1/*
   2 * Copyright (c) 2006, 2007, 2008, 2009 QLogic Corporation. All rights reserved.
   3 * Copyright (c) 2005, 2006 PathScale, Inc. All rights reserved.
   4 *
   5 * This software is available to you under a choice of one of two
   6 * licenses.  You may choose to be licensed under the terms of the GNU
   7 * General Public License (GPL) Version 2, available from the file
   8 * COPYING in the main directory of this source tree, or the
   9 * OpenIB.org BSD license below:
  10 *
  11 *     Redistribution and use in source and binary forms, with or
  12 *     without modification, are permitted provided that the following
  13 *     conditions are met:
  14 *
  15 *      - Redistributions of source code must retain the above
  16 *        copyright notice, this list of conditions and the following
  17 *        disclaimer.
  18 *
  19 *      - Redistributions in binary form must reproduce the above
  20 *        copyright notice, this list of conditions and the following
  21 *        disclaimer in the documentation and/or other materials
  22 *        provided with the distribution.
  23 *
  24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  25 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  26 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  27 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  28 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  29 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  30 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  31 * SOFTWARE.
  32 */
  33
  34#include <linux/io.h>
  35
  36#include "qib.h"
  37
  38/* cut down ridiculously long IB macro names */
  39#define OP(x) IB_OPCODE_RC_##x
  40
  41
  42static u32 restart_sge(struct rvt_sge_state *ss, struct rvt_swqe *wqe,
  43		       u32 psn, u32 pmtu)
  44{
  45	u32 len;
  46
  47	len = ((psn - wqe->psn) & QIB_PSN_MASK) * pmtu;
  48	return rvt_restart_sge(ss, wqe, len);
  49}
  50
  51/**
  52 * qib_make_rc_ack - construct a response packet (ACK, NAK, or RDMA read)
  53 * @dev: the device for this QP
  54 * @qp: a pointer to the QP
  55 * @ohdr: a pointer to the IB header being constructed
  56 * @pmtu: the path MTU
  57 *
  58 * Return 1 if constructed; otherwise, return 0.
  59 * Note that we are in the responder's side of the QP context.
  60 * Note the QP s_lock must be held.
  61 */
  62static int qib_make_rc_ack(struct qib_ibdev *dev, struct rvt_qp *qp,
  63			   struct ib_other_headers *ohdr, u32 pmtu)
  64{
  65	struct rvt_ack_entry *e;
  66	u32 hwords;
  67	u32 len;
  68	u32 bth0;
  69	u32 bth2;
  70
  71	/* Don't send an ACK if we aren't supposed to. */
  72	if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK))
  73		goto bail;
  74
  75	/* header size in 32-bit words LRH+BTH = (8+12)/4. */
  76	hwords = 5;
  77
  78	switch (qp->s_ack_state) {
  79	case OP(RDMA_READ_RESPONSE_LAST):
  80	case OP(RDMA_READ_RESPONSE_ONLY):
  81		e = &qp->s_ack_queue[qp->s_tail_ack_queue];
  82		if (e->rdma_sge.mr) {
  83			rvt_put_mr(e->rdma_sge.mr);
  84			e->rdma_sge.mr = NULL;
  85		}
  86		fallthrough;
  87	case OP(ATOMIC_ACKNOWLEDGE):
  88		/*
  89		 * We can increment the tail pointer now that the last
  90		 * response has been sent instead of only being
  91		 * constructed.
  92		 */
  93		if (++qp->s_tail_ack_queue > QIB_MAX_RDMA_ATOMIC)
  94			qp->s_tail_ack_queue = 0;
  95		fallthrough;
  96	case OP(SEND_ONLY):
  97	case OP(ACKNOWLEDGE):
  98		/* Check for no next entry in the queue. */
  99		if (qp->r_head_ack_queue == qp->s_tail_ack_queue) {
 100			if (qp->s_flags & RVT_S_ACK_PENDING)
 101				goto normal;
 102			goto bail;
 103		}
 104
 105		e = &qp->s_ack_queue[qp->s_tail_ack_queue];
 106		if (e->opcode == OP(RDMA_READ_REQUEST)) {
 107			/*
 108			 * If a RDMA read response is being resent and
 109			 * we haven't seen the duplicate request yet,
 110			 * then stop sending the remaining responses the
 111			 * responder has seen until the requester resends it.
 112			 */
 113			len = e->rdma_sge.sge_length;
 114			if (len && !e->rdma_sge.mr) {
 115				qp->s_tail_ack_queue = qp->r_head_ack_queue;
 116				goto bail;
 117			}
 118			/* Copy SGE state in case we need to resend */
 119			qp->s_rdma_mr = e->rdma_sge.mr;
 120			if (qp->s_rdma_mr)
 121				rvt_get_mr(qp->s_rdma_mr);
 122			qp->s_ack_rdma_sge.sge = e->rdma_sge;
 123			qp->s_ack_rdma_sge.num_sge = 1;
 124			qp->s_cur_sge = &qp->s_ack_rdma_sge;
 125			if (len > pmtu) {
 126				len = pmtu;
 127				qp->s_ack_state = OP(RDMA_READ_RESPONSE_FIRST);
 128			} else {
 129				qp->s_ack_state = OP(RDMA_READ_RESPONSE_ONLY);
 130				e->sent = 1;
 131			}
 132			ohdr->u.aeth = rvt_compute_aeth(qp);
 133			hwords++;
 134			qp->s_ack_rdma_psn = e->psn;
 135			bth2 = qp->s_ack_rdma_psn++ & QIB_PSN_MASK;
 136		} else {
 137			/* COMPARE_SWAP or FETCH_ADD */
 138			qp->s_cur_sge = NULL;
 139			len = 0;
 140			qp->s_ack_state = OP(ATOMIC_ACKNOWLEDGE);
 141			ohdr->u.at.aeth = rvt_compute_aeth(qp);
 142			ib_u64_put(e->atomic_data, &ohdr->u.at.atomic_ack_eth);
 143			hwords += sizeof(ohdr->u.at) / sizeof(u32);
 144			bth2 = e->psn & QIB_PSN_MASK;
 145			e->sent = 1;
 146		}
 147		bth0 = qp->s_ack_state << 24;
 148		break;
 149
 150	case OP(RDMA_READ_RESPONSE_FIRST):
 151		qp->s_ack_state = OP(RDMA_READ_RESPONSE_MIDDLE);
 152		fallthrough;
 153	case OP(RDMA_READ_RESPONSE_MIDDLE):
 154		qp->s_cur_sge = &qp->s_ack_rdma_sge;
 155		qp->s_rdma_mr = qp->s_ack_rdma_sge.sge.mr;
 156		if (qp->s_rdma_mr)
 157			rvt_get_mr(qp->s_rdma_mr);
 158		len = qp->s_ack_rdma_sge.sge.sge_length;
 159		if (len > pmtu)
 160			len = pmtu;
 161		else {
 162			ohdr->u.aeth = rvt_compute_aeth(qp);
 163			hwords++;
 164			qp->s_ack_state = OP(RDMA_READ_RESPONSE_LAST);
 165			e = &qp->s_ack_queue[qp->s_tail_ack_queue];
 166			e->sent = 1;
 167		}
 168		bth0 = qp->s_ack_state << 24;
 169		bth2 = qp->s_ack_rdma_psn++ & QIB_PSN_MASK;
 170		break;
 171
 172	default:
 173normal:
 174		/*
 175		 * Send a regular ACK.
 176		 * Set the s_ack_state so we wait until after sending
 177		 * the ACK before setting s_ack_state to ACKNOWLEDGE
 178		 * (see above).
 179		 */
 180		qp->s_ack_state = OP(SEND_ONLY);
 181		qp->s_flags &= ~RVT_S_ACK_PENDING;
 182		qp->s_cur_sge = NULL;
 183		if (qp->s_nak_state)
 184			ohdr->u.aeth =
 185				cpu_to_be32((qp->r_msn & IB_MSN_MASK) |
 186					    (qp->s_nak_state <<
 187					     IB_AETH_CREDIT_SHIFT));
 188		else
 189			ohdr->u.aeth = rvt_compute_aeth(qp);
 190		hwords++;
 191		len = 0;
 192		bth0 = OP(ACKNOWLEDGE) << 24;
 193		bth2 = qp->s_ack_psn & QIB_PSN_MASK;
 194	}
 195	qp->s_rdma_ack_cnt++;
 196	qp->s_hdrwords = hwords;
 197	qp->s_cur_size = len;
 198	qib_make_ruc_header(qp, ohdr, bth0, bth2);
 199	return 1;
 200
 201bail:
 202	qp->s_ack_state = OP(ACKNOWLEDGE);
 203	qp->s_flags &= ~(RVT_S_RESP_PENDING | RVT_S_ACK_PENDING);
 204	return 0;
 205}
 206
 207/**
 208 * qib_make_rc_req - construct a request packet (SEND, RDMA r/w, ATOMIC)
 209 * @qp: a pointer to the QP
 210 * @flags: unused
 211 *
 212 * Assumes the s_lock is held.
 213 *
 214 * Return 1 if constructed; otherwise, return 0.
 215 */
 216int qib_make_rc_req(struct rvt_qp *qp, unsigned long *flags)
 217{
 218	struct qib_qp_priv *priv = qp->priv;
 219	struct qib_ibdev *dev = to_idev(qp->ibqp.device);
 220	struct ib_other_headers *ohdr;
 221	struct rvt_sge_state *ss;
 222	struct rvt_swqe *wqe;
 223	u32 hwords;
 224	u32 len;
 225	u32 bth0;
 226	u32 bth2;
 227	u32 pmtu = qp->pmtu;
 228	char newreq;
 229	int ret = 0;
 230	int delta;
 231
 232	ohdr = &priv->s_hdr->u.oth;
 233	if (rdma_ah_get_ah_flags(&qp->remote_ah_attr) & IB_AH_GRH)
 234		ohdr = &priv->s_hdr->u.l.oth;
 235
 236	/* Sending responses has higher priority over sending requests. */
 237	if ((qp->s_flags & RVT_S_RESP_PENDING) &&
 238	    qib_make_rc_ack(dev, qp, ohdr, pmtu))
 239		goto done;
 240
 241	if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_SEND_OK)) {
 242		if (!(ib_rvt_state_ops[qp->state] & RVT_FLUSH_SEND))
 243			goto bail;
 244		/* We are in the error state, flush the work request. */
 245		if (qp->s_last == READ_ONCE(qp->s_head))
 246			goto bail;
 247		/* If DMAs are in progress, we can't flush immediately. */
 248		if (atomic_read(&priv->s_dma_busy)) {
 249			qp->s_flags |= RVT_S_WAIT_DMA;
 250			goto bail;
 251		}
 252		wqe = rvt_get_swqe_ptr(qp, qp->s_last);
 253		rvt_send_complete(qp, wqe, qp->s_last != qp->s_acked ?
