[openib-general] [PATCH 14 of 18] ipath - infiniband RC protocol support
Bryan O'Sullivan
bos at pathscale.com
Thu Mar 23 20:41:46 PST 2006
This is an implementation of the Infiniband RC ("reliable connection")
protocol.
Signed-off-by: Bryan O'Sullivan <bos at pathscale.com>
diff -r 572e99c2ab63 -r c57bdbdddd16 drivers/infiniband/hw/ipath/ipath_rc.c
--- /dev/null Thu Jan 1 00:00:00 1970 +0000
+++ b/drivers/infiniband/hw/ipath/ipath_rc.c Thu Mar 23 20:27:45 2006 -0800
@@ -0,0 +1,1864 @@
+/*
+ * Copyright (c) 2005, 2006 PathScale, Inc. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses. You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer in the documentation and/or other materials
+ * provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "ipath_verbs.h"
+#include "ips_common.h"
+
+/* cut down ridiculously long IB macro names */
+#define OP(x) IB_OPCODE_RC_##x
+
+/**
+ * ipath_init_restart- initialize the qp->s_sge after a restart
+ * @qp: the QP who's SGE we're restarting
+ * @wqe: the work queue to initialize the QP's SGE from
+ *
+ * The QP s_lock should be held.
+ */
+static void ipath_init_restart(struct ipath_qp *qp, struct ipath_swqe *wqe)
+{
+ struct ipath_ibdev *dev;
+ u32 len;
+
+ len = ((qp->s_psn - wqe->psn) & IPS_PSN_MASK) *
+ ib_mtu_enum_to_int(qp->path_mtu);
+ 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;
+ ipath_skip_sge(&qp->s_sge, len);
+ qp->s_len = wqe->length - len;
+ dev = to_idev(qp->ibqp.device);
+ spin_lock(&dev->pending_lock);
+ if (qp->timerwait.next == LIST_POISON1)
+ list_add_tail(&qp->timerwait,
+ &dev->pending[dev->pending_index]);
+ spin_unlock(&dev->pending_lock);
+}
+
+/**
+ * ipath_make_rc_ack - construct a response packet (ACK, NAK, or RDMA read)
+ * @qp: a pointer to the QP
+ * @ohdr: a pointer to the IB header being constructed
+ * @pmtu: the path MTU
+ *
+ * Return bth0 if constructed; otherwise, return 0.
+ * Note the QP s_lock must be held.
+ */
+static inline u32 ipath_make_rc_ack(struct ipath_qp *qp,
+ struct ipath_other_headers *ohdr,
+ u32 pmtu)
+{
+ struct ipath_sge_state *ss;
+ u32 hwords;
+ u32 len;
+ u32 bth0;
+
+ /* header size in 32-bit words LRH+BTH = (8+12)/4. */
+ hwords = 5;
+
+ /*
+ * Send a response. Note that we are in the responder's
+ * side of the QP context.
+ */
+ switch (qp->s_ack_state) {
+ case OP(RDMA_READ_REQUEST):
+ ss = &qp->s_rdma_sge;
+ len = qp->s_rdma_len;
+ if (len > pmtu) {
+ len = pmtu;
+ qp->s_ack_state = OP(RDMA_READ_RESPONSE_FIRST);
+ }
+ else
+ qp->s_ack_state = OP(RDMA_READ_RESPONSE_ONLY);
+ qp->s_rdma_len -= len;
+ bth0 = qp->s_ack_state << 24;
+ ohdr->u.aeth = ipath_compute_aeth(qp);
+ hwords++;
+ break;
+
+ case OP(RDMA_READ_RESPONSE_FIRST):
+ qp->s_ack_state = OP(RDMA_READ_RESPONSE_MIDDLE);
+ /* FALLTHROUGH */
+ case OP(RDMA_READ_RESPONSE_MIDDLE):
+ ss = &qp->s_rdma_sge;
+ len = qp->s_rdma_len;
+ if (len > pmtu)
+ len = pmtu;
+ else {
+ ohdr->u.aeth = ipath_compute_aeth(qp);
+ hwords++;
+ qp->s_ack_state = OP(RDMA_READ_RESPONSE_LAST);
+ }
+ qp->s_rdma_len -= len;
+ bth0 = qp->s_ack_state << 24;
+ break;
+
+ case OP(RDMA_READ_RESPONSE_LAST):
+ case OP(RDMA_READ_RESPONSE_ONLY):
+ /*
+ * We have to prevent new requests from changing
+ * the r_sge state while a ipath_verbs_send()
+ * is in progress.
+ * Changing r_state allows the receiver
+ * to continue processing new packets.
+ * We do it here now instead of above so
+ * that we are sure the packet was sent before
+ * changing the state.
