
                         struct mlx4_ib_qp *qp, unsigned *lso_seg_len)
{
        unsigned halign = ALIGN(sizeof *wqe + wr->wr.ud.hlen, 16);

        /*
         * This is a temporary limitation and will be removed in
         * a forthcoming FW release:
         */
        if (unlikely(halign > 64))
                return -EINVAL;

        if (unlikely(!(qp->flags & MLX4_IB_QP_LSO) &&
                     wr->num_sge > qp->sq.max_gs - (halign >> 4)))
                return -EINVAL;

        memcpy(wqe->header, wr->wr.ud.header, wr->wr.ud.hlen);

        /* make sure LSO header is written before overwriting stamping */
        wmb();

        wqe->mss_hdr_size = cpu_to_be32((wr->wr.ud.mss - wr->wr.ud.hlen) << 16 |
                                        wr->wr.ud.hlen);

        *lso_seg_len = halign;
        return 0;
}

int mlx4_ib_post_send(struct ib_qp *ibqp, struct ib_send_wr *wr,
                      struct ib_send_wr **bad_wr)
{
        struct mlx4_ib_qp *qp = to_mqp(ibqp);
        void *wqe;
        struct mlx4_wqe_ctrl_seg *ctrl;
        struct mlx4_wqe_data_seg *dseg;
        unsigned long flags;
        int nreq;
        int err = 0;
        unsigned ind;
        int uninitialized_var(stamp);
        int uninitialized_var(size);
        unsigned uninitialized_var(seglen);
        int i;

        spin_lock_irqsave(&qp->sq.lock, flags);

        ind = qp->sq_next_wqe;

        for (nreq = 0; wr; ++nreq, wr = wr->next) {
                if (mlx4_wq_overflow(&qp->sq, nreq, qp->ibqp.send_cq)) {
                        err = -ENOMEM;
                        *bad_wr = wr;
                        goto out;
                }

                if (unlikely(wr->num_sge > qp->sq.max_gs)) {
                        err = -EINVAL;
                        *bad_wr = wr;
                        goto out;
                }

                ctrl = wqe = get_send_wqe(qp, ind & (qp->sq.wqe_cnt - 1));
                qp->sq.wrid[(qp->sq.head + nreq) & (qp->sq.wqe_cnt - 1)] = wr->wr_id;

                ctrl->srcrb_flags =
                        (wr->send_flags & IB_SEND_SIGNALED ?
                         cpu_to_be32(MLX4_WQE_CTRL_CQ_UPDATE) : 0) |
                        (wr->send_flags & IB_SEND_SOLICITED ?
                         cpu_to_be32(MLX4_WQE_CTRL_SOLICITED) : 0) |
                        ((wr->send_flags & IB_SEND_IP_CSUM) ?
                         cpu_to_be32(MLX4_WQE_CTRL_IP_CSUM |
                                     MLX4_WQE_CTRL_TCP_UDP_CSUM) : 0) |
                        qp->sq_signal_bits;

                if (wr->opcode == IB_WR_SEND_WITH_IMM ||
                    wr->opcode == IB_WR_RDMA_WRITE_WITH_IMM)
                        ctrl->imm = wr->ex.imm_data;
                else
                        ctrl->imm = 0;

                wqe += sizeof *ctrl;
                size = sizeof *ctrl / 16;

                switch (ibqp->qp_type) {
                case IB_QPT_RC:
                case IB_QPT_UC:
                        switch (wr->opcode) {
                        case IB_WR_ATOMIC_CMP_AND_SWP:
                        case IB_WR_ATOMIC_FETCH_AND_ADD:
                                set_raddr_seg(wqe, wr->wr.atomic.remote_addr,
                                              wr->wr.atomic.rkey);
                                wqe  += sizeof (struct mlx4_wqe_raddr_seg);

                                set_atomic_seg(wqe, wr);
                                wqe  += sizeof (struct mlx4_wqe_atomic_seg);

                                size += (sizeof (struct mlx4_wqe_raddr_seg) +
                                         sizeof (struct mlx4_wqe_atomic_seg)) / 16;

                                break;

                        case IB_WR_RDMA_READ:
                        case IB_WR_RDMA_WRITE:
                        case IB_WR_RDMA_WRITE_WITH_IMM:
                                set_raddr_seg(wqe, wr->wr.rdma.remote_addr,
                                              wr->wr.rdma.rkey);
                                wqe  += sizeof (struct mlx4_wqe_raddr_seg);
                                size += sizeof (struct mlx4_wqe_raddr_seg) / 16;
                                break;

