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+/*
+ *
+ * This file is provided under a dual BSD/GPLv2 license. When using or
+ * redistributing this file, you may do so under either license.
+ *
+ * GPL LICENSE SUMMARY
+ *
+ * Copyright(c) 2015 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * BSD LICENSE
+ *
+ * Copyright(c) 2015 Intel Corporation.
+ *
+ * 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.
+ * - Neither the name of Intel Corporation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <linux/io.h>
+
+#include "hfi.h"
+#include "qp.h"
+#include "sdma.h"
+#include "trace.h"
+
+/* cut down ridiculously long IB macro names */
+#define OP(x) IB_OPCODE_RC_##x
+
+static void rc_timeout(unsigned long arg);
+
+static u32 restart_sge(struct hfi1_sge_state *ss, struct hfi1_swqe *wqe,
+ u32 psn, u32 pmtu)
+{
+ u32 len;
+
+ len = delta_psn(psn, wqe->psn) * pmtu;
+ ss->sge = wqe->sg_list[0];
+ ss->sg_list = wqe->sg_list + 1;
+ ss->num_sge = wqe->wr.num_sge;
+ ss->total_len = wqe->length;
+ hfi1_skip_sge(ss, len, 0);
+ return wqe->length - len;
+}
+
+static void start_timer(struct hfi1_qp *qp)
+{
+ qp->s_flags |= HFI1_S_TIMER;
+ qp->s_timer.function = rc_timeout;
+ /* 4.096 usec. * (1 << qp->timeout) */
+ qp->s_timer.expires = jiffies + qp->timeout_jiffies;
+ add_timer(&qp->s_timer);
+}
+
+/**
+ * make_rc_ack - construct a response packet (ACK, NAK, or RDMA read)
+ * @dev: the device for this QP
+ * @qp: a pointer to the QP
+ * @ohdr: a pointer to the IB header being constructed
+ * @pmtu: the path MTU
+ *
+ * Return 1 if constructed; otherwise, return 0.
+ * Note that we are in the responder's side of the QP context.
+ * Note the QP s_lock must be held.
+ */
+static int make_rc_ack(struct hfi1_ibdev *dev, struct hfi1_qp *qp,
+ struct hfi1_other_headers *ohdr, u32 pmtu)
+{
+ struct hfi1_ack_entry *e;
+ u32 hwords;
+ u32 len;
+ u32 bth0;
+ u32 bth2;
+ int middle = 0;
+
+ /* Don't send an ACK if we aren't supposed to. */
+ if (!(ib_hfi1_state_ops[qp->state] & HFI1_PROCESS_RECV_OK))
+ goto bail;
+
+ /* header size in 32-bit words LRH+BTH = (8+12)/4. */
+ hwords = 5;
+
+ switch (qp->s_ack_state) {
+ case OP(RDMA_READ_RESPONSE_LAST):
+ case OP(RDMA_READ_RESPONSE_ONLY):
+ e = &qp->s_ack_queue[qp->s_tail_ack_queue];
+ if (e->rdma_sge.mr) {
+ hfi1_put_mr(e->rdma_sge.mr);
+ e->rdma_sge.mr = NULL;
+ }
+ /* FALLTHROUGH */
+ case OP(ATOMIC_ACKNOWLEDGE):
+ /*
+ * We can increment the tail pointer now that the last
+ * response has been sent instead of only being
+ * constructed.
+ */
+ if (++qp->s_tail_ack_queue > HFI1_MAX_RDMA_ATOMIC)
+ qp->s_tail_ack_queue = 0;
+ /* FALLTHROUGH */
+ case OP(SEND_ONLY):
+ case OP(ACKNOWLEDGE):
+ /* Check for no next entry in the queue. */
+ if (qp->r_head_ack_queue == qp->s_tail_ack_queue) {
+ if (qp->s_flags & HFI1_S_ACK_PENDING)
+ goto normal;
+ goto bail;
+ }
+
+ e = &qp->s_ack_queue[qp->s_tail_ack_queue];
+ if (e->opcode == OP(RDMA_READ_REQUEST)) {
+ /*
+ * If a RDMA read response is being resent and
+ * we haven't seen the duplicate request yet,
+ * then stop sending the remaining responses the
+ * responder has seen until the requester re-sends it.
+ */
+ len = e->rdma_sge.sge_length;
+ if (len && !e->rdma_sge.mr) {
+ qp->s_tail_ack_queue = qp->r_head_ack_queue;
+ goto bail;
+ }
+ /* Copy SGE state in case we need to resend */
+ qp->s_rdma_mr = e->rdma_sge.mr;
+ if (qp->s_rdma_mr)
+ hfi1_get_mr(qp->s_rdma_mr);
+ qp->s_ack_rdma_sge.sge = e->rdma_sge;
+ qp->s_ack_rdma_sge.num_sge = 1;
+ qp->s_cur_sge = &qp->s_ack_rdma_sge;
+ if (len > pmtu) {
+ len = pmtu;
+ qp->s_ack_state = OP(RDMA_READ_RESPONSE_FIRST);
+ } else {
+ qp->s_ack_state = OP(RDMA_READ_RESPONSE_ONLY);
+ e->sent = 1;
+ }
+ ohdr->u.aeth = hfi1_compute_aeth(qp);
+ hwords++;
+ qp->s_ack_rdma_psn = e->psn;
+ bth2 = mask_psn(qp->s_ack_rdma_psn++);
+ } else {
+ /* COMPARE_SWAP or FETCH_ADD */
+ qp->s_cur_sge = NULL;
+ len = 0;
+ qp->s_ack_state = OP(ATOMIC_ACKNOWLEDGE);
+ ohdr->u.at.aeth = hfi1_compute_aeth(qp);
+ ohdr->u.at.atomic_ack_eth[0] =
+ cpu_to_be32(e->atomic_data >> 32);
+ ohdr->u.at.atomic_ack_eth[1] =
+ cpu_to_be32(e->atomic_data);
+ hwords += sizeof(ohdr->u.at) / sizeof(u32);
+ bth2 = mask_psn(e->psn);
+ e->sent = 1;
+ }
+ bth0 = qp->s_ack_state << 24;
+ break;
+
+ case OP(RDMA_READ_RESPONSE_FIRST):
+ qp->s_ack_state = OP(RDMA_READ_RESPONSE_MIDDLE);
+ /* FALLTHROUGH */
+ case OP(RDMA_READ_RESPONSE_MIDDLE):
+ qp->s_cur_sge = &qp->s_ack_rdma_sge;
+ qp->s_rdma_mr = qp->s_ack_rdma_sge.sge.mr;
+ if (qp->s_rdma_mr)
+ hfi1_get_mr(qp->s_rdma_mr);
+ len = qp->s_ack_rdma_sge.sge.sge_length;
+ if (len > pmtu) {
+ len = pmtu;
+ middle = HFI1_CAP_IS_KSET(SDMA_AHG);
+ } else {
+ ohdr->u.aeth = hfi1_compute_aeth(qp);
+ hwords++;
+ qp->s_ack_state = OP(RDMA_READ_RESPONSE_LAST);
+ e = &qp->s_ack_queue[qp->s_tail_ack_queue];
+ e->sent = 1;
+ }
+ bth0 = qp->s_ack_state << 24;
+ bth2 = mask_psn(qp->s_ack_rdma_psn++);
+ break;
+
+ default:
+normal:
+ /*
+ * Send a regular ACK.
+ * Set the s_ack_state so we wait until after sending
+ * the ACK before setting s_ack_state to ACKNOWLEDGE
+ * (see above).
+ */
+ qp->s_ack_state = OP(SEND_ONLY);
+ qp->s_flags &= ~HFI1_S_ACK_PENDING;
+ qp->s_cur_sge = NULL;
+ if (qp->s_nak_state)
+ ohdr->u.aeth =
+ cpu_to_be32((qp->r_msn & HFI1_MSN_MASK) |
+ (qp->s_nak_state <<
+ HFI1_AETH_CREDIT_SHIFT));
+ else
+ ohdr->u.aeth = hfi1_compute_aeth(qp);
+ hwords++;
+ len = 0;
+ bth0 = OP(ACKNOWLEDGE) << 24;
+ bth2 = mask_psn(qp->s_ack_psn);
+ }
+ qp->s_rdma_ack_cnt++;
+ qp->s_hdrwords = hwords;
+ qp->s_cur_size = len;
+ hfi1_make_ruc_header(qp, ohdr, bth0, bth2, middle);
+ return 1;
+
+bail:
+ qp->s_ack_state = OP(ACKNOWLEDGE);
+ qp->s_flags &= ~(HFI1_S_RESP_PENDING
+ | HFI1_S_ACK_PENDING
+ | HFI1_S_AHG_VALID);
+ return 0;
+}
+
+/**
+ * hfi1_make_rc_req - construct a request packet (SEND, RDMA r/w, ATOMIC)
+ * @qp: a pointer to the QP
+ *
+ * Return 1 if constructed; otherwise, return 0.
+ */
+int hfi1_make_rc_req(struct hfi1_qp *qp)
+{
+ struct hfi1_ibdev *dev = to_idev(qp->ibqp.device);
+ struct hfi1_other_headers *ohdr;
+ struct hfi1_sge_state *ss;
+ struct hfi1_swqe *wqe;
+ /* header size in 32-bit words LRH+BTH = (8+12)/4. */
+ u32 hwords = 5;
+ u32 len;
+ u32 bth0 = 0;
+ u32 bth2;
+ u32 pmtu = qp->pmtu;
+ char newreq;
+ unsigned long flags;
+ int ret = 0;
+ int middle = 0;
+ int delta;
+
+ ohdr = &qp->s_hdr->ibh.u.oth;
+ if (qp->remote_ah_attr.ah_flags & IB_AH_GRH)
+ ohdr = &qp->s_hdr->ibh.u.l.oth;
+
+ /*
+ * The lock is needed to synchronize between the sending tasklet,
+ * the receive interrupt handler, and timeout re-sends.
+ */
+ spin_lock_irqsave(&qp->s_lock, flags);
+
+ /* Sending responses has higher priority over sending requests. */
+ if ((qp->s_flags & HFI1_S_RESP_PENDING) &&
+ make_rc_ack(dev, qp, ohdr, pmtu))
+ goto done;
+
+ if (!(ib_hfi1_state_ops[qp->state] & HFI1_PROCESS_SEND_OK)) {
+ if (!(ib_hfi1_state_ops[qp->state] & HFI1_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_iowait.sdma_busy)) {
+ qp->s_flags |= HFI1_S_WAIT_DMA;
+ goto bail;
+ }
+ clear_ahg(qp);
+ wqe = get_swqe_ptr(qp, qp->s_last);
+ hfi1_send_complete(qp, wqe, qp->s_last != qp->s_acked ?
+ IB_WC_SUCCESS : IB_WC_WR_FLUSH_ERR);
+ /* will get called again */
+ goto done;
+ }
+
+ if (qp->s_flags & (HFI1_S_WAIT_RNR | HFI1_S_WAIT_ACK))
+ goto bail;
+
+ if (cmp_psn(qp->s_psn, qp->s_sending_hpsn) <= 0) {
+ if (cmp_psn(qp->s_sending_psn, qp->s_sending_hpsn) <= 0) {
+ qp->s_flags |= HFI1_S_WAIT_PSN;
+ goto bail;
+ }
+ qp->s_sending_psn = qp->s_psn;
+ qp->s_sending_hpsn = qp->s_psn - 1;
+ }
+
+ /* Send a request. */
+ wqe = get_swqe_ptr(qp, qp->s_cur);
+ switch (qp->s_state) {
+ default:
+ if (!(ib_hfi1_state_ops[qp->state] & HFI1_PROCESS_NEXT_SEND_OK))
+ goto bail;
+ /*
+ * Resend an old request or start a new one.
+ *
+ * We keep track of the current SWQE so that
+ * we don't reset the "furthest progress" state
+ * if we need to back up.
+ */
+ newreq = 0;
+ if (qp->s_cur == qp->s_tail) {
+ /* Check if send work queue is empty. */
+ if (qp->s_tail == qp->s_head) {
+ clear_ahg(qp);
+ goto bail;
+ }
+ /*
+ * If a fence is requested, wait for previous
+ * RDMA read and atomic operations to finish.
