text: /*
   * Copyright (c) 2006, 2007, 2008, 2009 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/spinlock.h>
  
  #include "qib.h"
  #include "qib_mad.h"
  
  /*
   * Convert the AETH RNR timeout code into the number of microseconds.
   */
  const u32 ib_qib_rnr_table[32] = {
  	655360,	/* 00: 655.36 */
  	10,	/* 01:    .01 */
  	20,	/* 02     .02 */
  	30,	/* 03:    .03 */
  	40,	/* 04:    .04 */
  	60,	/* 05:    .06 */
  	80,	/* 06:    .08 */
  	120,	/* 07:    .12 */
  	160,	/* 08:    .16 */
  	240,	/* 09:    .24 */
  	320,	/* 0A:    .32 */
  	480,	/* 0B:    .48 */
  	640,	/* 0C:    .64 */
  	960,	/* 0D:    .96 */
  	1280,	/* 0E:   1.28 */
  	1920,	/* 0F:   1.92 */
  	2560,	/* 10:   2.56 */
  	3840,	/* 11:   3.84 */
  	5120,	/* 12:   5.12 */
  	7680,	/* 13:   7.68 */
  	10240,	/* 14:  10.24 */
  	15360,	/* 15:  15.36 */
  	20480,	/* 16:  20.48 */
  	30720,	/* 17:  30.72 */
  	40960,	/* 18:  40.96 */
  	61440,	/* 19:  61.44 */
  	81920,	/* 1A:  81.92 */
  	122880,	/* 1B: 122.88 */
  	163840,	/* 1C: 163.84 */
  	245760,	/* 1D: 245.76 */
  	327680,	/* 1E: 327.68 */
  	491520	/* 1F: 491.52 */
  };
  
  /*
   * Validate a RWQE and fill in the SGE state.
   * Return 1 if OK.
   */
  static int qib_init_sge(struct qib_qp *qp, struct qib_rwqe *wqe)
  {
  	int i, j, ret;
  	struct ib_wc wc;
  	struct qib_lkey_table *rkt;
  	struct qib_pd *pd;
  	struct qib_sge_state *ss;
  
  	rkt = &to_idev(qp->ibqp.device)->lk_table;
  	pd = to_ipd(qp->ibqp.srq ? qp->ibqp.srq->pd : qp->ibqp.pd);
  	ss = &qp->r_sge;
  	ss->sg_list = qp->r_sg_list;
  	qp->r_len = 0;
  	for (i = j = 0; i < wqe->num_sge; i++) {
  		if (wqe->sg_list[i].length == 0)
  			continue;
  		/* Check LKEY */
  		if (!qib_lkey_ok(rkt, pd, j ? &ss->sg_list[j - 1] : &ss->sge,
  				 &wqe->sg_list[i], IB_ACCESS_LOCAL_WRITE))
  			goto bad_lkey;
  		qp->r_len += wqe->sg_list[i].length;
  		j++;
  	}
  	ss->num_sge = j;
  	ss->total_len = qp->r_len;
  	ret = 1;
  	goto bail;
  
  bad_lkey:
  	while (j) {
  		struct qib_sge *sge = --j ? &ss->sg_list[j - 1] : &ss->sge;
  
  		qib_put_mr(sge->mr);
  	}
  	ss->num_sge = 0;
  	memset(&wc, 0, sizeof(wc));
  	wc.wr_id = wqe->wr_id;
  	wc.status = IB_WC_LOC_PROT_ERR;
  	wc.opcode = IB_WC_RECV;
  	wc.qp = &qp->ibqp;
  	/* Signal solicited completion event. */
  	qib_cq_enter(to_icq(qp->ibqp.recv_cq), &wc, 1);
  	ret = 0;
  bail:
  	return ret;
  }
  
