drivers/infiniband/hw/ipath/ipath_ud.c - kernel/msm-4.9 - Gitiles

 /*
  * Copyright (c) 2006, 2007, 2008 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/sched.h>
 #include <rdma/ib_smi.h>

 #include "ipath_verbs.h"
 #include "ipath_kernel.h"

 /**
  * ipath_ud_loopback - handle send on loopback QPs
  * @sqp: the sending QP
  * @swqe: the send work request
  *
  * This is called from ipath_make_ud_req() to forward a WQE addressed
  * to the same HCA.
  * Note that the receive interrupt handler may be calling ipath_ud_rcv()
  * while this is being called.
  */
 static void ipath_ud_loopback(struct ipath_qp *sqp, struct ipath_swqe *swqe)
 {
 	struct ipath_ibdev *dev = to_idev(sqp->ibqp.device);
 	struct ipath_qp *qp;
 	struct ib_ah_attr *ah_attr;
 	unsigned long flags;
 	struct ipath_rq *rq;
 	struct ipath_srq *srq;
 	struct ipath_sge_state rsge;
 	struct ipath_sge *sge;
 	struct ipath_rwq *wq;
 	struct ipath_rwqe *wqe;
 	void (*handler)(struct ib_event *, void *);
 	struct ib_wc wc;
 	u32 tail;
 	u32 rlen;
 	u32 length;

 	qp = ipath_lookup_qpn(&dev->qp_table, swqe->wr.wr.ud.remote_qpn);
 	if (!qp || !(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_RECV_OK)) {
 		dev->n_pkt_drops++;
 		goto done;
 	}

 	/*
 	 * Check that the qkey matches (except for QP0, see 9.6.1.4.1).
 	 * Qkeys with the high order bit set mean use the
 	 * qkey from the QP context instead of the WR (see 10.2.5).
 	 */
 	if (unlikely(qp->ibqp.qp_num &&
 		     ((int) swqe->wr.wr.ud.remote_qkey < 0 ?
 		      sqp->qkey : swqe->wr.wr.ud.remote_qkey) != qp->qkey)) {
 		/* XXX OK to lose a count once in a while. */
 		dev->qkey_violations++;
 		dev->n_pkt_drops++;
 		goto drop;
 	}

 	/*
 	 * A GRH is expected to preceed the data even if not
 	 * present on the wire.
 	 */
 	length = swqe->length;
 	memset(&wc, 0, sizeof wc);
 	wc.byte_len = length + sizeof(struct ib_grh);

 	if (swqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
 		wc.wc_flags = IB_WC_WITH_IMM;
 		wc.ex.imm_data = swqe->wr.ex.imm_data;
 	}

 	/*
 	 * This would be a lot simpler if we could call ipath_get_rwqe()
 	 * but that uses state that the receive interrupt handler uses
 	 * so we would need to lock out receive interrupts while doing
 	 * local loopback.
 	 */
 	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;
 	}

 	/*
 	 * Get the next work request entry to find where to put the data.
 	 * Note that it is safe to drop the lock after changing rq->tail
 	 * since ipath_post_receive() won't fill the empty slot.
 	 */
 	spin_lock_irqsave(&rq->lock, flags);
 	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)) {
 		spin_unlock_irqrestore(&rq->lock, flags);
 		dev->n_pkt_drops++;
 		goto drop;
 	}
 	wqe = get_rwqe_ptr(rq, tail);
 	rsge.sg_list = qp->r_ud_sg_list;
 	if (!ipath_init_sge(qp, wqe, &rlen, &rsge)) {
 		spin_unlock_irqrestore(&rq->lock, flags);
 		dev->n_pkt_drops++;
 		goto drop;
 	}
 	/* Silently drop packets which are too big. */
 	if (wc.byte_len > rlen) {
 		spin_unlock_irqrestore(&rq->lock, flags);
 		dev->n_pkt_drops++;
 		goto drop;
 	}
 	if (++tail >= rq->size)
 		tail = 0;
 	wq->tail = tail;
 	wc.wr_id = wqe->wr_id;
 	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);
 		} else
 			spin_unlock_irqrestore(&rq->lock, flags);
 	} else
 		spin_unlock_irqrestore(&rq->lock, flags);

 	ah_attr = &to_iah(swqe->wr.wr.ud.ah)->attr;
 	if (ah_attr->ah_flags & IB_AH_GRH) {
 		ipath_copy_sge(&rsge, &ah_attr->grh, sizeof(struct ib_grh));
 		wc.wc_flags |= IB_WC_GRH;
 	} else
 		ipath_skip_sge(&rsge, sizeof(struct ib_grh));
 	sge = swqe->sg_list;
 	while (length) {
 		u32 len = sge->length;