 254			IB_WC_SUCCESS : IB_WC_WR_FLUSH_ERR);
 255		/* will get called again */
 256		goto done;
 257	}
 258
 259	if (qp->s_flags & (RVT_S_WAIT_RNR | RVT_S_WAIT_ACK))
 260		goto bail;
 261
 262	if (qib_cmp24(qp->s_psn, qp->s_sending_hpsn) <= 0) {
 263		if (qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) <= 0) {
 264			qp->s_flags |= RVT_S_WAIT_PSN;
 265			goto bail;
 266		}
 267		qp->s_sending_psn = qp->s_psn;
 268		qp->s_sending_hpsn = qp->s_psn - 1;
 269	}
 270
 271	/* header size in 32-bit words LRH+BTH = (8+12)/4. */
 272	hwords = 5;
 273	bth0 = 0;
 274
 275	/* Send a request. */
 276	wqe = rvt_get_swqe_ptr(qp, qp->s_cur);
 277	switch (qp->s_state) {
 278	default:
 279		if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_NEXT_SEND_OK))
 280			goto bail;
 281		/*
 282		 * Resend an old request or start a new one.
 283		 *
 284		 * We keep track of the current SWQE so that
 285		 * we don't reset the "furthest progress" state
 286		 * if we need to back up.
 287		 */
 288		newreq = 0;
 289		if (qp->s_cur == qp->s_tail) {
 290			/* Check if send work queue is empty. */
 291			if (qp->s_tail == READ_ONCE(qp->s_head))
 292				goto bail;
 293			/*
 294			 * If a fence is requested, wait for previous
 295			 * RDMA read and atomic operations to finish.
 296			 */
 297			if ((wqe->wr.send_flags & IB_SEND_FENCE) &&
 298			    qp->s_num_rd_atomic) {
 299				qp->s_flags |= RVT_S_WAIT_FENCE;
 300				goto bail;
 301			}
 302			newreq = 1;
 303			qp->s_psn = wqe->psn;
 304		}
 305		/*
 306		 * Note that we have to be careful not to modify the
 307		 * original work request since we may need to resend
 308		 * it.
 309		 */
 310		len = wqe->length;
 311		ss = &qp->s_sge;
 312		bth2 = qp->s_psn & QIB_PSN_MASK;
 313		switch (wqe->wr.opcode) {
 314		case IB_WR_SEND:
 315		case IB_WR_SEND_WITH_IMM:
 316			/* If no credit, return. */
 317			if (!rvt_rc_credit_avail(qp, wqe))
 318				goto bail;
 319			if (len > pmtu) {
 320				qp->s_state = OP(SEND_FIRST);
 321				len = pmtu;
 322				break;
 323			}
 324			if (wqe->wr.opcode == IB_WR_SEND)
 325				qp->s_state = OP(SEND_ONLY);
 326			else {
 327				qp->s_state = OP(SEND_ONLY_WITH_IMMEDIATE);
 328				/* Immediate data comes after the BTH */
 329				ohdr->u.imm_data = wqe->wr.ex.imm_data;
 330				hwords += 1;
 331			}
 332			if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 333				bth0 |= IB_BTH_SOLICITED;
 334			bth2 |= IB_BTH_REQ_ACK;
 335			if (++qp->s_cur == qp->s_size)
 336				qp->s_cur = 0;
 337			break;
 338
 339		case IB_WR_RDMA_WRITE:
 340			if (newreq && !(qp->s_flags & RVT_S_UNLIMITED_CREDIT))
 341				qp->s_lsn++;
 342			goto no_flow_control;
 343		case IB_WR_RDMA_WRITE_WITH_IMM:
 344			/* If no credit, return. */
 345			if (!rvt_rc_credit_avail(qp, wqe))
 346				goto bail;
 347no_flow_control:
 348			ohdr->u.rc.reth.vaddr =
 349				cpu_to_be64(wqe->rdma_wr.remote_addr);
 350			ohdr->u.rc.reth.rkey =
 351				cpu_to_be32(wqe->rdma_wr.rkey);
 352			ohdr->u.rc.reth.length = cpu_to_be32(len);
 353			hwords += sizeof(struct ib_reth) / sizeof(u32);
 354			if (len > pmtu) {
 355				qp->s_state = OP(RDMA_WRITE_FIRST);
 356				len = pmtu;
 357				break;
 358			}
 359			if (wqe->rdma_wr.wr.opcode == IB_WR_RDMA_WRITE)
 360				qp->s_state = OP(RDMA_WRITE_ONLY);
 361			else {
 362				qp->s_state = OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE);
 363				/* Immediate data comes after RETH */
 364				ohdr->u.rc.imm_data =
 365					wqe->rdma_wr.wr.ex.imm_data;
 366				hwords += 1;
 367				if (wqe->rdma_wr.wr.send_flags & IB_SEND_SOLICITED)
 368					bth0 |= IB_BTH_SOLICITED;
 369			}
 370			bth2 |= IB_BTH_REQ_ACK;
 371			if (++qp->s_cur == qp->s_size)
 372				qp->s_cur = 0;
 373			break;
 374
 375		case IB_WR_RDMA_READ:
 376			/*
 377			 * Don't allow more operations to be started
 378			 * than the QP limits allow.
 379			 */
 380			if (newreq) {
 381				if (qp->s_num_rd_atomic >=
 382				    qp->s_max_rd_atomic) {
 383					qp->s_flags |= RVT_S_WAIT_RDMAR;
 384					goto bail;
 385				}
 386				qp->s_num_rd_atomic++;
 387				if (!(qp->s_flags & RVT_S_UNLIMITED_CREDIT))
 388					qp->s_lsn++;
 389			}
 390
 391			ohdr->u.rc.reth.vaddr =
 392				cpu_to_be64(wqe->rdma_wr.remote_addr);
 393			ohdr->u.rc.reth.rkey =
 394				cpu_to_be32(wqe->rdma_wr.rkey);
 395			ohdr->u.rc.reth.length = cpu_to_be32(len);
 396			qp->s_state = OP(RDMA_READ_REQUEST);
 397			hwords += sizeof(ohdr->u.rc.reth) / sizeof(u32);
 398			ss = NULL;
 399			len = 0;
 400			bth2 |= IB_BTH_REQ_ACK;
 401			if (++qp->s_cur == qp->s_size)
 402				qp->s_cur = 0;
 403			break;
 404
 405		case IB_WR_ATOMIC_CMP_AND_SWP:
 406		case IB_WR_ATOMIC_FETCH_AND_ADD:
 407			/*
 408			 * Don't allow more operations to be started
 409			 * than the QP limits allow.
 410			 */
 411			if (newreq) {
 412				if (qp->s_num_rd_atomic >=
 413				    qp->s_max_rd_atomic) {
 414					qp->s_flags |= RVT_S_WAIT_RDMAR;
 415					goto bail;
 416				}
 417				qp->s_num_rd_atomic++;
 418				if (!(qp->s_flags & RVT_S_UNLIMITED_CREDIT))
 419					qp->s_lsn++;
 420			}
 421			if (wqe->atomic_wr.wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP) {
 422				qp->s_state = OP(COMPARE_SWAP);
 423				put_ib_ateth_swap(wqe->atomic_wr.swap,
 424						  &ohdr->u.atomic_eth);
 425				put_ib_ateth_compare(wqe->atomic_wr.compare_add,
 426						     &ohdr->u.atomic_eth);
 427			} else {
 428				qp->s_state = OP(FETCH_ADD);
 429				put_ib_ateth_swap(wqe->atomic_wr.compare_add,
 430						  &ohdr->u.atomic_eth);
 431				put_ib_ateth_compare(0, &ohdr->u.atomic_eth);
 432			}
 433			put_ib_ateth_vaddr(wqe->atomic_wr.remote_addr,
 434					   &ohdr->u.atomic_eth);
 435			ohdr->u.atomic_eth.rkey = cpu_to_be32(
 436				wqe->atomic_wr.rkey);
 437			hwords += sizeof(struct ib_atomic_eth) / sizeof(u32);
 438			ss = NULL;
 439			len = 0;
 440			bth2 |= IB_BTH_REQ_ACK;
 441			if (++qp->s_cur == qp->s_size)
 442				qp->s_cur = 0;
 443			break;
 444
 445		default:
 446			goto bail;
 447		}
 448		qp->s_sge.sge = wqe->sg_list[0];
 449		qp->s_sge.sg_list = wqe->sg_list + 1;
 450		qp->s_sge.num_sge = wqe->wr.num_sge;
 451		qp->s_sge.total_len = wqe->length;
 452		qp->s_len = wqe->length;
 453		if (newreq) {
 454			qp->s_tail++;
 455			if (qp->s_tail >= qp->s_size)
 456				qp->s_tail = 0;
 457		}
 458		if (wqe->wr.opcode == IB_WR_RDMA_READ)
 459			qp->s_psn = wqe->lpsn + 1;
 460		else
 461			qp->s_psn++;
 462		break;
 463
 464	case OP(RDMA_READ_RESPONSE_FIRST):
 465		/*
 466		 * qp->s_state is normally set to the opcode of the
 467		 * last packet constructed for new requests and therefore
 468		 * is never set to RDMA read response.
 469		 * RDMA_READ_RESPONSE_FIRST is used by the ACK processing
 470		 * thread to indicate a SEND needs to be restarted from an
 471		 * earlier PSN without interferring with the sending thread.
 472		 * See qib_restart_rc().
 473		 */
 474		qp->s_len = restart_sge(&qp->s_sge, wqe, qp->s_psn, pmtu);
 475		fallthrough;
 476	case OP(SEND_FIRST):
 477		qp->s_state = OP(SEND_MIDDLE);
 478		fallthrough;
 479	case OP(SEND_MIDDLE):
 480		bth2 = qp->s_psn++ & QIB_PSN_MASK;
 481		ss = &qp->s_sge;
 482		len = qp->s_len;
 483		if (len > pmtu) {
 484			len = pmtu;
 485			break;
 486		}
 487		if (wqe->wr.opcode == IB_WR_SEND)
 488			qp->s_state = OP(SEND_LAST);
 489		else {
 490			qp->s_state = OP(SEND_LAST_WITH_IMMEDIATE);
 491			/* Immediate data comes after the BTH */
 492			ohdr->u.imm_data = wqe->wr.ex.imm_data;
 493			hwords += 1;
 494		}
 495		if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 496			bth0 |= IB_BTH_SOLICITED;
 497		bth2 |= IB_BTH_REQ_ACK;
 498		qp->s_cur++;
 499		if (qp->s_cur >= qp->s_size)
 500			qp->s_cur = 0;
 501		break;
 502
 503	case OP(RDMA_READ_RESPONSE_LAST):
 504		/*
 505		 * qp->s_state is normally set to the opcode of the
 506		 * last packet constructed for new requests and therefore
 507		 * is never set to RDMA read response.
 508		 * RDMA_READ_RESPONSE_LAST is used by the ACK processing
 509		 * thread to indicate a RDMA write needs to be restarted from
 510		 * an earlier PSN without interferring with the sending thread.
 511		 * See qib_restart_rc().