  /**
   * qib_get_rwqe - copy the next RWQE into the QP's RWQE
   * @qp: the QP
   * @wr_id_only: update qp->r_wr_id only, not qp->r_sge
   *
   * Return -1 if there is a local error, 0 if no RWQE is available,
   * otherwise return 1.
   *
   * Can be called from interrupt level.
   */
  int qib_get_rwqe(struct qib_qp *qp, int wr_id_only)
  {
  	unsigned long flags;
  	struct qib_rq *rq;
  	struct qib_rwq *wq;
  	struct qib_srq *srq;
  	struct qib_rwqe *wqe;
  	void (*handler)(struct ib_event *, void *);
  	u32 tail;
  	int ret;
  
  	if (qp->ibqp.srq) {
  		srq = to_isrq(qp->ibqp.srq);
  		handler = srq->ibsrq.event_handler;
  		rq = &srq->rq;
  	} else {
  		srq = NULL;
  		handler = NULL;
  		rq = &qp->r_rq;
  	}
  
  	spin_lock_irqsave(&rq->lock, flags);
  	if (!(ib_qib_state_ops[qp->state] & QIB_PROCESS_RECV_OK)) {
  		ret = 0;
  		goto unlock;
  	}
  
  	wq = rq->wq;
  	tail = wq->tail;
  	/* Validate tail before using it since it is user writable. */
  	if (tail >= rq->size)
  		tail = 0;
  	if (unlikely(tail == wq->head)) {
  		ret = 0;
  		goto unlock;
  	}
  	/* Make sure entry is read after head index is read. */
  	smp_rmb();
  	wqe = get_rwqe_ptr(rq, tail);
  	/*
  	 * Even though we update the tail index in memory, the verbs
  	 * consumer is not supposed to post more entries until a
  	 * completion is generated.
  	 */
  	if (++tail >= rq->size)
  		tail = 0;
  	wq->tail = tail;
  	if (!wr_id_only && !qib_init_sge(qp, wqe)) {
  		ret = -1;
  		goto unlock;
  	}
  	qp->r_wr_id = wqe->wr_id;
  
  	ret = 1;
  	set_bit(QIB_R_WRID_VALID, &qp->r_aflags);
  	if (handler) {
  		u32 n;
  
  		/*
  		 * Validate head pointer value and compute
  		 * the number of remaining WQEs.
  		 */
  		n = wq->head;
  		if (n >= rq->size)
  			n = 0;
  		if (n < tail)
  			n += rq->size - tail;
  		else
  			n -= tail;
  		if (n < srq->limit) {
  			struct ib_event ev;
  
  			srq->limit = 0;
  			spin_unlock_irqrestore(&rq->lock, flags);
  			ev.device = qp->ibqp.device;
  			ev.element.srq = qp->ibqp.srq;
  			ev.event = IB_EVENT_SRQ_LIMIT_REACHED;
  			handler(&ev, srq->ibsrq.srq_context);
  			goto bail;
  		}
  	}
  unlock:
  	spin_unlock_irqrestore(&rq->lock, flags);
  bail:
  	return ret;
  }
  
  /*
   * Switch to alternate path.
   * The QP s_lock should be held and interrupts disabled.
   */
  void qib_migrate_qp(struct qib_qp *qp)
  {
  	struct ib_event ev;
  
  	qp->s_mig_state = IB_MIG_MIGRATED;
  	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;
  
  	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);
  }
  
  static __be64 get_sguid(struct qib_ibport *ibp, unsigned index)
  {
  	if (!index) {
  		struct qib_pportdata *ppd = ppd_from_ibp(ibp);
  
  		return ppd->guid;
  	} else
  		return ibp->guids[index - 1];
  }
  
  static int gid_ok(union ib_gid *gid, __be64 gid_prefix, __be64 id)
  {
  	return (gid->global.interface_id == id &&
  		(gid->global.subnet_prefix == gid_prefix ||
  		 gid->global.subnet_prefix == IB_DEFAULT_GID_PREFIX));
  }
  