 		if (len > length)
 			len = length;
 		if (len > sge->sge_length)
 			len = sge->sge_length;
 		BUG_ON(len == 0);
 		ipath_copy_sge(&rsge, sge->vaddr, len);
 		sge->vaddr += len;
 		sge->length -= len;
 		sge->sge_length -= len;
 		if (sge->sge_length == 0) {
 			if (--swqe->wr.num_sge)
 				sge++;
 		} else if (sge->length == 0 && sge->mr != NULL) {
 			if (++sge->n >= IPATH_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;
 		}
 		length -= len;
 	}
 	wc.status = IB_WC_SUCCESS;
 	wc.opcode = IB_WC_RECV;
 	wc.qp = &qp->ibqp;
 	wc.src_qp = sqp->ibqp.qp_num;
 	/* XXX do we know which pkey matched? Only needed for GSI. */
 	wc.pkey_index = 0;
 	wc.slid = dev->dd->ipath_lid |
 		(ah_attr->src_path_bits &
 		 ((1 << dev->dd->ipath_lmc) - 1));
 	wc.sl = ah_attr->sl;
 	wc.dlid_path_bits =
 		ah_attr->dlid & ((1 << dev->dd->ipath_lmc) - 1);
 	wc.port_num = 1;
 	/* Signal completion event if the solicited bit is set. */
 	ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
 		       swqe->wr.send_flags & IB_SEND_SOLICITED);
 drop:
 	if (atomic_dec_and_test(&qp->refcount))
 		wake_up(&qp->wait);
 done:;
 }

 /**
  * ipath_make_ud_req - construct a UD request packet
  * @qp: the QP
  *
  * Return 1 if constructed; otherwise, return 0.
  */
 int ipath_make_ud_req(struct ipath_qp *qp)
 {
 	struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
 	struct ipath_other_headers *ohdr;
 	struct ib_ah_attr *ah_attr;
 	struct ipath_swqe *wqe;
 	unsigned long flags;
 	u32 nwords;
 	u32 extra_bytes;
 	u32 bth0;
 	u16 lrh0;
 	u16 lid;
 	int ret = 0;
 	int next_cur;

 	spin_lock_irqsave(&qp->s_lock, flags);

 	if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_NEXT_SEND_OK)) {
 		if (!(ib_ipath_state_ops[qp->state] & IPATH_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 |= IPATH_S_WAIT_DMA;
 			goto bail;
 		}
 		wqe = get_swqe_ptr(qp, qp->s_last);
 		ipath_send_complete(qp, wqe, IB_WC_WR_FLUSH_ERR);
 		goto done;
 	}

 	if (qp->s_cur == qp->s_head)
 		goto bail;

 	wqe = get_swqe_ptr(qp, qp->s_cur);
 	next_cur = qp->s_cur + 1;
 	if (next_cur >= qp->s_size)
 		next_cur = 0;

 	/* Construct the header. */
 	ah_attr = &to_iah(wqe->wr.wr.ud.ah)->attr;
 	if (ah_attr->dlid >= IPATH_MULTICAST_LID_BASE) {
 		if (ah_attr->dlid != IPATH_PERMISSIVE_LID)
 			dev->n_multicast_xmit++;
 		else
 			dev->n_unicast_xmit++;
 	} else {
 		dev->n_unicast_xmit++;
 		lid = ah_attr->dlid & ~((1 << dev->dd->ipath_lmc) - 1);
 		if (unlikely(lid == dev->dd->ipath_lid)) {
 			/*
 			 * If DMAs are in progress, we can't generate
 			 * a completion for the loopback packet since
 			 * it would be out of order.
 			 * XXX Instead of waiting, we could queue a
 			 * zero length descriptor so we get a callback.
 			 */
 			if (atomic_read(&qp->s_dma_busy)) {
 				qp->s_flags |= IPATH_S_WAIT_DMA;
 				goto bail;
 			}
 			qp->s_cur = next_cur;
 			spin_unlock_irqrestore(&qp->s_lock, flags);
 			ipath_ud_loopback(qp, wqe);
 			spin_lock_irqsave(&qp->s_lock, flags);
 			ipath_send_complete(qp, wqe, IB_WC_SUCCESS);
 			goto done;
 		}
 	}

 	qp->s_cur = next_cur;
 	extra_bytes = -wqe->length & 3;
 	nwords = (wqe->length + extra_bytes) >> 2;

 	/* header size in 32-bit words LRH+BTH+DETH = (8+12+8)/4. */
 	qp->s_hdrwords = 7;
 	qp->s_cur_size = wqe->length;
 	qp->s_cur_sge = &qp->s_sge;
 	qp->s_dmult = ah_attr->static_rate;
 	qp->s_wqe = wqe;
 	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;