 512		 */
 513		qp->s_len = restart_sge(&qp->s_sge, wqe, qp->s_psn, pmtu);
 514		fallthrough;
 515	case OP(RDMA_WRITE_FIRST):
 516		qp->s_state = OP(RDMA_WRITE_MIDDLE);
 517		fallthrough;
 518	case OP(RDMA_WRITE_MIDDLE):
 519		bth2 = qp->s_psn++ & QIB_PSN_MASK;
 520		ss = &qp->s_sge;
 521		len = qp->s_len;
 522		if (len > pmtu) {
 523			len = pmtu;
 524			break;
 525		}
 526		if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
 527			qp->s_state = OP(RDMA_WRITE_LAST);
 528		else {
 529			qp->s_state = OP(RDMA_WRITE_LAST_WITH_IMMEDIATE);
 530			/* Immediate data comes after the BTH */
 531			ohdr->u.imm_data = wqe->wr.ex.imm_data;
 532			hwords += 1;
 533			if (wqe->wr.send_flags & IB_SEND_SOLICITED)
 534				bth0 |= IB_BTH_SOLICITED;
 535		}
 536		bth2 |= IB_BTH_REQ_ACK;
 537		qp->s_cur++;
 538		if (qp->s_cur >= qp->s_size)
 539			qp->s_cur = 0;
 540		break;
 541
 542	case OP(RDMA_READ_RESPONSE_MIDDLE):
 543		/*
 544		 * qp->s_state is normally set to the opcode of the
 545		 * last packet constructed for new requests and therefore
 546		 * is never set to RDMA read response.
 547		 * RDMA_READ_RESPONSE_MIDDLE is used by the ACK processing
 548		 * thread to indicate a RDMA read needs to be restarted from
 549		 * an earlier PSN without interferring with the sending thread.
 550		 * See qib_restart_rc().
 551		 */
 552		len = ((qp->s_psn - wqe->psn) & QIB_PSN_MASK) * pmtu;
 553		ohdr->u.rc.reth.vaddr =
 554			cpu_to_be64(wqe->rdma_wr.remote_addr + len);
 555		ohdr->u.rc.reth.rkey =
 556			cpu_to_be32(wqe->rdma_wr.rkey);
 557		ohdr->u.rc.reth.length = cpu_to_be32(wqe->length - len);
 558		qp->s_state = OP(RDMA_READ_REQUEST);
 559		hwords += sizeof(ohdr->u.rc.reth) / sizeof(u32);
 560		bth2 = (qp->s_psn & QIB_PSN_MASK) | IB_BTH_REQ_ACK;
 561		qp->s_psn = wqe->lpsn + 1;
 562		ss = NULL;
 563		len = 0;
 564		qp->s_cur++;
 565		if (qp->s_cur == qp->s_size)
 566			qp->s_cur = 0;
 567		break;
 568	}
 569	qp->s_sending_hpsn = bth2;
 570	delta = (((int) bth2 - (int) wqe->psn) << 8) >> 8;
 571	if (delta && delta % QIB_PSN_CREDIT == 0)
 572		bth2 |= IB_BTH_REQ_ACK;
 573	if (qp->s_flags & RVT_S_SEND_ONE) {
 574		qp->s_flags &= ~RVT_S_SEND_ONE;
 575		qp->s_flags |= RVT_S_WAIT_ACK;
 576		bth2 |= IB_BTH_REQ_ACK;
 577	}
 578	qp->s_len -= len;
 579	qp->s_hdrwords = hwords;
 580	qp->s_cur_sge = ss;
 581	qp->s_cur_size = len;
 582	qib_make_ruc_header(qp, ohdr, bth0 | (qp->s_state << 24), bth2);
 583done:
 584	return 1;
 585bail:
 586	qp->s_flags &= ~RVT_S_BUSY;
 587	return ret;
 588}
 589
 590/**
 591 * qib_send_rc_ack - Construct an ACK packet and send it
 592 * @qp: a pointer to the QP
 593 *
 594 * This is called from qib_rc_rcv() and qib_kreceive().
 595 * Note that RDMA reads and atomics are handled in the
 596 * send side QP state and tasklet.
 597 */
 598void qib_send_rc_ack(struct rvt_qp *qp)
 599{
 600	struct qib_devdata *dd = dd_from_ibdev(qp->ibqp.device);
 601	struct qib_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
 602	struct qib_pportdata *ppd = ppd_from_ibp(ibp);
 603	u64 pbc;
 604	u16 lrh0;
 605	u32 bth0;
 606	u32 hwords;
 607	u32 pbufn;
 608	u32 __iomem *piobuf;
 609	struct ib_header hdr;
 610	struct ib_other_headers *ohdr;
 611	u32 control;
 612	unsigned long flags;
 613
 614	spin_lock_irqsave(&qp->s_lock, flags);
 615
 616	if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK))
 617		goto unlock;
 618
 619	/* Don't send ACK or NAK if a RDMA read or atomic is pending. */
 620	if ((qp->s_flags & RVT_S_RESP_PENDING) || qp->s_rdma_ack_cnt)
 621		goto queue_ack;
 622
 623	/* Construct the header with s_lock held so APM doesn't change it. */
 624	ohdr = &hdr.u.oth;
 625	lrh0 = QIB_LRH_BTH;
 626	/* header size in 32-bit words LRH+BTH+AETH = (8+12+4)/4. */
 627	hwords = 6;
 628	if (unlikely(rdma_ah_get_ah_flags(&qp->remote_ah_attr) &
 629		     IB_AH_GRH)) {
 630		hwords += qib_make_grh(ibp, &hdr.u.l.grh,
 631				       rdma_ah_read_grh(&qp->remote_ah_attr),
 632				       hwords, 0);
 633		ohdr = &hdr.u.l.oth;
 634		lrh0 = QIB_LRH_GRH;
 635	}
 636	/* read pkey_index w/o lock (its atomic) */
 637	bth0 = qib_get_pkey(ibp, qp->s_pkey_index) | (OP(ACKNOWLEDGE) << 24);
 638	if (qp->s_mig_state == IB_MIG_MIGRATED)
 639		bth0 |= IB_BTH_MIG_REQ;
 640	if (qp->r_nak_state)
 641		ohdr->u.aeth = cpu_to_be32((qp->r_msn & IB_MSN_MASK) |
 642					    (qp->r_nak_state <<
 643					     IB_AETH_CREDIT_SHIFT));
 644	else
 645		ohdr->u.aeth = rvt_compute_aeth(qp);
 646	lrh0 |= ibp->sl_to_vl[rdma_ah_get_sl(&qp->remote_ah_attr)] << 12 |
 647		rdma_ah_get_sl(&qp->remote_ah_attr) << 4;
 648	hdr.lrh[0] = cpu_to_be16(lrh0);
 649	hdr.lrh[1] = cpu_to_be16(rdma_ah_get_dlid(&qp->remote_ah_attr));
 650	hdr.lrh[2] = cpu_to_be16(hwords + SIZE_OF_CRC);
 651	hdr.lrh[3] = cpu_to_be16(ppd->lid |
 652				 rdma_ah_get_path_bits(&qp->remote_ah_attr));
 653	ohdr->bth[0] = cpu_to_be32(bth0);
 654	ohdr->bth[1] = cpu_to_be32(qp->remote_qpn);
 655	ohdr->bth[2] = cpu_to_be32(qp->r_ack_psn & QIB_PSN_MASK);
 656
 657	spin_unlock_irqrestore(&qp->s_lock, flags);
 658
 659	/* Don't try to send ACKs if the link isn't ACTIVE */
 660	if (!(ppd->lflags & QIBL_LINKACTIVE))
 661		goto done;
 662
 663	control = dd->f_setpbc_control(ppd, hwords + SIZE_OF_CRC,
 664				       qp->s_srate, lrh0 >> 12);
 665	/* length is + 1 for the control dword */
 666	pbc = ((u64) control << 32) | (hwords + 1);
 667
 668	piobuf = dd->f_getsendbuf(ppd, pbc, &pbufn);
 669	if (!piobuf) {
 670		/*
 671		 * We are out of PIO buffers at the moment.
 672		 * Pass responsibility for sending the ACK to the
 673		 * send tasklet so that when a PIO buffer becomes
 674		 * available, the ACK is sent ahead of other outgoing
 675		 * packets.
 676		 */
 677		spin_lock_irqsave(&qp->s_lock, flags);
 678		goto queue_ack;
 679	}
 680
 681	/*
 682	 * Write the pbc.
 683	 * We have to flush after the PBC for correctness
 684	 * on some cpus or WC buffer can be written out of order.
 685	 */
 686	writeq(pbc, piobuf);
 687
 688	if (dd->flags & QIB_PIO_FLUSH_WC) {
 689		u32 *hdrp = (u32 *) &hdr;
 690
 691		qib_flush_wc();
 692		qib_pio_copy(piobuf + 2, hdrp, hwords - 1);
 693		qib_flush_wc();
 694		__raw_writel(hdrp[hwords - 1], piobuf + hwords + 1);
 695	} else
 696		qib_pio_copy(piobuf + 2, (u32 *) &hdr, hwords);
 697
 698	if (dd->flags & QIB_USE_SPCL_TRIG) {
 699		u32 spcl_off = (pbufn >= dd->piobcnt2k) ? 2047 : 1023;
 700
 701		qib_flush_wc();
 702		__raw_writel(0xaebecede, piobuf + spcl_off);
 703	}
 704
 705	qib_flush_wc();
 706	qib_sendbuf_done(dd, pbufn);
 707
 708	this_cpu_inc(ibp->pmastats->n_unicast_xmit);
 709	goto done;
 710
 711queue_ack:
 712	if (ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK) {
 713		this_cpu_inc(*ibp->rvp.rc_qacks);
 714		qp->s_flags |= RVT_S_ACK_PENDING | RVT_S_RESP_PENDING;
 715		qp->s_nak_state = qp->r_nak_state;
 716		qp->s_ack_psn = qp->r_ack_psn;
 717
 718		/* Schedule the send tasklet. */
 719		qib_schedule_send(qp);
 720	}
 721unlock:
 722	spin_unlock_irqrestore(&qp->s_lock, flags);
 723done:
 724	return;
 725}
 726
 727/**
 728 * reset_psn - reset the QP state to send starting from PSN
 729 * @qp: the QP
 730 * @psn: the packet sequence number to restart at
 731 *
 732 * This is called from qib_rc_rcv() to process an incoming RC ACK
 733 * for the given QP.
 734 * Called at interrupt level with the QP s_lock held.
 735 */
 736static void reset_psn(struct rvt_qp *qp, u32 psn)
 737{
 738	u32 n = qp->s_acked;
 739	struct rvt_swqe *wqe = rvt_get_swqe_ptr(qp, n);
 740	u32 opcode;
 741
 742	qp->s_cur = n;
 743
 744	/*
 745	 * If we are starting the request from the beginning,
 746	 * let the normal send code handle initialization.
 747	 */
 748	if (qib_cmp24(psn, wqe->psn) <= 0) {
 749		qp->s_state = OP(SEND_LAST);
 750		goto done;
 751	}
 752
 753	/* Find the work request opcode corresponding to the given PSN. */
 754	opcode = wqe->wr.opcode;
 755	for (;;) {
 756		int diff;
 757
 758		if (++n == qp->s_size)
 759			n = 0;
 760		if (n == qp->s_tail)
 761			break;
 762		wqe = rvt_get_swqe_ptr(qp, n);
 763		diff = qib_cmp24(psn, wqe->psn);
 764		if (diff < 0)
 765			break;
 766		qp->s_cur = n;
 767		/*
 768		 * If we are starting the request from the beginning,
 769		 * let the normal send code handle initialization.
