drivers/infiniband/hw/qib/qib_uc.c - kernel/bruno - Git at Google

 /*
  * Copyright (c) 2006, 2007, 2008, 2009, 2010 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 "qib.h"

 /* cut down ridiculously long IB macro names */
 #define OP(x) IB_OPCODE_UC_##x

 /**
  * qib_make_uc_req - construct a request packet (SEND, RDMA write)
  * @qp: a pointer to the QP
  *
  * Return 1 if constructed; otherwise, return 0.
  */
 int qib_make_uc_req(struct qib_qp *qp)
 {
 	struct qib_other_headers *ohdr;
 	struct qib_swqe *wqe;
 	unsigned long flags;
 	u32 hwords;
 	u32 bth0;
 	u32 len;
 	u32 pmtu = qp->pmtu;
 	int ret = 0;

 	spin_lock_irqsave(&qp->s_lock, flags);

 	if (!(ib_qib_state_ops[qp->state] & QIB_PROCESS_SEND_OK)) {
 		if (!(ib_qib_state_ops[qp->state] & QIB_FLUSH_SEND))
 			goto bail;
 		/* We are in the error state, flush the work request. */
 		if (qp->s_last == qp->s_head)
 			goto bail;
 		/* If DMAs are in progress, we can't flush immediately. */
 		if (atomic_read(&qp->s_dma_busy)) {
 			qp->s_flags |= QIB_S_WAIT_DMA;
 			goto bail;
 		}
 		wqe = get_swqe_ptr(qp, qp->s_last);
 		qib_send_complete(qp, wqe, IB_WC_WR_FLUSH_ERR);
 		goto done;
 	}

 	ohdr = &qp->s_hdr->u.oth;
 	if (qp->remote_ah_attr.ah_flags & IB_AH_GRH)
 		ohdr = &qp->s_hdr->u.l.oth;

 	/* header size in 32-bit words LRH+BTH = (8+12)/4. */
 	hwords = 5;
 	bth0 = 0;

 	/* Get the next send request. */
 	wqe = get_swqe_ptr(qp, qp->s_cur);
 	qp->s_wqe = NULL;
 	switch (qp->s_state) {
 	default:
 		if (!(ib_qib_state_ops[qp->state] &
 		    QIB_PROCESS_NEXT_SEND_OK))
 			goto bail;
 		/* Check if send work queue is empty. */
 		if (qp->s_cur == qp->s_head)
 			goto bail;
 		/*
 		 * Start a new request.
 		 */
 		wqe->psn = qp->s_next_psn;
 		qp->s_psn = qp->s_next_psn;
 		qp->s_sge.sge = wqe->sg_list[0];
 		qp->s_sge.sg_list = wqe->sg_list + 1;
 		qp->s_sge.num_sge = wqe->wr.num_sge;
 		qp->s_sge.total_len = wqe->length;
 		len = wqe->length;
 		qp->s_len = len;
 		switch (wqe->wr.opcode) {
 		case IB_WR_SEND:
 		case IB_WR_SEND_WITH_IMM:
 			if (len > pmtu) {
 				qp->s_state = OP(SEND_FIRST);
 				len = pmtu;
 				break;
 			}
 			if (wqe->wr.opcode == IB_WR_SEND)
 				qp->s_state = OP(SEND_ONLY);
 			else {
 				qp->s_state =
 					OP(SEND_ONLY_WITH_IMMEDIATE);
 				/* Immediate data comes after the BTH */
 				ohdr->u.imm_data = wqe->wr.ex.imm_data;
 				hwords += 1;
 			}
 			if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 				bth0 |= IB_BTH_SOLICITED;
 			qp->s_wqe = wqe;
 			if (++qp->s_cur >= qp->s_size)
 				qp->s_cur = 0;
 			break;

 		case IB_WR_RDMA_WRITE:
 		case IB_WR_RDMA_WRITE_WITH_IMM:
 			ohdr->u.rc.reth.vaddr =
 				cpu_to_be64(wqe->rdma_wr.remote_addr);
 			ohdr->u.rc.reth.rkey =
 				cpu_to_be32(wqe->rdma_wr.rkey);
 			ohdr->u.rc.reth.length = cpu_to_be32(len);
 			hwords += sizeof(struct ib_reth) / 4;
 			if (len > pmtu) {
 				qp->s_state = OP(RDMA_WRITE_FIRST);
 				len = pmtu;
 				break;
 			}
 			if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
 				qp->s_state = OP(RDMA_WRITE_ONLY);
 			else {
 				qp->s_state =
 					OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE);
 				/* Immediate data comes after the RETH */
 				ohdr->u.rc.imm_data = wqe->wr.ex.imm_data;
 				hwords += 1;
 				if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 					bth0 |= IB_BTH_SOLICITED;
 			}
 			qp->s_wqe = wqe;
 			if (++qp->s_cur >= qp->s_size)
 				qp->s_cur = 0;
 			break;