 	if (ah_attr->ah_flags & IB_AH_GRH) {
 		/* Header size in 32-bit words. */
 		qp->s_hdrwords += ipath_make_grh(dev, &qp->s_hdr.u.l.grh,
 						 &ah_attr->grh,
 						 qp->s_hdrwords, nwords);
 		lrh0 = IPATH_LRH_GRH;
 		ohdr = &qp->s_hdr.u.l.oth;
 		/*
 		 * Don't worry about sending to locally attached multicast
 		 * QPs.  It is unspecified by the spec. what happens.
 		 */
 	} else {
 		/* Header size in 32-bit words. */
 		lrh0 = IPATH_LRH_BTH;
 		ohdr = &qp->s_hdr.u.oth;
 	}
 	if (wqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
 		qp->s_hdrwords++;
 		ohdr->u.ud.imm_data = wqe->wr.ex.imm_data;
 		bth0 = IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE << 24;
 	} else
 		bth0 = IB_OPCODE_UD_SEND_ONLY << 24;
 	lrh0 |= ah_attr->sl << 4;
 	if (qp->ibqp.qp_type == IB_QPT_SMI)
 		lrh0 |= 0xF000;	/* Set VL (see ch. 13.5.3.1) */
 	qp->s_hdr.lrh[0] = cpu_to_be16(lrh0);
 	qp->s_hdr.lrh[1] = cpu_to_be16(ah_attr->dlid);	/* DEST LID */
 	qp->s_hdr.lrh[2] = cpu_to_be16(qp->s_hdrwords + nwords +
 					   SIZE_OF_CRC);
 	lid = dev->dd->ipath_lid;
 	if (lid) {
 		lid |= ah_attr->src_path_bits &
 			((1 << dev->dd->ipath_lmc) - 1);
 		qp->s_hdr.lrh[3] = cpu_to_be16(lid);
 	} else
 		qp->s_hdr.lrh[3] = IB_LID_PERMISSIVE;
 	if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 		bth0 |= 1 << 23;
 	bth0 |= extra_bytes << 20;
 	bth0 |= qp->ibqp.qp_type == IB_QPT_SMI ? IPATH_DEFAULT_P_KEY :
 		ipath_get_pkey(dev->dd, qp->s_pkey_index);
 	ohdr->bth[0] = cpu_to_be32(bth0);
 	/*
 	 * Use the multicast QP if the destination LID is a multicast LID.
 	 */
 	ohdr->bth[1] = ah_attr->dlid >= IPATH_MULTICAST_LID_BASE &&
 		ah_attr->dlid != IPATH_PERMISSIVE_LID ?
 		cpu_to_be32(IPATH_MULTICAST_QPN) :
 		cpu_to_be32(wqe->wr.wr.ud.remote_qpn);
 	ohdr->bth[2] = cpu_to_be32(qp->s_next_psn++ & IPATH_PSN_MASK);
 	/*
 	 * Qkeys with the high order bit set mean use the
 	 * qkey from the QP context instead of the WR (see 10.2.5).
 	 */
 	ohdr->u.ud.deth[0] = cpu_to_be32((int)wqe->wr.wr.ud.remote_qkey < 0 ?
 					 qp->qkey : wqe->wr.wr.ud.remote_qkey);
 	ohdr->u.ud.deth[1] = cpu_to_be32(qp->ibqp.qp_num);

 done:
 	ret = 1;
 	goto unlock;

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

 /**
  * ipath_ud_rcv - receive an incoming UD packet
  * @dev: the device the packet came in on
  * @hdr: the packet header
  * @has_grh: true if the packet has a GRH
  * @data: the packet data
  * @tlen: the packet length
  * @qp: the QP the packet came on
  *
  * This is called from ipath_qp_rcv() to process an incoming UD packet
  * for the given QP.
  * Called at interrupt level.
  */
 void ipath_ud_rcv(struct ipath_ibdev *dev, struct ipath_ib_header *hdr,
 		  int has_grh, void *data, u32 tlen, struct ipath_qp *qp)
 {
 	struct ipath_other_headers *ohdr;
 	int opcode;
 	u32 hdrsize;
 	u32 pad;
 	struct ib_wc wc;
 	u32 qkey;
 	u32 src_qp;
 	u16 dlid;
 	int header_in_data;

 	/* Check for GRH */
 	if (!has_grh) {
 		ohdr = &hdr->u.oth;
 		hdrsize = 8 + 12 + 8;	/* LRH + BTH + DETH */
 		qkey = be32_to_cpu(ohdr->u.ud.deth[0]);
 		src_qp = be32_to_cpu(ohdr->u.ud.deth[1]);
 		header_in_data = 0;
 	} else {
 		ohdr = &hdr->u.l.oth;
 		hdrsize = 8 + 40 + 12 + 8; /* LRH + GRH + BTH + DETH */
 		/*
 		 * The header with GRH is 68 bytes and the core driver sets
 		 * the eager header buffer size to 56 bytes so the last 12
 		 * bytes of the IB header is in the data buffer.
 		 */
 		header_in_data = dev->dd->ipath_rcvhdrentsize == 16;
 		if (header_in_data) {
 			qkey = be32_to_cpu(((__be32 *) data)[1]);
 			src_qp = be32_to_cpu(((__be32 *) data)[2]);
 			data += 12;
 		} else {
 			qkey = be32_to_cpu(ohdr->u.ud.deth[0]);
 			src_qp = be32_to_cpu(ohdr->u.ud.deth[1]);
 		}
 	}
 	src_qp &= IPATH_QPN_MASK;

