/*
 * Copyright (c) 2012, 2013 Intel Corporation.  All rights reserved.
 * Copyright (c) 2006 - 2012 QLogic Corporation.  * All rights reserved.
 * Copyright (c) 2005, 2006 PathScale, 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/err.h>
#include <linux/vmalloc.h>
#include <linux/jhash.h>
#ifdef CONFIG_DEBUG_FS
#include <linux/seq_file.h>
#endif

#include "qib.h"

#define BITS_PER_PAGE           (PAGE_SIZE*BITS_PER_BYTE)
#define BITS_PER_PAGE_MASK      (BITS_PER_PAGE-1)

static inline unsigned mk_qpn(struct qib_qpn_table *qpt,
                              struct qpn_map *map, unsigned off)
{
        return (map - qpt->map) * BITS_PER_PAGE + off;
}

static inline unsigned find_next_offset(struct qib_qpn_table *qpt,
                                        struct qpn_map *map, unsigned off,
                                        unsigned n)
{
        if (qpt->mask) {
                off++;
                if (((off & qpt->mask) >> 1) >= n)
                        off = (off | qpt->mask) + 2;
        } else
                off = find_next_zero_bit(map->page, BITS_PER_PAGE, off);
        return off;
}

/*
 * Convert the AETH credit code into the number of credits.
 */
static u32 credit_table[31] = {
        0,                      /* 0 */
        1,                      /* 1 */
        2,                      /* 2 */
        3,                      /* 3 */
        4,                      /* 4 */
        6,                      /* 5 */
        8,                      /* 6 */
        12,                     /* 7 */
        16,                     /* 8 */
        24,                     /* 9 */
        32,                     /* A */
        48,                     /* B */
        64,                     /* C */
        96,                     /* D */
        128,                    /* E */
        192,                    /* F */
        256,                    /* 10 */
        384,                    /* 11 */
        512,                    /* 12 */
        768,                    /* 13 */
        1024,                   /* 14 */
        1536,                   /* 15 */
        2048,                   /* 16 */
        3072,                   /* 17 */
        4096,                   /* 18 */
        6144,                   /* 19 */
        8192,                   /* 1A */
        12288,                  /* 1B */
        16384,                  /* 1C */
        24576,                  /* 1D */
        32768                   /* 1E */
};

static void get_map_page(struct qib_qpn_table *qpt, struct qpn_map *map)
{
        unsigned long page = get_zeroed_page(GFP_KERNEL);

        /*
         * Free the page if someone raced with us installing it.
         */

        spin_lock(&qpt->lock);
        if (map->page)
                free_page(page);
        else
                map->page = (void *)page;
        spin_unlock(&qpt->lock);
}

/*
 * Allocate the next available QPN or
 * zero/one for QP type IB_QPT_SMI/IB_QPT_GSI.
 */
static int alloc_qpn(struct qib_devdata *dd, struct qib_qpn_table *qpt,
                     enum ib_qp_type type, u8 port)
{
        u32 i, offset, max_scan, qpn;
        struct qpn_map *map;
        u32 ret;

        if (type == IB_QPT_SMI || type == IB_QPT_GSI) {
                unsigned n;

                ret = type == IB_QPT_GSI;
                n = 1 << (ret + 2 * (port - 1));
                spin_lock(&qpt->lock);
                if (qpt->flags & n)
                        ret = -EINVAL;
                else
                        qpt->flags |= n;
                spin_unlock(&qpt->lock);
                goto bail;
        }

        qpn = qpt->last + 2;
        if (qpn >= QPN_MAX)
                qpn = 2;
        if (qpt->mask && ((qpn & qpt->mask) >> 1) >= dd->n_krcv_queues)
                qpn = (qpn | qpt->mask) + 2;
        offset = qpn & BITS_PER_PAGE_MASK;
        map = &qpt->map[qpn / BITS_PER_PAGE];
        max_scan = qpt->nmaps - !offset;
        for (i = 0;;) {
                if (unlikely(!map->page)) {
                        get_map_page(qpt, map);
                        if (unlikely(!map->page))
                                break;
                }
                do {
                        if (!test_and_set_bit(offset, map->page)) {
                                qpt->last = qpn;
                                ret = qpn;
                                goto bail;
                        }
                        offset = find_next_offset(qpt, map, offset,
                                dd->n_krcv_queues);
                        qpn = mk_qpn(qpt, map, offset);
                        /*
                         * This test differs from alloc_pidmap().
                         * If find_next_offset() does find a zero
                         * bit, we don't need to check for QPN
                         * wrapping around past our starting QPN.
                         * We just need to be sure we don't loop
                         * forever.
                         */
                } while (offset < BITS_PER_PAGE && qpn < QPN_MAX);
                /*
                 * In order to keep the number of pages allocated to a
                 * minimum, we scan the all existing pages before increasing
                 * the size of the bitmap table.
                 */
                if (++i > max_scan) {
                        if (qpt->nmaps == QPNMAP_ENTRIES)
                                break;
                        map = &qpt->map[qpt->nmaps++];
                        offset = 0;
                } else if (map < &qpt->map[qpt->nmaps]) {
                        ++map;
                        offset = 0;
                } else {
                        map = &qpt->map[0];
                        offset = 2;
                }
                qpn = mk_qpn(qpt, map, offset);
        }

        ret = -ENOMEM;

bail:
        return ret;
}

static void free_qpn(struct qib_qpn_table *qpt, u32 qpn)
{
        struct qpn_map *map;

        map = qpt->map + qpn / BITS_PER_PAGE;
        if (map->page)
                clear_bit(qpn & BITS_PER_PAGE_MASK, map->page);
}

static inline unsigned qpn_hash(struct qib_ibdev *dev, u32 qpn)
{
        return jhash_1word(qpn, dev->qp_rnd) &
                (dev->qp_table_size - 1);
}