+ */
+ if ((wqe->wr.send_flags & IB_SEND_FENCE) &&
+ qp->s_num_rd_atomic) {
+ qp->s_flags |= HFI1_S_WAIT_FENCE;
+ goto bail;
+ }
+ wqe->psn = qp->s_next_psn;
+ newreq = 1;
+ }
+ /*
+ * Note that we have to be careful not to modify the
+ * original work request since we may need to resend
+ * it.
+ */
+ len = wqe->length;
+ ss = &qp->s_sge;
+ bth2 = mask_psn(qp->s_psn);
+ switch (wqe->wr.opcode) {
+ case IB_WR_SEND:
+ case IB_WR_SEND_WITH_IMM:
+ /* If no credit, return. */
+ if (!(qp->s_flags & HFI1_S_UNLIMITED_CREDIT) &&
+ cmp_msn(wqe->ssn, qp->s_lsn + 1) > 0) {
+ qp->s_flags |= HFI1_S_WAIT_SSN_CREDIT;
+ goto bail;
+ }
+ wqe->lpsn = wqe->psn;
+ if (len > pmtu) {
+ wqe->lpsn += (len - 1) / pmtu;
+ qp->s_state = OP(SEND_FIRST);
+ len = pmtu;
+ break;
+ }
+ if (wqe->wr.opcode == IB_WR_SEND)
+ qp->s_state = OP(SEND_ONLY);
+ else {
+ qp->s_state = OP(SEND_ONLY_WITH_IMMEDIATE);
+ /* Immediate data comes after the BTH */
+ ohdr->u.imm_data = wqe->wr.ex.imm_data;
+ hwords += 1;
+ }
+ if (wqe->wr.send_flags & IB_SEND_SOLICITED)
+ bth0 |= IB_BTH_SOLICITED;
+ bth2 |= IB_BTH_REQ_ACK;
+ if (++qp->s_cur == qp->s_size)
+ qp->s_cur = 0;
+ break;
+
+ case IB_WR_RDMA_WRITE:
+ if (newreq && !(qp->s_flags & HFI1_S_UNLIMITED_CREDIT))
+ qp->s_lsn++;
+ /* FALLTHROUGH */
+ case IB_WR_RDMA_WRITE_WITH_IMM:
+ /* If no credit, return. */
+ if (!(qp->s_flags & HFI1_S_UNLIMITED_CREDIT) &&
+ cmp_msn(wqe->ssn, qp->s_lsn + 1) > 0) {
+ qp->s_flags |= HFI1_S_WAIT_SSN_CREDIT;
+ goto bail;
+ }
+ ohdr->u.rc.reth.vaddr =
+ cpu_to_be64(wqe->wr.wr.rdma.remote_addr);
+ ohdr->u.rc.reth.rkey =
+ cpu_to_be32(wqe->wr.wr.rdma.rkey);
+ ohdr->u.rc.reth.length = cpu_to_be32(len);
+ hwords += sizeof(struct ib_reth) / sizeof(u32);
+ wqe->lpsn = wqe->psn;
+ if (len > pmtu) {
+ wqe->lpsn += (len - 1) / pmtu;
+ qp->s_state = OP(RDMA_WRITE_FIRST);
+ len = pmtu;
+ break;
+ }
+ if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
+ qp->s_state = OP(RDMA_WRITE_ONLY);
+ else {
+ qp->s_state =
+ OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE);
+ /* Immediate data comes after RETH */
+ ohdr->u.rc.imm_data = wqe->wr.ex.imm_data;
+ hwords += 1;
+ if (wqe->wr.send_flags & IB_SEND_SOLICITED)
+ bth0 |= IB_BTH_SOLICITED;
+ }
+ bth2 |= IB_BTH_REQ_ACK;
+ if (++qp->s_cur == qp->s_size)
+ qp->s_cur = 0;
+ break;
+
+ case IB_WR_RDMA_READ:
+ /*
+ * Don't allow more operations to be started
+ * than the QP limits allow.
+ */
+ if (newreq) {
+ if (qp->s_num_rd_atomic >=
+ qp->s_max_rd_atomic) {
+ qp->s_flags |= HFI1_S_WAIT_RDMAR;
+ goto bail;
+ }
+ qp->s_num_rd_atomic++;
+ if (!(qp->s_flags & HFI1_S_UNLIMITED_CREDIT))
+ qp->s_lsn++;
+ /*
+ * Adjust s_next_psn to count the
+ * expected number of responses.
+ */
+ if (len > pmtu)
+ qp->s_next_psn += (len - 1) / pmtu;
+ wqe->lpsn = qp->s_next_psn++;
+ }
+ ohdr->u.rc.reth.vaddr =
+ cpu_to_be64(wqe->wr.wr.rdma.remote_addr);
+ ohdr->u.rc.reth.rkey =
+ cpu_to_be32(wqe->wr.wr.rdma.rkey);
+ ohdr->u.rc.reth.length = cpu_to_be32(len);
+ qp->s_state = OP(RDMA_READ_REQUEST);
+ hwords += sizeof(ohdr->u.rc.reth) / sizeof(u32);
+ ss = NULL;
+ len = 0;
+ bth2 |= IB_BTH_REQ_ACK;
+ if (++qp->s_cur == qp->s_size)
+ qp->s_cur = 0;
+ break;
+
+ case IB_WR_ATOMIC_CMP_AND_SWP:
+ case IB_WR_ATOMIC_FETCH_AND_ADD:
+ /*
+ * Don't allow more operations to be started
+ * than the QP limits allow.
+ */
+ if (newreq) {
+ if (qp->s_num_rd_atomic >=
+ qp->s_max_rd_atomic) {
+ qp->s_flags |= HFI1_S_WAIT_RDMAR;
+ goto bail;
+ }
+ qp->s_num_rd_atomic++;
+ if (!(qp->s_flags & HFI1_S_UNLIMITED_CREDIT))
+ qp->s_lsn++;
+ wqe->lpsn = wqe->psn;
+ }
+ if (wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP) {
+ qp->s_state = OP(COMPARE_SWAP);
+ ohdr->u.atomic_eth.swap_data = cpu_to_be64(
+ wqe->wr.wr.atomic.swap);
+ ohdr->u.atomic_eth.compare_data = cpu_to_be64(
+ wqe->wr.wr.atomic.compare_add);
+ } else {
+ qp->s_state = OP(FETCH_ADD);
+ ohdr->u.atomic_eth.swap_data = cpu_to_be64(
+ wqe->wr.wr.atomic.compare_add);
+ ohdr->u.atomic_eth.compare_data = 0;
+ }
+ ohdr->u.atomic_eth.vaddr[0] = cpu_to_be32(
+ wqe->wr.wr.atomic.remote_addr >> 32);
+ ohdr->u.atomic_eth.vaddr[1] = cpu_to_be32(
+ wqe->wr.wr.atomic.remote_addr);
+ ohdr->u.atomic_eth.rkey = cpu_to_be32(
+ wqe->wr.wr.atomic.rkey);
+ hwords += sizeof(struct ib_atomic_eth) / sizeof(u32);
+ ss = NULL;
+ len = 0;
+ bth2 |= IB_BTH_REQ_ACK;
+ if (++qp->s_cur == qp->s_size)
+ qp->s_cur = 0;
+ break;
+
+ default:
+ goto bail;
+ }
+ qp->s_sge.sge = wqe->sg_list[0];
+ qp->s_sge.sg_list = wqe->sg_list + 1;
+ qp->s_sge.num_sge = wqe->wr.num_sge;
+ qp->s_sge.total_len = wqe->length;
+ qp->s_len = wqe->length;
+ if (newreq) {
+ qp->s_tail++;
+ if (qp->s_tail >= qp->s_size)
+ qp->s_tail = 0;
+ }
+ if (wqe->wr.opcode == IB_WR_RDMA_READ)
+ qp->s_psn = wqe->lpsn + 1;
+ else {
+ qp->s_psn++;
+ if (cmp_psn(qp->s_psn, qp->s_next_psn) > 0)
+ qp->s_next_psn = qp->s_psn;
+ }
+ break;
+
+ case OP(RDMA_READ_RESPONSE_FIRST):
+ /*
+ * qp->s_state is normally set to the opcode of the
+ * last packet constructed for new requests and therefore
+ * is never set to RDMA read response.
+ * RDMA_READ_RESPONSE_FIRST is used by the ACK processing
+ * thread to indicate a SEND needs to be restarted from an
+ * earlier PSN without interfering with the sending thread.
+ * See restart_rc().
+ */
+ qp->s_len = restart_sge(&qp->s_sge, wqe, qp->s_psn, pmtu);
+ /* FALLTHROUGH */
+ case OP(SEND_FIRST):
+ qp->s_state = OP(SEND_MIDDLE);
+ /* FALLTHROUGH */
+ case OP(SEND_MIDDLE):
+ bth2 = mask_psn(qp->s_psn++);
+ if (cmp_psn(qp->s_psn, qp->s_next_psn) > 0)
+ qp->s_next_psn = qp->s_psn;
+ ss = &qp->s_sge;
+ len = qp->s_len;
+ if (len > pmtu) {
+ len = pmtu;
+ middle = HFI1_CAP_IS_KSET(SDMA_AHG);
+ break;
+ }
+ if (wqe->wr.opcode == IB_WR_SEND)
+ qp->s_state = OP(SEND_LAST);
+ else {
+ qp->s_state = OP(SEND_LAST_WITH_IMMEDIATE);
+ /* Immediate data comes after the BTH */
+ ohdr->u.imm_data = wqe->wr.ex.imm_data;
+ hwords += 1;
+ }
+ if (wqe->wr.send_flags & IB_SEND_SOLICITED)
+ bth0 |= IB_BTH_SOLICITED;
+ bth2 |= IB_BTH_REQ_ACK;
+ qp->s_cur++;
+ if (qp->s_cur >= qp->s_size)
+ qp->s_cur = 0;
+ break;
+
+ case OP(RDMA_READ_RESPONSE_LAST):
+ /*
+ * qp->s_state is normally set to the opcode of the
+ * last packet constructed for new requests and therefore
+ * is never set to RDMA read response.
+ * RDMA_READ_RESPONSE_LAST is used by the ACK processing
+ * thread to indicate a RDMA write needs to be restarted from
+ * an earlier PSN without interfering with the sending thread.
+ * See restart_rc().
+ */
+ qp->s_len = restart_sge(&qp->s_sge, wqe, qp->s_psn, pmtu);
+ /* FALLTHROUGH */
+ case OP(RDMA_WRITE_FIRST):
+ qp->s_state = OP(RDMA_WRITE_MIDDLE);
+ /* FALLTHROUGH */
+ case OP(RDMA_WRITE_MIDDLE):
+ bth2 = mask_psn(qp->s_psn++);
+ if (cmp_psn(qp->s_psn, qp->s_next_psn) > 0)
+ qp->s_next_psn = qp->s_psn;
+ ss = &qp->s_sge;
+ len = qp->s_len;
+ if (len > pmtu) {
+ len = pmtu;
+ middle = HFI1_CAP_IS_KSET(SDMA_AHG);
+ break;
+ }
+ if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
+ qp->s_state = OP(RDMA_WRITE_LAST);
+ else {
+ qp->s_state = OP(RDMA_WRITE_LAST_WITH_IMMEDIATE);
+ /* Immediate data comes after the BTH */
+ ohdr->u.imm_data = wqe->wr.ex.imm_data;
+ hwords += 1;
+ if (wqe->wr.send_flags & IB_SEND_SOLICITED)
+ bth0 |= IB_BTH_SOLICITED;
+ }
+ bth2 |= IB_BTH_REQ_ACK;
+ qp->s_cur++;
+ if (qp->s_cur >= qp->s_size)
+ qp->s_cur = 0;
+ break;
+
+ case OP(RDMA_READ_RESPONSE_MIDDLE):
+ /*
+ * qp->s_state is normally set to the opcode of the
+ * last packet constructed for new requests and therefore
+ * is never set to RDMA read response.
+ * RDMA_READ_RESPONSE_MIDDLE is used by the ACK processing
+ * thread to indicate a RDMA read needs to be restarted from
+ * an earlier PSN without interfering with the sending thread.