 	/*
 	 * Check that the permissive LID is only used on QP0
 	 * and the QKEY matches (see 9.6.1.4.1 and 9.6.1.5.1).
 	 */
 	if (qp->ibqp.qp_num) {
 		if (unlikely(hdr->lrh[1] == IB_LID_PERMISSIVE ||
 			     hdr->lrh[3] == IB_LID_PERMISSIVE)) {
 			dev->n_pkt_drops++;
 			goto bail;
 		}
 		if (unlikely(qkey != qp->qkey)) {
 			/* XXX OK to lose a count once in a while. */
 			dev->qkey_violations++;
 			dev->n_pkt_drops++;
 			goto bail;
 		}
 	} else if (hdr->lrh[1] == IB_LID_PERMISSIVE ||
 		   hdr->lrh[3] == IB_LID_PERMISSIVE) {
 		struct ib_smp *smp = (struct ib_smp *) data;

 		if (smp->mgmt_class != IB_MGMT_CLASS_SUBN_DIRECTED_ROUTE) {
 			dev->n_pkt_drops++;
 			goto bail;
 		}
 	}

 	/*
 	 * The opcode is in the low byte when its in network order
 	 * (top byte when in host order).
 	 */
 	opcode = be32_to_cpu(ohdr->bth[0]) >> 24;
 	if (qp->ibqp.qp_num > 1 &&
 	    opcode == IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE) {
 		if (header_in_data) {
 			wc.ex.imm_data = *(__be32 *) data;
 			data += sizeof(__be32);
 		} else
 			wc.ex.imm_data = ohdr->u.ud.imm_data;
 		wc.wc_flags = IB_WC_WITH_IMM;
 		hdrsize += sizeof(u32);
 	} else if (opcode == IB_OPCODE_UD_SEND_ONLY) {
 		wc.ex.imm_data = 0;
 		wc.wc_flags = 0;
 	} else {
 		dev->n_pkt_drops++;
 		goto bail;
 	}

 	/* Get the number of bytes the message was padded by. */
 	pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
 	if (unlikely(tlen < (hdrsize + pad + 4))) {
 		/* Drop incomplete packets. */
 		dev->n_pkt_drops++;
 		goto bail;
 	}
 	tlen -= hdrsize + pad + 4;

 	/* Drop invalid MAD packets (see 13.5.3.1). */
 	if (unlikely((qp->ibqp.qp_num == 0 &&
 		      (tlen != 256 ||
 		       (be16_to_cpu(hdr->lrh[0]) >> 12) != 15)) ||
 		     (qp->ibqp.qp_num == 1 &&
 		      (tlen != 256 ||
 		       (be16_to_cpu(hdr->lrh[0]) >> 12) == 15)))) {
 		dev->n_pkt_drops++;
 		goto bail;
 	}

 	/*
 	 * A GRH is expected to preceed the data even if not
 	 * present on the wire.
 	 */
 	wc.byte_len = tlen + sizeof(struct ib_grh);

 	/*
 	 * Get the next work request entry to find where to put the data.
 	 */
 	if (qp->r_flags & IPATH_R_REUSE_SGE)
 		qp->r_flags &= ~IPATH_R_REUSE_SGE;
 	else if (!ipath_get_rwqe(qp, 0)) {
 		/*
 		 * Count VL15 packets dropped due to no receive buffer.
 		 * Otherwise, count them as buffer overruns since usually,
 		 * the HW will be able to receive packets even if there are
 		 * no QPs with posted receive buffers.
 		 */
 		if (qp->ibqp.qp_num == 0)
 			dev->n_vl15_dropped++;
 		else
 			dev->rcv_errors++;
 		goto bail;
 	}
 	/* Silently drop packets which are too big. */
 	if (wc.byte_len > qp->r_len) {
 		qp->r_flags |= IPATH_R_REUSE_SGE;
 		dev->n_pkt_drops++;
 		goto bail;
 	}
 	if (has_grh) {
 		ipath_copy_sge(&qp->r_sge, &hdr->u.l.grh,
 			       sizeof(struct ib_grh));
 		wc.wc_flags |= IB_WC_GRH;
 	} else
 		ipath_skip_sge(&qp->r_sge, sizeof(struct ib_grh));
 	ipath_copy_sge(&qp->r_sge, data,
 		       wc.byte_len - sizeof(struct ib_grh));
 	if (!test_and_clear_bit(IPATH_R_WRID_VALID, &qp->r_aflags))
 		goto bail;
 	wc.wr_id = qp->r_wr_id;
 	wc.status = IB_WC_SUCCESS;
 	wc.opcode = IB_WC_RECV;
 	wc.vendor_err = 0;
 	wc.qp = &qp->ibqp;
 	wc.src_qp = src_qp;
 	/* XXX do we know which pkey matched? Only needed for GSI. */
 	wc.pkey_index = 0;
 	wc.slid = be16_to_cpu(hdr->lrh[3]);
 	wc.sl = (be16_to_cpu(hdr->lrh[0]) >> 4) & 0xF;
 	dlid = be16_to_cpu(hdr->lrh[1]);
 	/*
 	 * Save the LMC lower bits if the destination LID is a unicast LID.
 	 */
 	wc.dlid_path_bits = dlid >= IPATH_MULTICAST_LID_BASE ? 0 :
 		dlid & ((1 << dev->dd->ipath_lmc) - 1);
 	wc.port_num = 1;
 	/* Signal completion event if the solicited bit is set. */
 	ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
 		       (ohdr->bth[0] &
 			cpu_to_be32(1 << 23)) != 0);

 bail:;
 }
	/*
	* Copyright (c) 2006, 2007, 2008 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/sched.h>
	#include <rdma/ib_smi.h>