+ */
+ qp->r_state = OP(RDMA_READ_RESPONSE_LAST);
+ qp->s_ack_state = OP(ACKNOWLEDGE);
+ return 0;
+
+ case OP(COMPARE_SWAP):
+ case OP(FETCH_ADD):
+ ss = NULL;
+ len = 0;
+ qp->r_state = OP(SEND_LAST);
+ qp->s_ack_state = OP(ACKNOWLEDGE);
+ bth0 = IB_OPCODE_ATOMIC_ACKNOWLEDGE << 24;
+ ohdr->u.at.aeth = ipath_compute_aeth(qp);
+ ohdr->u.at.atomic_ack_eth = cpu_to_be64(qp->s_ack_atomic);
+ hwords += sizeof(ohdr->u.at) / 4;
+ break;
+
+ default:
+ /* Send a regular ACK. */
+ ss = NULL;
+ len = 0;
+ qp->s_ack_state = OP(ACKNOWLEDGE);
+ bth0 = qp->s_ack_state << 24;
+ ohdr->u.aeth = ipath_compute_aeth(qp);
+ hwords++;
+ }
+ qp->s_hdrwords = hwords;
+ qp->s_cur_sge = ss;
+ qp->s_cur_size = len;
+
+ return bth0;
+}
+
+/**
+ * ipath_make_rc_req - construct a request packet (SEND, RDMA r/w, ATOMIC)
+ * @qp: a pointer to the QP
+ * @ohdr: a pointer to the IB header being constructed
+ * @pmtu: the path MTU
+ * @bth0p: pointer to the BTH opcode word
+ * @bth2p: pointer to the BTH PSN word
+ *
+ * Return 1 if constructed; otherwise, return 0.
+ * Note the QP s_lock must be held.
+ */
+static inline int ipath_make_rc_req(struct ipath_qp *qp,
+ struct ipath_other_headers *ohdr,
+ u32 pmtu, u32 *bth0p, u32 *bth2p)
+{
+ struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
+ struct ipath_sge_state *ss;
+ struct ipath_swqe *wqe;
+ u32 hwords;
+ u32 len;
+ u32 bth0;
+ u32 bth2;
+ char newreq;
+
+ if (!(ib_ipath_state_ops[qp->state] & IPATH_PROCESS_SEND_OK) ||
+ qp->s_rnr_timeout)
+ goto done;
+
+ /* header size in 32-bit words LRH+BTH = (8+12)/4. */
+ hwords = 5;
+ bth0 = 0;
+
+ /* Send a request. */
+ wqe = get_swqe_ptr(qp, qp->s_cur);
+ switch (qp->s_state) {
+ default:
+ /*
+ * 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)
+ goto done;
+ qp->s_psn = 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.
+ */
+ 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_len = len = wqe->length;
+ ss = &qp->s_sge;
+ bth2 = 0;
+ switch (wqe->wr.opcode) {
+ case IB_WR_SEND:
+ case IB_WR_SEND_WITH_IMM:
+ /* If no credit, return. */
+ if (qp->s_lsn != (u32) -1 &&
+ ipath_cmp24(wqe->ssn, qp->s_lsn + 1) > 0)
+ goto done;
+ 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.imm_data;
+ hwords += 1;
+ }
+ if (wqe->wr.send_flags & IB_SEND_SOLICITED)
+ bth0 |= 1 << 23;
+ bth2 = 1 << 31; /* Request ACK. */
+ if (++qp->s_cur == qp->s_size)
+ qp->s_cur = 0;
+ break;
+
+ case IB_WR_RDMA_WRITE:
+ if (newreq)
+ qp->s_lsn++;
+ /* FALLTHROUGH */
+ case IB_WR_RDMA_WRITE_WITH_IMM:
+ /* If no credit, return. */
+ if (qp->s_lsn != (u32) -1 &&
+ ipath_cmp24(wqe->ssn, qp->s_lsn + 1) > 0)
+ goto done;
+ 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) / 4;
+ 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.imm_data;
+ hwords += 1;
+ if (wqe->wr.send_flags & IB_SEND_SOLICITED)
+ bth0 |= 1 << 23;
+ }
+ bth2 = 1 << 31; /* Request ACK. */
+ if (++qp->s_cur == qp->s_size)
+ qp->s_cur = 0;
+ break;
+
+ case IB_WR_RDMA_READ:
+ 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) / 4;
+ if (newreq) {
+ 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++;
+ }
+ ss = NULL;
+ len = 0;
+ 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:
+ qp->s_state = (wqe->wr.opcode ==
+ IB_WR_ATOMIC_CMP_AND_SWP) ?
+ OP(COMPARE_SWAP) : OP(FETCH_ADD);
+ ohdr->u.atomic_eth.vaddr =
+ cpu_to_be64(wqe->wr.wr.atomic.remote_addr);
+ ohdr->u.atomic_eth.rkey =
+ cpu_to_be32(wqe->wr.wr.atomic.rkey);
+ 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);
+ hwords += sizeof(struct ib_atomic_eth) / 4;
+ if (newreq) {
+ qp->s_lsn++;
+ wqe->lpsn = wqe->psn;
+ }
+ if (++qp->s_cur == qp->s_size)
+ qp->s_cur = 0;
+ ss = NULL;
+ len = 0;
+ break;
+
+ default:
+ goto done;
+ }
+ if (newreq) {
+ qp->s_tail++;
+ if (qp->s_tail >= qp->s_size)
+ qp->s_tail = 0;
+ }
+ bth2 |= qp->s_psn++ & IPS_PSN_MASK;
+ if ((int)(qp->s_psn - qp->s_next_psn) > 0)
+ qp->s_next_psn = qp->s_psn;
+ spin_lock(&dev->pending_lock);
+ if (qp->timerwait.next == LIST_POISON1)
+ list_add_tail(&qp->timerwait,
+ &dev->pending[dev->pending_index]);
+ spin_unlock(&dev->pending_lock);
+ break;
+
+ case OP(RDMA_READ_RESPONSE_FIRST):
+ /*
+ * This case can only happen if a send is
+ * restarted. See ipath_restart_rc().