+ * See restart_rc().
+ */
+ len = (delta_psn(qp->s_psn, wqe->psn)) * pmtu;
+ ohdr->u.rc.reth.vaddr =
+ cpu_to_be64(wqe->wr.wr.rdma.remote_addr + len);
+ ohdr->u.rc.reth.rkey =
+ cpu_to_be32(wqe->wr.wr.rdma.rkey);
+ ohdr->u.rc.reth.length = cpu_to_be32(wqe->length - len);
+ qp->s_state = OP(RDMA_READ_REQUEST);
+ hwords += sizeof(ohdr->u.rc.reth) / sizeof(u32);
+ bth2 = mask_psn(qp->s_psn) | IB_BTH_REQ_ACK;
+ qp->s_psn = wqe->lpsn + 1;
+ ss = NULL;
+ len = 0;
+ qp->s_cur++;
+ if (qp->s_cur == qp->s_size)
+ qp->s_cur = 0;
+ break;
+ }
+ qp->s_sending_hpsn = bth2;
+ delta = delta_psn(bth2, wqe->psn);
+ if (delta && delta % HFI1_PSN_CREDIT == 0)
+ bth2 |= IB_BTH_REQ_ACK;
+ if (qp->s_flags & HFI1_S_SEND_ONE) {
+ qp->s_flags &= ~HFI1_S_SEND_ONE;
+ qp->s_flags |= HFI1_S_WAIT_ACK;
+ bth2 |= IB_BTH_REQ_ACK;
+ }
+ qp->s_len -= len;
+ qp->s_hdrwords = hwords;
+ qp->s_cur_sge = ss;
+ qp->s_cur_size = len;
+ hfi1_make_ruc_header(
+ qp,
+ ohdr,
+ bth0 | (qp->s_state << 24),
+ bth2,
+ middle);
+done:
+ ret = 1;
+ goto unlock;
+
+bail:
+ qp->s_flags &= ~HFI1_S_BUSY;
+unlock:
+ spin_unlock_irqrestore(&qp->s_lock, flags);
+ return ret;
+}
+
+/**
+ * hfi1_send_rc_ack - Construct an ACK packet and send it
+ * @qp: a pointer to the QP
+ *
+ * This is called from hfi1_rc_rcv() and handle_receive_interrupt().
+ * Note that RDMA reads and atomics are handled in the
+ * send side QP state and tasklet.
+ */
+void hfi1_send_rc_ack(struct hfi1_ctxtdata *rcd, struct hfi1_qp *qp,
+ int is_fecn)
+{
+ struct hfi1_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
+ struct hfi1_pportdata *ppd = ppd_from_ibp(ibp);
+ u64 pbc, pbc_flags = 0;
+ u16 lrh0;
+ u16 sc5;
+ u32 bth0;
+ u32 hwords;
+ u32 vl, plen;
+ struct send_context *sc;
+ struct pio_buf *pbuf;
+ struct hfi1_ib_header hdr;
+ struct hfi1_other_headers *ohdr;
+ unsigned long flags;
+
+ spin_lock_irqsave(&qp->s_lock, flags);
+
+ if (!(ib_hfi1_state_ops[qp->state] & HFI1_PROCESS_RECV_OK))
+ goto unlock;
+
+ /* Don't send ACK or NAK if a RDMA read or atomic is pending. */
+ if ((qp->s_flags & HFI1_S_RESP_PENDING) || qp->s_rdma_ack_cnt)
+ goto queue_ack;
+
+ /* Construct the header with s_lock held so APM doesn't change it. */
+ /* header size in 32-bit words LRH+BTH+AETH = (8+12+4)/4 */
+ hwords = 6;
+ if (unlikely(qp->remote_ah_attr.ah_flags & IB_AH_GRH)) {
+ hwords += hfi1_make_grh(ibp, &hdr.u.l.grh,
+ &qp->remote_ah_attr.grh, hwords, 0);
+ ohdr = &hdr.u.l.oth;
+ lrh0 = HFI1_LRH_GRH;
+ } else {
+ ohdr = &hdr.u.oth;
+ lrh0 = HFI1_LRH_BTH;
+ }
+ /* read pkey_index w/o lock (its atomic) */
+ bth0 = hfi1_get_pkey(ibp, qp->s_pkey_index) | (OP(ACKNOWLEDGE) << 24);
+ if (qp->s_mig_state == IB_MIG_MIGRATED)
+ bth0 |= IB_BTH_MIG_REQ;
+ if (qp->r_nak_state)
+ ohdr->u.aeth = cpu_to_be32((qp->r_msn & HFI1_MSN_MASK) |
+ (qp->r_nak_state <<
+ HFI1_AETH_CREDIT_SHIFT));
+ else
+ ohdr->u.aeth = hfi1_compute_aeth(qp);
+ sc5 = ibp->sl_to_sc[qp->remote_ah_attr.sl];
+ /* set PBC_DC_INFO bit (aka SC[4]) in pbc_flags */
+ pbc_flags |= ((!!(sc5 & 0x10)) << PBC_DC_INFO_SHIFT);
+ lrh0 |= (sc5 & 0xf) << 12 | (qp->remote_ah_attr.sl & 0xf) << 4;
+ hdr.lrh[0] = cpu_to_be16(lrh0);
+ hdr.lrh[1] = cpu_to_be16(qp->remote_ah_attr.dlid);
+ hdr.lrh[2] = cpu_to_be16(hwords + SIZE_OF_CRC);
+ hdr.lrh[3] = cpu_to_be16(ppd->lid | qp->remote_ah_attr.src_path_bits);
+ ohdr->bth[0] = cpu_to_be32(bth0);
+ ohdr->bth[1] = cpu_to_be32(qp->remote_qpn);
+ ohdr->bth[1] |= cpu_to_be32((!!is_fecn) << HFI1_BECN_SHIFT);
+ ohdr->bth[2] = cpu_to_be32(mask_psn(qp->r_ack_psn));
+
+ spin_unlock_irqrestore(&qp->s_lock, flags);
+
+ /* Don't try to send ACKs if the link isn't ACTIVE */
+ if (driver_lstate(ppd) != IB_PORT_ACTIVE)
+ goto done;
+
+ sc = rcd->sc;
+ plen = 2 /* PBC */ + hwords;
+ vl = sc_to_vlt(ppd->dd, sc5);
+ pbc = create_pbc(ppd, pbc_flags, qp->srate_mbps, vl, plen);
+
+ pbuf = sc_buffer_alloc(sc, plen, NULL, NULL);
+ if (!pbuf) {
+ /*
+ * We have no room to send at the moment. Pass
+ * responsibility for sending the ACK to the send tasklet
+ * so that when enough buffer space becomes available,
+ * the ACK is sent ahead of other outgoing packets.
+ */
+ spin_lock_irqsave(&qp->s_lock, flags);
+ goto queue_ack;
+ }
+
+ trace_output_ibhdr(dd_from_ibdev(qp->ibqp.device), &hdr);
+
+ /* write the pbc and data */
+ ppd->dd->pio_inline_send(ppd->dd, pbuf, pbc, &hdr, hwords);
+
+ goto done;
+
+queue_ack:
+ if (ib_hfi1_state_ops[qp->state] & HFI1_PROCESS_RECV_OK) {
+ this_cpu_inc(*ibp->rc_qacks);
+ qp->s_flags |= HFI1_S_ACK_PENDING | HFI1_S_RESP_PENDING;
+ qp->s_nak_state = qp->r_nak_state;
+ qp->s_ack_psn = qp->r_ack_psn;
+ if (is_fecn)
+ set_bit(HFI1_S_ECN, &qp->s_aflags);
+
+ /* Schedule the send tasklet. */
+ hfi1_schedule_send(qp);
+ }
+unlock:
+ spin_unlock_irqrestore(&qp->s_lock, flags);
+done:
+ return;
+}
+
+/**
+ * reset_psn - reset the QP state to send starting from PSN
+ * @qp: the QP
+ * @psn: the packet sequence number to restart at
+ *
+ * This is called from hfi1_rc_rcv() to process an incoming RC ACK
+ * for the given QP.
+ * Called at interrupt level with the QP s_lock held.
+ */
+static void reset_psn(struct hfi1_qp *qp, u32 psn)
+{
+ u32 n = qp->s_acked;
+ struct hfi1_swqe *wqe = get_swqe_ptr(qp, n);
+ u32 opcode;
+
+ qp->s_cur = n;
+
+ /*
+ * If we are starting the request from the beginning,
+ * let the normal send code handle initialization.
+ */
+ if (cmp_psn(psn, wqe->psn) <= 0) {
+ qp->s_state = OP(SEND_LAST);
+ goto done;
+ }
+
+ /* Find the work request opcode corresponding to the given PSN. */
+ opcode = wqe->wr.opcode;
+ for (;;) {
+ int diff;
+
+ if (++n == qp->s_size)
+ n = 0;
+ if (n == qp->s_tail)
+ break;
+ wqe = get_swqe_ptr(qp, n);
+ diff = cmp_psn(psn, wqe->psn);
+ if (diff < 0)
+ break;
+ qp->s_cur = n;
+ /*
+ * If we are starting the request from the beginning,
+ * let the normal send code handle initialization.
+ */
+ if (diff == 0) {
+ qp->s_state = OP(SEND_LAST);
+ goto done;
+ }
+ opcode = wqe->wr.opcode;
+ }
+
+ /*
+ * Set the state to restart in the middle of a request.
+ * Don't change the s_sge, s_cur_sge, or s_cur_size.
+ * See hfi1_make_rc_req().
+ */
+ switch (opcode) {
+ case IB_WR_SEND:
+ case IB_WR_SEND_WITH_IMM:
+ qp->s_state = OP(RDMA_READ_RESPONSE_FIRST);
+ break;
+
+ case IB_WR_RDMA_WRITE:
+ case IB_WR_RDMA_WRITE_WITH_IMM:
+ qp->s_state = OP(RDMA_READ_RESPONSE_LAST);
+ break;
+
+ case IB_WR_RDMA_READ:
+ qp->s_state = OP(RDMA_READ_RESPONSE_MIDDLE);
+ break;
+
+ default:
+ /*
+ * This case shouldn't happen since its only
+ * one PSN per req.
+ */
+ qp->s_state = OP(SEND_LAST);
+ }
+done:
+ qp->s_psn = psn;
+ /*
+ * Set HFI1_S_WAIT_PSN as rc_complete() may start the timer
+ * asynchronously before the send tasklet can get scheduled.
+ * Doing it in hfi1_make_rc_req() is too late.
+ */
+ if ((cmp_psn(qp->s_psn, qp->s_sending_hpsn) <= 0) &&
+ (cmp_psn(qp->s_sending_psn, qp->s_sending_hpsn) <= 0))
+ qp->s_flags |= HFI1_S_WAIT_PSN;
+ qp->s_flags &= ~HFI1_S_AHG_VALID;
+}
+
+/*
+ * Back up requester to resend the last un-ACKed request.
+ * The QP r_lock and s_lock should be held and interrupts disabled.
+ */
+static void restart_rc(struct hfi1_qp *qp, u32 psn, int wait)
+{
+ struct hfi1_swqe *wqe = get_swqe_ptr(qp, qp->s_acked);
+ struct hfi1_ibport *ibp;
+
+ if (qp->s_retry == 0) {
+ if (qp->s_mig_state == IB_MIG_ARMED) {
+ hfi1_migrate_qp(qp);
+ qp->s_retry = qp->s_retry_cnt;
+ } else if (qp->s_last == qp->s_acked) {
+ hfi1_send_complete(qp, wqe, IB_WC_RETRY_EXC_ERR);
+ hfi1_error_qp(qp, IB_WC_WR_FLUSH_ERR);
+ return;
+ } else /* need to handle delayed completion */
+ return;
+ } else
+ qp->s_retry--;
+
+ ibp = to_iport(qp->ibqp.device, qp->port_num);
+ if (wqe->wr.opcode == IB_WR_RDMA_READ)
+ ibp->n_rc_resends++;
+ else
+ ibp->n_rc_resends += delta_psn(qp->s_psn, psn);
+
+ qp->s_flags &= ~(HFI1_S_WAIT_FENCE | HFI1_S_WAIT_RDMAR |
+ HFI1_S_WAIT_SSN_CREDIT | HFI1_S_WAIT_PSN |
+ HFI1_S_WAIT_ACK);
+ if (wait)
+ qp->s_flags |= HFI1_S_SEND_ONE;
+ reset_psn(qp, psn);
+}
+
+/*
+ * This is called from s_timer for missing responses.