                        default:
                                /* No extra segments required for sends */
                                break;
                        }
                        break;

                case IB_QPT_UD:
                        set_datagram_seg(wqe, wr);
                        wqe  += sizeof (struct mlx4_wqe_datagram_seg);
                        size += sizeof (struct mlx4_wqe_datagram_seg) / 16;

                        if (wr->opcode == IB_WR_LSO) {
                                err = build_lso_seg(wqe, wr, qp, &seglen);
                                if (unlikely(err)) {
                                        *bad_wr = wr;
                                        goto out;
                                }
                                wqe  += seglen;
                                size += seglen / 16;
                        }
                        break;

                case IB_QPT_SMI:
                case IB_QPT_GSI:
                        err = build_mlx_header(to_msqp(qp), wr, ctrl, &seglen);
                        if (unlikely(err)) {
                                *bad_wr = wr;
                                goto out;
                        }
                        wqe  += seglen;
                        size += seglen / 16;
                        break;

                default:
                        break;
                }

                /*
                 * Write data segments in reverse order, so as to
                 * overwrite cacheline stamp last within each
                 * cacheline.  This avoids issues with WQE
                 * prefetching.
                 */

                dseg = wqe;
                dseg += wr->num_sge - 1;
                size += wr->num_sge * (sizeof (struct mlx4_wqe_data_seg) / 16);

                /* Add one more inline data segment for ICRC for MLX sends */
                if (unlikely(qp->ibqp.qp_type == IB_QPT_SMI ||
                             qp->ibqp.qp_type == IB_QPT_GSI)) {
                        set_mlx_icrc_seg(dseg + 1);
                        size += sizeof (struct mlx4_wqe_data_seg) / 16;
                }

                for (i = wr->num_sge - 1; i >= 0; --i, --dseg)
                        set_data_seg(dseg, wr->sg_list + i);

                ctrl->fence_size = (wr->send_flags & IB_SEND_FENCE ?
                                    MLX4_WQE_CTRL_FENCE : 0) | size;

                /*
                 * Make sure descriptor is fully written before
                 * setting ownership bit (because HW can start
                 * executing as soon as we do).
                 */
                wmb();

                if (wr->opcode < 0 || wr->opcode >= ARRAY_SIZE(mlx4_ib_opcode)) {
                        err = -EINVAL;
                        goto out;
                }

                ctrl->owner_opcode = mlx4_ib_opcode[wr->opcode] |
                        (ind & qp->sq.wqe_cnt ? cpu_to_be32(1 << 31) : 0);

                stamp = ind + qp->sq_spare_wqes;
                ind += DIV_ROUND_UP(size * 16, 1U << qp->sq.wqe_shift);

                /*
                 * We can improve latency by not stamping the last
                 * send queue WQE until after ringing the doorbell, so
                 * only stamp here if there are still more WQEs to post.
                 *
                 * Same optimization applies to padding with NOP wqe
                 * in case of WQE shrinking (used to prevent wrap-around
                 * in the middle of WR).
                 */
                if (wr->next) {
                        stamp_send_wqe(qp, stamp, size * 16);
                        ind = pad_wraparound(qp, ind);
                }

        }

out:
        if (likely(nreq)) {
                qp->sq.head += nreq;

                /*
                 * Make sure that descriptors are written before
                 * doorbell record.
                 */
                wmb();

                writel(qp->doorbell_qpn,
                       to_mdev(ibqp->device)->uar_map + MLX4_SEND_DOORBELL);

                /*
                 * Make sure doorbells don't leak out of SQ spinlock
                 * and reach the HCA out of order.
                 */
                mmiowb();

                stamp_send_wqe(qp, stamp, size * 16);

                ind = pad_wraparound(qp, ind);
                qp->sq_next_wqe = ind;
        }

        spin_unlock_irqrestore(&qp->sq.lock, flags);

        return err;
}

int mlx4_ib_post_recv(struct ib_qp *ibqp, struct ib_recv_wr *wr,
                      struct ib_recv_wr **bad_wr)
{
        struct mlx4_ib_qp *qp = to_mqp(ibqp);
        struct mlx4_wqe_data_seg *scat;
        unsigned long flags;
        int err = 0;
        int nreq;
        int ind;
        int i;

        spin_lock_irqsave(&qp->rq.lock, flags);

        ind = qp->rq.head & (qp->rq.wqe_cnt - 1);