	#include "ipath_verbs.h"
	#include "ipath_kernel.h"

	/**
	* ipath_ud_loopback - handle send on loopback QPs
	* @sqp: the sending QP
	* @swqe: the send work request
	*
	* This is called from ipath_make_ud_req() to forward a WQE addressed
	* to the same HCA.
	* Note that the receive interrupt handler may be calling ipath_ud_rcv()
	* while this is being called.
	*/
	static void ipath_ud_loopback(struct ipath_qp sqp, struct ipath_swqe swqe)
	{
	struct ipath_ibdev *dev = to_idev(sqp->ibqp.device);
	struct ipath_qp *qp;
	struct ib_ah_attr *ah_attr;
	unsigned long flags;
	struct ipath_rq *rq;
	struct ipath_srq *srq;
	struct ipath_sge_state rsge;
	struct ipath_sge *sge;
	struct ipath_rwq *wq;
	struct ipath_rwqe *wqe;
	void (handler)(struct ib_event , void *);
	struct ib_wc wc;
	u32 tail;
	u32 rlen;
	u32 length;

	qp = ipath_lookup_qpn(&dev->qp_table, swqe->wr.wr.ud.remote_qpn);
	if (!qp \|\| !(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_RECV_OK)) {
	dev->n_pkt_drops++;
	goto done;
	}

	/*
	* Check that the qkey matches (except for QP0, see 9.6.1.4.1).
	* Qkeys with the high order bit set mean use the
	* qkey from the QP context instead of the WR (see 10.2.5).
	*/
	if (unlikely(qp->ibqp.qp_num &&
	((int) swqe->wr.wr.ud.remote_qkey < 0 ?
	sqp->qkey : swqe->wr.wr.ud.remote_qkey) != qp->qkey)) {
	/* XXX OK to lose a count once in a while. */
	dev->qkey_violations++;
	dev->n_pkt_drops++;
	goto drop;
	}

	/*
	* A GRH is expected to preceed the data even if not
	* present on the wire.
	*/
	length = swqe->length;
	memset(&wc, 0, sizeof wc);
	wc.byte_len = length + sizeof(struct ib_grh);

	if (swqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
	wc.wc_flags = IB_WC_WITH_IMM;
	wc.ex.imm_data = swqe->wr.ex.imm_data;
	}

	/*
	* This would be a lot simpler if we could call ipath_get_rwqe()
	* but that uses state that the receive interrupt handler uses
	* so we would need to lock out receive interrupts while doing
	* local loopback.
	*/
	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;
	}

	/*
	* Get the next work request entry to find where to put the data.
	* Note that it is safe to drop the lock after changing rq->tail
	* since ipath_post_receive() won't fill the empty slot.
	*/
	spin_lock_irqsave(&rq->lock, flags);
	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)) {
	spin_unlock_irqrestore(&rq->lock, flags);
	dev->n_pkt_drops++;
	goto drop;
	}
	wqe = get_rwqe_ptr(rq, tail);
	rsge.sg_list = qp->r_ud_sg_list;
	if (!ipath_init_sge(qp, wqe, &rlen, &rsge)) {
	spin_unlock_irqrestore(&rq->lock, flags);
	dev->n_pkt_drops++;
	goto drop;
	}
	/* Silently drop packets which are too big. */
	if (wc.byte_len > rlen) {
	spin_unlock_irqrestore(&rq->lock, flags);
	dev->n_pkt_drops++;
	goto drop;
	}
	if (++tail >= rq->size)
	tail = 0;
	wq->tail = tail;
	wc.wr_id = wqe->wr_id;
	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);
	} else
	spin_unlock_irqrestore(&rq->lock, flags);
	} else
	spin_unlock_irqrestore(&rq->lock, flags);

	ah_attr = &to_iah(swqe->wr.wr.ud.ah)->attr;
	if (ah_attr->ah_flags & IB_AH_GRH) {
	ipath_copy_sge(&rsge, &ah_attr->grh, sizeof(struct ib_grh));
	wc.wc_flags \|= IB_WC_GRH;
	} else
	ipath_skip_sge(&rsge, sizeof(struct ib_grh));
	sge = swqe->sg_list;
	while (length) {
	u32 len = sge->length;