+ */
+static void rc_timeout(unsigned long arg)
+{
+ struct hfi1_qp *qp = (struct hfi1_qp *)arg;
+ struct hfi1_ibport *ibp;
+ unsigned long flags;
+
+ spin_lock_irqsave(&qp->r_lock, flags);
+ spin_lock(&qp->s_lock);
+ if (qp->s_flags & HFI1_S_TIMER) {
+ ibp = to_iport(qp->ibqp.device, qp->port_num);
+ ibp->n_rc_timeouts++;
+ qp->s_flags &= ~HFI1_S_TIMER;
+ del_timer(&qp->s_timer);
+ restart_rc(qp, qp->s_last_psn + 1, 1);
+ hfi1_schedule_send(qp);
+ }
+ spin_unlock(&qp->s_lock);
+ spin_unlock_irqrestore(&qp->r_lock, flags);
+}
+
+/*
+ * This is called from s_timer for RNR timeouts.
+ */
+void hfi1_rc_rnr_retry(unsigned long arg)
+{
+ struct hfi1_qp *qp = (struct hfi1_qp *)arg;
+ unsigned long flags;
+
+ spin_lock_irqsave(&qp->s_lock, flags);
+ if (qp->s_flags & HFI1_S_WAIT_RNR) {
+ qp->s_flags &= ~HFI1_S_WAIT_RNR;
+ del_timer(&qp->s_timer);
+ hfi1_schedule_send(qp);
+ }
+ spin_unlock_irqrestore(&qp->s_lock, flags);
+}
+
+/*
+ * Set qp->s_sending_psn to the next PSN after the given one.
+ * This would be psn+1 except when RDMA reads are present.
+ */
+static void reset_sending_psn(struct hfi1_qp *qp, u32 psn)
+{
+ struct hfi1_swqe *wqe;
+ u32 n = qp->s_last;
+
+ /* Find the work request corresponding to the given PSN. */
+ for (;;) {
+ wqe = get_swqe_ptr(qp, n);
+ if (cmp_psn(psn, wqe->lpsn) <= 0) {
+ if (wqe->wr.opcode == IB_WR_RDMA_READ)
+ qp->s_sending_psn = wqe->lpsn + 1;
+ else
+ qp->s_sending_psn = psn + 1;
+ break;
+ }
+ if (++n == qp->s_size)
+ n = 0;
+ if (n == qp->s_tail)
+ break;
+ }
+}
+
+/*
+ * This should be called with the QP s_lock held and interrupts disabled.
+ */
+void hfi1_rc_send_complete(struct hfi1_qp *qp, struct hfi1_ib_header *hdr)
+{
+ struct hfi1_other_headers *ohdr;
+ struct hfi1_swqe *wqe;
+ struct ib_wc wc;
+ unsigned i;
+ u32 opcode;
+ u32 psn;
+
+ if (!(ib_hfi1_state_ops[qp->state] & HFI1_PROCESS_OR_FLUSH_SEND))
+ return;
+
+ /* Find out where the BTH is */
+ if ((be16_to_cpu(hdr->lrh[0]) & 3) == HFI1_LRH_BTH)
+ ohdr = &hdr->u.oth;
+ else
+ ohdr = &hdr->u.l.oth;
+
+ opcode = be32_to_cpu(ohdr->bth[0]) >> 24;
+ if (opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
+ opcode <= OP(ATOMIC_ACKNOWLEDGE)) {
+ WARN_ON(!qp->s_rdma_ack_cnt);
+ qp->s_rdma_ack_cnt--;
+ return;
+ }
+
+ psn = be32_to_cpu(ohdr->bth[2]);
+ reset_sending_psn(qp, psn);
+
+ /*
+ * Start timer after a packet requesting an ACK has been sent and
+ * there are still requests that haven't been acked.
+ */
+ if ((psn & IB_BTH_REQ_ACK) && qp->s_acked != qp->s_tail &&
+ !(qp->s_flags &
+ (HFI1_S_TIMER | HFI1_S_WAIT_RNR | HFI1_S_WAIT_PSN)) &&
+ (ib_hfi1_state_ops[qp->state] & HFI1_PROCESS_RECV_OK))
+ start_timer(qp);
+
+ while (qp->s_last != qp->s_acked) {
+ wqe = get_swqe_ptr(qp, qp->s_last);
+ if (cmp_psn(wqe->lpsn, qp->s_sending_psn) >= 0 &&
+ cmp_psn(qp->s_sending_psn, qp->s_sending_hpsn) <= 0)
+ break;
+ for (i = 0; i < wqe->wr.num_sge; i++) {
+ struct hfi1_sge *sge = &wqe->sg_list[i];
+
+ hfi1_put_mr(sge->mr);
+ }
+ /* Post a send completion queue entry if requested. */
+ if (!(qp->s_flags & HFI1_S_SIGNAL_REQ_WR) ||
+ (wqe->wr.send_flags & IB_SEND_SIGNALED)) {
+ memset(&wc, 0, sizeof(wc));
+ wc.wr_id = wqe->wr.wr_id;
+ wc.status = IB_WC_SUCCESS;
+ wc.opcode = ib_hfi1_wc_opcode[wqe->wr.opcode];
+ wc.byte_len = wqe->length;
+ wc.qp = &qp->ibqp;
+ hfi1_cq_enter(to_icq(qp->ibqp.send_cq), &wc, 0);
+ }
+ if (++qp->s_last >= qp->s_size)
+ qp->s_last = 0;
+ }
+ /*
+ * If we were waiting for sends to complete before re-sending,
+ * and they are now complete, restart sending.
+ */
+ trace_hfi1_rc_sendcomplete(qp, psn);
+ if (qp->s_flags & HFI1_S_WAIT_PSN &&
+ cmp_psn(qp->s_sending_psn, qp->s_sending_hpsn) > 0) {
+ qp->s_flags &= ~HFI1_S_WAIT_PSN;
+ qp->s_sending_psn = qp->s_psn;
+ qp->s_sending_hpsn = qp->s_psn - 1;
+ hfi1_schedule_send(qp);
+ }
+}
+
+static inline void update_last_psn(struct hfi1_qp *qp, u32 psn)
+{
+ qp->s_last_psn = psn;
+}
+
+/*
+ * Generate a SWQE completion.
+ * This is similar to hfi1_send_complete but has to check to be sure
+ * that the SGEs are not being referenced if the SWQE is being resent.
+ */
+static struct hfi1_swqe *do_rc_completion(struct hfi1_qp *qp,
+ struct hfi1_swqe *wqe,
+ struct hfi1_ibport *ibp)
+{
+ struct ib_wc wc;
+ unsigned i;
+
+ /*
+ * Don't decrement refcount and don't generate a
+ * completion if the SWQE is being resent until the send
+ * is finished.
+ */
+ if (cmp_psn(wqe->lpsn, qp->s_sending_psn) < 0 ||
+ cmp_psn(qp->s_sending_psn, qp->s_sending_hpsn) > 0) {
+ for (i = 0; i < wqe->wr.num_sge; i++) {
+ struct hfi1_sge *sge = &wqe->sg_list[i];
+
+ hfi1_put_mr(sge->mr);
+ }
+ /* Post a send completion queue entry if requested. */
+ if (!(qp->s_flags & HFI1_S_SIGNAL_REQ_WR) ||
+ (wqe->wr.send_flags & IB_SEND_SIGNALED)) {
+ memset(&wc, 0, sizeof(wc));
+ wc.wr_id = wqe->wr.wr_id;
+ wc.status = IB_WC_SUCCESS;
+ wc.opcode = ib_hfi1_wc_opcode[wqe->wr.opcode];
+ wc.byte_len = wqe->length;
+ wc.qp = &qp->ibqp;
+ hfi1_cq_enter(to_icq(qp->ibqp.send_cq), &wc, 0);
+ }
+ if (++qp->s_last >= qp->s_size)
+ qp->s_last = 0;
+ } else {
+ struct hfi1_pportdata *ppd = ppd_from_ibp(ibp);
+
+ this_cpu_inc(*ibp->rc_delayed_comp);
+ /*
+ * If send progress not running attempt to progress
+ * SDMA queue.
+ */
+ if (ppd->dd->flags & HFI1_HAS_SEND_DMA) {
+ struct sdma_engine *engine;
+ u8 sc5;
+
+ /* For now use sc to find engine */
+ sc5 = ibp->sl_to_sc[qp->remote_ah_attr.sl];
+ engine = qp_to_sdma_engine(qp, sc5);
+ sdma_engine_progress_schedule(engine);
+ }
+ }
+
+ qp->s_retry = qp->s_retry_cnt;
+ update_last_psn(qp, wqe->lpsn);
+
+ /*
+ * If we are completing a request which is in the process of
+ * being resent, we can stop re-sending it since we know the
+ * responder has already seen it.
+ */
+ if (qp->s_acked == qp->s_cur) {
+ if (++qp->s_cur >= qp->s_size)
+ qp->s_cur = 0;
+ qp->s_acked = qp->s_cur;
+ wqe = get_swqe_ptr(qp, qp->s_cur);
+ if (qp->s_acked != qp->s_tail) {
+ qp->s_state = OP(SEND_LAST);
+ qp->s_psn = wqe->psn;
+ }
+ } else {
+ if (++qp->s_acked >= qp->s_size)
+ qp->s_acked = 0;
+ if (qp->state == IB_QPS_SQD && qp->s_acked == qp->s_cur)
+ qp->s_draining = 0;
+ wqe = get_swqe_ptr(qp, qp->s_acked);
+ }
+ return wqe;
+}
+
+/**
+ * do_rc_ack - process an incoming RC ACK
+ * @qp: the QP the ACK came in on
+ * @psn: the packet sequence number of the ACK
+ * @opcode: the opcode of the request that resulted in the ACK
+ *
+ * This is called from rc_rcv_resp() to process an incoming RC ACK
+ * for the given QP.
+ * Called at interrupt level with the QP s_lock held.
+ * Returns 1 if OK, 0 if current operation should be aborted (NAK).
+ */
+static int do_rc_ack(struct hfi1_qp *qp, u32 aeth, u32 psn, int opcode,
+ u64 val, struct hfi1_ctxtdata *rcd)
+{
+ struct hfi1_ibport *ibp;
+ enum ib_wc_status status;
+ struct hfi1_swqe *wqe;
+ int ret = 0;
+ u32 ack_psn;
+ int diff;
+
+ /* Remove QP from retry timer */
+ if (qp->s_flags & (HFI1_S_TIMER | HFI1_S_WAIT_RNR)) {
+ qp->s_flags &= ~(HFI1_S_TIMER | HFI1_S_WAIT_RNR);
+ del_timer(&qp->s_timer);
+ }
+
+ /*
+ * Note that NAKs implicitly ACK outstanding SEND and RDMA write
+ * requests and implicitly NAK RDMA read and atomic requests issued
+ * before the NAK'ed request. The MSN won't include the NAK'ed
+ * request but will include an ACK'ed request(s).
+ */
+ ack_psn = psn;
+ if (aeth >> 29)
+ ack_psn--;
+ wqe = get_swqe_ptr(qp, qp->s_acked);
+ ibp = to_iport(qp->ibqp.device, qp->port_num);
+
+ /*
+ * The MSN might be for a later WQE than the PSN indicates so
+ * only complete WQEs that the PSN finishes.
+ */
+ while ((diff = delta_psn(ack_psn, wqe->lpsn)) >= 0) {
+ /*
+ * RDMA_READ_RESPONSE_ONLY is a special case since
+ * we want to generate completion events for everything
+ * before the RDMA read, copy the data, then generate
+ * the completion for the read.