+ */
+ ipath_init_restart(qp, wqe);
+ /* FALLTHROUGH */
+ case OP(SEND_FIRST):
+ qp->s_state = OP(SEND_MIDDLE);
+ /* FALLTHROUGH */
+ case OP(SEND_MIDDLE):
+ bth2 = qp->s_psn++ & IPS_PSN_MASK;
+ if ((int)(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) {
+ /*
+ * Request an ACK every 1/2 MB to avoid
+ * retransmit timeouts.
+ */
+ if (((wqe->length - len) % (512 * 1024)) == 0)
+ bth2 |= 1 << 31;
+ len = pmtu;
+ break;
+ }
+ if (wqe->wr.opcode == IB_WR_SEND)
+ qp->s_state = OP(SEND_LAST);
+ else {
+ qp->s_state = OP(SEND_LAST_WITH_IMMEDIATE);
+ /* Immediate data comes after the BTH */
+ ohdr->u.imm_data = wqe->wr.imm_data;
+ hwords += 1;
+ }
+ if (wqe->wr.send_flags & IB_SEND_SOLICITED)
+ bth0 |= 1 << 23;
+ bth2 |= 1 << 31; /* Request ACK. */
+ qp->s_cur++;
+ if (qp->s_cur >= qp->s_size)
+ qp->s_cur = 0;
+ break;
+
+ case OP(RDMA_READ_RESPONSE_LAST):
+ /*
+ * This case can only happen if a RDMA write is
+ * restarted. See ipath_restart_rc().
+ */
+ ipath_init_restart(qp, wqe);
+ /* FALLTHROUGH */
+ case OP(RDMA_WRITE_FIRST):
+ qp->s_state = OP(RDMA_WRITE_MIDDLE);
+ /* FALLTHROUGH */
+ case OP(RDMA_WRITE_MIDDLE):
+ bth2 = qp->s_psn++ & IPS_PSN_MASK;
+ if ((int)(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) {
+ /*
+ * Request an ACK every 1/2 MB to avoid
+ * retransmit timeouts.
+ */
+ if (((wqe->length - len) % (512 * 1024)) == 0)
+ bth2 |= 1 << 31;
+ len = pmtu;
+ break;
+ }
+ if (wqe->wr.opcode == IB_WR_RDMA_WRITE)
+ qp->s_state = OP(RDMA_WRITE_LAST);
+ else {
+ qp->s_state = OP(RDMA_WRITE_LAST_WITH_IMMEDIATE);
+ /* Immediate data comes after the BTH */
+ ohdr->u.imm_data = wqe->wr.imm_data;
+ hwords += 1;
+ if (wqe->wr.send_flags & IB_SEND_SOLICITED)
+ bth0 |= 1 << 23;
+ }
+ bth2 |= 1 << 31; /* Request ACK. */
+ qp->s_cur++;
+ if (qp->s_cur >= qp->s_size)
+ qp->s_cur = 0;
+ break;
+
+ case OP(RDMA_READ_RESPONSE_MIDDLE):
+ /*
+ * This case can only happen if a RDMA read is
+ * restarted. See ipath_restart_rc().
+ */
+ ipath_init_restart(qp, wqe);
+ len = ((qp->s_psn - wqe->psn) & IPS_PSN_MASK) * 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(qp->s_len);
+ qp->s_state = OP(RDMA_READ_REQUEST);
+ hwords += sizeof(ohdr->u.rc.reth) / 4;
+ bth2 = qp->s_psn++ & IPS_PSN_MASK;
+ if ((int)(qp->s_psn - qp->s_next_psn) > 0)
+ qp->s_next_psn = qp->s_psn;
+ ss = NULL;
+ len = 0;
+ qp->s_cur++;
+ if (qp->s_cur == qp->s_size)
+ qp->s_cur = 0;
+ break;
+
+ case OP(RDMA_READ_REQUEST):
+ case OP(COMPARE_SWAP):
+ case OP(FETCH_ADD):
+ /*
+ * We shouldn't start anything new until this
+ * request is finished. The ACK will handle
+ * rescheduling us. XXX The number of outstanding
+ * ones is negotiated at connection setup time (see
+ * pg. 258,289)? XXX Also, if we support multiple
+ * outstanding requests, we need to check the WQE
+ * IB_SEND_FENCE flag and not send a new request if
+ * a RDMA read or atomic is pending.
