text: /*
   * Copyright (c) 2012 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>
  
  #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);
  
  	spin_lock_irqsave(&dev->qpt_lock, flags);
  	atomic_inc(&qp->refcount);
  
  	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);
  	synchronize_rcu();
  }
  
  /*
   * 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;
  
  	spin_lock_irqsave(&dev->qpt_lock, flags);
  
  	if (rcu_dereference_protected(ibp->qp0,
  			lockdep_is_held(&dev->qpt_lock)) == qp) {
  		atomic_dec(&qp->refcount);
  		rcu_assign_pointer(ibp->qp0, NULL);
  	} else if (rcu_dereference_protected(ibp->qp1,
  			lockdep_is_held(&dev->qpt_lock)) == qp) {
  		atomic_dec(&qp->refcount);
  		rcu_assign_pointer(ibp->qp1, NULL);
  	} else {
  		struct qib_qp *q;
  		struct qib_qp __rcu **qpp;
  
  		qpp = &dev->qp_table[n];
  		for (; (q = rcu_dereference_protected(*qpp,
  				lockdep_is_held(&dev->qpt_lock))) != NULL;
  				qpp = &q->next)
  			if (q == qp) {
  				atomic_dec(&qp->refcount);
  				*qpp = qp->next;
  				rcu_assign_pointer(qp->next, NULL);
  				break;
  			}
  	}
  
  	spin_unlock_irqrestore(&dev->qpt_lock, flags);
  	synchronize_rcu();
  }
  
  /**
   * 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_assign_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;
  
  	if (unlikely(qpn <= 1)) {
  		rcu_read_lock();
  		if (qpn == 0)
  			qp = rcu_dereference(ibp->qp0);
  		else
  			qp = rcu_dereference(ibp->qp1);
  	} else {
  		struct qib_ibdev *dev = &ppd_from_ibp(ibp)->dd->verbs_dev;
  		unsigned n = qpn_hash(dev, qpn);
  
  		rcu_read_lock();
  		for (qp = rcu_dereference(dev->qp_table[n]); qp;
  			qp = rcu_dereference(qp->next))
  			if (qp->ibqp.qp_num == qpn)
  				break;
  	}
  	if (qp)
  		if (unlikely(!atomic_inc_not_zero(&qp->refcount)))
  			qp = NULL;
  
  	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))
  		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) {
  		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);
  			}
  		}
  	}
  }
  