+ */
+ if (wqe->wr.opcode == IB_WR_RDMA_READ &&
+ opcode == OP(RDMA_READ_RESPONSE_ONLY) &&
+ diff == 0) {
+ ret = 1;
+ goto bail;
+ }
+ /*
+ * If this request is a RDMA read or atomic, and the ACK is
+ * for a later operation, this ACK NAKs the RDMA read or
+ * atomic. In other words, only a RDMA_READ_LAST or ONLY
+ * can ACK a RDMA read and likewise for atomic ops. Note
+ * that the NAK case can only happen if relaxed ordering is
+ * used and requests are sent after an RDMA read or atomic
+ * is sent but before the response is received.
+ */
+ if ((wqe->wr.opcode == IB_WR_RDMA_READ &&
+ (opcode != OP(RDMA_READ_RESPONSE_LAST) || diff != 0)) ||
+ ((wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
+ wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) &&
+ (opcode != OP(ATOMIC_ACKNOWLEDGE) || diff != 0))) {
+ /* Retry this request. */
+ if (!(qp->r_flags & HFI1_R_RDMAR_SEQ)) {
+ qp->r_flags |= HFI1_R_RDMAR_SEQ;
+ restart_rc(qp, qp->s_last_psn + 1, 0);
+ if (list_empty(&qp->rspwait)) {
+ qp->r_flags |= HFI1_R_RSP_SEND;
+ atomic_inc(&qp->refcount);
+ list_add_tail(&qp->rspwait,
+ &rcd->qp_wait_list);
+ }
+ }
+ /*
+ * No need to process the ACK/NAK since we are
+ * restarting an earlier request.
+ */
+ goto bail;
+ }
+ if (wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
+ wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) {
+ u64 *vaddr = wqe->sg_list[0].vaddr;
+ *vaddr = val;
+ }
+ if (qp->s_num_rd_atomic &&
+ (wqe->wr.opcode == IB_WR_RDMA_READ ||
+ wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
+ wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)) {
+ qp->s_num_rd_atomic--;
+ /* Restart sending task if fence is complete */
+ if ((qp->s_flags & HFI1_S_WAIT_FENCE) &&
+ !qp->s_num_rd_atomic) {
+ qp->s_flags &= ~(HFI1_S_WAIT_FENCE |
+ HFI1_S_WAIT_ACK);
+ hfi1_schedule_send(qp);
+ } else if (qp->s_flags & HFI1_S_WAIT_RDMAR) {
+ qp->s_flags &= ~(HFI1_S_WAIT_RDMAR |
+ HFI1_S_WAIT_ACK);
+ hfi1_schedule_send(qp);
+ }
+ }
+ wqe = do_rc_completion(qp, wqe, ibp);
+ if (qp->s_acked == qp->s_tail)
+ break;
+ }
+
+ switch (aeth >> 29) {
+ case 0: /* ACK */
+ this_cpu_inc(*ibp->rc_acks);
+ if (qp->s_acked != qp->s_tail) {
+ /*
+ * We are expecting more ACKs so
+ * reset the re-transmit timer.
+ */
+ start_timer(qp);
+ /*
+ * We can stop re-sending the earlier packets and
+ * continue with the next packet the receiver wants.
+ */
+ if (cmp_psn(qp->s_psn, psn) <= 0)
+ reset_psn(qp, psn + 1);
+ } else if (cmp_psn(qp->s_psn, psn) <= 0) {
+ qp->s_state = OP(SEND_LAST);
+ qp->s_psn = psn + 1;
+ }
+ if (qp->s_flags & HFI1_S_WAIT_ACK) {
+ qp->s_flags &= ~HFI1_S_WAIT_ACK;
+ hfi1_schedule_send(qp);
+ }
+ hfi1_get_credit(qp, aeth);
+ qp->s_rnr_retry = qp->s_rnr_retry_cnt;
+ qp->s_retry = qp->s_retry_cnt;
+ update_last_psn(qp, psn);
+ ret = 1;
+ goto bail;
+
+ case 1: /* RNR NAK */
+ ibp->n_rnr_naks++;
+ if (qp->s_acked == qp->s_tail)
+ goto bail;
+ if (qp->s_flags & HFI1_S_WAIT_RNR)
+ goto bail;
+ if (qp->s_rnr_retry == 0) {
+ status = IB_WC_RNR_RETRY_EXC_ERR;
+ goto class_b;
+ }
+ if (qp->s_rnr_retry_cnt < 7)
+ qp->s_rnr_retry--;
+
+ /* The last valid PSN is the previous PSN. */
+ update_last_psn(qp, psn - 1);
+
+ ibp->n_rc_resends += delta_psn(qp->s_psn, psn);
+
+ reset_psn(qp, psn);
+
+ qp->s_flags &= ~(HFI1_S_WAIT_SSN_CREDIT | HFI1_S_WAIT_ACK);
+ qp->s_flags |= HFI1_S_WAIT_RNR;
+ qp->s_timer.function = hfi1_rc_rnr_retry;
+ qp->s_timer.expires = jiffies + usecs_to_jiffies(
+ ib_hfi1_rnr_table[(aeth >> HFI1_AETH_CREDIT_SHIFT) &
+ HFI1_AETH_CREDIT_MASK]);
+ add_timer(&qp->s_timer);
+ goto bail;
+
+ case 3: /* NAK */
+ if (qp->s_acked == qp->s_tail)
+ goto bail;
+ /* The last valid PSN is the previous PSN. */
+ update_last_psn(qp, psn - 1);
+ switch ((aeth >> HFI1_AETH_CREDIT_SHIFT) &
+ HFI1_AETH_CREDIT_MASK) {
+ case 0: /* PSN sequence error */
+ ibp->n_seq_naks++;
+ /*
+ * Back up to the responder's expected PSN.
+ * Note that we might get a NAK in the middle of an
+ * RDMA READ response which terminates the RDMA
+ * READ.
+ */
+ restart_rc(qp, psn, 0);
+ hfi1_schedule_send(qp);
+ break;
+
+ case 1: /* Invalid Request */
+ status = IB_WC_REM_INV_REQ_ERR;
+ ibp->n_other_naks++;
+ goto class_b;
+
+ case 2: /* Remote Access Error */
+ status = IB_WC_REM_ACCESS_ERR;
+ ibp->n_other_naks++;
+ goto class_b;
+
+ case 3: /* Remote Operation Error */
+ status = IB_WC_REM_OP_ERR;
+ ibp->n_other_naks++;
+class_b:
+ if (qp->s_last == qp->s_acked) {
+ hfi1_send_complete(qp, wqe, status);
+ hfi1_error_qp(qp, IB_WC_WR_FLUSH_ERR);
+ }
+ break;
+
+ default:
+ /* Ignore other reserved NAK error codes */
+ goto reserved;
+ }
+ qp->s_retry = qp->s_retry_cnt;
+ qp->s_rnr_retry = qp->s_rnr_retry_cnt;
+ goto bail;
+
+ default: /* 2: reserved */
+reserved:
+ /* Ignore reserved NAK codes. */
+ goto bail;
+ }
+
+bail:
+ return ret;
+}
+
+/*
+ * We have seen an out of sequence RDMA read middle or last packet.
+ * This ACKs SENDs and RDMA writes up to the first RDMA read or atomic SWQE.
+ */
+static void rdma_seq_err(struct hfi1_qp *qp, struct hfi1_ibport *ibp, u32 psn,
+ struct hfi1_ctxtdata *rcd)
+{
+ struct hfi1_swqe *wqe;
+
+ /* Remove QP from retry timer */
+ if (qp->s_flags & (HFI1_S_TIMER | HFI1_S_WAIT_RNR)) {
+ qp->s_flags &= ~(HFI1_S_TIMER | HFI1_S_WAIT_RNR);
+ del_timer(&qp->s_timer);
+ }
+
+ wqe = get_swqe_ptr(qp, qp->s_acked);
+
+ while (cmp_psn(psn, wqe->lpsn) > 0) {
+ if (wqe->wr.opcode == IB_WR_RDMA_READ ||
+ wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
+ wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)
+ break;
+ wqe = do_rc_completion(qp, wqe, ibp);
+ }
+
+ ibp->n_rdma_seq++;
+ qp->r_flags |= HFI1_R_RDMAR_SEQ;
+ restart_rc(qp, qp->s_last_psn + 1, 0);
+ if (list_empty(&qp->rspwait)) {
+ qp->r_flags |= HFI1_R_RSP_SEND;
+ atomic_inc(&qp->refcount);
+ list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
+ }
+}
+
+/**
+ * rc_rcv_resp - process an incoming RC response packet
+ * @ibp: the port this packet came in on
+ * @ohdr: the other headers for this packet
+ * @data: the packet data
+ * @tlen: the packet length
+ * @qp: the QP for this packet
+ * @opcode: the opcode for this packet
+ * @psn: the packet sequence number for this packet
+ * @hdrsize: the header length
+ * @pmtu: the path MTU
+ *
+ * This is called from hfi1_rc_rcv() to process an incoming RC response
+ * packet for the given QP.
+ * Called at interrupt level.
+ */
+static void rc_rcv_resp(struct hfi1_ibport *ibp,
+ struct hfi1_other_headers *ohdr,
+ void *data, u32 tlen, struct hfi1_qp *qp,
+ u32 opcode, u32 psn, u32 hdrsize, u32 pmtu,
+ struct hfi1_ctxtdata *rcd)
+{
+ struct hfi1_swqe *wqe;
+ enum ib_wc_status status;
+ unsigned long flags;
+ int diff;
+ u32 pad;
+ u32 aeth;
+ u64 val;
+
+ spin_lock_irqsave(&qp->s_lock, flags);
+ if (!(ib_hfi1_state_ops[qp->state] & HFI1_PROCESS_RECV_OK))
+ goto ack_done;
+
+ /* Ignore invalid responses. */
+ if (cmp_psn(psn, qp->s_next_psn) >= 0)
+ goto ack_done;
+
+ /* Ignore duplicate responses. */
+ diff = cmp_psn(psn, qp->s_last_psn);
+ if (unlikely(diff <= 0)) {
+ /* Update credits for "ghost" ACKs */
+ if (diff == 0 && opcode == OP(ACKNOWLEDGE)) {
+ aeth = be32_to_cpu(ohdr->u.aeth);
+ if ((aeth >> 29) == 0)
+ hfi1_get_credit(qp, aeth);
+ }
+ goto ack_done;
+ }
+
+ /*
+ * Skip everything other than the PSN we expect, if we are waiting
+ * for a reply to a restarted RDMA read or atomic op.
+ */
+ if (qp->r_flags & HFI1_R_RDMAR_SEQ) {
+ if (cmp_psn(psn, qp->s_last_psn + 1) != 0)
+ goto ack_done;
+ qp->r_flags &= ~HFI1_R_RDMAR_SEQ;
+ }
+
+ if (unlikely(qp->s_acked == qp->s_tail))
+ goto ack_done;
+ wqe = get_swqe_ptr(qp, qp->s_acked);
+ status = IB_WC_SUCCESS;
+
+ switch (opcode) {
+ case OP(ACKNOWLEDGE):
+ case OP(ATOMIC_ACKNOWLEDGE):
+ case OP(RDMA_READ_RESPONSE_FIRST):
+ aeth = be32_to_cpu(ohdr->u.aeth);
+ if (opcode == OP(ATOMIC_ACKNOWLEDGE)) {
+ __be32 *p = ohdr->u.at.atomic_ack_eth;
+
+ val = ((u64) be32_to_cpu(p[0]) << 32) |
+ be32_to_cpu(p[1]);
+ } else
+ val = 0;
+ if (!do_rc_ack(qp, aeth, psn, opcode, val, rcd) ||
+ opcode != OP(RDMA_READ_RESPONSE_FIRST))
+ goto ack_done;
+ hdrsize += 4;
+ wqe = get_swqe_ptr(qp, qp->s_acked);
+ if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
+ goto ack_op_err;
+ /*
+ * If this is a response to a resent RDMA read, we
+ * have to be careful to copy the data to the right
+ * location.