 		default:
 			goto bail;
 		}
 		break;

 	case OP(SEND_FIRST):
 		qp->s_state = OP(SEND_MIDDLE);
 		/* FALLTHROUGH */
 	case OP(SEND_MIDDLE):
 		len = qp->s_len;
 		if (len > pmtu) {
 			len = pmtu;
 			break;
 		}
 		if (wqe->wr.opcode == IB_WR_SEND)
 			qp->s_state = OP(SEND_LAST);
 		else {
 			qp->s_state = OP(SEND_LAST_WITH_IMMEDIATE);
 			/* Immediate data comes after the BTH */
 			ohdr->u.imm_data = wqe->wr.ex.imm_data;
 			hwords += 1;
 		}
 		if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 			bth0 |= IB_BTH_SOLICITED;
 		qp->s_wqe = wqe;
 		if (++qp->s_cur >= qp->s_size)
 			qp->s_cur = 0;
 		break;

 	case OP(RDMA_WRITE_FIRST):
 		qp->s_state = OP(RDMA_WRITE_MIDDLE);
 		/* FALLTHROUGH */
 	case OP(RDMA_WRITE_MIDDLE):
 		len = qp->s_len;
 		if (len > pmtu) {
 			len = pmtu;
 			break;
 		}
 		if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
 			qp->s_state = OP(RDMA_WRITE_LAST);
 		else {
 			qp->s_state =
 				OP(RDMA_WRITE_LAST_WITH_IMMEDIATE);
 			/* Immediate data comes after the BTH */
 			ohdr->u.imm_data = wqe->wr.ex.imm_data;
 			hwords += 1;
 			if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 				bth0 |= IB_BTH_SOLICITED;
 		}
 		qp->s_wqe = wqe;
 		if (++qp->s_cur >= qp->s_size)
 			qp->s_cur = 0;
 		break;
 	}
 	qp->s_len -= len;
 	qp->s_hdrwords = hwords;
 	qp->s_cur_sge = &qp->s_sge;
 	qp->s_cur_size = len;
 	qib_make_ruc_header(qp, ohdr, bth0 | (qp->s_state << 24),
 			    qp->s_next_psn++ & QIB_PSN_MASK);
 done:
 	ret = 1;
 	goto unlock;

 bail:
 	qp->s_flags &= ~QIB_S_BUSY;
 unlock:
 	spin_unlock_irqrestore(&qp->s_lock, flags);
 	return ret;
 }

 /**
  * qib_uc_rcv - handle an incoming UC packet
  * @ibp: the port the packet came in on
  * @hdr: the header of the packet
  * @has_grh: true if the packet has a GRH
  * @data: the packet data
  * @tlen: the length of the packet
  * @qp: the QP for this packet.
  *
  * This is called from qib_qp_rcv() to process an incoming UC packet
  * for the given QP.
  * Called at interrupt level.
  */
 void qib_uc_rcv(struct qib_ibport *ibp, struct qib_ib_header *hdr,
 		int has_grh, void *data, u32 tlen, struct qib_qp *qp)
 {
 	struct qib_other_headers *ohdr;
 	u32 opcode;
 	u32 hdrsize;
 	u32 psn;
 	u32 pad;
 	struct ib_wc wc;
 	u32 pmtu = qp->pmtu;
 	struct ib_reth *reth;
 	int ret;

 	/* Check for GRH */
 	if (!has_grh) {
 		ohdr = &hdr->u.oth;
 		hdrsize = 8 + 12;       /* LRH + BTH */
 	} else {
 		ohdr = &hdr->u.l.oth;
 		hdrsize = 8 + 40 + 12;  /* LRH + GRH + BTH */
 	}

 	opcode = be32_to_cpu(ohdr->bth[0]);
 	if (qib_ruc_check_hdr(ibp, hdr, has_grh, qp, opcode))
 		return;

 	psn = be32_to_cpu(ohdr->bth[2]);
 	opcode >>= 24;