 770		 */
 771		if (diff == 0) {
 772			qp->s_state = OP(SEND_LAST);
 773			goto done;
 774		}
 775		opcode = wqe->wr.opcode;
 776	}
 777
 778	/*
 779	 * Set the state to restart in the middle of a request.
 780	 * Don't change the s_sge, s_cur_sge, or s_cur_size.
 781	 * See qib_make_rc_req().
 782	 */
 783	switch (opcode) {
 784	case IB_WR_SEND:
 785	case IB_WR_SEND_WITH_IMM:
 786		qp->s_state = OP(RDMA_READ_RESPONSE_FIRST);
 787		break;
 788
 789	case IB_WR_RDMA_WRITE:
 790	case IB_WR_RDMA_WRITE_WITH_IMM:
 791		qp->s_state = OP(RDMA_READ_RESPONSE_LAST);
 792		break;
 793
 794	case IB_WR_RDMA_READ:
 795		qp->s_state = OP(RDMA_READ_RESPONSE_MIDDLE);
 796		break;
 797
 798	default:
 799		/*
 800		 * This case shouldn't happen since its only
 801		 * one PSN per req.
 802		 */
 803		qp->s_state = OP(SEND_LAST);
 804	}
 805done:
 806	qp->s_psn = psn;
 807	/*
 808	 * Set RVT_S_WAIT_PSN as qib_rc_complete() may start the timer
 809	 * asynchronously before the send tasklet can get scheduled.
 810	 * Doing it in qib_make_rc_req() is too late.
 811	 */
 812	if ((qib_cmp24(qp->s_psn, qp->s_sending_hpsn) <= 0) &&
 813	    (qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) <= 0))
 814		qp->s_flags |= RVT_S_WAIT_PSN;
 815}
 816
 817/*
 818 * Back up requester to resend the last un-ACKed request.
 819 * The QP r_lock and s_lock should be held and interrupts disabled.
 820 */
 821void qib_restart_rc(struct rvt_qp *qp, u32 psn, int wait)
 822{
 823	struct rvt_swqe *wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
 824	struct qib_ibport *ibp;
 825
 826	if (qp->s_retry == 0) {
 827		if (qp->s_mig_state == IB_MIG_ARMED) {
 828			qib_migrate_qp(qp);
 829			qp->s_retry = qp->s_retry_cnt;
 830		} else if (qp->s_last == qp->s_acked) {
 831			rvt_send_complete(qp, wqe, IB_WC_RETRY_EXC_ERR);
 832			rvt_error_qp(qp, IB_WC_WR_FLUSH_ERR);
 833			return;
 834		} else /* XXX need to handle delayed completion */
 835			return;
 836	} else
 837		qp->s_retry--;
 838
 839	ibp = to_iport(qp->ibqp.device, qp->port_num);
 840	if (wqe->wr.opcode == IB_WR_RDMA_READ)
 841		ibp->rvp.n_rc_resends++;
 842	else
 843		ibp->rvp.n_rc_resends += (qp->s_psn - psn) & QIB_PSN_MASK;
 844
 845	qp->s_flags &= ~(RVT_S_WAIT_FENCE | RVT_S_WAIT_RDMAR |
 846			 RVT_S_WAIT_SSN_CREDIT | RVT_S_WAIT_PSN |
 847			 RVT_S_WAIT_ACK);
 848	if (wait)
 849		qp->s_flags |= RVT_S_SEND_ONE;
 850	reset_psn(qp, psn);
 851}
 852
 853/*
 854 * Set qp->s_sending_psn to the next PSN after the given one.
 855 * This would be psn+1 except when RDMA reads are present.
 856 */
 857static void reset_sending_psn(struct rvt_qp *qp, u32 psn)
 858{
 859	struct rvt_swqe *wqe;
 860	u32 n = qp->s_last;
 861
 862	/* Find the work request corresponding to the given PSN. */
 863	for (;;) {
 864		wqe = rvt_get_swqe_ptr(qp, n);
 865		if (qib_cmp24(psn, wqe->lpsn) <= 0) {
 866			if (wqe->wr.opcode == IB_WR_RDMA_READ)
 867				qp->s_sending_psn = wqe->lpsn + 1;
 868			else
 869				qp->s_sending_psn = psn + 1;
 870			break;
 871		}
 872		if (++n == qp->s_size)
 873			n = 0;
 874		if (n == qp->s_tail)
 875			break;
 876	}
 877}
 878
 879/*
 880 * This should be called with the QP s_lock held and interrupts disabled.
 881 */
 882void qib_rc_send_complete(struct rvt_qp *qp, struct ib_header *hdr)
 883{
 884	struct ib_other_headers *ohdr;
 885	struct rvt_swqe *wqe;
 886	u32 opcode;
 887	u32 psn;
 888
 889	if (!(ib_rvt_state_ops[qp->state] & RVT_SEND_OR_FLUSH_OR_RECV_OK))
 890		return;
 891
 892	/* Find out where the BTH is */
 893	if ((be16_to_cpu(hdr->lrh[0]) & 3) == QIB_LRH_BTH)
 894		ohdr = &hdr->u.oth;
 895	else
 896		ohdr = &hdr->u.l.oth;
 897
 898	opcode = be32_to_cpu(ohdr->bth[0]) >> 24;
 899	if (opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
 900	    opcode <= OP(ATOMIC_ACKNOWLEDGE)) {
 901		WARN_ON(!qp->s_rdma_ack_cnt);
 902		qp->s_rdma_ack_cnt--;
 903		return;
 904	}
 905
 906	psn = be32_to_cpu(ohdr->bth[2]);
 907	reset_sending_psn(qp, psn);
 908
 909	/*
 910	 * Start timer after a packet requesting an ACK has been sent and
 911	 * there are still requests that haven't been acked.
 912	 */
 913	if ((psn & IB_BTH_REQ_ACK) && qp->s_acked != qp->s_tail &&
 914	    !(qp->s_flags & (RVT_S_TIMER | RVT_S_WAIT_RNR | RVT_S_WAIT_PSN)) &&
 915	    (ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK))
 916		rvt_add_retry_timer(qp);
 917
 918	while (qp->s_last != qp->s_acked) {
 919		wqe = rvt_get_swqe_ptr(qp, qp->s_last);
 920		if (qib_cmp24(wqe->lpsn, qp->s_sending_psn) >= 0 &&
 921		    qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) <= 0)
 922			break;
 923		rvt_qp_complete_swqe(qp,
 924				     wqe,
 925				     ib_qib_wc_opcode[wqe->wr.opcode],
 926				     IB_WC_SUCCESS);
 927	}
 928	/*
 929	 * If we were waiting for sends to complete before resending,
 930	 * and they are now complete, restart sending.
 931	 */
 932	if (qp->s_flags & RVT_S_WAIT_PSN &&
 933	    qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) > 0) {
 934		qp->s_flags &= ~RVT_S_WAIT_PSN;
 935		qp->s_sending_psn = qp->s_psn;
 936		qp->s_sending_hpsn = qp->s_psn - 1;
 937		qib_schedule_send(qp);
 938	}
 939}
 940
 941static inline void update_last_psn(struct rvt_qp *qp, u32 psn)
 942{
 943	qp->s_last_psn = psn;
 944}
 945
 946/*
 947 * Generate a SWQE completion.
 948 * This is similar to qib_send_complete but has to check to be sure
 949 * that the SGEs are not being referenced if the SWQE is being resent.
 950 */
 951static struct rvt_swqe *do_rc_completion(struct rvt_qp *qp,
 952					 struct rvt_swqe *wqe,
 953					 struct qib_ibport *ibp)
 954{
 955	/*
 956	 * Don't decrement refcount and don't generate a
 957	 * completion if the SWQE is being resent until the send
 958	 * is finished.
 959	 */
 960	if (qib_cmp24(wqe->lpsn, qp->s_sending_psn) < 0 ||
 961	    qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) > 0)
 962		rvt_qp_complete_swqe(qp,
 963				     wqe,
 964				     ib_qib_wc_opcode[wqe->wr.opcode],
 965				     IB_WC_SUCCESS);
 966	else
 967		this_cpu_inc(*ibp->rvp.rc_delayed_comp);
 968
 969	qp->s_retry = qp->s_retry_cnt;
 970	update_last_psn(qp, wqe->lpsn);
 971
 972	/*
 973	 * If we are completing a request which is in the process of
 974	 * being resent, we can stop resending it since we know the
 975	 * responder has already seen it.
 976	 */
 977	if (qp->s_acked == qp->s_cur) {
 978		if (++qp->s_cur >= qp->s_size)
 979			qp->s_cur = 0;
 980		qp->s_acked = qp->s_cur;
 981		wqe = rvt_get_swqe_ptr(qp, qp->s_cur);
 982		if (qp->s_acked != qp->s_tail) {
 983			qp->s_state = OP(SEND_LAST);
 984			qp->s_psn = wqe->psn;
 985		}
 986	} else {
 987		if (++qp->s_acked >= qp->s_size)
 988			qp->s_acked = 0;
 989		if (qp->state == IB_QPS_SQD && qp->s_acked == qp->s_cur)
 990			qp->s_draining = 0;
 991		wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
 992	}
 993	return wqe;
 994}
 995
 996/*
 997 * do_rc_ack - process an incoming RC ACK
 998 * @qp: the QP the ACK came in on
 999 * @psn: the packet sequence number of the ACK
1000 * @opcode: the opcode of the request that resulted in the ACK
1001 *
1002 * This is called from qib_rc_rcv_resp() to process an incoming RC ACK
1003 * for the given QP.
1004 * Called at interrupt level with the QP s_lock held.
1005 * Returns 1 if OK, 0 if current operation should be aborted (NAK).
1006 */
1007static int do_rc_ack(struct rvt_qp *qp, u32 aeth, u32 psn, int opcode,
1008		     u64 val, struct qib_ctxtdata *rcd)
1009{
1010	struct qib_ibport *ibp;
1011	enum ib_wc_status status;
1012	struct rvt_swqe *wqe;
1013	int ret = 0;
1014	u32 ack_psn;
1015	int diff;
1016
1017	/*
1018	 * Note that NAKs implicitly ACK outstanding SEND and RDMA write
1019	 * requests and implicitly NAK RDMA read and atomic requests issued
1020	 * before the NAK'ed request.  The MSN won't include the NAK'ed
1021	 * request but will include an ACK'ed request(s).
1022	 */
1023	ack_psn = psn;
1024	if (aeth >> IB_AETH_NAK_SHIFT)
1025		ack_psn--;
1026	wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
1027	ibp = to_iport(qp->ibqp.device, qp->port_num);
1028
1029	/*
1030	 * The MSN might be for a later WQE than the PSN indicates so
1031	 * only complete WQEs that the PSN finishes.
1032	 */
1033	while ((diff = qib_cmp24(ack_psn, wqe->lpsn)) >= 0) {
1034		/*
1035		 * RDMA_READ_RESPONSE_ONLY is a special case since
1036		 * we want to generate completion events for everything
1037		 * before the RDMA read, copy the data, then generate
1038		 * the completion for the read.