+ */
+ qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
+ wqe, psn, pmtu);
+ goto read_middle;
+
+ case OP(RDMA_READ_RESPONSE_MIDDLE):
+ /* no AETH, no ACK */
+ if (unlikely(cmp_psn(psn, qp->s_last_psn + 1)))
+ goto ack_seq_err;
+ if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
+ goto ack_op_err;
+read_middle:
+ if (unlikely(tlen != (hdrsize + pmtu + 4)))
+ goto ack_len_err;
+ if (unlikely(pmtu >= qp->s_rdma_read_len))
+ goto ack_len_err;
+
+ /*
+ * We got a response so update the timeout.
+ * 4.096 usec. * (1 << qp->timeout)
+ */
+ qp->s_flags |= HFI1_S_TIMER;
+ mod_timer(&qp->s_timer, jiffies + qp->timeout_jiffies);
+ if (qp->s_flags & HFI1_S_WAIT_ACK) {
+ qp->s_flags &= ~HFI1_S_WAIT_ACK;
+ hfi1_schedule_send(qp);
+ }
+
+ if (opcode == OP(RDMA_READ_RESPONSE_MIDDLE))
+ qp->s_retry = qp->s_retry_cnt;
+
+ /*
+ * Update the RDMA receive state but do the copy w/o
+ * holding the locks and blocking interrupts.
+ */
+ qp->s_rdma_read_len -= pmtu;
+ update_last_psn(qp, psn);
+ spin_unlock_irqrestore(&qp->s_lock, flags);
+ hfi1_copy_sge(&qp->s_rdma_read_sge, data, pmtu, 0);
+ goto bail;
+
+ case OP(RDMA_READ_RESPONSE_ONLY):
+ aeth = be32_to_cpu(ohdr->u.aeth);
+ if (!do_rc_ack(qp, aeth, psn, opcode, 0, rcd))
+ goto ack_done;
+ /* Get the number of bytes the message was padded by. */
+ pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
+ /*
+ * Check that the data size is >= 0 && <= pmtu.
+ * Remember to account for the AETH header (4) and
+ * ICRC (4).
+ */
+ if (unlikely(tlen < (hdrsize + pad + 8)))
+ goto ack_len_err;
+ /*
+ * If this is a response to a resent RDMA read, we
+ * have to be careful to copy the data to the right
+ * location.
+ */
+ wqe = get_swqe_ptr(qp, qp->s_acked);
+ qp->s_rdma_read_len = restart_sge(&qp->s_rdma_read_sge,
+ wqe, psn, pmtu);
+ goto read_last;
+
+ case OP(RDMA_READ_RESPONSE_LAST):
+ /* ACKs READ req. */
+ if (unlikely(cmp_psn(psn, qp->s_last_psn + 1)))
+ goto ack_seq_err;
+ if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
+ goto ack_op_err;
+ /* Get the number of bytes the message was padded by. */
+ pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
+ /*
+ * Check that the data size is >= 1 && <= pmtu.
+ * Remember to account for the AETH header (4) and
+ * ICRC (4).
+ */
+ if (unlikely(tlen <= (hdrsize + pad + 8)))
+ goto ack_len_err;
+read_last:
+ tlen -= hdrsize + pad + 8;
+ if (unlikely(tlen != qp->s_rdma_read_len))
+ goto ack_len_err;
+ aeth = be32_to_cpu(ohdr->u.aeth);
+ hfi1_copy_sge(&qp->s_rdma_read_sge, data, tlen, 0);
+ WARN_ON(qp->s_rdma_read_sge.num_sge);
+ (void) do_rc_ack(qp, aeth, psn,
+ OP(RDMA_READ_RESPONSE_LAST), 0, rcd);
+ goto ack_done;
+ }
+
+ack_op_err:
+ status = IB_WC_LOC_QP_OP_ERR;
+ goto ack_err;
+
+ack_seq_err:
+ rdma_seq_err(qp, ibp, psn, rcd);
+ goto ack_done;
+
+ack_len_err:
+ status = IB_WC_LOC_LEN_ERR;
+ack_err:
+ if (qp->s_last == qp->s_acked) {
+ hfi1_send_complete(qp, wqe, status);
+ hfi1_error_qp(qp, IB_WC_WR_FLUSH_ERR);
+ }
+ack_done:
+ spin_unlock_irqrestore(&qp->s_lock, flags);
+bail:
+ return;
+}
+
+/**
+ * rc_rcv_error - process an incoming duplicate or error RC packet
+ * @ohdr: the other headers for this packet
+ * @data: the packet data
+ * @qp: the QP for this packet
+ * @opcode: the opcode for this packet
+ * @psn: the packet sequence number for this packet
+ * @diff: the difference between the PSN and the expected PSN
+ *
+ * This is called from hfi1_rc_rcv() to process an unexpected
+ * incoming RC packet for the given QP.
+ * Called at interrupt level.
+ * Return 1 if no more processing is needed; otherwise return 0 to
+ * schedule a response to be sent.
+ */
+static int rc_rcv_error(struct hfi1_other_headers *ohdr, void *data,
+ struct hfi1_qp *qp, u32 opcode, u32 psn, int diff,
+ struct hfi1_ctxtdata *rcd)
+{
+ struct hfi1_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
+ struct hfi1_ack_entry *e;
+ unsigned long flags;
+ u8 i, prev;
+ int old_req;
+
+ if (diff > 0) {
+ /*
+ * Packet sequence error.
+ * A NAK will ACK earlier sends and RDMA writes.
+ * Don't queue the NAK if we already sent one.
+ */
+ if (!qp->r_nak_state) {
+ ibp->n_rc_seqnak++;
+ qp->r_nak_state = IB_NAK_PSN_ERROR;
+ /* Use the expected PSN. */
+ qp->r_ack_psn = qp->r_psn;
+ /*
+ * Wait to send the sequence NAK until all packets
+ * in the receive queue have been processed.
+ * Otherwise, we end up propagating congestion.
+ */
+ if (list_empty(&qp->rspwait)) {
+ qp->r_flags |= HFI1_R_RSP_NAK;
+ atomic_inc(&qp->refcount);
+ list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
+ }
+ }
+ goto done;
+ }
+
+ /*
+ * Handle a duplicate request. Don't re-execute SEND, RDMA
+ * write or atomic op. Don't NAK errors, just silently drop
+ * the duplicate request. Note that r_sge, r_len, and
+ * r_rcv_len may be in use so don't modify them.
+ *
+ * We are supposed to ACK the earliest duplicate PSN but we
+ * can coalesce an outstanding duplicate ACK. We have to
+ * send the earliest so that RDMA reads can be restarted at
+ * the requester's expected PSN.
+ *
+ * First, find where this duplicate PSN falls within the
+ * ACKs previously sent.
+ * old_req is true if there is an older response that is scheduled
+ * to be sent before sending this one.
+ */
+ e = NULL;
+ old_req = 1;
+ ibp->n_rc_dupreq++;
+
+ spin_lock_irqsave(&qp->s_lock, flags);
+
+ for (i = qp->r_head_ack_queue; ; i = prev) {
+ if (i == qp->s_tail_ack_queue)
+ old_req = 0;
+ if (i)
+ prev = i - 1;
+ else
+ prev = HFI1_MAX_RDMA_ATOMIC;
+ if (prev == qp->r_head_ack_queue) {
+ e = NULL;
+ break;
+ }
+ e = &qp->s_ack_queue[prev];
+ if (!e->opcode) {
+ e = NULL;
+ break;
+ }
+ if (cmp_psn(psn, e->psn) >= 0) {
+ if (prev == qp->s_tail_ack_queue &&
+ cmp_psn(psn, e->lpsn) <= 0)
+ old_req = 0;
+ break;
+ }
+ }
+ switch (opcode) {
+ case OP(RDMA_READ_REQUEST): {
+ struct ib_reth *reth;
+ u32 offset;
+ u32 len;
+
+ /*
+ * If we didn't find the RDMA read request in the ack queue,
+ * we can ignore this request.
+ */
+ if (!e || e->opcode != OP(RDMA_READ_REQUEST))
+ goto unlock_done;
+ /* RETH comes after BTH */
+ reth = &ohdr->u.rc.reth;
+ /*
+ * Address range must be a subset of the original
+ * request and start on pmtu boundaries.
+ * We reuse the old ack_queue slot since the requester
+ * should not back up and request an earlier PSN for the
+ * same request.
+ */
+ offset = delta_psn(psn, e->psn) * qp->pmtu;
+ len = be32_to_cpu(reth->length);
+ if (unlikely(offset + len != e->rdma_sge.sge_length))
+ goto unlock_done;
+ if (e->rdma_sge.mr) {
+ hfi1_put_mr(e->rdma_sge.mr);
+ e->rdma_sge.mr = NULL;
+ }
+ if (len != 0) {
+ u32 rkey = be32_to_cpu(reth->rkey);
+ u64 vaddr = be64_to_cpu(reth->vaddr);
+ int ok;
+
+ ok = hfi1_rkey_ok(qp, &e->rdma_sge, len, vaddr, rkey,
+ IB_ACCESS_REMOTE_READ);
+ if (unlikely(!ok))
+ goto unlock_done;
+ } else {
+ e->rdma_sge.vaddr = NULL;
+ e->rdma_sge.length = 0;
+ e->rdma_sge.sge_length = 0;
+ }
+ e->psn = psn;
+ if (old_req)
+ goto unlock_done;
+ qp->s_tail_ack_queue = prev;
+ break;
+ }
+
+ case OP(COMPARE_SWAP):
+ case OP(FETCH_ADD): {
+ /*
+ * If we didn't find the atomic request in the ack queue
+ * or the send tasklet is already backed up to send an
+ * earlier entry, we can ignore this request.
+ */
+ if (!e || e->opcode != (u8) opcode || old_req)
+ goto unlock_done;
+ qp->s_tail_ack_queue = prev;
+ break;
+ }
+
+ default:
+ /*
+ * Ignore this operation if it doesn't request an ACK
+ * or an earlier RDMA read or atomic is going to be resent.
+ */
+ if (!(psn & IB_BTH_REQ_ACK) || old_req)
+ goto unlock_done;
+ /*
+ * Resend the most recent ACK if this request is
+ * after all the previous RDMA reads and atomics.
+ */
+ if (i == qp->r_head_ack_queue) {
+ spin_unlock_irqrestore(&qp->s_lock, flags);
+ qp->r_nak_state = 0;
+ qp->r_ack_psn = qp->r_psn - 1;
+ goto send_ack;
+ }
+
+ /*
+ * Resend the RDMA read or atomic op which
+ * ACKs this duplicate request.