/*
 * Put the QP into the hash table.
 * The hash table holds a reference to the QP.
 */
static void insert_qp(struct qib_ibdev *dev, struct qib_qp *qp)
{
        struct qib_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
        unsigned long flags;
        unsigned n = qpn_hash(dev, qp->ibqp.qp_num);

        atomic_inc(&qp->refcount);
        spin_lock_irqsave(&dev->qpt_lock, flags);

        if (qp->ibqp.qp_num == 0)
                rcu_assign_pointer(ibp->qp0, qp);
        else if (qp->ibqp.qp_num == 1)
                rcu_assign_pointer(ibp->qp1, qp);
        else {
                qp->next = dev->qp_table[n];
                rcu_assign_pointer(dev->qp_table[n], qp);
        }

        spin_unlock_irqrestore(&dev->qpt_lock, flags);
}

/*
 * Remove the QP from the table so it can't be found asynchronously by
 * the receive interrupt routine.
 */
static void remove_qp(struct qib_ibdev *dev, struct qib_qp *qp)
{
        struct qib_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
        unsigned n = qpn_hash(dev, qp->ibqp.qp_num);
        unsigned long flags;
        int removed = 1;

        spin_lock_irqsave(&dev->qpt_lock, flags);

        if (rcu_dereference_protected(ibp->qp0,
                        lockdep_is_held(&dev->qpt_lock)) == qp) {
                RCU_INIT_POINTER(ibp->qp0, NULL);
        } else if (rcu_dereference_protected(ibp->qp1,
                        lockdep_is_held(&dev->qpt_lock)) == qp) {
                RCU_INIT_POINTER(ibp->qp1, NULL);
        } else {
                struct qib_qp *q;
                struct qib_qp __rcu **qpp;

                removed = 0;
                qpp = &dev->qp_table[n];
                for (; (q = rcu_dereference_protected(*qpp,
                                lockdep_is_held(&dev->qpt_lock))) != NULL;
                                qpp = &q->next)
                        if (q == qp) {
                                RCU_INIT_POINTER(*qpp,
                                        rcu_dereference_protected(qp->next,
                                         lockdep_is_held(&dev->qpt_lock)));
                                removed = 1;
                                break;
                        }
        }

        spin_unlock_irqrestore(&dev->qpt_lock, flags);
        if (removed) {
                synchronize_rcu();
                atomic_dec(&qp->refcount);
        }
}

/**
 * qib_free_all_qps - check for QPs still in use
 * @qpt: the QP table to empty
 *
 * There should not be any QPs still in use.
 * Free memory for table.
 */
unsigned qib_free_all_qps(struct qib_devdata *dd)
{
        struct qib_ibdev *dev = &dd->verbs_dev;
        unsigned long flags;
        struct qib_qp *qp;
        unsigned n, qp_inuse = 0;

        for (n = 0; n < dd->num_pports; n++) {
                struct qib_ibport *ibp = &dd->pport[n].ibport_data;

                if (!qib_mcast_tree_empty(ibp))
                        qp_inuse++;
                rcu_read_lock();
                if (rcu_dereference(ibp->qp0))
                        qp_inuse++;
                if (rcu_dereference(ibp->qp1))
                        qp_inuse++;
                rcu_read_unlock();
        }

        spin_lock_irqsave(&dev->qpt_lock, flags);
        for (n = 0; n < dev->qp_table_size; n++) {
                qp = rcu_dereference_protected(dev->qp_table[n],
                        lockdep_is_held(&dev->qpt_lock));
                RCU_INIT_POINTER(dev->qp_table[n], NULL);

                for (; qp; qp = rcu_dereference_protected(qp->next,
                                        lockdep_is_held(&dev->qpt_lock)))
                        qp_inuse++;
        }
        spin_unlock_irqrestore(&dev->qpt_lock, flags);
        synchronize_rcu();

        return qp_inuse;
}

/**
 * qib_lookup_qpn - return the QP with the given QPN
 * @qpt: the QP table
 * @qpn: the QP number to look up
 *
 * The caller is responsible for decrementing the QP reference count
 * when done.
 */
struct qib_qp *qib_lookup_qpn(struct qib_ibport *ibp, u32 qpn)
{
        struct qib_qp *qp = NULL;

        rcu_read_lock();
        if (unlikely(qpn <= 1)) {
                if (qpn == 0)
                        qp = rcu_dereference(ibp->qp0);
                else
                        qp = rcu_dereference(ibp->qp1);
                if (qp)
                        atomic_inc(&qp->refcount);
        } else {
                struct qib_ibdev *dev = &ppd_from_ibp(ibp)->dd->verbs_dev;
                unsigned n = qpn_hash(dev, qpn);

                for (qp = rcu_dereference(dev->qp_table[n]); qp;
                        qp = rcu_dereference(qp->next))
                        if (qp->ibqp.qp_num == qpn) {
                                atomic_inc(&qp->refcount);
                                break;
                        }
        }
        rcu_read_unlock();
        return qp;
}

/**
 * qib_reset_qp - initialize the QP state to the reset state
 * @qp: the QP to reset
 * @type: the QP type
 */
static void qib_reset_qp(struct qib_qp *qp, enum ib_qp_type type)
{
        qp->remote_qpn = 0;
        qp->qkey = 0;
        qp->qp_access_flags = 0;
        atomic_set(&qp->s_dma_busy, 0);
        qp->s_flags &= QIB_S_SIGNAL_REQ_WR;
        qp->s_hdrwords = 0;
        qp->s_wqe = NULL;
        qp->s_draining = 0;
        qp->s_next_psn = 0;
        qp->s_last_psn = 0;
        qp->s_sending_psn = 0;
        qp->s_sending_hpsn = 0;
        qp->s_psn = 0;
        qp->r_psn = 0;
        qp->r_msn = 0;
        if (type == IB_QPT_RC) {
                qp->s_state = IB_OPCODE_RC_SEND_LAST;
                qp->r_state = IB_OPCODE_RC_SEND_LAST;
        } else {
                qp->s_state = IB_OPCODE_UC_SEND_LAST;
                qp->r_state = IB_OPCODE_UC_SEND_LAST;
        }
        qp->s_ack_state = IB_OPCODE_RC_ACKNOWLEDGE;
        qp->r_nak_state = 0;
        qp->r_aflags = 0;
        qp->r_flags = 0;
        qp->s_head = 0;
        qp->s_tail = 0;
        qp->s_cur = 0;
        qp->s_acked = 0;
        qp->s_last = 0;
        qp->s_ssn = 1;
        qp->s_lsn = 0;
        qp->s_mig_state = IB_MIG_MIGRATED;
        memset(qp->s_ack_queue, 0, sizeof(qp->s_ack_queue));
        qp->r_head_ack_queue = 0;
        qp->s_tail_ack_queue = 0;
        qp->s_num_rd_atomic = 0;
        if (qp->r_rq.wq) {
                qp->r_rq.wq->head = 0;
                qp->r_rq.wq->tail = 0;
        }
        qp->r_sge.num_sge = 0;
}