+ */
+ goto done;
+ }
+ qp->s_len -= len;
+ qp->s_hdrwords = hwords;
+ qp->s_cur_sge = ss;
+ qp->s_cur_size = len;
+ *bth0p = bth0 | (qp->s_state << 24);
+ *bth2p = bth2;
+ return 1;
+
+done:
+ return 0;
+}
+
+static inline void ipath_make_rc_grh(struct ipath_qp *qp,
+ struct ib_global_route *grh,
+ u32 nwords)
+{
+ struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
+
+ /* GRH header size in 32-bit words. */
+ qp->s_hdrwords += 10;
+ qp->s_hdr.u.l.grh.version_tclass_flow =
+ cpu_to_be32((6 << 28) |
+ (grh->traffic_class << 20) |
+ grh->flow_label);
+ qp->s_hdr.u.l.grh.paylen =
+ cpu_to_be16(((qp->s_hdrwords - 12) + nwords +
+ SIZE_OF_CRC) << 2);
+ /* next_hdr is defined by C8-7 in ch. 8.4.1 */
+ qp->s_hdr.u.l.grh.next_hdr = 0x1B;
+ qp->s_hdr.u.l.grh.hop_limit = grh->hop_limit;
+ /* The SGID is 32-bit aligned. */
+ qp->s_hdr.u.l.grh.sgid.global.subnet_prefix = dev->gid_prefix;
+ qp->s_hdr.u.l.grh.sgid.global.interface_id =
+ ipath_layer_get_guid(dev->dd);
+ qp->s_hdr.u.l.grh.dgid = grh->dgid;
+}
+
+/**
+ * ipath_do_rc_send - perform a send on an RC QP
+ * @data: contains a pointer to the QP
+ *
+ * Process entries in the send work queue until credit or queue is
+ * exhausted. Only allow one CPU to send a packet per QP (tasklet).
+ * Otherwise, after we drop the QP s_lock, two threads could send
+ * packets out of order.
+ */
+void ipath_do_rc_send(unsigned long data)
+{
+ struct ipath_qp *qp = (struct ipath_qp *)data;
+ struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
+ unsigned long flags;
+ u16 lrh0;
+ u32 nwords;
+ u32 extra_bytes;
+ u32 bth0;
+ u32 bth2;
+ u32 pmtu = ib_mtu_enum_to_int(qp->path_mtu);
+ struct ipath_other_headers *ohdr;
+
+ if (test_and_set_bit(IPATH_S_BUSY, &qp->s_flags))
+ goto bail;
+
+ if (unlikely(qp->remote_ah_attr.dlid ==
+ ipath_layer_get_lid(dev->dd))) {
+ struct ib_wc wc;
+
+ /*
+ * Pass in an uninitialized ib_wc to be consistent with
+ * other places where ipath_ruc_loopback() is called.
+ */
+ ipath_ruc_loopback(qp, &wc);
+ goto clear;
+ }
+
+ ohdr = &qp->s_hdr.u.oth;
+ if (qp->remote_ah_attr.ah_flags & IB_AH_GRH)
+ ohdr = &qp->s_hdr.u.l.oth;
+
+again:
+ /* Check for a constructed packet to be sent. */
+ if (qp->s_hdrwords != 0) {
+ /*
+ * If no PIO bufs are available, return.
+ * An interrupt will call ipath_ib_piobufavail()
+ * when one is available.
+ */
+ _VERBS_INFO("h %u %p\n", qp->s_hdrwords, &qp->s_hdr);
+ _VERBS_INFO("d %u %p %u %p %u %u %u %u\n", qp->s_cur_size,
+ qp->s_cur_sge->sg_list,
+ qp->s_cur_sge->num_sge,
+ qp->s_cur_sge->sge.vaddr,
+ qp->s_cur_sge->sge.sge_length,
+ qp->s_cur_sge->sge.length,
+ qp->s_cur_sge->sge.m,
+ qp->s_cur_sge->sge.n);
+ if (ipath_verbs_send(dev->dd, qp->s_hdrwords,
+ (u32 *) &qp->s_hdr, qp->s_cur_size,
+ qp->s_cur_sge)) {
+ ipath_no_bufs_available(qp, dev);
+ goto bail;
+ }
+ dev->n_unicast_xmit++;
+ /* Record that we sent the packet and s_hdr is empty. */
+ qp->s_hdrwords = 0;
+ }
+
+ /*
+ * The lock is needed to synchronize between
+ * setting qp->s_ack_state, resend timer, and post_send().