+ */
+ qp->s_tail_ack_queue = i;
+ break;
+ }
+ qp->s_ack_state = OP(ACKNOWLEDGE);
+ qp->s_flags |= HFI1_S_RESP_PENDING;
+ qp->r_nak_state = 0;
+ hfi1_schedule_send(qp);
+
+unlock_done:
+ spin_unlock_irqrestore(&qp->s_lock, flags);
+done:
+ return 1;
+
+send_ack:
+ return 0;
+}
+
+void hfi1_rc_error(struct hfi1_qp *qp, enum ib_wc_status err)
+{
+ unsigned long flags;
+ int lastwqe;
+
+ spin_lock_irqsave(&qp->s_lock, flags);
+ lastwqe = hfi1_error_qp(qp, err);
+ spin_unlock_irqrestore(&qp->s_lock, flags);
+
+ if (lastwqe) {
+ struct ib_event ev;
+
+ ev.device = qp->ibqp.device;
+ ev.element.qp = &qp->ibqp;
+ ev.event = IB_EVENT_QP_LAST_WQE_REACHED;
+ qp->ibqp.event_handler(&ev, qp->ibqp.qp_context);
+ }
+}
+
+static inline void update_ack_queue(struct hfi1_qp *qp, unsigned n)
+{
+ unsigned next;
+
+ next = n + 1;
+ if (next > HFI1_MAX_RDMA_ATOMIC)
+ next = 0;
+ qp->s_tail_ack_queue = next;
+ qp->s_ack_state = OP(ACKNOWLEDGE);
+}
+
+static void log_cca_event(struct hfi1_pportdata *ppd, u8 sl, u32 rlid,
+ u32 lqpn, u32 rqpn, u8 svc_type)
+{
+ struct opa_hfi1_cong_log_event_internal *cc_event;
+
+ if (sl >= OPA_MAX_SLS)
+ return;
+
+ spin_lock(&ppd->cc_log_lock);
+
+ ppd->threshold_cong_event_map[sl/8] |= 1 << (sl % 8);
+ ppd->threshold_event_counter++;
+
+ cc_event = &ppd->cc_events[ppd->cc_log_idx++];
+ if (ppd->cc_log_idx == OPA_CONG_LOG_ELEMS)
+ ppd->cc_log_idx = 0;
+ cc_event->lqpn = lqpn & HFI1_QPN_MASK;
+ cc_event->rqpn = rqpn & HFI1_QPN_MASK;
+ cc_event->sl = sl;
+ cc_event->svc_type = svc_type;
+ cc_event->rlid = rlid;
+ /* keep timestamp in units of 1.024 usec */
+ cc_event->timestamp = ktime_to_ns(ktime_get()) / 1024;
+
+ spin_unlock(&ppd->cc_log_lock);
+}
+
+void process_becn(struct hfi1_pportdata *ppd, u8 sl, u16 rlid, u32 lqpn,
+ u32 rqpn, u8 svc_type)
+{
+ struct cca_timer *cca_timer;
+ u16 ccti, ccti_incr, ccti_timer, ccti_limit;
+ u8 trigger_threshold;
+ struct cc_state *cc_state;
+
+ if (sl >= OPA_MAX_SLS)
+ return;
+
+ cca_timer = &ppd->cca_timer[sl];
+
+ rcu_read_lock();
+
+ cc_state = get_cc_state(ppd);
+
+ if (cc_state == NULL) {
+ rcu_read_unlock();
+ return;
+ }
+
+ /*
+ * 1) increase CCTI (for this SL)
+ * 2) select IPG (i.e., call set_link_ipg())
+ * 3) start timer
+ */
+ ccti_limit = cc_state->cct.ccti_limit;
+ ccti_incr = cc_state->cong_setting.entries[sl].ccti_increase;
+ ccti_timer = cc_state->cong_setting.entries[sl].ccti_timer;
+ trigger_threshold =
+ cc_state->cong_setting.entries[sl].trigger_threshold;
+
+ spin_lock(&ppd->cca_timer_lock);
+
+ if (cca_timer->ccti < ccti_limit) {
+ if (cca_timer->ccti + ccti_incr <= ccti_limit)
+ cca_timer->ccti += ccti_incr;
+ else
+ cca_timer->ccti = ccti_limit;
+ set_link_ipg(ppd);
+ }
+
+ spin_unlock(&ppd->cca_timer_lock);
+
+ rcu_read_unlock();
+
+ ccti = cca_timer->ccti;
+
+ if (!hrtimer_active(&cca_timer->hrtimer)) {
+ /* ccti_timer is in units of 1.024 usec */
+ unsigned long nsec = 1024 * ccti_timer;
+
+ hrtimer_start(&cca_timer->hrtimer, ns_to_ktime(nsec),
+ HRTIMER_MODE_REL);
+ }
+
+ if ((trigger_threshold != 0) && (ccti >= trigger_threshold))
+ log_cca_event(ppd, sl, rlid, lqpn, rqpn, svc_type);
+}
+
+/**
+ * hfi1_rc_rcv - process an incoming RC packet
+ * @rcd: the context pointer
+ * @hdr: the header of this packet
+ * @rcv_flags: flags relevant to rcv processing
+ * @data: the packet data
+ * @tlen: the packet length
+ * @qp: the QP for this packet
+ *
+ * This is called from qp_rcv() to process an incoming RC packet
+ * for the given QP.
+ * Called at interrupt level.
+ */
+void hfi1_rc_rcv(struct hfi1_ctxtdata *rcd, struct hfi1_ib_header *hdr,
+ u32 rcv_flags, void *data, u32 tlen, struct hfi1_qp *qp)
+{
+ struct hfi1_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
+ struct hfi1_pportdata *ppd = ppd_from_ibp(ibp);
+ struct hfi1_other_headers *ohdr;
+ u32 bth0, opcode;
+ u32 hdrsize;
+ u32 psn;
+ u32 pad;
+ u8 sl;
+ struct ib_wc wc;
+ u32 pmtu = qp->pmtu;
+ int diff;
+ struct ib_reth *reth;
+ unsigned long flags;
+ int has_grh = rcv_flags & HFI1_HAS_GRH;
+ int ret, is_becn, is_fecn;
+
+ /* Check for GRH */
+ if (!has_grh) {
+ ohdr = &hdr->u.oth;
+ hdrsize = 8 + 12; /* LRH + BTH */
+ } else {
+ ohdr = &hdr->u.l.oth;
+ hdrsize = 8 + 40 + 12; /* LRH + GRH + BTH */
+ }
+
+ sl = qp->remote_ah_attr.sl;
+
+ bth0 = be32_to_cpu(ohdr->bth[0]);
+ if (hfi1_ruc_check_hdr(ibp, hdr, has_grh, qp, bth0))
+ return;
+
+ is_becn = (be32_to_cpu(ohdr->bth[1]) >> HFI1_BECN_SHIFT) &
+ HFI1_BECN_MASK;
+ if (is_becn) {
+ u16 rlid = qp->remote_ah_attr.dlid;
+ u32 lqpn, rqpn;
+
+ lqpn = qp->ibqp.qp_num;
+ rqpn = qp->remote_qpn;
+ process_becn(ppd, sl, rlid, lqpn, rqpn, IB_CC_SVCTYPE_RC);
+ }
+
+ is_fecn = (be32_to_cpu(ohdr->bth[1]) >> HFI1_FECN_SHIFT) &
+ HFI1_FECN_MASK;
+
+ psn = be32_to_cpu(ohdr->bth[2]);
+ opcode = bth0 >> 24;
+
+ /*
+ * Process responses (ACKs) before anything else. Note that the
+ * packet sequence number will be for something in the send work
+ * queue rather than the expected receive packet sequence number.
+ * In other words, this QP is the requester.
+ */
+ if (opcode >= OP(RDMA_READ_RESPONSE_FIRST) &&
+ opcode <= OP(ATOMIC_ACKNOWLEDGE)) {
+ rc_rcv_resp(ibp, ohdr, data, tlen, qp, opcode, psn,
+ hdrsize, pmtu, rcd);
+ if (is_fecn)
+ goto send_ack;
+ return;
+ }
+
+ /* Compute 24 bits worth of difference. */
+ diff = delta_psn(psn, qp->r_psn);
+ if (unlikely(diff)) {
+ if (rc_rcv_error(ohdr, data, qp, opcode, psn, diff, rcd))
+ return;
+ goto send_ack;
+ }
+
+ /* Check for opcode sequence errors. */
+ switch (qp->r_state) {
+ case OP(SEND_FIRST):
+ case OP(SEND_MIDDLE):
+ if (opcode == OP(SEND_MIDDLE) ||
+ opcode == OP(SEND_LAST) ||
+ opcode == OP(SEND_LAST_WITH_IMMEDIATE))
+ break;
+ goto nack_inv;
+
+ case OP(RDMA_WRITE_FIRST):
+ case OP(RDMA_WRITE_MIDDLE):
+ if (opcode == OP(RDMA_WRITE_MIDDLE) ||
+ opcode == OP(RDMA_WRITE_LAST) ||
+ opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
+ break;
+ goto nack_inv;
+
+ default:
+ if (opcode == OP(SEND_MIDDLE) ||
+ opcode == OP(SEND_LAST) ||
+ opcode == OP(SEND_LAST_WITH_IMMEDIATE) ||
+ opcode == OP(RDMA_WRITE_MIDDLE) ||
+ opcode == OP(RDMA_WRITE_LAST) ||
+ opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE))
+ goto nack_inv;
+ /*
+ * Note that it is up to the requester to not send a new
+ * RDMA read or atomic operation before receiving an ACK
+ * for the previous operation.
+ */
+ break;
+ }
+
+ if (qp->state == IB_QPS_RTR && !(qp->r_flags & HFI1_R_COMM_EST)) {
+ qp->r_flags |= HFI1_R_COMM_EST;
+ if (qp->ibqp.event_handler) {
+ struct ib_event ev;
+
+ ev.device = qp->ibqp.device;
+ ev.element.qp = &qp->ibqp;
+ ev.event = IB_EVENT_COMM_EST;
+ qp->ibqp.event_handler(&ev, qp->ibqp.qp_context);
+ }
+ }
+
+ /* OK, process the packet. */
+ switch (opcode) {
+ case OP(SEND_FIRST):
+ ret = hfi1_get_rwqe(qp, 0);
+ if (ret < 0)
+ goto nack_op_err;
+ if (!ret)
+ goto rnr_nak;
+ qp->r_rcv_len = 0;
+ /* FALLTHROUGH */
+ case OP(SEND_MIDDLE):
+ case OP(RDMA_WRITE_MIDDLE):
+send_middle:
+ /* Check for invalid length PMTU or posted rwqe len. */
+ if (unlikely(tlen != (hdrsize + pmtu + 4)))
+ goto nack_inv;
+ qp->r_rcv_len += pmtu;
+ if (unlikely(qp->r_rcv_len > qp->r_len))
+ goto nack_inv;
+ hfi1_copy_sge(&qp->r_sge, data, pmtu, 1);
+ break;
+
+ case OP(RDMA_WRITE_LAST_WITH_IMMEDIATE):
+ /* consume RWQE */
+ ret = hfi1_get_rwqe(qp, 1);
+ if (ret < 0)
+ goto nack_op_err;
+ if (!ret)
+ goto rnr_nak;
+ goto send_last_imm;
+
+ case OP(SEND_ONLY):
+ case OP(SEND_ONLY_WITH_IMMEDIATE):
+ ret = hfi1_get_rwqe(qp, 0);
+ if (ret < 0)
+ goto nack_op_err;
+ if (!ret)
+ goto rnr_nak;
+ qp->r_rcv_len = 0;
+ if (opcode == OP(SEND_ONLY))
+ goto no_immediate_data;
+ /* FALLTHROUGH for SEND_ONLY_WITH_IMMEDIATE */
+ case OP(SEND_LAST_WITH_IMMEDIATE):
+send_last_imm:
+ wc.ex.imm_data = ohdr->u.imm_data;
+ hdrsize += 4;
+ wc.wc_flags = IB_WC_WITH_IMM;
+ goto send_last;
+ case OP(SEND_LAST):
+ case OP(RDMA_WRITE_LAST):
+no_immediate_data:
+ wc.wc_flags = 0;
+ wc.ex.imm_data = 0;
+send_last:
+ /* Get the number of bytes the message was padded by. */
+ pad = (bth0 >> 20) & 3;
+ /* Check for invalid length. */
+ /* LAST len should be >= 1 */
+ if (unlikely(tlen < (hdrsize + pad + 4)))
+ goto nack_inv;
+ /* Don't count the CRC. */
+ tlen -= (hdrsize + pad + 4);
+ wc.byte_len = tlen + qp->r_rcv_len;
+ if (unlikely(wc.byte_len > qp->r_len))
+ goto nack_inv;
+ hfi1_copy_sge(&qp->r_sge, data, tlen, 1);
+ hfi1_put_ss(&qp->r_sge);
+ qp->r_msn++;
+ if (!test_and_clear_bit(HFI1_R_WRID_VALID, &qp->r_aflags))
+ break;
+ wc.wr_id = qp->r_wr_id;
+ wc.status = IB_WC_SUCCESS;
+ if (opcode == OP(RDMA_WRITE_LAST_WITH_IMMEDIATE) ||
+ opcode == OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE))
+ wc.opcode = IB_WC_RECV_RDMA_WITH_IMM;
+ else
+ wc.opcode = IB_WC_RECV;
+ wc.qp = &qp->ibqp;
+ wc.src_qp = qp->remote_qpn;
+ wc.slid = qp->remote_ah_attr.dlid;
+ /*
+ * It seems that IB mandates the presence of an SL in a
+ * work completion only for the UD transport (see section
+ * 11.4.2 of IBTA Vol. 1).
+ *
+ * However, the way the SL is chosen below is consistent
+ * with the way that IB/qib works and is trying avoid
+ * introducing incompatibilities.
+ *
+ * See also OPA Vol. 1, section 9.7.6, and table 9-17.