  /*
   *
   * This should be called with the QP r_lock held.
   *
   * The s_lock will be acquired around the qib_migrate_qp() call.
   */
  int qib_ruc_check_hdr(struct qib_ibport *ibp, struct qib_ib_header *hdr,
  		      int has_grh, struct qib_qp *qp, u32 bth0)
  {
  	__be64 guid;
  	unsigned long flags;
  
  	if (qp->s_mig_state == IB_MIG_ARMED && (bth0 & IB_BTH_MIG_REQ)) {
  		if (!has_grh) {
  			if (qp->alt_ah_attr.ah_flags & IB_AH_GRH)
  				goto err;
  		} else {
  			if (!(qp->alt_ah_attr.ah_flags & IB_AH_GRH))
  				goto err;
  			guid = get_sguid(ibp, qp->alt_ah_attr.grh.sgid_index);
  			if (!gid_ok(&hdr->u.l.grh.dgid, ibp->gid_prefix, guid))
  				goto err;
  			if (!gid_ok(&hdr->u.l.grh.sgid,
  			    qp->alt_ah_attr.grh.dgid.global.subnet_prefix,
  			    qp->alt_ah_attr.grh.dgid.global.interface_id))
  				goto err;
  		}
  		if (!qib_pkey_ok((u16)bth0,
  				 qib_get_pkey(ibp, qp->s_alt_pkey_index))) {
  			qib_bad_pqkey(ibp, IB_NOTICE_TRAP_BAD_PKEY,
  				      (u16)bth0,
  				      (be16_to_cpu(hdr->lrh[0]) >> 4) & 0xF,
  				      0, qp->ibqp.qp_num,
  				      hdr->lrh[3], hdr->lrh[1]);
  			goto err;
  		}
  		/* Validate the SLID. See Ch. 9.6.1.5 and 17.2.8 */
  		if (be16_to_cpu(hdr->lrh[3]) != qp->alt_ah_attr.dlid ||
  		    ppd_from_ibp(ibp)->port != qp->alt_ah_attr.port_num)
  			goto err;
  		spin_lock_irqsave(&qp->s_lock, flags);
  		qib_migrate_qp(qp);
  		spin_unlock_irqrestore(&qp->s_lock, flags);
  	} else {
  		if (!has_grh) {
  			if (qp->remote_ah_attr.ah_flags & IB_AH_GRH)
  				goto err;
  		} else {
  			if (!(qp->remote_ah_attr.ah_flags & IB_AH_GRH))
  				goto err;
  			guid = get_sguid(ibp,
  					 qp->remote_ah_attr.grh.sgid_index);
  			if (!gid_ok(&hdr->u.l.grh.dgid, ibp->gid_prefix, guid))
  				goto err;
  			if (!gid_ok(&hdr->u.l.grh.sgid,
  			    qp->remote_ah_attr.grh.dgid.global.subnet_prefix,
  			    qp->remote_ah_attr.grh.dgid.global.interface_id))
  				goto err;
  		}
  		if (!qib_pkey_ok((u16)bth0,
  				 qib_get_pkey(ibp, qp->s_pkey_index))) {
  			qib_bad_pqkey(ibp, IB_NOTICE_TRAP_BAD_PKEY,
  				      (u16)bth0,
  				      (be16_to_cpu(hdr->lrh[0]) >> 4) & 0xF,
  				      0, qp->ibqp.qp_num,
  				      hdr->lrh[3], hdr->lrh[1]);
  			goto err;
  		}
  		/* Validate the SLID. See Ch. 9.6.1.5 */
  		if (be16_to_cpu(hdr->lrh[3]) != qp->remote_ah_attr.dlid ||
  		    ppd_from_ibp(ibp)->port != qp->port_num)
  			goto err;
  		if (qp->s_mig_state == IB_MIG_REARM &&
  		    !(bth0 & IB_BTH_MIG_REQ))
  			qp->s_mig_state = IB_MIG_ARMED;
  	}
  
  	return 0;
  