	if (len > length)
	len = length;
	if (len > sge->sge_length)
	len = sge->sge_length;
	BUG_ON(len == 0);
	ipath_copy_sge(&rsge, sge->vaddr, len);
	sge->vaddr += len;
	sge->length -= len;
	sge->sge_length -= len;
	if (sge->sge_length == 0) {
	if (--swqe->wr.num_sge)
	sge++;
	} else if (sge->length == 0 && sge->mr != NULL) {
	if (++sge->n >= IPATH_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;
	}
	length -= len;
	}
	wc.status = IB_WC_SUCCESS;
	wc.opcode = IB_WC_RECV;
	wc.qp = &qp->ibqp;
	wc.src_qp = sqp->ibqp.qp_num;
	/* XXX do we know which pkey matched? Only needed for GSI. */
	wc.pkey_index = 0;
	wc.slid = dev->dd->ipath_lid \|
	(ah_attr->src_path_bits &
	((1 << dev->dd->ipath_lmc) - 1));
	wc.sl = ah_attr->sl;
	wc.dlid_path_bits =
	ah_attr->dlid & ((1 << dev->dd->ipath_lmc) - 1);
	wc.port_num = 1;
	/* Signal completion event if the solicited bit is set. */
	ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
	swqe->wr.send_flags & IB_SEND_SOLICITED);
	drop:
	if (atomic_dec_and_test(&qp->refcount))
	wake_up(&qp->wait);
	done:;
	}

	/**
	* ipath_make_ud_req - construct a UD request packet
	* @qp: the QP
	*
	* Return 1 if constructed; otherwise, return 0.
	*/
	int ipath_make_ud_req(struct ipath_qp *qp)
	{
	struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
	struct ipath_other_headers *ohdr;
	struct ib_ah_attr *ah_attr;
	struct ipath_swqe *wqe;
	unsigned long flags;
	u32 nwords;
	u32 extra_bytes;
	u32 bth0;
	u16 lrh0;
	u16 lid;
	int ret = 0;
	int next_cur;

	spin_lock_irqsave(&qp->s_lock, flags);

	if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_NEXT_SEND_OK)) {
	if (!(ib_ipath_state_ops[qp->state] & IPATH_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 \|= IPATH_S_WAIT_DMA;
	goto bail;
	}
	wqe = get_swqe_ptr(qp, qp->s_last);
	ipath_send_complete(qp, wqe, IB_WC_WR_FLUSH_ERR);
	goto done;
	}

	if (qp->s_cur == qp->s_head)
	goto bail;

	wqe = get_swqe_ptr(qp, qp->s_cur);
	next_cur = qp->s_cur + 1;
	if (next_cur >= qp->s_size)
	next_cur = 0;

	/* Construct the header. */
	ah_attr = &to_iah(wqe->wr.wr.ud.ah)->attr;
	if (ah_attr->dlid >= IPATH_MULTICAST_LID_BASE) {
	if (ah_attr->dlid != IPATH_PERMISSIVE_LID)
	dev->n_multicast_xmit++;
	else
	dev->n_unicast_xmit++;
	} else {
	dev->n_unicast_xmit++;
	lid = ah_attr->dlid & ~((1 << dev->dd->ipath_lmc) - 1);
	if (unlikely(lid == dev->dd->ipath_lid)) {
	/*
	* If DMAs are in progress, we can't generate
	* a completion for the loopback packet since
	* it would be out of order.
	* XXX Instead of waiting, we could queue a
	* zero length descriptor so we get a callback.
	*/
	if (atomic_read(&qp->s_dma_busy)) {
	qp->s_flags \|= IPATH_S_WAIT_DMA;
	goto bail;
	}
	qp->s_cur = next_cur;
	spin_unlock_irqrestore(&qp->s_lock, flags);
	ipath_ud_loopback(qp, wqe);
	spin_lock_irqsave(&qp->s_lock, flags);
	ipath_send_complete(qp, wqe, IB_WC_SUCCESS);
	goto done;
	}
	}

	qp->s_cur = next_cur;
	extra_bytes = -wqe->length & 3;
	nwords = (wqe->length + extra_bytes) >> 2;

	/* header size in 32-bit words LRH+BTH+DETH = (8+12+8)/4. */
	qp->s_hdrwords = 7;
	qp->s_cur_size = wqe->length;
	qp->s_cur_sge = &qp->s_sge;
	qp->s_dmult = ah_attr->static_rate;
	qp->s_wqe = wqe;
	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;