 	/* Compare the PSN verses the expected PSN. */
 	if (unlikely(qib_cmp24(psn, qp->r_psn) != 0)) {
 		/*
 		 * Handle a sequence error.
 		 * Silently drop any current message.
 		 */
 		qp->r_psn = psn;
 inv:
 		if (qp->r_state == OP(SEND_FIRST) ||
 		    qp->r_state == OP(SEND_MIDDLE)) {
 			set_bit(QIB_R_REWIND_SGE, &qp->r_aflags);
 			qp->r_sge.num_sge = 0;
 		} else
 			qib_put_ss(&qp->r_sge);
 		qp->r_state = OP(SEND_LAST);
 		switch (opcode) {
 		case OP(SEND_FIRST):
 		case OP(SEND_ONLY):
 		case OP(SEND_ONLY_WITH_IMMEDIATE):
 			goto send_first;

 		case OP(RDMA_WRITE_FIRST):
 		case OP(RDMA_WRITE_ONLY):
 		case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE):
 			goto rdma_first;

 		default:
 			goto drop;
 		}
 	}

 	/* Check for opcode sequence errors. */
 	switch (qp->r_state) {
 	case OP(SEND_FIRST):
 	case OP(SEND_MIDDLE):
 		if (opcode == OP(SEND_MIDDLE) ||
 		    opcode == OP(SEND_LAST) ||
 		    opcode == OP(SEND_LAST_WITH_IMMEDIATE))
 			break;
 		goto inv;

 	case OP(RDMA_WRITE_FIRST):
 	case OP(RDMA_WRITE_MIDDLE):
 		if (opcode == OP(RDMA_WRITE_MIDDLE) ||
 		    opcode == OP(RDMA_WRITE_LAST) ||
 		    opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
 			break;
 		goto inv;

 	default:
 		if (opcode == OP(SEND_FIRST) ||
 		    opcode == OP(SEND_ONLY) ||
 		    opcode == OP(SEND_ONLY_WITH_IMMEDIATE) ||
 		    opcode == OP(RDMA_WRITE_FIRST) ||
 		    opcode == OP(RDMA_WRITE_ONLY) ||
 		    opcode == OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE))
 			break;
 		goto inv;
 	}

 	if (qp->state == IB_QPS_RTR && !(qp->r_flags & QIB_R_COMM_EST)) {
 		qp->r_flags |= QIB_R_COMM_EST;
 		if (qp->ibqp.event_handler) {
 			struct ib_event ev;

 			ev.device = qp->ibqp.device;
 			ev.element.qp = &qp->ibqp;
 			ev.event = IB_EVENT_COMM_EST;
 			qp->ibqp.event_handler(&ev, qp->ibqp.qp_context);
 		}
 	}

 	/* OK, process the packet. */
 	switch (opcode) {
 	case OP(SEND_FIRST):
 	case OP(SEND_ONLY):
 	case OP(SEND_ONLY_WITH_IMMEDIATE):
 send_first:
 		if (test_and_clear_bit(QIB_R_REWIND_SGE, &qp->r_aflags))
 			qp->r_sge = qp->s_rdma_read_sge;
 		else {
 			ret = qib_get_rwqe(qp, 0);
 			if (ret < 0)
 				goto op_err;
 			if (!ret)
 				goto drop;
 			/*
 			 * qp->s_rdma_read_sge will be the owner
 			 * of the mr references.
 			 */
 			qp->s_rdma_read_sge = qp->r_sge;
 		}
 		qp->r_rcv_len = 0;
 		if (opcode == OP(SEND_ONLY))
 			goto no_immediate_data;
 		else if (opcode == OP(SEND_ONLY_WITH_IMMEDIATE))
 			goto send_last_imm;
 		/* FALLTHROUGH */
 	case OP(SEND_MIDDLE):
 		/* Check for invalid length PMTU or posted rwqe len. */
 		if (unlikely(tlen != (hdrsize + pmtu + 4)))
 			goto rewind;
 		qp->r_rcv_len += pmtu;
 		if (unlikely(qp->r_rcv_len > qp->r_len))
 			goto rewind;
 		qib_copy_sge(&qp->r_sge, data, pmtu, 0);
 		break;

 	case OP(SEND_LAST_WITH_IMMEDIATE):
 send_last_imm:
 		wc.ex.imm_data = ohdr->u.imm_data;
 		hdrsize += 4;
 		wc.wc_flags = IB_WC_WITH_IMM;
 		goto send_last;
 	case OP(SEND_LAST):
 no_immediate_data:
 		wc.ex.imm_data = 0;
 		wc.wc_flags = 0;
 send_last:
 		/* Get the number of bytes the message was padded by. */
 		pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
 		/* Check for invalid length. */
 		/* XXX LAST len should be >= 1 */
 		if (unlikely(tlen < (hdrsize + pad + 4)))
 			goto rewind;
 		/* Don't count the CRC. */
 		tlen -= (hdrsize + pad + 4);
 		wc.byte_len = tlen + qp->r_rcv_len;
 		if (unlikely(wc.byte_len > qp->r_len))
 			goto rewind;
 		wc.opcode = IB_WC_RECV;
 		qib_copy_sge(&qp->r_sge, data, tlen, 0);
 		qib_put_ss(&qp->s_rdma_read_sge);
 last_imm:
 		wc.wr_id = qp->r_wr_id;
 		wc.status = IB_WC_SUCCESS;
 		wc.qp = &qp->ibqp;
 		wc.src_qp = qp->remote_qpn;
 		wc.slid = qp->remote_ah_attr.dlid;
 		wc.sl = qp->remote_ah_attr.sl;
 		/* zero fields that are N/A */
 		wc.vendor_err = 0;
 		wc.pkey_index = 0;
 		wc.dlid_path_bits = 0;
 		wc.port_num = 0;
 		/* Signal completion event if the solicited bit is set. */
 		qib_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
 			     (ohdr->bth[0] &
 				cpu_to_be32(IB_BTH_SOLICITED)) != 0);
 		break;