+ */
+ wc.sl = qp->remote_ah_attr.sl;
+ /* zero fields that are N/A */
+ wc.vendor_err = 0;
+ wc.pkey_index = 0;
+ wc.dlid_path_bits = 0;
+ wc.port_num = 0;
+ /* Signal completion event if the solicited bit is set. */
+ hfi1_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
+ (bth0 & IB_BTH_SOLICITED) != 0);
+ break;
+
+ case OP(RDMA_WRITE_FIRST):
+ case OP(RDMA_WRITE_ONLY):
+ case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE):
+ if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_WRITE)))
+ goto nack_inv;
+ /* consume RWQE */
+ reth = &ohdr->u.rc.reth;
+ hdrsize += sizeof(*reth);
+ qp->r_len = be32_to_cpu(reth->length);
+ qp->r_rcv_len = 0;
+ qp->r_sge.sg_list = NULL;
+ if (qp->r_len != 0) {
+ u32 rkey = be32_to_cpu(reth->rkey);
+ u64 vaddr = be64_to_cpu(reth->vaddr);
+ int ok;
+
+ /* Check rkey & NAK */
+ ok = hfi1_rkey_ok(qp, &qp->r_sge.sge, qp->r_len, vaddr,
+ rkey, IB_ACCESS_REMOTE_WRITE);
+ if (unlikely(!ok))
+ goto nack_acc;
+ qp->r_sge.num_sge = 1;
+ } else {
+ qp->r_sge.num_sge = 0;
+ qp->r_sge.sge.mr = NULL;
+ qp->r_sge.sge.vaddr = NULL;
+ qp->r_sge.sge.length = 0;
+ qp->r_sge.sge.sge_length = 0;
+ }
+ if (opcode == OP(RDMA_WRITE_FIRST))
+ goto send_middle;
+ else if (opcode == OP(RDMA_WRITE_ONLY))
+ goto no_immediate_data;
+ ret = hfi1_get_rwqe(qp, 1);
+ if (ret < 0)
+ goto nack_op_err;
+ if (!ret)
+ goto rnr_nak;
+ wc.ex.imm_data = ohdr->u.rc.imm_data;
+ hdrsize += 4;
+ wc.wc_flags = IB_WC_WITH_IMM;
+ goto send_last;
+
+ case OP(RDMA_READ_REQUEST): {
+ struct hfi1_ack_entry *e;
+ u32 len;
+ u8 next;
+
+ if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_READ)))
+ goto nack_inv;
+ next = qp->r_head_ack_queue + 1;
+ /* s_ack_queue is size HFI1_MAX_RDMA_ATOMIC+1 so use > not >= */
+ if (next > HFI1_MAX_RDMA_ATOMIC)
+ next = 0;
+ spin_lock_irqsave(&qp->s_lock, flags);
+ if (unlikely(next == qp->s_tail_ack_queue)) {
+ if (!qp->s_ack_queue[next].sent)
+ goto nack_inv_unlck;
+ update_ack_queue(qp, next);
+ }
+ e = &qp->s_ack_queue[qp->r_head_ack_queue];
+ if (e->opcode == OP(RDMA_READ_REQUEST) && e->rdma_sge.mr) {
+ hfi1_put_mr(e->rdma_sge.mr);
+ e->rdma_sge.mr = NULL;
+ }
+ reth = &ohdr->u.rc.reth;
+ len = be32_to_cpu(reth->length);
+ if (len) {
+ u32 rkey = be32_to_cpu(reth->rkey);
+ u64 vaddr = be64_to_cpu(reth->vaddr);
+ int ok;
+
+ /* Check rkey & NAK */
+ ok = hfi1_rkey_ok(qp, &e->rdma_sge, len, vaddr,
+ rkey, IB_ACCESS_REMOTE_READ);
+ if (unlikely(!ok))
+ goto nack_acc_unlck;
+ /*
+ * Update the next expected PSN. We add 1 later
+ * below, so only add the remainder here.
+ */
+ if (len > pmtu)
+ qp->r_psn += (len - 1) / pmtu;
+ } else {
+ e->rdma_sge.mr = NULL;
+ e->rdma_sge.vaddr = NULL;
+ e->rdma_sge.length = 0;
+ e->rdma_sge.sge_length = 0;
+ }
+ e->opcode = opcode;
+ e->sent = 0;
+ e->psn = psn;
+ e->lpsn = qp->r_psn;
+ /*
+ * We need to increment the MSN here instead of when we
+ * finish sending the result since a duplicate request would
+ * increment it more than once.
+ */
+ qp->r_msn++;
+ qp->r_psn++;
+ qp->r_state = opcode;
+ qp->r_nak_state = 0;
+ qp->r_head_ack_queue = next;
+
+ /* Schedule the send tasklet. */
+ qp->s_flags |= HFI1_S_RESP_PENDING;
+ hfi1_schedule_send(qp);
+
+ spin_unlock_irqrestore(&qp->s_lock, flags);
+ if (is_fecn)
+ goto send_ack;
+ return;
+ }
+
+ case OP(COMPARE_SWAP):
+ case OP(FETCH_ADD): {
+ struct ib_atomic_eth *ateth;
+ struct hfi1_ack_entry *e;
+ u64 vaddr;
+ atomic64_t *maddr;
+ u64 sdata;
+ u32 rkey;
+ u8 next;
+
+ if (unlikely(!(qp->qp_access_flags & IB_ACCESS_REMOTE_ATOMIC)))
+ goto nack_inv;
+ next = qp->r_head_ack_queue + 1;
+ if (next > HFI1_MAX_RDMA_ATOMIC)
+ next = 0;
+ spin_lock_irqsave(&qp->s_lock, flags);
+ if (unlikely(next == qp->s_tail_ack_queue)) {
+ if (!qp->s_ack_queue[next].sent)
+ goto nack_inv_unlck;
+ update_ack_queue(qp, next);
+ }
+ e = &qp->s_ack_queue[qp->r_head_ack_queue];
+ if (e->opcode == OP(RDMA_READ_REQUEST) && e->rdma_sge.mr) {
+ hfi1_put_mr(e->rdma_sge.mr);
+ e->rdma_sge.mr = NULL;
+ }
+ ateth = &ohdr->u.atomic_eth;
+ vaddr = ((u64) be32_to_cpu(ateth->vaddr[0]) << 32) |
+ be32_to_cpu(ateth->vaddr[1]);
+ if (unlikely(vaddr & (sizeof(u64) - 1)))
+ goto nack_inv_unlck;
+ rkey = be32_to_cpu(ateth->rkey);
+ /* Check rkey & NAK */
+ if (unlikely(!hfi1_rkey_ok(qp, &qp->r_sge.sge, sizeof(u64),
+ vaddr, rkey,
+ IB_ACCESS_REMOTE_ATOMIC)))
+ goto nack_acc_unlck;
+ /* Perform atomic OP and save result. */
+ maddr = (atomic64_t *) qp->r_sge.sge.vaddr;
+ sdata = be64_to_cpu(ateth->swap_data);
+ e->atomic_data = (opcode == OP(FETCH_ADD)) ?
+ (u64) atomic64_add_return(sdata, maddr) - sdata :
+ (u64) cmpxchg((u64 *) qp->r_sge.sge.vaddr,
+ be64_to_cpu(ateth->compare_data),
+ sdata);
+ hfi1_put_mr(qp->r_sge.sge.mr);
+ qp->r_sge.num_sge = 0;
+ e->opcode = opcode;
+ e->sent = 0;
+ e->psn = psn;
+ e->lpsn = psn;
+ qp->r_msn++;
+ qp->r_psn++;
+ qp->r_state = opcode;
+ qp->r_nak_state = 0;
+ qp->r_head_ack_queue = next;
+
+ /* Schedule the send tasklet. */
+ qp->s_flags |= HFI1_S_RESP_PENDING;
+ hfi1_schedule_send(qp);
+
+ spin_unlock_irqrestore(&qp->s_lock, flags);
+ if (is_fecn)
+ goto send_ack;
+ return;
+ }
+
+ default:
+ /* NAK unknown opcodes. */
+ goto nack_inv;
+ }
+ qp->r_psn++;
+ qp->r_state = opcode;
+ qp->r_ack_psn = psn;
+ qp->r_nak_state = 0;
+ /* Send an ACK if requested or required. */
+ if (psn & (1 << 31))
+ goto send_ack;
+ return;
+
+rnr_nak:
+ qp->r_nak_state = IB_RNR_NAK | qp->r_min_rnr_timer;
+ qp->r_ack_psn = qp->r_psn;
+ /* Queue RNR NAK for later */
+ if (list_empty(&qp->rspwait)) {
+ qp->r_flags |= HFI1_R_RSP_NAK;
+ atomic_inc(&qp->refcount);
+ list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
+ }
+ return;
+
+nack_op_err:
+ hfi1_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
+ qp->r_nak_state = IB_NAK_REMOTE_OPERATIONAL_ERROR;
+ qp->r_ack_psn = qp->r_psn;
+ /* Queue NAK for later */
+ if (list_empty(&qp->rspwait)) {
+ qp->r_flags |= HFI1_R_RSP_NAK;
+ atomic_inc(&qp->refcount);
+ list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
+ }
+ return;
+
+nack_inv_unlck:
+ spin_unlock_irqrestore(&qp->s_lock, flags);
+nack_inv:
+ hfi1_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
+ qp->r_nak_state = IB_NAK_INVALID_REQUEST;
+ qp->r_ack_psn = qp->r_psn;
+ /* Queue NAK for later */
+ if (list_empty(&qp->rspwait)) {
+ qp->r_flags |= HFI1_R_RSP_NAK;
+ atomic_inc(&qp->refcount);
+ list_add_tail(&qp->rspwait, &rcd->qp_wait_list);
+ }
+ return;
+
+nack_acc_unlck:
+ spin_unlock_irqrestore(&qp->s_lock, flags);
+nack_acc:
+ hfi1_rc_error(qp, IB_WC_LOC_PROT_ERR);
+ qp->r_nak_state = IB_NAK_REMOTE_ACCESS_ERROR;
+ qp->r_ack_psn = qp->r_psn;
+send_ack:
+ hfi1_send_rc_ack(rcd, qp, is_fecn);
+}
+
+void hfi1_rc_hdrerr(
+ struct hfi1_ctxtdata *rcd,
+ struct hfi1_ib_header *hdr,
+ u32 rcv_flags,
+ struct hfi1_qp *qp)
+{
+ int has_grh = rcv_flags & HFI1_HAS_GRH;
+ struct hfi1_other_headers *ohdr;
+ struct hfi1_ibport *ibp = to_iport(qp->ibqp.device, qp->port_num);
+ int diff;
+ u8 opcode;
+ u32 psn;
+
+ /* Check for GRH */
+ ohdr = &hdr->u.oth;
+ if (has_grh)
+ ohdr = &hdr->u.l.oth;
+
+ opcode = be32_to_cpu(ohdr->bth[0]);
+ if (hfi1_ruc_check_hdr(ibp, hdr, has_grh, qp, opcode))
+ return;
+
+ psn = be32_to_cpu(ohdr->bth[2]);
+ opcode >>= 24;
+
+ /* Only deal with RDMA Writes for now */
+ if (opcode < IB_OPCODE_RC_RDMA_READ_RESPONSE_FIRST) {
+ diff = delta_psn(psn, qp->r_psn);
+ if (!qp->r_nak_state && diff >= 0) {
+ ibp->n_rc_seqnak++;
+ qp->r_nak_state = IB_NAK_PSN_ERROR;
+ /* Use the expected PSN. */
+ qp->r_ack_psn = qp->r_psn;
+ /*
+ * Wait to send the sequence
+ * NAK until all packets
+ * in the receive queue have
+ * been processed.
+ * Otherwise, we end up
+ * propagating congestion.
+ */
+ if (list_empty(&qp->rspwait)) {
+ qp->r_flags |= HFI1_R_RSP_NAK;
+ atomic_inc(&qp->refcount);
+ list_add_tail(
+ &qp->rspwait,
+ &rcd->qp_wait_list);
+ }
+ } /* Out of sequence NAK */
+ } /* QP Request NAKs */
+}