  err:
  	return 1;
  }
  
  /**
   * qib_ruc_loopback - handle UC and RC lookback requests
   * @sqp: the sending QP
   *
   * This is called from qib_do_send() to
   * forward a WQE addressed to the same HCA.
   * Note that although we are single threaded due to the tasklet, we still
   * have to protect against post_send().  We don't have to worry about
   * receive interrupts since this is a connected protocol and all packets
   * will pass through here.
   */
  static void qib_ruc_loopback(struct qib_qp *sqp)
  {
  	struct qib_ibport *ibp = to_iport(sqp->ibqp.device, sqp->port_num);
  	struct qib_qp *qp;
  	struct qib_swqe *wqe;
  	struct qib_sge *sge;
  	unsigned long flags;
  	struct ib_wc wc;
  	u64 sdata;
  	atomic64_t *maddr;
  	enum ib_wc_status send_status;
  	int release;
  	int ret;
  
  	/*
  	 * Note that we check the responder QP state after
  	 * checking the requester's state.
  	 */
  	qp = qib_lookup_qpn(ibp, sqp->remote_qpn);
  
  	spin_lock_irqsave(&sqp->s_lock, flags);
  
  	/* Return if we are already busy processing a work request. */
  	if ((sqp->s_flags & (QIB_S_BUSY | QIB_S_ANY_WAIT)) ||
  	    !(ib_qib_state_ops[sqp->state] & QIB_PROCESS_OR_FLUSH_SEND))
  		goto unlock;
  
  	sqp->s_flags |= QIB_S_BUSY;
  
  again:
  	if (sqp->s_last == sqp->s_head)
  		goto clr_busy;
  	wqe = get_swqe_ptr(sqp, sqp->s_last);
  
  	/* Return if it is not OK to start a new work reqeust. */
  	if (!(ib_qib_state_ops[sqp->state] & QIB_PROCESS_NEXT_SEND_OK)) {
  		if (!(ib_qib_state_ops[sqp->state] & QIB_FLUSH_SEND))
  			goto clr_busy;
  		/* We are in the error state, flush the work request. */
  		send_status = IB_WC_WR_FLUSH_ERR;
  		goto flush_send;
  	}
  
  	/*
  	 * We can rely on the entry not changing without the s_lock
  	 * being held until we update s_last.
  	 * We increment s_cur to indicate s_last is in progress.
  	 */
  	if (sqp->s_last == sqp->s_cur) {
  		if (++sqp->s_cur >= sqp->s_size)
  			sqp->s_cur = 0;
  	}
  	spin_unlock_irqrestore(&sqp->s_lock, flags);
  
  	if (!qp || !(ib_qib_state_ops[qp->state] & QIB_PROCESS_RECV_OK) ||
  	    qp->ibqp.qp_type != sqp->ibqp.qp_type) {
  		ibp->n_pkt_drops++;
  		/*
  		 * For RC, the requester would timeout and retry so
  		 * shortcut the timeouts and just signal too many retries.
  		 */
  		if (sqp->ibqp.qp_type == IB_QPT_RC)
  			send_status = IB_WC_RETRY_EXC_ERR;
  		else
  			send_status = IB_WC_SUCCESS;
  		goto serr;
  	}
  
  	memset(&wc, 0, sizeof wc);
  	send_status = IB_WC_SUCCESS;
  
  	release = 1;
  	sqp->s_sge.sge = wqe->sg_list[0];
  	sqp->s_sge.sg_list = wqe->sg_list + 1;
  	sqp->s_sge.num_sge = wqe->wr.num_sge;
  	sqp->s_len = wqe->length;
  	switch (wqe->wr.opcode) {
  	case IB_WR_SEND_WITH_IMM:
  		wc.wc_flags = IB_WC_WITH_IMM;
  		wc.ex.imm_data = wqe->wr.ex.imm_data;
  		/* FALLTHROUGH */
  	case IB_WR_SEND:
  		ret = qib_get_rwqe(qp, 0);
  		if (ret < 0)
  			goto op_err;
  		if (!ret)
  			goto rnr_nak;
  		break;
  