 	case OP(RDMA_WRITE_FIRST):
 	case OP(RDMA_WRITE_ONLY):
 	case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE): /* consume RWQE */
 rdma_first:
 		if (unlikely(!(qp->qp_access_flags &
 			       IB_ACCESS_REMOTE_WRITE))) {
 			goto drop;
 		}
 		reth = &ohdr->u.rc.reth;
 		hdrsize += sizeof(*reth);
 		qp->r_len = be32_to_cpu(reth->length);
 		qp->r_rcv_len = 0;
 		qp->r_sge.sg_list = NULL;
 		if (qp->r_len != 0) {
 			u32 rkey = be32_to_cpu(reth->rkey);
 			u64 vaddr = be64_to_cpu(reth->vaddr);
 			int ok;

 			/* Check rkey */
 			ok = qib_rkey_ok(qp, &qp->r_sge.sge, qp->r_len,
 					 vaddr, rkey, IB_ACCESS_REMOTE_WRITE);
 			if (unlikely(!ok))
 				goto drop;
 			qp->r_sge.num_sge = 1;
 		} else {
 			qp->r_sge.num_sge = 0;
 			qp->r_sge.sge.mr = NULL;
 			qp->r_sge.sge.vaddr = NULL;
 			qp->r_sge.sge.length = 0;
 			qp->r_sge.sge.sge_length = 0;
 		}
 		if (opcode == OP(RDMA_WRITE_ONLY))
 			goto rdma_last;
 		else if (opcode == OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE)) {
 			wc.ex.imm_data = ohdr->u.rc.imm_data;
 			goto rdma_last_imm;
 		}
 		/* FALLTHROUGH */
 	case OP(RDMA_WRITE_MIDDLE):
 		/* Check for invalid length PMTU or posted rwqe len. */
 		if (unlikely(tlen != (hdrsize + pmtu + 4)))
 			goto drop;
 		qp->r_rcv_len += pmtu;
 		if (unlikely(qp->r_rcv_len > qp->r_len))
 			goto drop;
 		qib_copy_sge(&qp->r_sge, data, pmtu, 1);
 		break;

 	case OP(RDMA_WRITE_LAST_WITH_IMMEDIATE):
 		wc.ex.imm_data = ohdr->u.imm_data;
 rdma_last_imm:
 		hdrsize += 4;
 		wc.wc_flags = IB_WC_WITH_IMM;

 		/* Get the number of bytes the message was padded by. */
 		pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
 		/* Check for invalid length. */
 		/* XXX LAST len should be >= 1 */
 		if (unlikely(tlen < (hdrsize + pad + 4)))
 			goto drop;
 		/* Don't count the CRC. */
 		tlen -= (hdrsize + pad + 4);
 		if (unlikely(tlen + qp->r_rcv_len != qp->r_len))
 			goto drop;
 		if (test_and_clear_bit(QIB_R_REWIND_SGE, &qp->r_aflags))
 			qib_put_ss(&qp->s_rdma_read_sge);
 		else {
 			ret = qib_get_rwqe(qp, 1);
 			if (ret < 0)
 				goto op_err;
 			if (!ret)
 				goto drop;
 		}
 		wc.byte_len = qp->r_len;
 		wc.opcode = IB_WC_RECV_RDMA_WITH_IMM;
 		qib_copy_sge(&qp->r_sge, data, tlen, 1);
 		qib_put_ss(&qp->r_sge);
 		goto last_imm;

 	case OP(RDMA_WRITE_LAST):
 rdma_last:
 		/* Get the number of bytes the message was padded by. */
 		pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
 		/* Check for invalid length. */
 		/* XXX LAST len should be >= 1 */
 		if (unlikely(tlen < (hdrsize + pad + 4)))
 			goto drop;
 		/* Don't count the CRC. */
 		tlen -= (hdrsize + pad + 4);
 		if (unlikely(tlen + qp->r_rcv_len != qp->r_len))
 			goto drop;
 		qib_copy_sge(&qp->r_sge, data, tlen, 1);
 		qib_put_ss(&qp->r_sge);
 		break;

 	default:
 		/* Drop packet for unknown opcodes. */
 		goto drop;
 	}
 	qp->r_psn++;
 	qp->r_state = opcode;
 	return;

 rewind:
 	set_bit(QIB_R_REWIND_SGE, &qp->r_aflags);
 	qp->r_sge.num_sge = 0;
 drop:
 	ibp->n_pkt_drops++;
 	return;

 op_err:
 	qib_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
 	return;