+ */
+ spin_lock_irqsave(&qp->s_lock, flags);
+
+ /* Sending responses has higher priority over sending requests. */
+ if (qp->s_ack_state != OP(ACKNOWLEDGE) &&
+ (bth0 = ipath_make_rc_ack(qp, ohdr, pmtu)) != 0)
+ bth2 = qp->s_ack_psn++ & IPS_PSN_MASK;
+ else if (!ipath_make_rc_req(qp, ohdr, pmtu, &bth0, &bth2))
+ goto done;
+
+ spin_unlock_irqrestore(&qp->s_lock, flags);
+
+ /* Construct the header. */
+ extra_bytes = (4 - qp->s_cur_size) & 3;
+ nwords = (qp->s_cur_size + extra_bytes) >> 2;
+ lrh0 = IPS_LRH_BTH;
+ if (unlikely(qp->remote_ah_attr.ah_flags & IB_AH_GRH)) {
+ ipath_make_rc_grh(qp, &qp->remote_ah_attr.grh, nwords);
+ lrh0 = IPS_LRH_GRH;
+ }
+ lrh0 |= qp->remote_ah_attr.sl << 4;
+ qp->s_hdr.lrh[0] = cpu_to_be16(lrh0);
+ qp->s_hdr.lrh[1] = cpu_to_be16(qp->remote_ah_attr.dlid);
+ qp->s_hdr.lrh[2] = cpu_to_be16(qp->s_hdrwords + nwords + SIZE_OF_CRC);
+ qp->s_hdr.lrh[3] = cpu_to_be16(ipath_layer_get_lid(dev->dd));
+ bth0 |= ipath_layer_get_pkey(dev->dd, qp->s_pkey_index);
+ bth0 |= extra_bytes << 20;
+ ohdr->bth[0] = cpu_to_be32(bth0);
+ ohdr->bth[1] = cpu_to_be32(qp->remote_qpn);
+ ohdr->bth[2] = cpu_to_be32(bth2);
+
+ /* Check for more work to do. */
+ goto again;
+
+done:
+ spin_unlock_irqrestore(&qp->s_lock, flags);
+clear:
+ clear_bit(IPATH_S_BUSY, &qp->s_flags);
+bail:
+ return;
+}
+
+static void send_rc_ack(struct ipath_qp *qp)
+{
+ struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
+ u16 lrh0;
+ u32 bth0;
+ struct ipath_other_headers *ohdr;
+
+ /* Construct the header. */
+ ohdr = &qp->s_hdr.u.oth;
+ lrh0 = IPS_LRH_BTH;
+ /* header size in 32-bit words LRH+BTH+AETH = (8+12+4)/4. */
+ qp->s_hdrwords = 6;
+ if (unlikely(qp->remote_ah_attr.ah_flags & IB_AH_GRH)) {
+ ipath_make_rc_grh(qp, &qp->remote_ah_attr.grh, 0);
+ ohdr = &qp->s_hdr.u.l.oth;
+ lrh0 = IPS_LRH_GRH;
+ }
+ bth0 = ipath_layer_get_pkey(dev->dd, qp->s_pkey_index);
+ ohdr->u.aeth = ipath_compute_aeth(qp);
+ if (qp->s_ack_state >= OP(COMPARE_SWAP)) {
+ bth0 |= IB_OPCODE_ATOMIC_ACKNOWLEDGE << 24;
+ ohdr->u.at.atomic_ack_eth = cpu_to_be64(qp->s_ack_atomic);
+ qp->s_hdrwords += sizeof(ohdr->u.at.atomic_ack_eth) / 4;
+ }
+ else
+ bth0 |= OP(ACKNOWLEDGE) << 24;
+ lrh0 |= qp->remote_ah_attr.sl << 4;
+ qp->s_hdr.lrh[0] = cpu_to_be16(lrh0);
+ qp->s_hdr.lrh[1] = cpu_to_be16(qp->remote_ah_attr.dlid);
+ qp->s_hdr.lrh[2] = cpu_to_be16(qp->s_hdrwords + SIZE_OF_CRC);
+ qp->s_hdr.lrh[3] = cpu_to_be16(ipath_layer_get_lid(dev->dd));
+ ohdr->bth[0] = cpu_to_be32(bth0);
+ ohdr->bth[1] = cpu_to_be32(qp->remote_qpn);
+ ohdr->bth[2] = cpu_to_be32(qp->s_ack_psn & IPS_PSN_MASK);
+
+ /*
+ * If we can send the ACK, clear the ACK state.
+ */
+ if (ipath_verbs_send(dev->dd, qp->s_hdrwords, (u32 *) &qp->s_hdr,
+ 0, NULL) == 0) {
+ qp->s_ack_state = OP(ACKNOWLEDGE);
+ dev->n_rc_qacks++;
+ dev->n_unicast_xmit++;
+ }
+}
+
+/**
+ * ipath_restart_rc - back up requester to resend the last un-ACKed request
+ * @qp: the QP to restart
+ * @psn: packet sequence number for the request
+ * @wc: the work completion request
+ *
+ * The QP s_lock should be held.
+ */
+void ipath_restart_rc(struct ipath_qp *qp, u32 psn, struct ib_wc *wc)
+{
+ struct ipath_swqe *wqe = get_swqe_ptr(qp, qp->s_last);
+ struct ipath_ibdev *dev;
+ u32 n;
+
+ /*
+ * If there are no requests pending, we are done.