        for (nreq = 0; wr; ++nreq, wr = wr->next) {
                if (mlx4_wq_overflow(&qp->rq, nreq, qp->ibqp.send_cq)) {
                        err = -ENOMEM;
                        *bad_wr = wr;
                        goto out;
                }

                if (unlikely(wr->num_sge > qp->rq.max_gs)) {
                        err = -EINVAL;
                        *bad_wr = wr;
                        goto out;
                }

                scat = get_recv_wqe(qp, ind);

                for (i = 0; i < wr->num_sge; ++i)
                        __set_data_seg(scat + i, wr->sg_list + i);

                if (i < qp->rq.max_gs) {
                        scat[i].byte_count = 0;
                        scat[i].lkey       = cpu_to_be32(MLX4_INVALID_LKEY);
                        scat[i].addr       = 0;
                }

                qp->rq.wrid[ind] = wr->wr_id;

                ind = (ind + 1) & (qp->rq.wqe_cnt - 1);
        }

out:
        if (likely(nreq)) {
                qp->rq.head += nreq;

                /*
                 * Make sure that descriptors are written before
                 * doorbell record.
                 */
                wmb();

                *qp->db.db = cpu_to_be32(qp->rq.head & 0xffff);
        }

        spin_unlock_irqrestore(&qp->rq.lock, flags);

        return err;
}

static inline enum ib_qp_state to_ib_qp_state(enum mlx4_qp_state mlx4_state)
{
        switch (mlx4_state) {
        case MLX4_QP_STATE_RST:      return IB_QPS_RESET;
        case MLX4_QP_STATE_INIT:     return IB_QPS_INIT;
        case MLX4_QP_STATE_RTR:      return IB_QPS_RTR;
        case MLX4_QP_STATE_RTS:      return IB_QPS_RTS;
        case MLX4_QP_STATE_SQ_DRAINING:
        case MLX4_QP_STATE_SQD:      return IB_QPS_SQD;
        case MLX4_QP_STATE_SQER:     return IB_QPS_SQE;
        case MLX4_QP_STATE_ERR:      return IB_QPS_ERR;
        default:                     return -1;
        }
}

static inline enum ib_mig_state to_ib_mig_state(int mlx4_mig_state)
{
        switch (mlx4_mig_state) {
        case MLX4_QP_PM_ARMED:          return IB_MIG_ARMED;
        case MLX4_QP_PM_REARM:          return IB_MIG_REARM;
        case MLX4_QP_PM_MIGRATED:       return IB_MIG_MIGRATED;
        default: return -1;
        }
}

static int to_ib_qp_access_flags(int mlx4_flags)
{
        int ib_flags = 0;

        if (mlx4_flags & MLX4_QP_BIT_RRE)
                ib_flags |= IB_ACCESS_REMOTE_READ;
        if (mlx4_flags & MLX4_QP_BIT_RWE)
                ib_flags |= IB_ACCESS_REMOTE_WRITE;
        if (mlx4_flags & MLX4_QP_BIT_RAE)
                ib_flags |= IB_ACCESS_REMOTE_ATOMIC;

        return ib_flags;
}

static void to_ib_ah_attr(struct mlx4_dev *dev, struct ib_ah_attr *ib_ah_attr,
                                struct mlx4_qp_path *path)
{
        memset(ib_ah_attr, 0, sizeof *ib_ah_attr);
        ib_ah_attr->port_num      = path->sched_queue & 0x40 ? 2 : 1;

        if (ib_ah_attr->port_num == 0 || ib_ah_attr->port_num > dev->caps.num_ports)
                return;

        ib_ah_attr->dlid          = be16_to_cpu(path->rlid);
        ib_ah_attr->sl            = (path->sched_queue >> 2) & 0xf;
        ib_ah_attr->src_path_bits = path->grh_mylmc & 0x7f;
        ib_ah_attr->static_rate   = path->static_rate ? path->static_rate - 5 : 0;
        ib_ah_attr->ah_flags      = (path->grh_mylmc & (1 << 7)) ? IB_AH_GRH : 0;
        if (ib_ah_attr->ah_flags) {
                ib_ah_attr->grh.sgid_index = path->mgid_index;
                ib_ah_attr->grh.hop_limit  = path->hop_limit;
                ib_ah_attr->grh.traffic_class =
                        (be32_to_cpu(path->tclass_flowlabel) >> 20) & 0xff;
                ib_ah_attr->grh.flow_label =
                        be32_to_cpu(path->tclass_flowlabel) & 0xfffff;
                memcpy(ib_ah_attr->grh.dgid.raw,
                        path->rgid, sizeof ib_ah_attr->grh.dgid.raw);
        }
}