 }
	/*
	* Copyright (c) 2006, 2007, 2008, 2009, 2010 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 "qib.h"

	/* cut down ridiculously long IB macro names */
	#define OP(x) IB_OPCODE_UC_##x

	/**
	* qib_make_uc_req - construct a request packet (SEND, RDMA write)
	* @qp: a pointer to the QP
	*
	* Return 1 if constructed; otherwise, return 0.
	*/
	int qib_make_uc_req(struct qib_qp *qp)
	{
	struct qib_other_headers *ohdr;
	struct qib_swqe *wqe;
	unsigned long flags;
	u32 hwords;
	u32 bth0;
	u32 len;
	u32 pmtu = qp->pmtu;
	int ret = 0;

	spin_lock_irqsave(&qp->s_lock, flags);

	if (!(ib_qib_state_ops[qp->state] & QIB_PROCESS_SEND_OK)) {
	if (!(ib_qib_state_ops[qp->state] & QIB_FLUSH_SEND))
	goto bail;
	/* We are in the error state, flush the work request. */
	if (qp->s_last == qp->s_head)
	goto bail;
	/* If DMAs are in progress, we can't flush immediately. */
	if (atomic_read(&qp->s_dma_busy)) {
	qp->s_flags \|= QIB_S_WAIT_DMA;
	goto bail;
	}
	wqe = get_swqe_ptr(qp, qp->s_last);
	qib_send_complete(qp, wqe, IB_WC_WR_FLUSH_ERR);
	goto done;
	}

	ohdr = &qp->s_hdr->u.oth;
	if (qp->remote_ah_attr.ah_flags & IB_AH_GRH)
	ohdr = &qp->s_hdr->u.l.oth;

	/* header size in 32-bit words LRH+BTH = (8+12)/4. */
	hwords = 5;
	bth0 = 0;

	/* Get the next send request. */
	wqe = get_swqe_ptr(qp, qp->s_cur);
	qp->s_wqe = NULL;
	switch (qp->s_state) {
	default:
	if (!(ib_qib_state_ops[qp->state] &
	QIB_PROCESS_NEXT_SEND_OK))
	goto bail;
	/* Check if send work queue is empty. */
	if (qp->s_cur == qp->s_head)
	goto bail;
	/*
	* Start a new request.
	*/
	wqe->psn = qp->s_next_psn;
	qp->s_psn = qp->s_next_psn;
	qp->s_sge.sge = wqe->sg_list[0];
	qp->s_sge.sg_list = wqe->sg_list + 1;
	qp->s_sge.num_sge = wqe->wr.num_sge;
	qp->s_sge.total_len = wqe->length;
	len = wqe->length;
	qp->s_len = len;
	switch (wqe->wr.opcode) {
	case IB_WR_SEND:
	case IB_WR_SEND_WITH_IMM:
	if (len > pmtu) {
	qp->s_state = OP(SEND_FIRST);
	len = pmtu;
	break;
	}
	if (wqe->wr.opcode == IB_WR_SEND)
	qp->s_state = OP(SEND_ONLY);
	else {
	qp->s_state =
	OP(SEND_ONLY_WITH_IMMEDIATE);
	/* Immediate data comes after the BTH */
	ohdr->u.imm_data = wqe->wr.ex.imm_data;
	hwords += 1;
	}
	if (wqe->wr.send_flags & IB_SEND_SOLICITED)
	bth0 \|= IB_BTH_SOLICITED;
	qp->s_wqe = wqe;
	if (++qp->s_cur >= qp->s_size)
	qp->s_cur = 0;
	break;

	case IB_WR_RDMA_WRITE:
	case IB_WR_RDMA_WRITE_WITH_IMM:
	ohdr->u.rc.reth.vaddr =
	cpu_to_be64(wqe->rdma_wr.remote_addr);
	ohdr->u.rc.reth.rkey =
	cpu_to_be32(wqe->rdma_wr.rkey);
	ohdr->u.rc.reth.length = cpu_to_be32(len);
	hwords += sizeof(struct ib_reth) / 4;
	if (len > pmtu) {
	qp->s_state = OP(RDMA_WRITE_FIRST);
	len = pmtu;
	break;
	}
	if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
	qp->s_state = OP(RDMA_WRITE_ONLY);
	else {
	qp->s_state =
	OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE);
	/* Immediate data comes after the RETH */
	ohdr->u.rc.imm_data = wqe->wr.ex.imm_data;
	hwords += 1;
	if (wqe->wr.send_flags & IB_SEND_SOLICITED)
	bth0 \|= IB_BTH_SOLICITED;
	}
	qp->s_wqe = wqe;
	if (++qp->s_cur >= qp->s_size)
	qp->s_cur = 0;
	break;