  	case IB_WR_RDMA_WRITE_WITH_IMM:
  		if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_WRITE)))
  			goto inv_err;
  		wc.wc_flags = IB_WC_WITH_IMM;
  		wc.ex.imm_data = wqe->wr.ex.imm_data;
  		ret = qib_get_rwqe(qp, 1);
  		if (ret < 0)
  			goto op_err;
  		if (!ret)
  			goto rnr_nak;
  		/* FALLTHROUGH */
  	case IB_WR_RDMA_WRITE:
  		if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_WRITE)))
  			goto inv_err;
  		if (wqe->length == 0)
  			break;
  		if (unlikely(!qib_rkey_ok(qp, &qp->r_sge.sge, wqe->length,
  					  wqe->wr.wr.rdma.remote_addr,
  					  wqe->wr.wr.rdma.rkey,
  					  IB_ACCESS_REMOTE_WRITE)))
  			goto acc_err;
  		qp->r_sge.sg_list = NULL;
  		qp->r_sge.num_sge = 1;
  		qp->r_sge.total_len = wqe->length;
  		break;
  
  	case IB_WR_RDMA_READ:
  		if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_READ)))
  			goto inv_err;
  		if (unlikely(!qib_rkey_ok(qp, &sqp->s_sge.sge, wqe->length,
  					  wqe->wr.wr.rdma.remote_addr,
  					  wqe->wr.wr.rdma.rkey,
  					  IB_ACCESS_REMOTE_READ)))
  			goto acc_err;
  		release = 0;
  		sqp->s_sge.sg_list = NULL;
  		sqp->s_sge.num_sge = 1;
  		qp->r_sge.sge = wqe->sg_list[0];
  		qp->r_sge.sg_list = wqe->sg_list + 1;
  		qp->r_sge.num_sge = wqe->wr.num_sge;
  		qp->r_sge.total_len = wqe->length;
  		break;
  
  	case IB_WR_ATOMIC_CMP_AND_SWP:
  	case IB_WR_ATOMIC_FETCH_AND_ADD:
  		if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_ATOMIC)))
  			goto inv_err;
  		if (unlikely(!qib_rkey_ok(qp, &qp->r_sge.sge, sizeof(u64),
  					  wqe->wr.wr.atomic.remote_addr,
  					  wqe->wr.wr.atomic.rkey,
  					  IB_ACCESS_REMOTE_ATOMIC)))
  			goto acc_err;
  		/* Perform atomic OP and save result. */
  		maddr = (atomic64_t *) qp->r_sge.sge.vaddr;
  		sdata = wqe->wr.wr.atomic.compare_add;
  		*(u64 *) sqp->s_sge.sge.vaddr =
  			(wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) ?
  			(u64) atomic64_add_return(sdata, maddr) - sdata :
  			(u64) cmpxchg((u64 *) qp->r_sge.sge.vaddr,
  				      sdata, wqe->wr.wr.atomic.swap);
  		qib_put_mr(qp->r_sge.sge.mr);
  		qp->r_sge.num_sge = 0;
  		goto send_comp;
  
  	default:
  		send_status = IB_WC_LOC_QP_OP_ERR;
  		goto serr;
  	}
  
  	sge = &sqp->s_sge.sge;
  	while (sqp->s_len) {
  		u32 len = sqp->s_len;
  
  		if (len > sge->length)
  			len = sge->length;
  		if (len > sge->sge_length)
  			len = sge->sge_length;
  		BUG_ON(len == 0);
  		qib_copy_sge(&qp->r_sge, sge->vaddr, len, release);
  		sge->vaddr += len;
  		sge->length -= len;
  		sge->sge_length -= len;
  		if (sge->sge_length == 0) {
  			if (!release)
  				qib_put_mr(sge->mr);
  			if (--sqp->s_sge.num_sge)
  				*sge = *sqp->s_sge.sg_list++;
  		} else if (sge->length == 0 && sge->mr->lkey) {
  			if (++sge->n >= QIB_SEGSZ) {
  				if (++sge->m >= sge->mr->mapsz)
  					break;
  				sge->n = 0;
  			}
  			sge->vaddr =
  				sge->mr->map[sge->m]->segs[sge->n].vaddr;
  			sge->length =
  				sge->mr->map[sge->m]->segs[sge->n].length;
  		}
  		sqp->s_len -= len;
  	}
  	if (release)
  		qib_put_ss(&qp->r_sge);
  