static void clear_mr_refs(struct qib_qp *qp, int clr_sends)
{
        unsigned n;

        if (test_and_clear_bit(QIB_R_REWIND_SGE, &qp->r_aflags))
                qib_put_ss(&qp->s_rdma_read_sge);

        qib_put_ss(&qp->r_sge);

        if (clr_sends) {
                while (qp->s_last != qp->s_head) {
                        struct qib_swqe *wqe = get_swqe_ptr(qp, qp->s_last);
                        unsigned i;

                        for (i = 0; i < wqe->wr.num_sge; i++) {
                                struct qib_sge *sge = &wqe->sg_list[i];

                                qib_put_mr(sge->mr);
                        }
                        if (qp->ibqp.qp_type == IB_QPT_UD ||
                            qp->ibqp.qp_type == IB_QPT_SMI ||
                            qp->ibqp.qp_type == IB_QPT_GSI)
                                atomic_dec(&to_iah(wqe->wr.wr.ud.ah)->refcount);
                        if (++qp->s_last >= qp->s_size)
                                qp->s_last = 0;
                }
                if (qp->s_rdma_mr) {
                        qib_put_mr(qp->s_rdma_mr);
                        qp->s_rdma_mr = NULL;
                }
        }

        if (qp->ibqp.qp_type != IB_QPT_RC)
                return;

        for (n = 0; n < ARRAY_SIZE(qp->s_ack_queue); n++) {
                struct qib_ack_entry *e = &qp->s_ack_queue[n];

                if (e->opcode == IB_OPCODE_RC_RDMA_READ_REQUEST &&
                    e->rdma_sge.mr) {
                        qib_put_mr(e->rdma_sge.mr);
                        e->rdma_sge.mr = NULL;
                }
        }
}

/**
 * qib_error_qp - put a QP into the error state
 * @qp: the QP to put into the error state
 * @err: the receive completion error to signal if a RWQE is active
 *
 * Flushes both send and receive work queues.
 * Returns true if last WQE event should be generated.
 * The QP r_lock and s_lock should be held and interrupts disabled.
 * If we are already in error state, just return.
 */
int qib_error_qp(struct qib_qp *qp, enum ib_wc_status err)
{
        struct qib_ibdev *dev = to_idev(qp->ibqp.device);
        struct ib_wc wc;
        int ret = 0;

        if (qp->state == IB_QPS_ERR || qp->state == IB_QPS_RESET)
                goto bail;

        qp->state = IB_QPS_ERR;

        if (qp->s_flags & (QIB_S_TIMER | QIB_S_WAIT_RNR)) {
                qp->s_flags &= ~(QIB_S_TIMER | QIB_S_WAIT_RNR);
                del_timer(&qp->s_timer);
        }

        if (qp->s_flags & QIB_S_ANY_WAIT_SEND)
                qp->s_flags &= ~QIB_S_ANY_WAIT_SEND;

        spin_lock(&dev->pending_lock);
        if (!list_empty(&qp->iowait) && !(qp->s_flags & QIB_S_BUSY)) {
                qp->s_flags &= ~QIB_S_ANY_WAIT_IO;
                list_del_init(&qp->iowait);
        }
        spin_unlock(&dev->pending_lock);

        if (!(qp->s_flags & QIB_S_BUSY)) {
                qp->s_hdrwords = 0;
                if (qp->s_rdma_mr) {
                        qib_put_mr(qp->s_rdma_mr);
                        qp->s_rdma_mr = NULL;
                }
                if (qp->s_tx) {
                        qib_put_txreq(qp->s_tx);
                        qp->s_tx = NULL;
                }
        }

        /* Schedule the sending tasklet to drain the send work queue. */
        if (qp->s_last != qp->s_head)
                qib_schedule_send(qp);

        clear_mr_refs(qp, 0);

        memset(&wc, 0, sizeof(wc));
        wc.qp = &qp->ibqp;
        wc.opcode = IB_WC_RECV;

        if (test_and_clear_bit(QIB_R_WRID_VALID, &qp->r_aflags)) {
                wc.wr_id = qp->r_wr_id;
                wc.status = err;
                qib_cq_enter(to_icq(qp->ibqp.recv_cq), &wc, 1);
        }
        wc.status = IB_WC_WR_FLUSH_ERR;

        if (qp->r_rq.wq) {
                struct qib_rwq *wq;
                u32 head;
                u32 tail;

                spin_lock(&qp->r_rq.lock);