	default:
	goto bail;
	}
	break;

	case OP(SEND_FIRST):
	qp->s_state = OP(SEND_MIDDLE);
	/* FALLTHROUGH */
	case OP(SEND_MIDDLE):
	len = qp->s_len;
	if (len > pmtu) {
	len = pmtu;
	break;
	}
	if (wqe->wr.opcode == IB_WR_SEND)
	qp->s_state = OP(SEND_LAST);
	else {
	qp->s_state = OP(SEND_LAST_WITH_IMMEDIATE);
	/* Immediate data comes after the BTH */
	ohdr->u.imm_data = wqe->wr.ex.imm_data;
	hwords += 1;
	}
	if (wqe->wr.send_flags & IB_SEND_SOLICITED)
	bth0 \|= IB_BTH_SOLICITED;
	qp->s_wqe = wqe;
	if (++qp->s_cur >= qp->s_size)
	qp->s_cur = 0;
	break;

	case OP(RDMA_WRITE_FIRST):
	qp->s_state = OP(RDMA_WRITE_MIDDLE);
	/* FALLTHROUGH */
	case OP(RDMA_WRITE_MIDDLE):
	len = qp->s_len;
	if (len > pmtu) {
	len = pmtu;
	break;
	}
	if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
	qp->s_state = OP(RDMA_WRITE_LAST);
	else {
	qp->s_state =
	OP(RDMA_WRITE_LAST_WITH_IMMEDIATE);
	/* Immediate data comes after the BTH */
	ohdr->u.imm_data = wqe->wr.ex.imm_data;
	hwords += 1;
	if (wqe->wr.send_flags & IB_SEND_SOLICITED)
	bth0 \|= IB_BTH_SOLICITED;
	}
	qp->s_wqe = wqe;
	if (++qp->s_cur >= qp->s_size)
	qp->s_cur = 0;
	break;
	}
	qp->s_len -= len;
	qp->s_hdrwords = hwords;
	qp->s_cur_sge = &qp->s_sge;
	qp->s_cur_size = len;
	qib_make_ruc_header(qp, ohdr, bth0 \| (qp->s_state << 24),
	qp->s_next_psn++ & QIB_PSN_MASK);
	done:
	ret = 1;
	goto unlock;

	bail:
	qp->s_flags &= ~QIB_S_BUSY;
	unlock:
	spin_unlock_irqrestore(&qp->s_lock, flags);
	return ret;
	}

	/**
	* qib_uc_rcv - handle an incoming UC packet
	* @ibp: the port the packet came in on
	* @hdr: the header of the packet
	* @has_grh: true if the packet has a GRH
	* @data: the packet data
	* @tlen: the length of the packet
	* @qp: the QP for this packet.
	*
	* This is called from qib_qp_rcv() to process an incoming UC packet
	* for the given QP.
	* Called at interrupt level.
	*/
	void qib_uc_rcv(struct qib_ibport ibp, struct qib_ib_header hdr,
	int has_grh, void data, u32 tlen, struct qib_qp qp)
	{
	struct qib_other_headers *ohdr;
	u32 opcode;
	u32 hdrsize;
	u32 psn;
	u32 pad;
	struct ib_wc wc;
	u32 pmtu = qp->pmtu;
	struct ib_reth *reth;
	int ret;

	/* Check for GRH */
	if (!has_grh) {
	ohdr = &hdr->u.oth;
	hdrsize = 8 + 12; /* LRH + BTH */
	} else {
	ohdr = &hdr->u.l.oth;
	hdrsize = 8 + 40 + 12; /* LRH + GRH + BTH */
	}

	opcode = be32_to_cpu(ohdr->bth[0]);
	if (qib_ruc_check_hdr(ibp, hdr, has_grh, qp, opcode))
	return;

	psn = be32_to_cpu(ohdr->bth[2]);
	opcode >>= 24;