  	if (!test_and_clear_bit(QIB_R_WRID_VALID, &qp->r_aflags))
  		goto send_comp;
  
  	if (wqe->wr.opcode == IB_WR_RDMA_WRITE_WITH_IMM)
  		wc.opcode = IB_WC_RECV_RDMA_WITH_IMM;
  	else
  		wc.opcode = IB_WC_RECV;
  	wc.wr_id = qp->r_wr_id;
  	wc.status = IB_WC_SUCCESS;
  	wc.byte_len = wqe->length;
  	wc.qp = &qp->ibqp;
  	wc.src_qp = qp->remote_qpn;
  	wc.slid = qp->remote_ah_attr.dlid;
  	wc.sl = qp->remote_ah_attr.sl;
  	wc.port_num = 1;
  	/* Signal completion event if the solicited bit is set. */
  	qib_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
  		       wqe->wr.send_flags & IB_SEND_SOLICITED);
  
  send_comp:
  	spin_lock_irqsave(&sqp->s_lock, flags);
  	ibp->n_loop_pkts++;
  flush_send:
  	sqp->s_rnr_retry = sqp->s_rnr_retry_cnt;
  	qib_send_complete(sqp, wqe, send_status);
  	goto again;
  
  rnr_nak:
  	/* Handle RNR NAK */
  	if (qp->ibqp.qp_type == IB_QPT_UC)
  		goto send_comp;
  	ibp->n_rnr_naks++;
  	/*
  	 * Note: we don't need the s_lock held since the BUSY flag
  	 * makes this single threaded.
  	 */
  	if (sqp->s_rnr_retry == 0) {
  		send_status = IB_WC_RNR_RETRY_EXC_ERR;
  		goto serr;
  	}
  	if (sqp->s_rnr_retry_cnt < 7)
  		sqp->s_rnr_retry--;
  	spin_lock_irqsave(&sqp->s_lock, flags);
  	if (!(ib_qib_state_ops[sqp->state] & QIB_PROCESS_RECV_OK))
  		goto clr_busy;
  	sqp->s_flags |= QIB_S_WAIT_RNR;
  	sqp->s_timer.function = qib_rc_rnr_retry;
  	sqp->s_timer.expires = jiffies +
  		usecs_to_jiffies(ib_qib_rnr_table[qp->r_min_rnr_timer]);
  	add_timer(&sqp->s_timer);
  	goto clr_busy;
  
  op_err:
  	send_status = IB_WC_REM_OP_ERR;
  	wc.status = IB_WC_LOC_QP_OP_ERR;
  	goto err;
  
  inv_err:
  	send_status = IB_WC_REM_INV_REQ_ERR;
  	wc.status = IB_WC_LOC_QP_OP_ERR;
  	goto err;
  
  acc_err:
  	send_status = IB_WC_REM_ACCESS_ERR;
  	wc.status = IB_WC_LOC_PROT_ERR;
  err:
  	/* responder goes to error state */
  	qib_rc_error(qp, wc.status);
  
  serr:
  	spin_lock_irqsave(&sqp->s_lock, flags);
  	qib_send_complete(sqp, wqe, send_status);
  	if (sqp->ibqp.qp_type == IB_QPT_RC) {
  		int lastwqe = qib_error_qp(sqp, IB_WC_WR_FLUSH_ERR);
  
  		sqp->s_flags &= ~QIB_S_BUSY;
  		spin_unlock_irqrestore(&sqp->s_lock, flags);
  		if (lastwqe) {
  			struct ib_event ev;
  
  			ev.device = sqp->ibqp.device;
  			ev.element.qp = &sqp->ibqp;
  			ev.event = IB_EVENT_QP_LAST_WQE_REACHED;
  			sqp->ibqp.event_handler(&ev, sqp->ibqp.qp_context);
  		}
  		goto done;
  	}
  clr_busy:
  	sqp->s_flags &= ~QIB_S_BUSY;
  unlock:
  	spin_unlock_irqrestore(&sqp->s_lock, flags);
  done:
  	if (qp && atomic_dec_and_test(&qp->refcount))
  		wake_up(&qp->wait);
  }
  