int mlx4_ib_query_qp(struct ib_qp *ibqp, struct ib_qp_attr *qp_attr, int qp_attr_mask,
                     struct ib_qp_init_attr *qp_init_attr)
{
        struct mlx4_ib_dev *dev = to_mdev(ibqp->device);
        struct mlx4_ib_qp *qp = to_mqp(ibqp);
        struct mlx4_qp_context context;
        int mlx4_state;
        int err = 0;

        mutex_lock(&qp->mutex);

        if (qp->state == IB_QPS_RESET) {
                qp_attr->qp_state = IB_QPS_RESET;
                goto done;
        }

        err = mlx4_qp_query(dev->dev, &qp->mqp, &context);
        if (err) {
                err = -EINVAL;
                goto out;
        }

        mlx4_state = be32_to_cpu(context.flags) >> 28;

        qp->state                    = to_ib_qp_state(mlx4_state);
        qp_attr->qp_state            = qp->state;
        qp_attr->path_mtu            = context.mtu_msgmax >> 5;
        qp_attr->path_mig_state      =
                to_ib_mig_state((be32_to_cpu(context.flags) >> 11) & 0x3);
        qp_attr->qkey                = be32_to_cpu(context.qkey);
        qp_attr->rq_psn              = be32_to_cpu(context.rnr_nextrecvpsn) & 0xffffff;
        qp_attr->sq_psn              = be32_to_cpu(context.next_send_psn) & 0xffffff;
        qp_attr->dest_qp_num         = be32_to_cpu(context.remote_qpn) & 0xffffff;
        qp_attr->qp_access_flags     =
                to_ib_qp_access_flags(be32_to_cpu(context.params2));

        if (qp->ibqp.qp_type == IB_QPT_RC || qp->ibqp.qp_type == IB_QPT_UC) {
                to_ib_ah_attr(dev->dev, &qp_attr->ah_attr, &context.pri_path);
                to_ib_ah_attr(dev->dev, &qp_attr->alt_ah_attr, &context.alt_path);
                qp_attr->alt_pkey_index = context.alt_path.pkey_index & 0x7f;
                qp_attr->alt_port_num   = qp_attr->alt_ah_attr.port_num;
        }

        qp_attr->pkey_index = context.pri_path.pkey_index & 0x7f;
        if (qp_attr->qp_state == IB_QPS_INIT)
                qp_attr->port_num = qp->port;
        else
                qp_attr->port_num = context.pri_path.sched_queue & 0x40 ? 2 : 1;

        /* qp_attr->en_sqd_async_notify is only applicable in modify qp */
        qp_attr->sq_draining = mlx4_state == MLX4_QP_STATE_SQ_DRAINING;

        qp_attr->max_rd_atomic = 1 << ((be32_to_cpu(context.params1) >> 21) & 0x7);

        qp_attr->max_dest_rd_atomic =
                1 << ((be32_to_cpu(context.params2) >> 21) & 0x7);
        qp_attr->min_rnr_timer      =
                (be32_to_cpu(context.rnr_nextrecvpsn) >> 24) & 0x1f;
        qp_attr->timeout            = context.pri_path.ackto >> 3;
        qp_attr->retry_cnt          = (be32_to_cpu(context.params1) >> 16) & 0x7;
        qp_attr->rnr_retry          = (be32_to_cpu(context.params1) >> 13) & 0x7;
        qp_attr->alt_timeout        = context.alt_path.ackto >> 3;

done:
        qp_attr->cur_qp_state        = qp_attr->qp_state;
        qp_attr->cap.max_recv_wr     = qp->rq.wqe_cnt;
        qp_attr->cap.max_recv_sge    = qp->rq.max_gs;

        if (!ibqp->uobject) {
                qp_attr->cap.max_send_wr  = qp->sq.wqe_cnt;
                qp_attr->cap.max_send_sge = qp->sq.max_gs;
        } else {
                qp_attr->cap.max_send_wr  = 0;
                qp_attr->cap.max_send_sge = 0;
        }

        /*
         * We don't support inline sends for kernel QPs (yet), and we
         * don't know what userspace's value should be.
         */
        qp_attr->cap.max_inline_data = 0;

        qp_init_attr->cap            = qp_attr->cap;

out:
        mutex_unlock(&qp->mutex);
        return err;
}