	/* Compare the PSN verses the expected PSN. */
	if (unlikely(qib_cmp24(psn, qp->r_psn) != 0)) {
	/*
	* Handle a sequence error.
	* Silently drop any current message.
	*/
	qp->r_psn = psn;
	inv:
	if (qp->r_state == OP(SEND_FIRST) \|\|
	qp->r_state == OP(SEND_MIDDLE)) {
	set_bit(QIB_R_REWIND_SGE, &qp->r_aflags);
	qp->r_sge.num_sge = 0;
	} else
	qib_put_ss(&qp->r_sge);
	qp->r_state = OP(SEND_LAST);
	switch (opcode) {
	case OP(SEND_FIRST):
	case OP(SEND_ONLY):
	case OP(SEND_ONLY_WITH_IMMEDIATE):
	goto send_first;

	case OP(RDMA_WRITE_FIRST):
	case OP(RDMA_WRITE_ONLY):
	case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE):
	goto rdma_first;

	default:
	goto drop;
	}
	}

	/* Check for opcode sequence errors. */
	switch (qp->r_state) {
	case OP(SEND_FIRST):
	case OP(SEND_MIDDLE):
	if (opcode == OP(SEND_MIDDLE) \|\|
	opcode == OP(SEND_LAST) \|\|
	opcode == OP(SEND_LAST_WITH_IMMEDIATE))
	break;
	goto inv;

	case OP(RDMA_WRITE_FIRST):
	case OP(RDMA_WRITE_MIDDLE):
	if (opcode == OP(RDMA_WRITE_MIDDLE) \|\|
	opcode == OP(RDMA_WRITE_LAST) \|\|
	opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
	break;
	goto inv;

	default:
	if (opcode == OP(SEND_FIRST) \|\|
	opcode == OP(SEND_ONLY) \|\|
	opcode == OP(SEND_ONLY_WITH_IMMEDIATE) \|\|
	opcode == OP(RDMA_WRITE_FIRST) \|\|
	opcode == OP(RDMA_WRITE_ONLY) \|\|
	opcode == OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE))
	break;
	goto inv;
	}

	if (qp->state == IB_QPS_RTR && !(qp->r_flags & QIB_R_COMM_EST)) {
	qp->r_flags \|= QIB_R_COMM_EST;
	if (qp->ibqp.event_handler) {
	struct ib_event ev;

	ev.device = qp->ibqp.device;
	ev.element.qp = &qp->ibqp;
	ev.event = IB_EVENT_COMM_EST;
	qp->ibqp.event_handler(&ev, qp->ibqp.qp_context);
	}
	}

	/* OK, process the packet. */
	switch (opcode) {
	case OP(SEND_FIRST):
	case OP(SEND_ONLY):
	case OP(SEND_ONLY_WITH_IMMEDIATE):
	send_first:
	if (test_and_clear_bit(QIB_R_REWIND_SGE, &qp->r_aflags))
	qp->r_sge = qp->s_rdma_read_sge;
	else {
	ret = qib_get_rwqe(qp, 0);
	if (ret < 0)
	goto op_err;
	if (!ret)
	goto drop;
	/*
	* qp->s_rdma_read_sge will be the owner
	* of the mr references.
	*/
	qp->s_rdma_read_sge = qp->r_sge;
	}
	qp->r_rcv_len = 0;
	if (opcode == OP(SEND_ONLY))
	goto no_immediate_data;
	else if (opcode == OP(SEND_ONLY_WITH_IMMEDIATE))
	goto send_last_imm;
	/* FALLTHROUGH */
	case OP(SEND_MIDDLE):
	/* Check for invalid length PMTU or posted rwqe len. */
	if (unlikely(tlen != (hdrsize + pmtu + 4)))
	goto rewind;
	qp->r_rcv_len += pmtu;
	if (unlikely(qp->r_rcv_len > qp->r_len))
	goto rewind;
	qib_copy_sge(&qp->r_sge, data, pmtu, 0);
	break;

	case OP(SEND_LAST_WITH_IMMEDIATE):
	send_last_imm:
	wc.ex.imm_data = ohdr->u.imm_data;
	hdrsize += 4;
	wc.wc_flags = IB_WC_WITH_IMM;
	goto send_last;
	case OP(SEND_LAST):
	no_immediate_data:
	wc.ex.imm_data = 0;
	wc.wc_flags = 0;
	send_last:
	/* Get the number of bytes the message was padded by. */
	pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
	/* Check for invalid length. */
	/* XXX LAST len should be >= 1 */
	if (unlikely(tlen < (hdrsize + pad + 4)))
	goto rewind;
	/* Don't count the CRC. */
	tlen -= (hdrsize + pad + 4);
	wc.byte_len = tlen + qp->r_rcv_len;
	if (unlikely(wc.byte_len > qp->r_len))
	goto rewind;
	wc.opcode = IB_WC_RECV;
	qib_copy_sge(&qp->r_sge, data, tlen, 0);
	qib_put_ss(&qp->s_rdma_read_sge);
	last_imm:
	wc.wr_id = qp->r_wr_id;
	wc.status = IB_WC_SUCCESS;
	wc.qp = &qp->ibqp;
	wc.src_qp = qp->remote_qpn;
	wc.slid = qp->remote_ah_attr.dlid;
	wc.sl = qp->remote_ah_attr.sl;
	/* zero fields that are N/A */
	wc.vendor_err = 0;
	wc.pkey_index = 0;
	wc.dlid_path_bits = 0;
	wc.port_num = 0;
	/* Signal completion event if the solicited bit is set. */
	qib_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
	(ohdr->bth[0] &
	cpu_to_be32(IB_BTH_SOLICITED)) != 0);
	break;