                /* sanity check pointers before trusting them */
                wq = qp->r_rq.wq;
                head = wq->head;
                if (head >= qp->r_rq.size)
                        head = 0;
                tail = wq->tail;
                if (tail >= qp->r_rq.size)
                        tail = 0;
                while (tail != head) {
                        wc.wr_id = get_rwqe_ptr(&qp->r_rq, tail)->wr_id;
                        if (++tail >= qp->r_rq.size)
                                tail = 0;
                        qib_cq_enter(to_icq(qp->ibqp.recv_cq), &wc, 1);
                }
                wq->tail = tail;

                spin_unlock(&qp->r_rq.lock);
        } else if (qp->ibqp.event_handler)
                ret = 1;

bail:
        return ret;
}

/**
 * qib_modify_qp - modify the attributes of a queue pair
 * @ibqp: the queue pair who's attributes we're modifying
 * @attr: the new attributes
 * @attr_mask: the mask of attributes to modify
 * @udata: user data for libibverbs.so
 *
 * Returns 0 on success, otherwise returns an errno.
 */
int qib_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr,
                  int attr_mask, struct ib_udata *udata)
{
        struct qib_ibdev *dev = to_idev(ibqp->device);
        struct qib_qp *qp = to_iqp(ibqp);
        enum ib_qp_state cur_state, new_state;
        struct ib_event ev;
        int lastwqe = 0;
        int mig = 0;
        int ret;
        u32 pmtu = 0; /* for gcc warning only */

        spin_lock_irq(&qp->r_lock);
        spin_lock(&qp->s_lock);

        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, IB_LINK_LAYER_UNSPECIFIED))
                goto inval;

        if (attr_mask & IB_QP_AV) {
                if (attr->ah_attr.dlid >= QIB_MULTICAST_LID_BASE)
                        goto inval;
                if (qib_check_ah(qp->ibqp.device, &attr->ah_attr))
                        goto inval;
        }

        if (attr_mask & IB_QP_ALT_PATH) {
                if (attr->alt_ah_attr.dlid >= QIB_MULTICAST_LID_BASE)
                        goto inval;
                if (qib_check_ah(qp->ibqp.device, &attr->alt_ah_attr))
                        goto inval;
                if (attr->alt_pkey_index >= qib_get_npkeys(dd_from_dev(dev)))
                        goto inval;
        }

        if (attr_mask & IB_QP_PKEY_INDEX)
                if (attr->pkey_index >= qib_get_npkeys(dd_from_dev(dev)))
                        goto inval;

        if (attr_mask & IB_QP_MIN_RNR_TIMER)
                if (attr->min_rnr_timer > 31)
                        goto inval;

        if (attr_mask & IB_QP_PORT)
                if (qp->ibqp.qp_type == IB_QPT_SMI ||
                    qp->ibqp.qp_type == IB_QPT_GSI ||
                    attr->port_num == 0 ||
                    attr->port_num > ibqp->device->phys_port_cnt)
                        goto inval;

        if (attr_mask & IB_QP_DEST_QPN)
                if (attr->dest_qp_num > QIB_QPN_MASK)
                        goto inval;

        if (attr_mask & IB_QP_RETRY_CNT)
                if (attr->retry_cnt > 7)
                        goto inval;

        if (attr_mask & IB_QP_RNR_RETRY)
                if (attr->rnr_retry > 7)
                        goto inval;

        /*
         * Don't allow invalid path_mtu values.  OK to set greater
         * than the active mtu (or even the max_cap, if we have tuned
         * that to a small mtu.  We'll set qp->path_mtu
         * to the lesser of requested attribute mtu and active,
         * for packetizing messages.
         * Note that the QP port has to be set in INIT and MTU in RTR.
         */
        if (attr_mask & IB_QP_PATH_MTU) {
                struct qib_devdata *dd = dd_from_dev(dev);
                int mtu, pidx = qp->port_num - 1;

                mtu = ib_mtu_enum_to_int(attr->path_mtu);
                if (mtu == -1)
                        goto inval;
                if (mtu > dd->pport[pidx].ibmtu) {
                        switch (dd->pport[pidx].ibmtu) {
                        case 4096:
                                pmtu = IB_MTU_4096;
                                break;
                        case 2048:
                                pmtu = IB_MTU_2048;
                                break;
                        case 1024:
                                pmtu = IB_MTU_1024;
                                break;
                        case 512:
                                pmtu = IB_MTU_512;
                                break;
                        case 256:
                                pmtu = IB_MTU_256;
                                break;
                        default:
                                pmtu = IB_MTU_2048;
                        }
                } else
                        pmtu = attr->path_mtu;
        }

        if (attr_mask & IB_QP_PATH_MIG_STATE) {
                if (attr->path_mig_state == IB_MIG_REARM) {
                        if (qp->s_mig_state == IB_MIG_ARMED)
                                goto inval;
                        if (new_state != IB_QPS_RTS)
                                goto inval;
                } else if (attr->path_mig_state == IB_MIG_MIGRATED) {
                        if (qp->s_mig_state == IB_MIG_REARM)
                                goto inval;
                        if (new_state != IB_QPS_RTS && new_state != IB_QPS_SQD)
                                goto inval;
                        if (qp->s_mig_state == IB_MIG_ARMED)
                                mig = 1;
                } else
                        goto inval;
        }

        if (attr_mask & IB_QP_MAX_DEST_RD_ATOMIC)
                if (attr->max_dest_rd_atomic > QIB_MAX_RDMA_ATOMIC)
                        goto inval;

        switch (new_state) {
        case IB_QPS_RESET:
                if (qp->state != IB_QPS_RESET) {
                        qp->state = IB_QPS_RESET;
                        spin_lock(&dev->pending_lock);
                        if (!list_empty(&qp->iowait))
                                list_del_init(&qp->iowait);
                        spin_unlock(&dev->pending_lock);
                        qp->s_flags &= ~(QIB_S_TIMER | QIB_S_ANY_WAIT);
                        spin_unlock(&qp->s_lock);
                        spin_unlock_irq(&qp->r_lock);
                        /* Stop the sending work queue and retry timer */
                        cancel_work_sync(&qp->s_work);
                        del_timer_sync(&qp->s_timer);
                        wait_event(qp->wait_dma, !atomic_read(&qp->s_dma_busy));
                        if (qp->s_tx) {
                                qib_put_txreq(qp->s_tx);
                                qp->s_tx = NULL;
                        }
                        remove_qp(dev, qp);
                        wait_event(qp->wait, !atomic_read(&qp->refcount));
                        spin_lock_irq(&qp->r_lock);
                        spin_lock(&qp->s_lock);
                        clear_mr_refs(qp, 1);
                        qib_reset_qp(qp, ibqp->qp_type);
                }
                break;