	if (ah_attr->ah_flags & IB_AH_GRH) {
	/* Header size in 32-bit words. */
	qp->s_hdrwords += ipath_make_grh(dev, &qp->s_hdr.u.l.grh,
	&ah_attr->grh,
	qp->s_hdrwords, nwords);
	lrh0 = IPATH_LRH_GRH;
	ohdr = &qp->s_hdr.u.l.oth;
	/*
	* Don't worry about sending to locally attached multicast
	* QPs. It is unspecified by the spec. what happens.
	*/
	} else {
	/* Header size in 32-bit words. */
	lrh0 = IPATH_LRH_BTH;
	ohdr = &qp->s_hdr.u.oth;
	}
	if (wqe->wr.opcode == IB_WR_SEND_WITH_IMM) {
	qp->s_hdrwords++;
	ohdr->u.ud.imm_data = wqe->wr.ex.imm_data;
	bth0 = IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE << 24;
	} else
	bth0 = IB_OPCODE_UD_SEND_ONLY << 24;
	lrh0 \|= ah_attr->sl << 4;
	if (qp->ibqp.qp_type == IB_QPT_SMI)
	lrh0 \|= 0xF000; /* Set VL (see ch. 13.5.3.1) */
	qp->s_hdr.lrh[0] = cpu_to_be16(lrh0);
	qp->s_hdr.lrh[1] = cpu_to_be16(ah_attr->dlid); /* DEST LID */
	qp->s_hdr.lrh[2] = cpu_to_be16(qp->s_hdrwords + nwords +
	SIZE_OF_CRC);
	lid = dev->dd->ipath_lid;
	if (lid) {
	lid \|= ah_attr->src_path_bits &
	((1 << dev->dd->ipath_lmc) - 1);
	qp->s_hdr.lrh[3] = cpu_to_be16(lid);
	} else
	qp->s_hdr.lrh[3] = IB_LID_PERMISSIVE;
	if (wqe->wr.send_flags & IB_SEND_SOLICITED)
	bth0 \|= 1 << 23;
	bth0 \|= extra_bytes << 20;
	bth0 \|= qp->ibqp.qp_type == IB_QPT_SMI ? IPATH_DEFAULT_P_KEY :
	ipath_get_pkey(dev->dd, qp->s_pkey_index);
	ohdr->bth[0] = cpu_to_be32(bth0);
	/*
	* Use the multicast QP if the destination LID is a multicast LID.
	*/
	ohdr->bth[1] = ah_attr->dlid >= IPATH_MULTICAST_LID_BASE &&
	ah_attr->dlid != IPATH_PERMISSIVE_LID ?
	cpu_to_be32(IPATH_MULTICAST_QPN) :
	cpu_to_be32(wqe->wr.wr.ud.remote_qpn);
	ohdr->bth[2] = cpu_to_be32(qp->s_next_psn++ & IPATH_PSN_MASK);
	/*
	* Qkeys with the high order bit set mean use the
	* qkey from the QP context instead of the WR (see 10.2.5).
	*/
	ohdr->u.ud.deth[0] = cpu_to_be32((int)wqe->wr.wr.ud.remote_qkey < 0 ?
	qp->qkey : wqe->wr.wr.ud.remote_qkey);
	ohdr->u.ud.deth[1] = cpu_to_be32(qp->ibqp.qp_num);

	done:
	ret = 1;
	goto unlock;

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

	/**
	* ipath_ud_rcv - receive an incoming UD packet
	* @dev: the device the packet came in on
	* @hdr: the packet header
	* @has_grh: true if the packet has a GRH
	* @data: the packet data
	* @tlen: the packet length
	* @qp: the QP the packet came on
	*
	* This is called from ipath_qp_rcv() to process an incoming UD packet
	* for the given QP.
	* Called at interrupt level.
	*/
	void ipath_ud_rcv(struct ipath_ibdev dev, struct ipath_ib_header hdr,
	int has_grh, void data, u32 tlen, struct ipath_qp qp)
	{
	struct ipath_other_headers *ohdr;
	int opcode;
	u32 hdrsize;
	u32 pad;
	struct ib_wc wc;
	u32 qkey;
	u32 src_qp;
	u16 dlid;
	int header_in_data;

	/* Check for GRH */
	if (!has_grh) {
	ohdr = &hdr->u.oth;
	hdrsize = 8 + 12 + 8; /* LRH + BTH + DETH */
	qkey = be32_to_cpu(ohdr->u.ud.deth[0]);
	src_qp = be32_to_cpu(ohdr->u.ud.deth[1]);
	header_in_data = 0;
	} else {
	ohdr = &hdr->u.l.oth;
	hdrsize = 8 + 40 + 12 + 8; /* LRH + GRH + BTH + DETH */
	/*
	* The header with GRH is 68 bytes and the core driver sets
	* the eager header buffer size to 56 bytes so the last 12
	* bytes of the IB header is in the data buffer.
	*/
	header_in_data = dev->dd->ipath_rcvhdrentsize == 16;
	if (header_in_data) {
	qkey = be32_to_cpu(((__be32 *) data)[1]);
	src_qp = be32_to_cpu(((__be32 *) data)[2]);
	data += 12;
	} else {
	qkey = be32_to_cpu(ohdr->u.ud.deth[0]);
	src_qp = be32_to_cpu(ohdr->u.ud.deth[1]);
	}
	}
	src_qp &= IPATH_QPN_MASK;