+ */
+ if (ipath_cmp24(psn, qp->s_next_psn) >= 0 ||
+ qp->s_last == qp->s_tail)
+ goto done;
+
+ if (qp->s_retry == 0) {
+ wc->wr_id = wqe->wr.wr_id;
+ wc->status = IB_WC_RETRY_EXC_ERR;
+ wc->opcode = ib_ipath_wc_opcode[wqe->wr.opcode];
+ wc->vendor_err = 0;
+ wc->byte_len = 0;
+ wc->qp_num = qp->ibqp.qp_num;
+ wc->src_qp = qp->remote_qpn;
+ wc->pkey_index = 0;
+ wc->slid = qp->remote_ah_attr.dlid;
+ wc->sl = qp->remote_ah_attr.sl;
+ wc->dlid_path_bits = 0;
+ wc->port_num = 0;
+ ipath_sqerror_qp(qp, wc);
+ goto bail;
+ }
+ qp->s_retry--;
+
+ /*
+ * Remove the QP from the timeout queue.
+ * Note: it may already have been removed by ipath_ib_timer().
+ */
+ dev = to_idev(qp->ibqp.device);
+ spin_lock(&dev->pending_lock);
+ if (qp->timerwait.next != LIST_POISON1)
+ list_del(&qp->timerwait);
+ spin_unlock(&dev->pending_lock);
+
+ if (wqe->wr.opcode == IB_WR_RDMA_READ)
+ dev->n_rc_resends++;
+ else
+ dev->n_rc_resends += (int)qp->s_psn - (int)psn;
+
+ /*
+ * If we are starting the request from the beginning, let the
+ * normal send code handle initialization.
+ */
+ qp->s_cur = qp->s_last;
+ if (ipath_cmp24(psn, wqe->psn) <= 0) {
+ qp->s_state = OP(SEND_LAST);
+ qp->s_psn = wqe->psn;
+ } else {
+ n = qp->s_cur;
+ for (;;) {
+ if (++n == qp->s_size)
+ n = 0;
+ if (n == qp->s_tail) {
+ if (ipath_cmp24(psn, qp->s_next_psn) >= 0) {
+ qp->s_cur = n;
+ wqe = get_swqe_ptr(qp, n);
+ }
+ break;
+ }
+ wqe = get_swqe_ptr(qp, n);
+ if (ipath_cmp24(psn, wqe->psn) < 0)
+ break;
+ qp->s_cur = n;
+ }
+ qp->s_psn = psn;
+
+ /*
+ * Reset the state to restart in the middle of a request.
+ * Don't change the s_sge, s_cur_sge, or s_cur_size.
+ * See ipath_do_rc_send().
+ */
+ switch (wqe->wr.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:
+ tasklet_hi_schedule(&qp->s_task);
+
+bail:
+ 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 ipath_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 ipath_qp *qp, u32 psn)
+{
+ struct ipath_swqe *wqe;
+ u32 n;
+
+ n = qp->s_cur;
+ wqe = get_swqe_ptr(qp, n);
+ for (;;) {
+ if (++n == qp->s_size)
+ n = 0;
+ if (n == qp->s_tail) {
+ if (ipath_cmp24(psn, qp->s_next_psn) >= 0) {
+ qp->s_cur = n;
+ wqe = get_swqe_ptr(qp, n);
+ }
+ break;
+ }
+ wqe = get_swqe_ptr(qp, n);
+ if (ipath_cmp24(psn, wqe->psn) < 0)
+ break;
+ qp->s_cur = n;
+ }
+ qp->s_psn = psn;
+
+ /*
+ * 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 ipath_do_rc_send().
+ */
+ switch (wqe->wr.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);
+ }
+}
+
+/**
+ * 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 ipath_rc_rcv() 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 ipath_qp *qp, u32 aeth, u32 psn, int opcode)
+{
+ struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
+ struct ib_wc wc;
+ struct ipath_swqe *wqe;
+ int ret = 0;
+
+ /*
+ * Remove the QP from the timeout queue (or RNR timeout queue).
+ * If ipath_ib_timer() has already removed it,
+ * it's OK since we hold the QP s_lock and ipath_restart_rc()
+ * just won't find anything to restart if we ACK everything.
+ */
+ spin_lock(&dev->pending_lock);
+ if (qp->timerwait.next != LIST_POISON1)
+ list_del(&qp->timerwait);
+ spin_unlock(&dev->pending_lock);
+
+ /*
+ * 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).
+ */
+ wqe = get_swqe_ptr(qp, qp->s_last);
+
+ /* Nothing is pending to ACK/NAK. */
+ if (qp->s_last == qp->s_tail)
+ goto bail;
+
+ /*
+ * The MSN might be for a later WQE than the PSN indicates so
+ * only complete WQEs that the PSN finishes.
+ */
+ while (ipath_cmp24(psn, wqe->lpsn) >= 0) {
+ /* If we are ACKing a WQE, the MSN should be >= the SSN. */
+ if (ipath_cmp24(aeth, wqe->ssn) < 0)
+ break;
+ /*
+ * 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)) ||
+ ((wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
+ wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) &&
+ (opcode != OP(ATOMIC_ACKNOWLEDGE) ||
+ ipath_cmp24(wqe->psn, psn) != 0))) {
+ /*
+ * The last valid PSN seen is the previous
+ * request's.
+ */
+ qp->s_last_psn = wqe->psn - 1;
+ /* Retry this request. */
+ ipath_restart_rc(qp, wqe->psn, &wc);
+ /*
+ * No need to process the ACK/NAK since we are
+ * restarting an earlier request.