1039		 */
1040		if (wqe->wr.opcode == IB_WR_RDMA_READ &&
1041		    opcode == OP(RDMA_READ_RESPONSE_ONLY) &&
1042		    diff == 0) {
1043			ret = 1;
1044			goto bail;
1045		}
1046		/*
1047		 * If this request is a RDMA read or atomic, and the ACK is
1048		 * for a later operation, this ACK NAKs the RDMA read or
1049		 * atomic.  In other words, only a RDMA_READ_LAST or ONLY
1050		 * can ACK a RDMA read and likewise for atomic ops.  Note
1051		 * that the NAK case can only happen if relaxed ordering is
1052		 * used and requests are sent after an RDMA read or atomic
1053		 * is sent but before the response is received.
1054		 */
1055		if ((wqe->wr.opcode == IB_WR_RDMA_READ &&
1056		     (opcode != OP(RDMA_READ_RESPONSE_LAST) || diff != 0)) ||
1057		    ((wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1058		      wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) &&
1059		     (opcode != OP(ATOMIC_ACKNOWLEDGE) || diff != 0))) {
1060			/* Retry this request. */
1061			if (!(qp->r_flags & RVT_R_RDMAR_SEQ)) {
1062				qp->r_flags |= RVT_R_RDMAR_SEQ;
1063				qib_restart_rc(qp, qp->s_last_psn + 1, 0);
1064				if (list_empty(&qp->rspwait)) {
1065					qp->r_flags |= RVT_R_RSP_SEND;
1066					rvt_get_qp(qp);
1067					list_add_tail(&qp->rspwait,
1068						      &rcd->qp_wait_list);
1069				}
1070			}
1071			/*
1072			 * No need to process the ACK/NAK since we are
1073			 * restarting an earlier request.
1074			 */
1075			goto bail;
1076		}
1077		if (wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1078		    wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) {
1079			u64 *vaddr = wqe->sg_list[0].vaddr;
1080			*vaddr = val;
1081		}
1082		if (qp->s_num_rd_atomic &&
1083		    (wqe->wr.opcode == IB_WR_RDMA_READ ||
1084		     wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1085		     wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)) {
1086			qp->s_num_rd_atomic--;
1087			/* Restart sending task if fence is complete */
1088			if ((qp->s_flags & RVT_S_WAIT_FENCE) &&
1089			    !qp->s_num_rd_atomic) {
1090				qp->s_flags &= ~(RVT_S_WAIT_FENCE |
1091						 RVT_S_WAIT_ACK);
1092				qib_schedule_send(qp);
1093			} else if (qp->s_flags & RVT_S_WAIT_RDMAR) {
1094				qp->s_flags &= ~(RVT_S_WAIT_RDMAR |
1095						 RVT_S_WAIT_ACK);
1096				qib_schedule_send(qp);
1097			}
1098		}
1099		wqe = do_rc_completion(qp, wqe, ibp);
1100		if (qp->s_acked == qp->s_tail)
1101			break;
1102	}
1103
1104	switch (aeth >> IB_AETH_NAK_SHIFT) {
1105	case 0:         /* ACK */
1106		this_cpu_inc(*ibp->rvp.rc_acks);
1107		if (qp->s_acked != qp->s_tail) {
1108			/*
1109			 * We are expecting more ACKs so
1110			 * reset the retransmit timer.
1111			 */
1112			rvt_mod_retry_timer(qp);
1113			/*
1114			 * We can stop resending the earlier packets and
1115			 * continue with the next packet the receiver wants.
1116			 */
1117			if (qib_cmp24(qp->s_psn, psn) <= 0)
1118				reset_psn(qp, psn + 1);
1119		} else {
1120			/* No more acks - kill all timers */
1121			rvt_stop_rc_timers(qp);
1122			if (qib_cmp24(qp->s_psn, psn) <= 0) {
1123				qp->s_state = OP(SEND_LAST);
1124				qp->s_psn = psn + 1;
1125			}
1126		}
1127		if (qp->s_flags & RVT_S_WAIT_ACK) {
1128			qp->s_flags &= ~RVT_S_WAIT_ACK;
1129			qib_schedule_send(qp);
1130		}
1131		rvt_get_credit(qp, aeth);
1132		qp->s_rnr_retry = qp->s_rnr_retry_cnt;
1133		qp->s_retry = qp->s_retry_cnt;
1134		update_last_psn(qp, psn);
1135		return 1;
1136
1137	case 1:         /* RNR NAK */
1138		ibp->rvp.n_rnr_naks++;
1139		if (qp->s_acked == qp->s_tail)
1140			goto bail;
1141		if (qp->s_flags & RVT_S_WAIT_RNR)
1142			goto bail;
1143		if (qp->s_rnr_retry == 0) {
1144			status = IB_WC_RNR_RETRY_EXC_ERR;
1145			goto class_b;
1146		}
1147		if (qp->s_rnr_retry_cnt < 7)
1148			qp->s_rnr_retry--;
1149
1150		/* The last valid PSN is the previous PSN. */
1151		update_last_psn(qp, psn - 1);
1152
1153		ibp->rvp.n_rc_resends += (qp->s_psn - psn) & QIB_PSN_MASK;
1154
1155		reset_psn(qp, psn);
1156
1157		qp->s_flags &= ~(RVT_S_WAIT_SSN_CREDIT | RVT_S_WAIT_ACK);
1158		rvt_stop_rc_timers(qp);
1159		rvt_add_rnr_timer(qp, aeth);
1160		return 0;
1161
1162	case 3:         /* NAK */
1163		if (qp->s_acked == qp->s_tail)
1164			goto bail;
1165		/* The last valid PSN is the previous PSN. */
1166		update_last_psn(qp, psn - 1);
1167		switch ((aeth >> IB_AETH_CREDIT_SHIFT) &
1168			IB_AETH_CREDIT_MASK) {
1169		case 0: /* PSN sequence error */
1170			ibp->rvp.n_seq_naks++;
1171			/*
1172			 * Back up to the responder's expected PSN.
1173			 * Note that we might get a NAK in the middle of an
1174			 * RDMA READ response which terminates the RDMA
1175			 * READ.
1176			 */
1177			qib_restart_rc(qp, psn, 0);
1178			qib_schedule_send(qp);
1179			break;
1180
1181		case 1: /* Invalid Request */
1182			status = IB_WC_REM_INV_REQ_ERR;
1183			ibp->rvp.n_other_naks++;
1184			goto class_b;
1185
1186		case 2: /* Remote Access Error */
1187			status = IB_WC_REM_ACCESS_ERR;
1188			ibp->rvp.n_other_naks++;
1189			goto class_b;
1190
1191		case 3: /* Remote Operation Error */
1192			status = IB_WC_REM_OP_ERR;
1193			ibp->rvp.n_other_naks++;
1194class_b:
1195			if (qp->s_last == qp->s_acked) {
1196				rvt_send_complete(qp, wqe, status);
1197				rvt_error_qp(qp, IB_WC_WR_FLUSH_ERR);
1198			}
1199			break;
1200
1201		default:
1202			/* Ignore other reserved NAK error codes */
1203			goto reserved;
1204		}
1205		qp->s_retry = qp->s_retry_cnt;
1206		qp->s_rnr_retry = qp->s_rnr_retry_cnt;
1207		goto bail;
1208
1209	default:                /* 2: reserved */
1210reserved:
1211		/* Ignore reserved NAK codes. */
1212		goto bail;
1213	}
1214
1215bail:
1216	rvt_stop_rc_timers(qp);
1217	return ret;
1218}
1219
1220/*
1221 * We have seen an out of sequence RDMA read middle or last packet.
1222 * This ACKs SENDs and RDMA writes up to the first RDMA read or atomic SWQE.
1223 */
1224static void rdma_seq_err(struct rvt_qp *qp, struct qib_ibport *ibp, u32 psn,
1225			 struct qib_ctxtdata *rcd)
1226{
1227	struct rvt_swqe *wqe;
1228
1229	/* Remove QP from retry timer */
1230	rvt_stop_rc_timers(qp);
1231
1232	wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
1233
1234	while (qib_cmp24(psn, wqe->lpsn) > 0) {
1235		if (wqe->wr.opcode == IB_WR_RDMA_READ ||
1236		    wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
1237		    wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)
1238			break;
1239		wqe = do_rc_completion(qp, wqe, ibp);
1240	}
1241
1242	ibp->rvp.n_rdma_seq++;
1243	qp->r_flags |= RVT_R_RDMAR_SEQ;
1244	qib_restart_rc(qp, qp->s_last_psn + 1, 0);
1245	if (list_empty(&qp->rspwait)) {
1246		qp->r_flags |= RVT_R_RSP_SEND;
1247		rvt_get_qp(qp);
1248		list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
1249	}
1250}
1251
1252/**
1253 * qib_rc_rcv_resp - process an incoming RC response packet
1254 * @ibp: the port this packet came in on
1255 * @ohdr: the other headers for this packet
1256 * @data: the packet data
1257 * @tlen: the packet length
1258 * @qp: the QP for this packet
1259 * @opcode: the opcode for this packet
1260 * @psn: the packet sequence number for this packet
1261 * @hdrsize: the header length
1262 * @pmtu: the path MTU
1263 * @rcd: the context pointer
1264 *
1265 * This is called from qib_rc_rcv() to process an incoming RC response
1266 * packet for the given QP.
1267 * Called at interrupt level.
1268 */
1269static void qib_rc_rcv_resp(struct qib_ibport *ibp,
1270			    struct ib_other_headers *ohdr,
1271			    void *data, u32 tlen,
1272			    struct rvt_qp *qp,
1273			    u32 opcode,
1274			    u32 psn, u32 hdrsize, u32 pmtu,
1275			    struct qib_ctxtdata *rcd)
1276{
1277	struct rvt_swqe *wqe;
1278	struct qib_pportdata *ppd = ppd_from_ibp(ibp);
1279	enum ib_wc_status status;
1280	unsigned long flags;
1281	int diff;
1282	u32 pad;
1283	u32 aeth;
1284	u64 val;
1285
1286	if (opcode != OP(RDMA_READ_RESPONSE_MIDDLE)) {
1287		/*
1288		 * If ACK'd PSN on SDMA busy list try to make progress to
1289		 * reclaim SDMA credits.
1290		 */
1291		if ((qib_cmp24(psn, qp->s_sending_psn) >= 0) &&
1292		    (qib_cmp24(qp->s_sending_psn, qp->s_sending_hpsn) <= 0)) {
1293
1294			/*
1295			 * If send tasklet not running attempt to progress
1296			 * SDMA queue.