        case IB_QPS_RTR:
                /* Allow event to retrigger if QP set to RTR more than once */
                qp->r_flags &= ~QIB_R_COMM_EST;
                qp->state = new_state;
                break;

        case IB_QPS_SQD:
                qp->s_draining = qp->s_last != qp->s_cur;
                qp->state = new_state;
                break;

        case IB_QPS_SQE:
                if (qp->ibqp.qp_type == IB_QPT_RC)
                        goto inval;
                qp->state = new_state;
                break;

        case IB_QPS_ERR:
                lastwqe = qib_error_qp(qp, IB_WC_WR_FLUSH_ERR);
                break;

        default:
                qp->state = new_state;
                break;
        }

        if (attr_mask & IB_QP_PKEY_INDEX)
                qp->s_pkey_index = attr->pkey_index;

        if (attr_mask & IB_QP_PORT)
                qp->port_num = attr->port_num;

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

        if (attr_mask & IB_QP_SQ_PSN) {
                qp->s_next_psn = attr->sq_psn & QIB_PSN_MASK;
                qp->s_psn = qp->s_next_psn;
                qp->s_sending_psn = qp->s_next_psn;
                qp->s_last_psn = qp->s_next_psn - 1;
                qp->s_sending_hpsn = qp->s_last_psn;
        }

        if (attr_mask & IB_QP_RQ_PSN)
                qp->r_psn = attr->rq_psn & QIB_PSN_MASK;

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

        if (attr_mask & IB_QP_AV) {
                qp->remote_ah_attr = attr->ah_attr;
                qp->s_srate = attr->ah_attr.static_rate;
        }

        if (attr_mask & IB_QP_ALT_PATH) {
                qp->alt_ah_attr = attr->alt_ah_attr;
                qp->s_alt_pkey_index = attr->alt_pkey_index;
        }

        if (attr_mask & IB_QP_PATH_MIG_STATE) {
                qp->s_mig_state = attr->path_mig_state;
                if (mig) {
                        qp->remote_ah_attr = qp->alt_ah_attr;
                        qp->port_num = qp->alt_ah_attr.port_num;
                        qp->s_pkey_index = qp->s_alt_pkey_index;
                }
        }

        if (attr_mask & IB_QP_PATH_MTU) {
                qp->path_mtu = pmtu;
                qp->pmtu = ib_mtu_enum_to_int(pmtu);
        }

        if (attr_mask & IB_QP_RETRY_CNT) {
                qp->s_retry_cnt = attr->retry_cnt;
                qp->s_retry = attr->retry_cnt;
        }

        if (attr_mask & IB_QP_RNR_RETRY) {
                qp->s_rnr_retry_cnt = attr->rnr_retry;
                qp->s_rnr_retry = attr->rnr_retry;
        }

        if (attr_mask & IB_QP_MIN_RNR_TIMER)
                qp->r_min_rnr_timer = attr->min_rnr_timer;

        if (attr_mask & IB_QP_TIMEOUT) {
                qp->timeout = attr->timeout;
                qp->timeout_jiffies =
                        usecs_to_jiffies((4096UL * (1UL << qp->timeout)) /
                                1000UL);
        }

        if (attr_mask & IB_QP_QKEY)
                qp->qkey = attr->qkey;

        if (attr_mask & IB_QP_MAX_DEST_RD_ATOMIC)
                qp->r_max_rd_atomic = attr->max_dest_rd_atomic;

        if (attr_mask & IB_QP_MAX_QP_RD_ATOMIC)
                qp->s_max_rd_atomic = attr->max_rd_atomic;

        spin_unlock(&qp->s_lock);
        spin_unlock_irq(&qp->r_lock);

        if (cur_state == IB_QPS_RESET && new_state == IB_QPS_INIT)
                insert_qp(dev, qp);

        if (lastwqe) {
                ev.device = qp->ibqp.device;
                ev.element.qp = &qp->ibqp;
                ev.event = IB_EVENT_QP_LAST_WQE_REACHED;
                qp->ibqp.event_handler(&ev, qp->ibqp.qp_context);
        }
        if (mig) {
                ev.device = qp->ibqp.device;
                ev.element.qp = &qp->ibqp;
                ev.event = IB_EVENT_PATH_MIG;
                qp->ibqp.event_handler(&ev, qp->ibqp.qp_context);
        }
        ret = 0;
        goto bail;

inval:
        spin_unlock(&qp->s_lock);
        spin_unlock_irq(&qp->r_lock);
        ret = -EINVAL;

bail:
        return ret;
}

int qib_query_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr,
                 int attr_mask, struct ib_qp_init_attr *init_attr)
{
        struct qib_qp *qp = to_iqp(ibqp);

        attr->qp_state = qp->state;
        attr->cur_qp_state = attr->qp_state;
        attr->path_mtu = qp->path_mtu;
        attr->path_mig_state = qp->s_mig_state;
        attr->qkey = qp->qkey;
        attr->rq_psn = qp->r_psn & QIB_PSN_MASK;
        attr->sq_psn = qp->s_next_psn & QIB_PSN_MASK;
        attr->dest_qp_num = qp->remote_qpn;
        attr->qp_access_flags = qp->qp_access_flags;
        attr->cap.max_send_wr = qp->s_size - 1;
        attr->cap.max_recv_wr = qp->ibqp.srq ? 0 : qp->r_rq.size - 1;
        attr->cap.max_send_sge = qp->s_max_sge;
        attr->cap.max_recv_sge = qp->r_rq.max_sge;
        attr->cap.max_inline_data = 0;
        attr->ah_attr = qp->remote_ah_attr;
        attr->alt_ah_attr = qp->alt_ah_attr;
        attr->pkey_index = qp->s_pkey_index;
        attr->alt_pkey_index = qp->s_alt_pkey_index;
        attr->en_sqd_async_notify = 0;
        attr->sq_draining = qp->s_draining;
        attr->max_rd_atomic = qp->s_max_rd_atomic;
        attr->max_dest_rd_atomic = qp->r_max_rd_atomic;
        attr->min_rnr_timer = qp->r_min_rnr_timer;
        attr->port_num = qp->port_num;
        attr->timeout = qp->timeout;
        attr->retry_cnt = qp->s_retry_cnt;
        attr->rnr_retry = qp->s_rnr_retry_cnt;
        attr->alt_port_num = qp->alt_ah_attr.port_num;
        attr->alt_timeout = qp->alt_timeout;