  /**
   * qib_make_grh - construct a GRH header
   * @ibp: a pointer to the IB port
   * @hdr: a pointer to the GRH header being constructed
   * @grh: the global route address to send to
   * @hwords: the number of 32 bit words of header being sent
   * @nwords: the number of 32 bit words of data being sent
   *
   * Return the size of the header in 32 bit words.
   */
  u32 qib_make_grh(struct qib_ibport *ibp, struct ib_grh *hdr,
  		 struct ib_global_route *grh, u32 hwords, u32 nwords)
  {
  	hdr->version_tclass_flow =
  		cpu_to_be32((IB_GRH_VERSION << IB_GRH_VERSION_SHIFT) |
  			    (grh->traffic_class << IB_GRH_TCLASS_SHIFT) |
  			    (grh->flow_label << IB_GRH_FLOW_SHIFT));
  	hdr->paylen = cpu_to_be16((hwords - 2 + nwords + SIZE_OF_CRC) << 2);
  	/* next_hdr is defined by C8-7 in ch. 8.4.1 */
  	hdr->next_hdr = IB_GRH_NEXT_HDR;
  	hdr->hop_limit = grh->hop_limit;
  	/* The SGID is 32-bit aligned. */
  	hdr->sgid.global.subnet_prefix = ibp->gid_prefix;
  	hdr->sgid.global.interface_id = grh->sgid_index ?
  		ibp->guids[grh->sgid_index - 1] : ppd_from_ibp(ibp)->guid;
  	hdr->dgid = grh->dgid;
  
  	/* GRH header size in 32-bit words. */
  	return sizeof(struct ib_grh) / sizeof(u32);
  }
  
  void qib_make_ruc_header(struct qib_qp *qp, struct qib_other_headers *ohdr,
  			 u32 bth0, u32 bth2)
  {
  	struct qib_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
  	u16 lrh0;
  	u32 nwords;
  	u32 extra_bytes;
  
  	/* Construct the header. */
  	extra_bytes = -qp->s_cur_size & 3;
  	nwords = (qp->s_cur_size + extra_bytes) >> 2;
  	lrh0 = QIB_LRH_BTH;
  	if (unlikely(qp->remote_ah_attr.ah_flags & IB_AH_GRH)) {
  		qp->s_hdrwords += qib_make_grh(ibp, &qp->s_hdr->u.l.grh,
  					       &qp->remote_ah_attr.grh,
  					       qp->s_hdrwords, nwords);
  		lrh0 = QIB_LRH_GRH;
  	}
  	lrh0 |= ibp->sl_to_vl[qp->remote_ah_attr.sl] << 12 |
  		qp->remote_ah_attr.sl << 4;
  	qp->s_hdr->lrh[0] = cpu_to_be16(lrh0);
  	qp->s_hdr->lrh[1] = cpu_to_be16(qp->remote_ah_attr.dlid);
  	qp->s_hdr->lrh[2] = cpu_to_be16(qp->s_hdrwords + nwords + SIZE_OF_CRC);
  	qp->s_hdr->lrh[3] = cpu_to_be16(ppd_from_ibp(ibp)->lid |
  				       qp->remote_ah_attr.src_path_bits);
  	bth0 |= qib_get_pkey(ibp, qp->s_pkey_index);
  	bth0 |= extra_bytes << 20;
  	if (qp->s_mig_state == IB_MIG_MIGRATED)
  		bth0 |= IB_BTH_MIG_REQ;
  	ohdr->bth[0] = cpu_to_be32(bth0);
  	ohdr->bth[1] = cpu_to_be32(qp->remote_qpn);
  	ohdr->bth[2] = cpu_to_be32(bth2);
  }
  