1297			 */
1298			if (!(qp->s_flags & RVT_S_BUSY)) {
1299				/* Acquire SDMA Lock */
1300				spin_lock_irqsave(&ppd->sdma_lock, flags);
1301				/* Invoke sdma make progress */
1302				qib_sdma_make_progress(ppd);
1303				/* Release SDMA Lock */
1304				spin_unlock_irqrestore(&ppd->sdma_lock, flags);
1305			}
1306		}
1307	}
1308
1309	spin_lock_irqsave(&qp->s_lock, flags);
1310	if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK))
1311		goto ack_done;
1312
1313	/* Ignore invalid responses. */
1314	if (qib_cmp24(psn, READ_ONCE(qp->s_next_psn)) >= 0)
1315		goto ack_done;
1316
1317	/* Ignore duplicate responses. */
1318	diff = qib_cmp24(psn, qp->s_last_psn);
1319	if (unlikely(diff <= 0)) {
1320		/* Update credits for "ghost" ACKs */
1321		if (diff == 0 && opcode == OP(ACKNOWLEDGE)) {
1322			aeth = be32_to_cpu(ohdr->u.aeth);
1323			if ((aeth >> IB_AETH_NAK_SHIFT) == 0)
1324				rvt_get_credit(qp, aeth);
1325		}
1326		goto ack_done;
1327	}
1328
1329	/*
1330	 * Skip everything other than the PSN we expect, if we are waiting
1331	 * for a reply to a restarted RDMA read or atomic op.
1332	 */
1333	if (qp->r_flags & RVT_R_RDMAR_SEQ) {
1334		if (qib_cmp24(psn, qp->s_last_psn + 1) != 0)
1335			goto ack_done;
1336		qp->r_flags &= ~RVT_R_RDMAR_SEQ;
1337	}
1338
1339	if (unlikely(qp->s_acked == qp->s_tail))
1340		goto ack_done;
1341	wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
1342	status = IB_WC_SUCCESS;
1343
1344	switch (opcode) {
1345	case OP(ACKNOWLEDGE):
1346	case OP(ATOMIC_ACKNOWLEDGE):
1347	case OP(RDMA_READ_RESPONSE_FIRST):
1348		aeth = be32_to_cpu(ohdr->u.aeth);
1349		if (opcode == OP(ATOMIC_ACKNOWLEDGE))
1350			val = ib_u64_get(&ohdr->u.at.atomic_ack_eth);
1351		else
1352			val = 0;
1353		if (!do_rc_ack(qp, aeth, psn, opcode, val, rcd) ||
1354		    opcode != OP(RDMA_READ_RESPONSE_FIRST))
1355			goto ack_done;
1356		hdrsize += 4;
1357		wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
1358		if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1359			goto ack_op_err;
1360		/*
1361		 * If this is a response to a resent RDMA read, we
1362		 * have to be careful to copy the data to the right
1363		 * location.
1364		 */
1365		qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
1366						  wqe, psn, pmtu);
1367		goto read_middle;
1368
1369	case OP(RDMA_READ_RESPONSE_MIDDLE):
1370		/* no AETH, no ACK */
1371		if (unlikely(qib_cmp24(psn, qp->s_last_psn + 1)))
1372			goto ack_seq_err;
1373		if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1374			goto ack_op_err;
1375read_middle:
1376		if (unlikely(tlen != (hdrsize + pmtu + 4)))
1377			goto ack_len_err;
1378		if (unlikely(pmtu >= qp->s_rdma_read_len))
1379			goto ack_len_err;
1380
1381		/*
1382		 * We got a response so update the timeout.
1383		 * 4.096 usec. * (1 << qp->timeout)
1384		 */
1385		rvt_mod_retry_timer(qp);
1386		if (qp->s_flags & RVT_S_WAIT_ACK) {
1387			qp->s_flags &= ~RVT_S_WAIT_ACK;
1388			qib_schedule_send(qp);
1389		}
1390
1391		if (opcode == OP(RDMA_READ_RESPONSE_MIDDLE))
1392			qp->s_retry = qp->s_retry_cnt;
1393
1394		/*
1395		 * Update the RDMA receive state but do the copy w/o
1396		 * holding the locks and blocking interrupts.
1397		 */
1398		qp->s_rdma_read_len -= pmtu;
1399		update_last_psn(qp, psn);
1400		spin_unlock_irqrestore(&qp->s_lock, flags);
1401		rvt_copy_sge(qp, &qp->s_rdma_read_sge,
1402			     data, pmtu, false, false);
1403		goto bail;
1404
1405	case OP(RDMA_READ_RESPONSE_ONLY):
1406		aeth = be32_to_cpu(ohdr->u.aeth);
1407		if (!do_rc_ack(qp, aeth, psn, opcode, 0, rcd))
1408			goto ack_done;
1409		/* Get the number of bytes the message was padded by. */
1410		pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1411		/*
1412		 * Check that the data size is >= 0 && <= pmtu.
1413		 * Remember to account for the AETH header (4) and
1414		 * ICRC (4).
1415		 */
1416		if (unlikely(tlen < (hdrsize + pad + 8)))
1417			goto ack_len_err;
1418		/*
1419		 * If this is a response to a resent RDMA read, we
1420		 * have to be careful to copy the data to the right
1421		 * location.
1422		 */
1423		wqe = rvt_get_swqe_ptr(qp, qp->s_acked);
1424		qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
1425						  wqe, psn, pmtu);
1426		goto read_last;
1427
1428	case OP(RDMA_READ_RESPONSE_LAST):
1429		/* ACKs READ req. */
1430		if (unlikely(qib_cmp24(psn, qp->s_last_psn + 1)))
1431			goto ack_seq_err;
1432		if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
1433			goto ack_op_err;
1434		/* Get the number of bytes the message was padded by. */
1435		pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1436		/*
1437		 * Check that the data size is >= 1 && <= pmtu.
1438		 * Remember to account for the AETH header (4) and
1439		 * ICRC (4).
1440		 */
1441		if (unlikely(tlen <= (hdrsize + pad + 8)))
1442			goto ack_len_err;
1443read_last:
1444		tlen -= hdrsize + pad + 8;
1445		if (unlikely(tlen != qp->s_rdma_read_len))
1446			goto ack_len_err;
1447		aeth = be32_to_cpu(ohdr->u.aeth);
1448		rvt_copy_sge(qp, &qp->s_rdma_read_sge,
1449			     data, tlen, false, false);
1450		WARN_ON(qp->s_rdma_read_sge.num_sge);
1451		(void) do_rc_ack(qp, aeth, psn,
1452				 OP(RDMA_READ_RESPONSE_LAST), 0, rcd);
1453		goto ack_done;
1454	}
1455
1456ack_op_err:
1457	status = IB_WC_LOC_QP_OP_ERR;
1458	goto ack_err;
1459
1460ack_seq_err:
1461	rdma_seq_err(qp, ibp, psn, rcd);
1462	goto ack_done;
1463
1464ack_len_err:
1465	status = IB_WC_LOC_LEN_ERR;
1466ack_err:
1467	if (qp->s_last == qp->s_acked) {
1468		rvt_send_complete(qp, wqe, status);
1469		rvt_error_qp(qp, IB_WC_WR_FLUSH_ERR);
1470	}
1471ack_done:
1472	spin_unlock_irqrestore(&qp->s_lock, flags);
1473bail:
1474	return;
1475}
1476
1477/**
1478 * qib_rc_rcv_error - process an incoming duplicate or error RC packet
1479 * @ohdr: the other headers for this packet
1480 * @data: the packet data
1481 * @qp: the QP for this packet
1482 * @opcode: the opcode for this packet
1483 * @psn: the packet sequence number for this packet
1484 * @diff: the difference between the PSN and the expected PSN
1485 * @rcd: the context pointer
1486 *
1487 * This is called from qib_rc_rcv() to process an unexpected
1488 * incoming RC packet for the given QP.
1489 * Called at interrupt level.
1490 * Return 1 if no more processing is needed; otherwise return 0 to
1491 * schedule a response to be sent.
1492 */
1493static int qib_rc_rcv_error(struct ib_other_headers *ohdr,
1494			    void *data,
1495			    struct rvt_qp *qp,
1496			    u32 opcode,
1497			    u32 psn,
1498			    int diff,
1499			    struct qib_ctxtdata *rcd)
1500{
1501	struct qib_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
1502	struct rvt_ack_entry *e;
1503	unsigned long flags;
1504	u8 i, prev;
1505	int old_req;
1506
1507	if (diff > 0) {
1508		/*
1509		 * Packet sequence error.
1510		 * A NAK will ACK earlier sends and RDMA writes.
1511		 * Don't queue the NAK if we already sent one.
1512		 */
1513		if (!qp->r_nak_state) {
1514			ibp->rvp.n_rc_seqnak++;
1515			qp->r_nak_state = IB_NAK_PSN_ERROR;
1516			/* Use the expected PSN. */
1517			qp->r_ack_psn = qp->r_psn;
1518			/*
1519			 * Wait to send the sequence NAK until all packets
1520			 * in the receive queue have been processed.
1521			 * Otherwise, we end up propagating congestion.
1522			 */
1523			if (list_empty(&qp->rspwait)) {
1524				qp->r_flags |= RVT_R_RSP_NAK;
1525				rvt_get_qp(qp);
1526				list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
1527			}
1528		}
1529		goto done;
1530	}
1531
1532	/*
1533	 * Handle a duplicate request.  Don't re-execute SEND, RDMA
1534	 * write or atomic op.  Don't NAK errors, just silently drop
1535	 * the duplicate request.  Note that r_sge, r_len, and
1536	 * r_rcv_len may be in use so don't modify them.
1537	 *
1538	 * We are supposed to ACK the earliest duplicate PSN but we
1539	 * can coalesce an outstanding duplicate ACK.  We have to
1540	 * send the earliest so that RDMA reads can be restarted at
1541	 * the requester's expected PSN.
1542	 *
1543	 * First, find where this duplicate PSN falls within the
1544	 * ACKs previously sent.
1545	 * old_req is true if there is an older response that is scheduled
1546	 * to be sent before sending this one.
1547	 */
1548	e = NULL;
1549	old_req = 1;
1550	ibp->rvp.n_rc_dupreq++;
1551
1552	spin_lock_irqsave(&qp->s_lock, flags);
1553
1554	for (i = qp->r_head_ack_queue; ; i = prev) {
1555		if (i == qp->s_tail_ack_queue)
1556			old_req = 0;
1557		if (i)
1558			prev = i - 1;
1559		else
1560			prev = QIB_MAX_RDMA_ATOMIC;
1561		if (prev == qp->r_head_ack_queue) {
1562			e = NULL;
1563			break;
1564		}
1565		e = &qp->s_ack_queue[prev];
1566		if (!e->opcode) {
1567			e = NULL;
1568			break;
1569		}
1570		if (qib_cmp24(psn, e->psn) >= 0) {
1571			if (prev == qp->s_tail_ack_queue &&
1572			    qib_cmp24(psn, e->lpsn) <= 0)
1573				old_req = 0;
1574			break;
1575		}
1576	}
1577	switch (opcode) {
1578	case OP(RDMA_READ_REQUEST): {
1579		struct ib_reth *reth;
1580		u32 offset;
1581		u32 len;
1582
1583		/*
1584		 * If we didn't find the RDMA read request in the ack queue,
1585		 * we can ignore this request.
1586		 */
1587		if (!e || e->opcode != OP(RDMA_READ_REQUEST))
1588			goto unlock_done;
1589		/* RETH comes after BTH */
1590		reth = &ohdr->u.rc.reth;
1591		/*
1592		 * Address range must be a subset of the original
1593		 * request and start on pmtu boundaries.