        init_attr->event_handler = qp->ibqp.event_handler;
        init_attr->qp_context = qp->ibqp.qp_context;
        init_attr->send_cq = qp->ibqp.send_cq;
        init_attr->recv_cq = qp->ibqp.recv_cq;
        init_attr->srq = qp->ibqp.srq;
        init_attr->cap = attr->cap;
        if (qp->s_flags & QIB_S_SIGNAL_REQ_WR)
                init_attr->sq_sig_type = IB_SIGNAL_REQ_WR;
        else
                init_attr->sq_sig_type = IB_SIGNAL_ALL_WR;
        init_attr->qp_type = qp->ibqp.qp_type;
        init_attr->port_num = qp->port_num;
        return 0;
}

/**
 * qib_compute_aeth - compute the AETH (syndrome + MSN)
 * @qp: the queue pair to compute the AETH for
 *
 * Returns the AETH.
 */
__be32 qib_compute_aeth(struct qib_qp *qp)
{
        u32 aeth = qp->r_msn & QIB_MSN_MASK;

        if (qp->ibqp.srq) {
                /*
                 * Shared receive queues don't generate credits.
                 * Set the credit field to the invalid value.
                 */
                aeth |= QIB_AETH_CREDIT_INVAL << QIB_AETH_CREDIT_SHIFT;
        } else {
                u32 min, max, x;
                u32 credits;
                struct qib_rwq *wq = qp->r_rq.wq;
                u32 head;
                u32 tail;

                /* sanity check pointers before trusting them */
                head = wq->head;
                if (head >= qp->r_rq.size)
                        head = 0;
                tail = wq->tail;
                if (tail >= qp->r_rq.size)
                        tail = 0;
                /*
                 * Compute the number of credits available (RWQEs).
                 * XXX Not holding the r_rq.lock here so there is a small
                 * chance that the pair of reads are not atomic.
                 */
                credits = head - tail;
                if ((int)credits < 0)
                        credits += qp->r_rq.size;
                /*
                 * Binary search the credit table to find the code to
                 * use.
                 */
                min = 0;
                max = 31;
                for (;;) {
                        x = (min + max) / 2;
                        if (credit_table[x] == credits)
                                break;
                        if (credit_table[x] > credits)
                                max = x;
                        else if (min == x)
                                break;
                        else
                                min = x;
                }
                aeth |= x << QIB_AETH_CREDIT_SHIFT;
        }
        return cpu_to_be32(aeth);
}

/**
 * qib_create_qp - create a queue pair for a device
 * @ibpd: the protection domain who's device we create the queue pair for
 * @init_attr: the attributes of the queue pair
 * @udata: user data for libibverbs.so
 *
 * Returns the queue pair on success, otherwise returns an errno.
 *
 * Called by the ib_create_qp() core verbs function.
 */
struct ib_qp *qib_create_qp(struct ib_pd *ibpd,
                            struct ib_qp_init_attr *init_attr,
                            struct ib_udata *udata)
{
        struct qib_qp *qp;
        int err;
        struct qib_swqe *swq = NULL;
        struct qib_ibdev *dev;
        struct qib_devdata *dd;
        size_t sz;
        size_t sg_list_sz;
        struct ib_qp *ret;

        if (init_attr->cap.max_send_sge > ib_qib_max_sges ||
            init_attr->cap.max_send_wr > ib_qib_max_qp_wrs ||
            init_attr->create_flags) {
                ret = ERR_PTR(-EINVAL);
                goto bail;
        }

        /* Check receive queue parameters if no SRQ is specified. */
        if (!init_attr->srq) {
                if (init_attr->cap.max_recv_sge > ib_qib_max_sges ||
                    init_attr->cap.max_recv_wr > ib_qib_max_qp_wrs) {
                        ret = ERR_PTR(-EINVAL);
                        goto bail;
                }

                if (init_attr->cap.max_send_sge +
                    init_attr->cap.max_send_wr +
                    init_attr->cap.max_recv_sge +
                    init_attr->cap.max_recv_wr == 0) {
                        ret = ERR_PTR(-EINVAL);
                        goto bail;
                }
        }

        switch (init_attr->qp_type) {
        case IB_QPT_SMI:
        case IB_QPT_GSI:
                if (init_attr->port_num == 0 ||
                    init_attr->port_num > ibpd->device->phys_port_cnt) {
                        ret = ERR_PTR(-EINVAL);
                        goto bail;
                }
        case IB_QPT_UC:
        case IB_QPT_RC:
        case IB_QPT_UD:
                sz = sizeof(struct qib_sge) *
                        init_attr->cap.max_send_sge +
                        sizeof(struct qib_swqe);
                swq = vmalloc((init_attr->cap.max_send_wr + 1) * sz);
                if (swq == NULL) {
                        ret = ERR_PTR(-ENOMEM);
                        goto bail;
                }
                sz = sizeof(*qp);
                sg_list_sz = 0;
                if (init_attr->srq) {
                        struct qib_srq *srq = to_isrq(init_attr->srq);