+ */
+ goto bail;
+ }
+ /* Post a send completion queue entry if requested. */
+ if (!test_bit(IPATH_S_SIGNAL_REQ_WR, &qp->s_flags) ||
+ (wqe->wr.send_flags & IB_SEND_SIGNALED)) {
+ wc.wr_id = wqe->wr.wr_id;
+ wc.status = IB_WC_SUCCESS;
+ wc.opcode = ib_ipath_wc_opcode[wqe->wr.opcode];
+ wc.vendor_err = 0;
+ wc.byte_len = wqe->length;
+ wc.qp_num = qp->ibqp.qp_num;
+ wc.src_qp = qp->remote_qpn;
+ wc.pkey_index = 0;
+ wc.slid = qp->remote_ah_attr.dlid;
+ wc.sl = qp->remote_ah_attr.sl;
+ wc.dlid_path_bits = 0;
+ wc.port_num = 0;
+ ipath_cq_enter(to_icq(qp->ibqp.send_cq), &wc, 0);
+ }
+ qp->s_retry = qp->s_retry_cnt;
+ /*
+ * If we are completing a request which is in the process
+ * of being resent, we can stop resending it since we know
+ * the responder has already seen it.
+ */
+ if (qp->s_last == qp->s_cur) {
+ if (++qp->s_cur >= qp->s_size)
+ qp->s_cur = 0;
+ wqe = get_swqe_ptr(qp, qp->s_cur);
+ qp->s_state = OP(SEND_LAST);
+ qp->s_psn = wqe->psn;
+ }
+ if (++qp->s_last >= qp->s_size)
+ qp->s_last = 0;
+ wqe = get_swqe_ptr(qp, qp->s_last);
+ if (qp->s_last == qp->s_tail)
+ break;
+ }
+
+ switch (aeth >> 29) {
+ case 0: /* ACK */
+ dev->n_rc_acks++;
+ /* If this is a partial ACK, reset the retransmit timer. */
+ if (qp->s_last != qp->s_tail) {
+ spin_lock(&dev->pending_lock);
+ list_add_tail(&qp->timerwait,
+ &dev->pending[dev->pending_index]);
+ spin_unlock(&dev->pending_lock);
+ }
+ ipath_get_credit(qp, aeth);
+ qp->s_rnr_retry = qp->s_rnr_retry_cnt;
+ qp->s_retry = qp->s_retry_cnt;
+ qp->s_last_psn = psn;
+ ret = 1;
+ goto bail;
+
+ case 1: /* RNR NAK */
+ dev->n_rnr_naks++;
+ if (qp->s_rnr_retry == 0) {
+ if (qp->s_last == qp->s_tail)
+ goto bail;
+
+ wc.status = IB_WC_RNR_RETRY_EXC_ERR;
+ goto class_b;
+ }
+ if (qp->s_rnr_retry_cnt < 7)
+ qp->s_rnr_retry--;
+ if (qp->s_last == qp->s_tail)
+ goto bail;
+
+ /* The last valid PSN seen is the previous request's. */
+ qp->s_last_psn = wqe->psn - 1;
+
+ dev->n_rc_resends += (int)qp->s_psn - (int)psn;
+
+ /*
+ * If we are starting the request from the beginning, let
+ * the normal send code handle initialization.
+ */
+ qp->s_cur = qp->s_last;
+ wqe = get_swqe_ptr(qp, qp->s_cur);
+ if (ipath_cmp24(psn, wqe->psn) <= 0) {
+ qp->s_state = OP(SEND_LAST);
+ qp->s_psn = wqe->psn;
+ } else
+ reset_psn(qp, psn);
+
+ qp->s_rnr_timeout =
+ ib_ipath_rnr_table[(aeth >> IPS_AETH_CREDIT_SHIFT) &
+ IPS_AETH_CREDIT_MASK];
+ ipath_insert_rnr_queue(qp);
+ goto bail;
+
+ case 3: /* NAK */
+ /* The last valid PSN seen is the previous request's. */
+ if (qp->s_last != qp->s_tail)
+ qp->s_last_psn = wqe->psn - 1;
+ switch ((aeth >> IPS_AETH_CREDIT_SHIFT) &
+ IPS_AETH_CREDIT_MASK) {
+ case 0: /* PSN sequence error */
+ dev->n_seq_naks++;
+ /*
+ * Back up to the responder's expected PSN.
+ * XXX Note that we might get a NAK in the
+ * middle of an RDMA READ response which
+ * terminates the RDMA READ.