1594		 * We reuse the old ack_queue slot since the requester
1595		 * should not back up and request an earlier PSN for the
1596		 * same request.
1597		 */
1598		offset = ((psn - e->psn) & QIB_PSN_MASK) *
1599			qp->pmtu;
1600		len = be32_to_cpu(reth->length);
1601		if (unlikely(offset + len != e->rdma_sge.sge_length))
1602			goto unlock_done;
1603		if (e->rdma_sge.mr) {
1604			rvt_put_mr(e->rdma_sge.mr);
1605			e->rdma_sge.mr = NULL;
1606		}
1607		if (len != 0) {
1608			u32 rkey = be32_to_cpu(reth->rkey);
1609			u64 vaddr = be64_to_cpu(reth->vaddr);
1610			int ok;
1611
1612			ok = rvt_rkey_ok(qp, &e->rdma_sge, len, vaddr, rkey,
1613					 IB_ACCESS_REMOTE_READ);
1614			if (unlikely(!ok))
1615				goto unlock_done;
1616		} else {
1617			e->rdma_sge.vaddr = NULL;
1618			e->rdma_sge.length = 0;
1619			e->rdma_sge.sge_length = 0;
1620		}
1621		e->psn = psn;
1622		if (old_req)
1623			goto unlock_done;
1624		qp->s_tail_ack_queue = prev;
1625		break;
1626	}
1627
1628	case OP(COMPARE_SWAP):
1629	case OP(FETCH_ADD): {
1630		/*
1631		 * If we didn't find the atomic request in the ack queue
1632		 * or the send tasklet is already backed up to send an
1633		 * earlier entry, we can ignore this request.
1634		 */
1635		if (!e || e->opcode != (u8) opcode || old_req)
1636			goto unlock_done;
1637		qp->s_tail_ack_queue = prev;
1638		break;
1639	}
1640
1641	default:
1642		/*
1643		 * Ignore this operation if it doesn't request an ACK
1644		 * or an earlier RDMA read or atomic is going to be resent.
1645		 */
1646		if (!(psn & IB_BTH_REQ_ACK) || old_req)
1647			goto unlock_done;
1648		/*
1649		 * Resend the most recent ACK if this request is
1650		 * after all the previous RDMA reads and atomics.
1651		 */
1652		if (i == qp->r_head_ack_queue) {
1653			spin_unlock_irqrestore(&qp->s_lock, flags);
1654			qp->r_nak_state = 0;
1655			qp->r_ack_psn = qp->r_psn - 1;
1656			goto send_ack;
1657		}
1658		/*
1659		 * Try to send a simple ACK to work around a Mellanox bug
1660		 * which doesn't accept a RDMA read response or atomic
1661		 * response as an ACK for earlier SENDs or RDMA writes.
1662		 */
1663		if (!(qp->s_flags & RVT_S_RESP_PENDING)) {
1664			spin_unlock_irqrestore(&qp->s_lock, flags);
1665			qp->r_nak_state = 0;
1666			qp->r_ack_psn = qp->s_ack_queue[i].psn - 1;
1667			goto send_ack;
1668		}
1669		/*
1670		 * Resend the RDMA read or atomic op which
1671		 * ACKs this duplicate request.
1672		 */
1673		qp->s_tail_ack_queue = i;
1674		break;
1675	}
1676	qp->s_ack_state = OP(ACKNOWLEDGE);
1677	qp->s_flags |= RVT_S_RESP_PENDING;
1678	qp->r_nak_state = 0;
1679	qib_schedule_send(qp);
1680
1681unlock_done:
1682	spin_unlock_irqrestore(&qp->s_lock, flags);
1683done:
1684	return 1;
1685
1686send_ack:
1687	return 0;
1688}
1689
1690static inline void qib_update_ack_queue(struct rvt_qp *qp, unsigned n)
1691{
1692	unsigned next;
1693
1694	next = n + 1;
1695	if (next > QIB_MAX_RDMA_ATOMIC)
1696		next = 0;
1697	qp->s_tail_ack_queue = next;
1698	qp->s_ack_state = OP(ACKNOWLEDGE);
1699}
1700
1701/**
1702 * qib_rc_rcv - process an incoming RC packet
1703 * @rcd: the context pointer
1704 * @hdr: the header of this packet
1705 * @has_grh: true if the header has a GRH
1706 * @data: the packet data
1707 * @tlen: the packet length
1708 * @qp: the QP for this packet
1709 *
1710 * This is called from qib_qp_rcv() to process an incoming RC packet
1711 * for the given QP.
1712 * Called at interrupt level.
1713 */
1714void qib_rc_rcv(struct qib_ctxtdata *rcd, struct ib_header *hdr,
1715		int has_grh, void *data, u32 tlen, struct rvt_qp *qp)
1716{
1717	struct qib_ibport *ibp = &rcd->ppd->ibport_data;
1718	struct ib_other_headers *ohdr;
1719	u32 opcode;
1720	u32 hdrsize;
1721	u32 psn;
1722	u32 pad;
1723	struct ib_wc wc;
1724	u32 pmtu = qp->pmtu;
1725	int diff;
1726	struct ib_reth *reth;
1727	unsigned long flags;
1728	int ret;
1729
1730	/* Check for GRH */
1731	if (!has_grh) {
1732		ohdr = &hdr->u.oth;
1733		hdrsize = 8 + 12;       /* LRH + BTH */
1734	} else {
1735		ohdr = &hdr->u.l.oth;
1736		hdrsize = 8 + 40 + 12;  /* LRH + GRH + BTH */
1737	}
1738
1739	opcode = be32_to_cpu(ohdr->bth[0]);
1740	if (qib_ruc_check_hdr(ibp, hdr, has_grh, qp, opcode))
1741		return;
1742
1743	psn = be32_to_cpu(ohdr->bth[2]);
1744	opcode >>= 24;
1745
1746	/*
1747	 * Process responses (ACKs) before anything else.  Note that the
1748	 * packet sequence number will be for something in the send work
1749	 * queue rather than the expected receive packet sequence number.
1750	 * In other words, this QP is the requester.
1751	 */
1752	if (opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
1753	    opcode <= OP(ATOMIC_ACKNOWLEDGE)) {
1754		qib_rc_rcv_resp(ibp, ohdr, data, tlen, qp, opcode, psn,
1755				hdrsize, pmtu, rcd);
1756		return;
1757	}
1758
1759	/* Compute 24 bits worth of difference. */
1760	diff = qib_cmp24(psn, qp->r_psn);
1761	if (unlikely(diff)) {
1762		if (qib_rc_rcv_error(ohdr, data, qp, opcode, psn, diff, rcd))
1763			return;
1764		goto send_ack;
1765	}
1766
1767	/* Check for opcode sequence errors. */
1768	switch (qp->r_state) {
1769	case OP(SEND_FIRST):
1770	case OP(SEND_MIDDLE):
1771		if (opcode == OP(SEND_MIDDLE) ||
1772		    opcode == OP(SEND_LAST) ||
1773		    opcode == OP(SEND_LAST_WITH_IMMEDIATE))
1774			break;
1775		goto nack_inv;
1776
1777	case OP(RDMA_WRITE_FIRST):
1778	case OP(RDMA_WRITE_MIDDLE):
1779		if (opcode == OP(RDMA_WRITE_MIDDLE) ||
1780		    opcode == OP(RDMA_WRITE_LAST) ||
1781		    opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
1782			break;
1783		goto nack_inv;
1784
1785	default:
1786		if (opcode == OP(SEND_MIDDLE) ||
1787		    opcode == OP(SEND_LAST) ||
1788		    opcode == OP(SEND_LAST_WITH_IMMEDIATE) ||
1789		    opcode == OP(RDMA_WRITE_MIDDLE) ||
1790		    opcode == OP(RDMA_WRITE_LAST) ||
1791		    opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
1792			goto nack_inv;
1793		/*
1794		 * Note that it is up to the requester to not send a new
1795		 * RDMA read or atomic operation before receiving an ACK
1796		 * for the previous operation.