  /**
   * qib_do_send - perform a send on a QP
   * @work: contains a pointer to the QP
   *
   * Process entries in the send work queue until credit or queue is
   * exhausted.  Only allow one CPU to send a packet per QP (tasklet).
   * Otherwise, two threads could send packets out of order.
   */
  void qib_do_send(struct work_struct *work)
  {
  	struct qib_qp *qp = container_of(work, struct qib_qp, s_work);
  	struct qib_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
  	struct qib_pportdata *ppd = ppd_from_ibp(ibp);
  	int (*make_req)(struct qib_qp *qp);
  	unsigned long flags;
  
  	if ((qp->ibqp.qp_type == IB_QPT_RC ||
  	     qp->ibqp.qp_type == IB_QPT_UC) &&
  	    (qp->remote_ah_attr.dlid & ~((1 << ppd->lmc) - 1)) == ppd->lid) {
  		qib_ruc_loopback(qp);
  		return;
  	}
  
  	if (qp->ibqp.qp_type == IB_QPT_RC)
  		make_req = qib_make_rc_req;
  	else if (qp->ibqp.qp_type == IB_QPT_UC)
  		make_req = qib_make_uc_req;
  	else
  		make_req = qib_make_ud_req;
  
  	spin_lock_irqsave(&qp->s_lock, flags);
  
  	/* Return if we are already busy processing a work request. */
  	if (!qib_send_ok(qp)) {
  		spin_unlock_irqrestore(&qp->s_lock, flags);
  		return;
  	}
  
  	qp->s_flags |= QIB_S_BUSY;
  
  	spin_unlock_irqrestore(&qp->s_lock, flags);
  
  	do {
  		/* Check for a constructed packet to be sent. */
  		if (qp->s_hdrwords != 0) {
  			/*
  			 * If the packet cannot be sent now, return and
  			 * the send tasklet will be woken up later.
  			 */
  			if (qib_verbs_send(qp, qp->s_hdr, qp->s_hdrwords,
  					   qp->s_cur_sge, qp->s_cur_size))
  				break;
  			/* Record that s_hdr is empty. */
  			qp->s_hdrwords = 0;
  		}
  	} while (make_req(qp));
  }
  
  /*
   * This should be called with s_lock held.
   */
  void qib_send_complete(struct qib_qp *qp, struct qib_swqe *wqe,
  		       enum ib_wc_status status)
  {
  	u32 old_last, last;
  	unsigned i;
  
  	if (!(ib_qib_state_ops[qp->state] & QIB_PROCESS_OR_FLUSH_SEND))
  		return;
  
  	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);
  
  	/* See ch. 11.2.4.1 and 10.7.3.1 */
  	if (!(qp->s_flags & QIB_S_SIGNAL_REQ_WR) ||
  	    (wqe->wr.send_flags & IB_SEND_SIGNALED) ||
  	    status != IB_WC_SUCCESS) {
  		struct ib_wc wc;
  
  		memset(&wc, 0, sizeof wc);
  		wc.wr_id = wqe->wr.wr_id;
  		wc.status = status;
  		wc.opcode = ib_qib_wc_opcode[wqe->wr.opcode];
  		wc.qp = &qp->ibqp;
  		if (status == IB_WC_SUCCESS)
  			wc.byte_len = wqe->length;
  		qib_cq_enter(to_icq(qp->ibqp.send_cq), &wc,
  			     status != IB_WC_SUCCESS);
  	}
  
  	last = qp->s_last;
  	old_last = last;
  	if (++last >= qp->s_size)
  		last = 0;
  	qp->s_last = last;
  	if (qp->s_acked == old_last)
  		qp->s_acked = last;
  	if (qp->s_cur == old_last)
  		qp->s_cur = last;
  	if (qp->s_tail == old_last)
  		qp->s_tail = last;
  	if (qp->state == IB_QPS_SQD && last == qp->s_cur)
  		qp->s_draining = 0;
  }
  