                        if (srq->rq.max_sge > 1)
                                sg_list_sz = sizeof(*qp->r_sg_list) *
                                        (srq->rq.max_sge - 1);
                } else if (init_attr->cap.max_recv_sge > 1)
                        sg_list_sz = sizeof(*qp->r_sg_list) *
                                (init_attr->cap.max_recv_sge - 1);
                qp = kzalloc(sz + sg_list_sz, GFP_KERNEL);
                if (!qp) {
                        ret = ERR_PTR(-ENOMEM);
                        goto bail_swq;
                }
                RCU_INIT_POINTER(qp->next, NULL);
                qp->s_hdr = kzalloc(sizeof(*qp->s_hdr), GFP_KERNEL);
                if (!qp->s_hdr) {
                        ret = ERR_PTR(-ENOMEM);
                        goto bail_qp;
                }
                qp->timeout_jiffies =
                        usecs_to_jiffies((4096UL * (1UL << qp->timeout)) /
                                1000UL);
                if (init_attr->srq)
                        sz = 0;
                else {
                        qp->r_rq.size = init_attr->cap.max_recv_wr + 1;
                        qp->r_rq.max_sge = init_attr->cap.max_recv_sge;
                        sz = (sizeof(struct ib_sge) * qp->r_rq.max_sge) +
                                sizeof(struct qib_rwqe);
                        qp->r_rq.wq = vmalloc_user(sizeof(struct qib_rwq) +
                                                   qp->r_rq.size * sz);
                        if (!qp->r_rq.wq) {
                                ret = ERR_PTR(-ENOMEM);
                                goto bail_qp;
                        }
                }

                /*
                 * ib_create_qp() will initialize qp->ibqp
                 * except for qp->ibqp.qp_num.
                 */
                spin_lock_init(&qp->r_lock);
                spin_lock_init(&qp->s_lock);
                spin_lock_init(&qp->r_rq.lock);
                atomic_set(&qp->refcount, 0);
                init_waitqueue_head(&qp->wait);
                init_waitqueue_head(&qp->wait_dma);
                init_timer(&qp->s_timer);
                qp->s_timer.data = (unsigned long)qp;
                INIT_WORK(&qp->s_work, qib_do_send);
                INIT_LIST_HEAD(&qp->iowait);
                INIT_LIST_HEAD(&qp->rspwait);
                qp->state = IB_QPS_RESET;
                qp->s_wq = swq;
                qp->s_size = init_attr->cap.max_send_wr + 1;
                qp->s_max_sge = init_attr->cap.max_send_sge;
                if (init_attr->sq_sig_type == IB_SIGNAL_REQ_WR)
                        qp->s_flags = QIB_S_SIGNAL_REQ_WR;
                dev = to_idev(ibpd->device);
                dd = dd_from_dev(dev);
                err = alloc_qpn(dd, &dev->qpn_table, init_attr->qp_type,
                                init_attr->port_num);
                if (err < 0) {
                        ret = ERR_PTR(err);
                        vfree(qp->r_rq.wq);
                        goto bail_qp;
                }
                qp->ibqp.qp_num = err;
                qp->port_num = init_attr->port_num;
                qib_reset_qp(qp, init_attr->qp_type);
                break;

        default:
                /* Don't support raw QPs */
                ret = ERR_PTR(-ENOSYS);
                goto bail;
        }

        init_attr->cap.max_inline_data = 0;

        /*
         * Return the address of the RWQ as the offset to mmap.
         * See qib_mmap() for details.
         */
        if (udata && udata->outlen >= sizeof(__u64)) {
                if (!qp->r_rq.wq) {
                        __u64 offset = 0;

                        err = ib_copy_to_udata(udata, &offset,
                                               sizeof(offset));
                        if (err) {
                                ret = ERR_PTR(err);
                                goto bail_ip;
                        }
                } else {
                        u32 s = sizeof(struct qib_rwq) + qp->r_rq.size * sz;

                        qp->ip = qib_create_mmap_info(dev, s,
                                                      ibpd->uobject->context,
                                                      qp->r_rq.wq);
                        if (!qp->ip) {
                                ret = ERR_PTR(-ENOMEM);
                                goto bail_ip;
                        }

                        err = ib_copy_to_udata(udata, &(qp->ip->offset),
                                               sizeof(qp->ip->offset));
                        if (err) {
                                ret = ERR_PTR(err);
                                goto bail_ip;
                        }
                }
        }

        spin_lock(&dev->n_qps_lock);
        if (dev->n_qps_allocated == ib_qib_max_qps) {
                spin_unlock(&dev->n_qps_lock);
                ret = ERR_PTR(-ENOMEM);
                goto bail_ip;
        }

        dev->n_qps_allocated++;
        spin_unlock(&dev->n_qps_lock);

        if (qp->ip) {
                spin_lock_irq(&dev->pending_lock);
                list_add(&qp->ip->pending_mmaps, &dev->pending_mmaps);
                spin_unlock_irq(&dev->pending_lock);
        }

        ret = &qp->ibqp;
        goto bail;

bail_ip:
        if (qp->ip)
                kref_put(&qp->ip->ref, qib_release_mmap_info);
        else
                vfree(qp->r_rq.wq);
        free_qpn(&dev->qpn_table, qp->ibqp.qp_num);
bail_qp:
        kfree(qp->s_hdr);
        kfree(qp);
bail_swq:
        vfree(swq);
bail:
        return ret;
}

/**
 * qib_destroy_qp - destroy a queue pair
 * @ibqp: the queue pair to destroy
 *
 * Returns 0 on success.
 *
 * Note that this can be called while the QP is actively sending or
 * receiving!
 */
int qib_destroy_qp(struct ib_qp *ibqp)
{
        struct qib_qp *qp = to_iqp(ibqp);
        struct qib_ibdev *dev = to_idev(ibqp->device);