	case OP(RDMA_WRITE_FIRST):
	case OP(RDMA_WRITE_ONLY):
	case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE): /* consume RWQE */
	rdma_first:
	if (unlikely(!(qp->qp_access_flags &
	IB_ACCESS_REMOTE_WRITE))) {
	goto drop;
	}
	reth = &ohdr->u.rc.reth;
	hdrsize += sizeof(*reth);
	qp->r_len = be32_to_cpu(reth->length);
	qp->r_rcv_len = 0;
	qp->r_sge.sg_list = NULL;
	if (qp->r_len != 0) {
	u32 rkey = be32_to_cpu(reth->rkey);
	u64 vaddr = be64_to_cpu(reth->vaddr);
	int ok;

	/* Check rkey */
	ok = qib_rkey_ok(qp, &qp->r_sge.sge, qp->r_len,
	vaddr, rkey, IB_ACCESS_REMOTE_WRITE);
	if (unlikely(!ok))
	goto drop;
	qp->r_sge.num_sge = 1;
	} else {
	qp->r_sge.num_sge = 0;
	qp->r_sge.sge.mr = NULL;
	qp->r_sge.sge.vaddr = NULL;
	qp->r_sge.sge.length = 0;
	qp->r_sge.sge.sge_length = 0;
	}
	if (opcode == OP(RDMA_WRITE_ONLY))
	goto rdma_last;
	else if (opcode == OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE)) {
	wc.ex.imm_data = ohdr->u.rc.imm_data;
	goto rdma_last_imm;
	}
	/* FALLTHROUGH */
	case OP(RDMA_WRITE_MIDDLE):
	/* Check for invalid length PMTU or posted rwqe len. */
	if (unlikely(tlen != (hdrsize + pmtu + 4)))
	goto drop;
	qp->r_rcv_len += pmtu;
	if (unlikely(qp->r_rcv_len > qp->r_len))
	goto drop;
	qib_copy_sge(&qp->r_sge, data, pmtu, 1);
	break;

	case OP(RDMA_WRITE_LAST_WITH_IMMEDIATE):
	wc.ex.imm_data = ohdr->u.imm_data;
	rdma_last_imm:
	hdrsize += 4;
	wc.wc_flags = IB_WC_WITH_IMM;

	/* Get the number of bytes the message was padded by. */
	pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
	/* Check for invalid length. */
	/* XXX LAST len should be >= 1 */
	if (unlikely(tlen < (hdrsize + pad + 4)))
	goto drop;
	/* Don't count the CRC. */
	tlen -= (hdrsize + pad + 4);
	if (unlikely(tlen + qp->r_rcv_len != qp->r_len))
	goto drop;
	if (test_and_clear_bit(QIB_R_REWIND_SGE, &qp->r_aflags))
	qib_put_ss(&qp->s_rdma_read_sge);
	else {
	ret = qib_get_rwqe(qp, 1);
	if (ret < 0)
	goto op_err;
	if (!ret)
	goto drop;
	}
	wc.byte_len = qp->r_len;
	wc.opcode = IB_WC_RECV_RDMA_WITH_IMM;
	qib_copy_sge(&qp->r_sge, data, tlen, 1);
	qib_put_ss(&qp->r_sge);
	goto last_imm;

	case OP(RDMA_WRITE_LAST):
	rdma_last:
	/* Get the number of bytes the message was padded by. */
	pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
	/* Check for invalid length. */
	/* XXX LAST len should be >= 1 */
	if (unlikely(tlen < (hdrsize + pad + 4)))
	goto drop;
	/* Don't count the CRC. */
	tlen -= (hdrsize + pad + 4);
	if (unlikely(tlen + qp->r_rcv_len != qp->r_len))
	goto drop;
	qib_copy_sge(&qp->r_sge, data, tlen, 1);
	qib_put_ss(&qp->r_sge);
	break;

	default:
	/* Drop packet for unknown opcodes. */
	goto drop;
	}
	qp->r_psn++;
	qp->r_state = opcode;
	return;

	rewind:
	set_bit(QIB_R_REWIND_SGE, &qp->r_aflags);
	qp->r_sge.num_sge = 0;
	drop:
	ibp->n_pkt_drops++;
	return;

	op_err:
	qib_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
	return;

	}