1797		 */
1798		break;
1799	}
1800
1801	if (qp->state == IB_QPS_RTR && !(qp->r_flags & RVT_R_COMM_EST))
1802		rvt_comm_est(qp);
1803
1804	/* OK, process the packet. */
1805	switch (opcode) {
1806	case OP(SEND_FIRST):
1807		ret = rvt_get_rwqe(qp, false);
1808		if (ret < 0)
1809			goto nack_op_err;
1810		if (!ret)
1811			goto rnr_nak;
1812		qp->r_rcv_len = 0;
1813		fallthrough;
1814	case OP(SEND_MIDDLE):
1815	case OP(RDMA_WRITE_MIDDLE):
1816send_middle:
1817		/* Check for invalid length PMTU or posted rwqe len. */
1818		if (unlikely(tlen != (hdrsize + pmtu + 4)))
1819			goto nack_inv;
1820		qp->r_rcv_len += pmtu;
1821		if (unlikely(qp->r_rcv_len > qp->r_len))
1822			goto nack_inv;
1823		rvt_copy_sge(qp, &qp->r_sge, data, pmtu, true, false);
1824		break;
1825
1826	case OP(RDMA_WRITE_LAST_WITH_IMMEDIATE):
1827		/* consume RWQE */
1828		ret = rvt_get_rwqe(qp, true);
1829		if (ret < 0)
1830			goto nack_op_err;
1831		if (!ret)
1832			goto rnr_nak;
1833		goto send_last_imm;
1834
1835	case OP(SEND_ONLY):
1836	case OP(SEND_ONLY_WITH_IMMEDIATE):
1837		ret = rvt_get_rwqe(qp, false);
1838		if (ret < 0)
1839			goto nack_op_err;
1840		if (!ret)
1841			goto rnr_nak;
1842		qp->r_rcv_len = 0;
1843		if (opcode == OP(SEND_ONLY))
1844			goto no_immediate_data;
1845		fallthrough;	/* for SEND_ONLY_WITH_IMMEDIATE */
1846	case OP(SEND_LAST_WITH_IMMEDIATE):
1847send_last_imm:
1848		wc.ex.imm_data = ohdr->u.imm_data;
1849		hdrsize += 4;
1850		wc.wc_flags = IB_WC_WITH_IMM;
1851		goto send_last;
1852	case OP(SEND_LAST):
1853	case OP(RDMA_WRITE_LAST):
1854no_immediate_data:
1855		wc.wc_flags = 0;
1856		wc.ex.imm_data = 0;
1857send_last:
1858		/* Get the number of bytes the message was padded by. */
1859		pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
1860		/* Check for invalid length. */
1861		/* XXX LAST len should be >= 1 */
1862		if (unlikely(tlen < (hdrsize + pad + 4)))
1863			goto nack_inv;
1864		/* Don't count the CRC. */
1865		tlen -= (hdrsize + pad + 4);
1866		wc.byte_len = tlen + qp->r_rcv_len;
1867		if (unlikely(wc.byte_len > qp->r_len))
1868			goto nack_inv;
1869		rvt_copy_sge(qp, &qp->r_sge, data, tlen, true, false);
1870		rvt_put_ss(&qp->r_sge);
1871		qp->r_msn++;
1872		if (!test_and_clear_bit(RVT_R_WRID_VALID, &qp->r_aflags))
1873			break;
1874		wc.wr_id = qp->r_wr_id;
1875		wc.status = IB_WC_SUCCESS;
1876		if (opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE) ||
1877		    opcode == OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE))
1878			wc.opcode = IB_WC_RECV_RDMA_WITH_IMM;
1879		else
1880			wc.opcode = IB_WC_RECV;
1881		wc.qp = &qp->ibqp;
1882		wc.src_qp = qp->remote_qpn;
1883		wc.slid = rdma_ah_get_dlid(&qp->remote_ah_attr);
1884		wc.sl = rdma_ah_get_sl(&qp->remote_ah_attr);
1885		/* zero fields that are N/A */
1886		wc.vendor_err = 0;
1887		wc.pkey_index = 0;
1888		wc.dlid_path_bits = 0;
1889		wc.port_num = 0;
1890		/* Signal completion event if the solicited bit is set. */
1891		rvt_recv_cq(qp, &wc, ib_bth_is_solicited(ohdr));
1892		break;
1893
1894	case OP(RDMA_WRITE_FIRST):
1895	case OP(RDMA_WRITE_ONLY):
1896	case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE):
1897		if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_WRITE)))
1898			goto nack_inv;
1899		/* consume RWQE */
1900		reth = &ohdr->u.rc.reth;
1901		hdrsize += sizeof(*reth);
1902		qp->r_len = be32_to_cpu(reth->length);
1903		qp->r_rcv_len = 0;
1904		qp->r_sge.sg_list = NULL;
1905		if (qp->r_len != 0) {
1906			u32 rkey = be32_to_cpu(reth->rkey);
1907			u64 vaddr = be64_to_cpu(reth->vaddr);
1908			int ok;
1909
1910			/* Check rkey & NAK */
1911			ok = rvt_rkey_ok(qp, &qp->r_sge.sge, qp->r_len, vaddr,
1912					 rkey, IB_ACCESS_REMOTE_WRITE);
1913			if (unlikely(!ok))
1914				goto nack_acc;
1915			qp->r_sge.num_sge = 1;
1916		} else {
1917			qp->r_sge.num_sge = 0;
1918			qp->r_sge.sge.mr = NULL;
1919			qp->r_sge.sge.vaddr = NULL;
1920			qp->r_sge.sge.length = 0;
1921			qp->r_sge.sge.sge_length = 0;
1922		}
1923		if (opcode == OP(RDMA_WRITE_FIRST))
1924			goto send_middle;
1925		else if (opcode == OP(RDMA_WRITE_ONLY))
1926			goto no_immediate_data;
1927		ret = rvt_get_rwqe(qp, true);
1928		if (ret < 0)
1929			goto nack_op_err;
1930		if (!ret) {
1931			rvt_put_ss(&qp->r_sge);
1932			goto rnr_nak;
1933		}
1934		wc.ex.imm_data = ohdr->u.rc.imm_data;
1935		hdrsize += 4;
1936		wc.wc_flags = IB_WC_WITH_IMM;
1937		goto send_last;
1938
1939	case OP(RDMA_READ_REQUEST): {
1940		struct rvt_ack_entry *e;
1941		u32 len;
1942		u8 next;
1943
1944		if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_READ)))
1945			goto nack_inv;
1946		next = qp->r_head_ack_queue + 1;
1947		/* s_ack_queue is size QIB_MAX_RDMA_ATOMIC+1 so use > not >= */
1948		if (next > QIB_MAX_RDMA_ATOMIC)
1949			next = 0;
1950		spin_lock_irqsave(&qp->s_lock, flags);
1951		if (unlikely(next == qp->s_tail_ack_queue)) {
1952			if (!qp->s_ack_queue[next].sent)
1953				goto nack_inv_unlck;
1954			qib_update_ack_queue(qp, next);
1955		}
1956		e = &qp->s_ack_queue[qp->r_head_ack_queue];
1957		if (e->opcode == OP(RDMA_READ_REQUEST) && e->rdma_sge.mr) {
1958			rvt_put_mr(e->rdma_sge.mr);
1959			e->rdma_sge.mr = NULL;
1960		}
1961		reth = &ohdr->u.rc.reth;
1962		len = be32_to_cpu(reth->length);
1963		if (len) {
1964			u32 rkey = be32_to_cpu(reth->rkey);
1965			u64 vaddr = be64_to_cpu(reth->vaddr);
1966			int ok;
1967
1968			/* Check rkey & NAK */
1969			ok = rvt_rkey_ok(qp, &e->rdma_sge, len, vaddr,
1970					 rkey, IB_ACCESS_REMOTE_READ);
1971			if (unlikely(!ok))
1972				goto nack_acc_unlck;
1973			/*
1974			 * Update the next expected PSN.  We add 1 later
1975			 * below, so only add the remainder here.
1976			 */
1977			qp->r_psn += rvt_div_mtu(qp, len - 1);
1978		} else {
1979			e->rdma_sge.mr = NULL;
1980			e->rdma_sge.vaddr = NULL;
1981			e->rdma_sge.length = 0;
1982			e->rdma_sge.sge_length = 0;
1983		}
1984		e->opcode = opcode;
1985		e->sent = 0;
1986		e->psn = psn;
1987		e->lpsn = qp->r_psn;
1988		/*
1989		 * We need to increment the MSN here instead of when we
1990		 * finish sending the result since a duplicate request would
1991		 * increment it more than once.
1992		 */
1993		qp->r_msn++;
1994		qp->r_psn++;
1995		qp->r_state = opcode;
1996		qp->r_nak_state = 0;
1997		qp->r_head_ack_queue = next;
1998
1999		/* Schedule the send tasklet. */
2000		qp->s_flags |= RVT_S_RESP_PENDING;
2001		qib_schedule_send(qp);
2002
2003		goto sunlock;
2004	}
2005
2006	case OP(COMPARE_SWAP):
2007	case OP(FETCH_ADD): {
2008		struct ib_atomic_eth *ateth;
2009		struct rvt_ack_entry *e;
2010		u64 vaddr;
2011		atomic64_t *maddr;
2012		u64 sdata;
2013		u32 rkey;
2014		u8 next;
2015
2016		if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_ATOMIC)))
2017			goto nack_inv;
2018		next = qp->r_head_ack_queue + 1;
2019		if (next > QIB_MAX_RDMA_ATOMIC)
2020			next = 0;
2021		spin_lock_irqsave(&qp->s_lock, flags);
2022		if (unlikely(next == qp->s_tail_ack_queue)) {
2023			if (!qp->s_ack_queue[next].sent)
2024				goto nack_inv_unlck;
2025			qib_update_ack_queue(qp, next);
2026		}
2027		e = &qp->s_ack_queue[qp->r_head_ack_queue];
2028		if (e->opcode == OP(RDMA_READ_REQUEST) && e->rdma_sge.mr) {
2029			rvt_put_mr(e->rdma_sge.mr);
2030			e->rdma_sge.mr = NULL;
2031		}
2032		ateth = &ohdr->u.atomic_eth;
2033		vaddr = get_ib_ateth_vaddr(ateth);
2034		if (unlikely(vaddr & (sizeof(u64) - 1)))
2035			goto nack_inv_unlck;
2036		rkey = be32_to_cpu(ateth->rkey);
2037		/* Check rkey & NAK */
2038		if (unlikely(!rvt_rkey_ok(qp, &qp->r_sge.sge, sizeof(u64),
2039					  vaddr, rkey,
2040					  IB_ACCESS_REMOTE_ATOMIC)))
2041			goto nack_acc_unlck;
2042		/* Perform atomic OP and save result. */
2043		maddr = (atomic64_t *) qp->r_sge.sge.vaddr;
2044		sdata = get_ib_ateth_swap(ateth);
2045		e->atomic_data = (opcode == OP(FETCH_ADD)) ?
2046			(u64) atomic64_add_return(sdata, maddr) - sdata :
2047			(u64) cmpxchg((u64 *) qp->r_sge.sge.vaddr,
2048				      get_ib_ateth_compare(ateth),
2049				      sdata);
2050		rvt_put_mr(qp->r_sge.sge.mr);
2051		qp->r_sge.num_sge = 0;
2052		e->opcode = opcode;
2053		e->sent = 0;
2054		e->psn = psn;
2055		e->lpsn = psn;
2056		qp->r_msn++;
2057		qp->r_psn++;
2058		qp->r_state = opcode;
2059		qp->r_nak_state = 0;
2060		qp->r_head_ack_queue = next;
2061
2062		/* Schedule the send tasklet. */
2063		qp->s_flags |= RVT_S_RESP_PENDING;
2064		qib_schedule_send(qp);
2065
2066		goto sunlock;
2067	}
2068
2069	default:
2070		/* NAK unknown opcodes. */
2071		goto nack_inv;
2072	}
2073	qp->r_psn++;
2074	qp->r_state = opcode;
2075	qp->r_ack_psn = psn;
2076	qp->r_nak_state = 0;
2077	/* Send an ACK if requested or required. */
2078	if (psn & (1 << 31))
2079		goto send_ack;
2080	return;
2081
2082rnr_nak:
2083	qp->r_nak_state = IB_RNR_NAK | qp->r_min_rnr_timer;
2084	qp->r_ack_psn = qp->r_psn;
2085	/* Queue RNR NAK for later */
2086	if (list_empty(&qp->rspwait)) {
2087		qp->r_flags |= RVT_R_RSP_NAK;
2088		rvt_get_qp(qp);
2089		list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
2090	}
2091	return;
2092
2093nack_op_err:
2094	rvt_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
2095	qp->r_nak_state = IB_NAK_REMOTE_OPERATIONAL_ERROR;
2096	qp->r_ack_psn = qp->r_psn;
2097	/* Queue NAK for later */
2098	if (list_empty(&qp->rspwait)) {
2099		qp->r_flags |= RVT_R_RSP_NAK;
2100		rvt_get_qp(qp);
2101		list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
2102	}
2103	return;
2104
2105nack_inv_unlck:
2106	spin_unlock_irqrestore(&qp->s_lock, flags);
2107nack_inv:
2108	rvt_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
2109	qp->r_nak_state = IB_NAK_INVALID_REQUEST;
2110	qp->r_ack_psn = qp->r_psn;
2111	/* Queue NAK for later */
2112	if (list_empty(&qp->rspwait)) {
2113		qp->r_flags |= RVT_R_RSP_NAK;
2114		rvt_get_qp(qp);
2115		list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
2116	}
2117	return;
2118
2119nack_acc_unlck:
2120	spin_unlock_irqrestore(&qp->s_lock, flags);
2121nack_acc:
2122	rvt_rc_error(qp, IB_WC_LOC_PROT_ERR);
2123	qp->r_nak_state = IB_NAK_REMOTE_ACCESS_ERROR;
2124	qp->r_ack_psn = qp->r_psn;
2125send_ack:
2126	qib_send_rc_ack(qp);
2127	return;
2128
2129sunlock:
2130	spin_unlock_irqrestore(&qp->s_lock, flags);
2131}