        /* Make sure HW and driver activity is stopped. */
        spin_lock_irq(&qp->s_lock);
        if (qp->state != IB_QPS_RESET) {
                qp->state = IB_QPS_RESET;
                spin_lock(&dev->pending_lock);
                if (!list_empty(&qp->iowait))
                        list_del_init(&qp->iowait);
                spin_unlock(&dev->pending_lock);
                qp->s_flags &= ~(QIB_S_TIMER | QIB_S_ANY_WAIT);
                spin_unlock_irq(&qp->s_lock);
                cancel_work_sync(&qp->s_work);
                del_timer_sync(&qp->s_timer);
                wait_event(qp->wait_dma, !atomic_read(&qp->s_dma_busy));
                if (qp->s_tx) {
                        qib_put_txreq(qp->s_tx);
                        qp->s_tx = NULL;
                }
                remove_qp(dev, qp);
                wait_event(qp->wait, !atomic_read(&qp->refcount));
                clear_mr_refs(qp, 1);
        } else
                spin_unlock_irq(&qp->s_lock);

        /* all user's cleaned up, mark it available */
        free_qpn(&dev->qpn_table, qp->ibqp.qp_num);
        spin_lock(&dev->n_qps_lock);
        dev->n_qps_allocated--;
        spin_unlock(&dev->n_qps_lock);

        if (qp->ip)
                kref_put(&qp->ip->ref, qib_release_mmap_info);
        else
                vfree(qp->r_rq.wq);
        vfree(qp->s_wq);
        kfree(qp->s_hdr);
        kfree(qp);
        return 0;
}

/**
 * qib_init_qpn_table - initialize the QP number table for a device
 * @qpt: the QPN table
 */
void qib_init_qpn_table(struct qib_devdata *dd, struct qib_qpn_table *qpt)
{
        spin_lock_init(&qpt->lock);
        qpt->last = 1;          /* start with QPN 2 */
        qpt->nmaps = 1;
        qpt->mask = dd->qpn_mask;
}

/**
 * qib_free_qpn_table - free the QP number table for a device
 * @qpt: the QPN table
 */
void qib_free_qpn_table(struct qib_qpn_table *qpt)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(qpt->map); i++)
                if (qpt->map[i].page)
                        free_page((unsigned long) qpt->map[i].page);
}

/**
 * qib_get_credit - flush the send work queue of a QP
 * @qp: the qp who's send work queue to flush
 * @aeth: the Acknowledge Extended Transport Header
 *
 * The QP s_lock should be held.
 */
void qib_get_credit(struct qib_qp *qp, u32 aeth)
{
        u32 credit = (aeth >> QIB_AETH_CREDIT_SHIFT) & QIB_AETH_CREDIT_MASK;

        /*
         * If the credit is invalid, we can send
         * as many packets as we like.  Otherwise, we have to
         * honor the credit field.
         */
        if (credit == QIB_AETH_CREDIT_INVAL) {
                if (!(qp->s_flags & QIB_S_UNLIMITED_CREDIT)) {
                        qp->s_flags |= QIB_S_UNLIMITED_CREDIT;
                        if (qp->s_flags & QIB_S_WAIT_SSN_CREDIT) {
                                qp->s_flags &= ~QIB_S_WAIT_SSN_CREDIT;
                                qib_schedule_send(qp);
                        }
                }
        } else if (!(qp->s_flags & QIB_S_UNLIMITED_CREDIT)) {
                /* Compute new LSN (i.e., MSN + credit) */
                credit = (aeth + credit_table[credit]) & QIB_MSN_MASK;
                if (qib_cmp24(credit, qp->s_lsn) > 0) {
                        qp->s_lsn = credit;
                        if (qp->s_flags & QIB_S_WAIT_SSN_CREDIT) {
                                qp->s_flags &= ~QIB_S_WAIT_SSN_CREDIT;
                                qib_schedule_send(qp);
                        }
                }
        }
}

#ifdef CONFIG_DEBUG_FS

struct qib_qp_iter {
        struct qib_ibdev *dev;
        struct qib_qp *qp;
        int n;
};

struct qib_qp_iter *qib_qp_iter_init(struct qib_ibdev *dev)
{
        struct qib_qp_iter *iter;

        iter = kzalloc(sizeof(*iter), GFP_KERNEL);
        if (!iter)
                return NULL;

        iter->dev = dev;
        if (qib_qp_iter_next(iter)) {
                kfree(iter);
                return NULL;
        }

        return iter;
}

int qib_qp_iter_next(struct qib_qp_iter *iter)
{
        struct qib_ibdev *dev = iter->dev;
        int n = iter->n;
        int ret = 1;
        struct qib_qp *pqp = iter->qp;
        struct qib_qp *qp;

        for (; n < dev->qp_table_size; n++) {
                if (pqp)
                        qp = rcu_dereference(pqp->next);
                else
                        qp = rcu_dereference(dev->qp_table[n]);
                pqp = qp;
                if (qp) {
                        iter->qp = qp;
                        iter->n = n;
                        return 0;
                }
        }
        return ret;
}

static const char * const qp_type_str[] = {
        "SMI", "GSI", "RC", "UC", "UD",
};

void qib_qp_iter_print(struct seq_file *s, struct qib_qp_iter *iter)
{
        struct qib_swqe *wqe;
        struct qib_qp *qp = iter->qp;

        wqe = get_swqe_ptr(qp, qp->s_last);
        seq_printf(s,
                   "N %d QP%u %s %u %u %u f=%x %u %u %u %u %u PSN %x %x %x %x %x (%u %u %u %u %u %u) QP%u LID %x\n",
                   iter->n,
                   qp->ibqp.qp_num,
                   qp_type_str[qp->ibqp.qp_type],
                   qp->state,
                   wqe->wr.opcode,
                   qp->s_hdrwords,
                   qp->s_flags,
                   atomic_read(&qp->s_dma_busy),
                   !list_empty(&qp->iowait),
                   qp->timeout,
                   wqe->ssn,
                   qp->s_lsn,
                   qp->s_last_psn,
                   qp->s_psn, qp->s_next_psn,
                   qp->s_sending_psn, qp->s_sending_hpsn,
                   qp->s_last, qp->s_acked, qp->s_cur,
                   qp->s_tail, qp->s_head, qp->s_size,
                   qp->remote_qpn,
                   qp->remote_ah_attr.dlid);
}

#endif