	/*
	* Check that the permissive LID is only used on QP0
	* and the QKEY matches (see 9.6.1.4.1 and 9.6.1.5.1).
	*/
	if (qp->ibqp.qp_num) {
	if (unlikely(hdr->lrh[1] == IB_LID_PERMISSIVE \|\|
	hdr->lrh[3] == IB_LID_PERMISSIVE)) {
	dev->n_pkt_drops++;
	goto bail;
	}
	if (unlikely(qkey != qp->qkey)) {
	/* XXX OK to lose a count once in a while. */
	dev->qkey_violations++;
	dev->n_pkt_drops++;
	goto bail;
	}
	} else if (hdr->lrh[1] == IB_LID_PERMISSIVE \|\|
	hdr->lrh[3] == IB_LID_PERMISSIVE) {
	struct ib_smp smp = (struct ib_smp ) data;

	if (smp->mgmt_class != IB_MGMT_CLASS_SUBN_DIRECTED_ROUTE) {
	dev->n_pkt_drops++;
	goto bail;
	}
	}

	/*
	* The opcode is in the low byte when its in network order
	* (top byte when in host order).
	*/
	opcode = be32_to_cpu(ohdr->bth[0]) >> 24;
	if (qp->ibqp.qp_num > 1 &&
	opcode == IB_OPCODE_UD_SEND_ONLY_WITH_IMMEDIATE) {
	if (header_in_data) {
	wc.ex.imm_data = (__be32 ) data;
	data += sizeof(__be32);
	} else
	wc.ex.imm_data = ohdr->u.ud.imm_data;
	wc.wc_flags = IB_WC_WITH_IMM;
	hdrsize += sizeof(u32);
	} else if (opcode == IB_OPCODE_UD_SEND_ONLY) {
	wc.ex.imm_data = 0;
	wc.wc_flags = 0;
	} else {
	dev->n_pkt_drops++;
	goto bail;
	}

	/* Get the number of bytes the message was padded by. */
	pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
	if (unlikely(tlen < (hdrsize + pad + 4))) {
	/* Drop incomplete packets. */
	dev->n_pkt_drops++;
	goto bail;
	}
	tlen -= hdrsize + pad + 4;

	/* Drop invalid MAD packets (see 13.5.3.1). */
	if (unlikely((qp->ibqp.qp_num == 0 &&
	(tlen != 256 \|\|
	(be16_to_cpu(hdr->lrh[0]) >> 12) != 15)) \|\|
	(qp->ibqp.qp_num == 1 &&
	(tlen != 256 \|\|
	(be16_to_cpu(hdr->lrh[0]) >> 12) == 15)))) {
	dev->n_pkt_drops++;
	goto bail;
	}

	/*
	* A GRH is expected to preceed the data even if not
	* present on the wire.
	*/
	wc.byte_len = tlen + sizeof(struct ib_grh);

	/*
	* Get the next work request entry to find where to put the data.
	*/
	if (qp->r_flags & IPATH_R_REUSE_SGE)
	qp->r_flags &= ~IPATH_R_REUSE_SGE;
	else if (!ipath_get_rwqe(qp, 0)) {
	/*
	* Count VL15 packets dropped due to no receive buffer.
	* Otherwise, count them as buffer overruns since usually,
	* the HW will be able to receive packets even if there are
	* no QPs with posted receive buffers.
	*/
	if (qp->ibqp.qp_num == 0)
	dev->n_vl15_dropped++;
	else
	dev->rcv_errors++;
	goto bail;
	}
	/* Silently drop packets which are too big. */
	if (wc.byte_len > qp->r_len) {
	qp->r_flags \|= IPATH_R_REUSE_SGE;
	dev->n_pkt_drops++;
	goto bail;
	}
	if (has_grh) {
	ipath_copy_sge(&qp->r_sge, &hdr->u.l.grh,
	sizeof(struct ib_grh));
	wc.wc_flags \|= IB_WC_GRH;
	} else
	ipath_skip_sge(&qp->r_sge, sizeof(struct ib_grh));
	ipath_copy_sge(&qp->r_sge, data,
	wc.byte_len - sizeof(struct ib_grh));
	if (!test_and_clear_bit(IPATH_R_WRID_VALID, &qp->r_aflags))
	goto bail;
	wc.wr_id = qp->r_wr_id;
	wc.status = IB_WC_SUCCESS;
	wc.opcode = IB_WC_RECV;
	wc.vendor_err = 0;
	wc.qp = &qp->ibqp;
	wc.src_qp = src_qp;
	/* XXX do we know which pkey matched? Only needed for GSI. */
	wc.pkey_index = 0;
	wc.slid = be16_to_cpu(hdr->lrh[3]);
	wc.sl = (be16_to_cpu(hdr->lrh[0]) >> 4) & 0xF;
	dlid = be16_to_cpu(hdr->lrh[1]);
	/*
	* Save the LMC lower bits if the destination LID is a unicast LID.
	*/
	wc.dlid_path_bits = dlid >= IPATH_MULTICAST_LID_BASE ? 0 :
	dlid & ((1 << dev->dd->ipath_lmc) - 1);
	wc.port_num = 1;
	/* Signal completion event if the solicited bit is set. */
	ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
	(ohdr->bth[0] &
	cpu_to_be32(1 << 23)) != 0);

	bail:;
	}