+ */
+ if (qp->s_last == qp->s_tail)
+ break;
+
+ if (ipath_cmp24(psn, wqe->psn) < 0)
+ break;
+
+ /* Retry the request. */
+ ipath_restart_rc(qp, psn, &wc);
+ break;
+
+ case 1: /* Invalid Request */
+ wc.status = IB_WC_REM_INV_REQ_ERR;
+ dev->n_other_naks++;
+ goto class_b;
+
+ case 2: /* Remote Access Error */
+ wc.status = IB_WC_REM_ACCESS_ERR;
+ dev->n_other_naks++;
+ goto class_b;
+
+ case 3: /* Remote Operation Error */
+ wc.status = IB_WC_REM_OP_ERR;
+ dev->n_other_naks++;
+ class_b:
+ wc.wr_id = wqe->wr.wr_id;
+ wc.opcode = ib_ipath_wc_opcode[wqe->wr.opcode];
+ wc.vendor_err = 0;
+ wc.byte_len = 0;
+ wc.qp_num = qp->ibqp.qp_num;
+ wc.src_qp = qp->remote_qpn;
+ wc.pkey_index = 0;
+ wc.slid = qp->remote_ah_attr.dlid;
+ wc.sl = qp->remote_ah_attr.sl;
+ wc.dlid_path_bits = 0;
+ wc.port_num = 0;
+ ipath_sqerror_qp(qp, &wc);
+ break;
+
+ default:
+ /* Ignore other reserved NAK error codes */
+ goto reserved;
+ }
+ qp->s_rnr_retry = qp->s_rnr_retry_cnt;
+ goto bail;
+
+ default: /* 2: reserved */
+ reserved:
+ /* Ignore reserved NAK codes. */
+ goto bail;
+ }
+
+bail:
+ return ret;
+}
+
+/**
+ * ipath_rc_rcv_resp - process an incoming RC response packet
+ * @dev: the device 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
+ * @header_in_data: true if part of the header data is in the data buffer
+ *
+ * This is called from ipath_rc_rcv() to process an incoming RC response
+ * packet for the given QP.
+ * Called at interrupt level.
+ */
+static inline void ipath_rc_rcv_resp(struct ipath_ibdev *dev,
+ struct ipath_other_headers *ohdr,
+ void *data, u32 tlen,
+ struct ipath_qp *qp,
+ u32 opcode,
+ u32 psn, u32 hdrsize, u32 pmtu,
+ int header_in_data)
+{
+ unsigned long flags;
+ struct ib_wc wc;
+ int diff;
+ u32 pad;
+ u32 aeth;
+
+ spin_lock_irqsave(&qp->s_lock, flags);
+
+ /* Ignore invalid responses. */
+ if (ipath_cmp24(psn, qp->s_next_psn) >= 0)
+ goto ack_done;
+
+ /* Ignore duplicate responses. */
+ diff = ipath_cmp24(psn, qp->s_last_psn);
+ if (unlikely(diff <= 0)) {
+ /* Update credits for "ghost" ACKs */
+ if (diff == 0 && opcode == OP(ACKNOWLEDGE)) {
+ if (!header_in_data)
+ aeth = be32_to_cpu(ohdr->u.aeth);
+ else {
+ aeth = be32_to_cpu(((u32 *) data)[0]);
+ data += sizeof(u32);
+ }
+ if ((aeth >> 29) == 0)
+ ipath_get_credit(qp, aeth);
+ }
+ goto ack_done;
+ }
+
+ switch (opcode) {
+ case OP(ACKNOWLEDGE):
+ case OP(ATOMIC_ACKNOWLEDGE):
+ case OP(RDMA_READ_RESPONSE_FIRST):
+ if (!header_in_data)
+ aeth = be32_to_cpu(ohdr->u.aeth);
+ else {
+ aeth = be32_to_cpu(((u32 *) data)[0]);
+ data += sizeof(u32);
+ }
+ if (opcode == OP(ATOMIC_ACKNOWLEDGE))
+ *(u64 *) qp->s_sge.sge.vaddr = *(u64 *) data;
+ if (!do_rc_ack(qp, aeth, psn, opcode) ||
+ opcode != OP(RDMA_READ_RESPONSE_FIRST))
+ goto ack_done;
+ hdrsize += 4;
+ /*
+ * do_rc_ack() has already checked the PSN so skip
+ * the sequence check.
+ */
+ goto rdma_read;
+
+ case OP(RDMA_READ_RESPONSE_MIDDLE):
+ /* no AETH, no ACK */
+ if (unlikely(ipath_cmp24(psn, qp->s_last_psn + 1))) {
+ dev->n_rdma_seq++;
+ ipath_restart_rc(qp, qp->s_last_psn + 1, &wc);
+ goto ack_done;
+ }
+ rdma_read:
+ if (unlikely(qp->s_state != OP(RDMA_READ_REQUEST)))
+ goto ack_done;
+ if (unlikely(tlen != (hdrsize + pmtu + 4)))
+ goto ack_done;
+ if (unlikely(pmtu >= qp->s_len))
+ goto ack_done;
+ /* We got a response so update the timeout. */
+ if (unlikely(qp->s_last == qp->s_tail ||
+ get_swqe_ptr(qp, qp->s_last)->wr.opcode !=
+ IB_WR_RDMA_READ))
+ goto ack_done;
+ spin_lock(&dev->pending_lock);
+ if (qp->s_rnr_timeout == 0 &&
+ qp->timerwait.next != LIST_POISON1)
+ list_move_tail(&qp->timerwait,
+ &dev->pending[dev->pending_index]);
+ spin_unlock(&dev->pending_lock);
+ /*
+ * Update the RDMA receive state but do the copy w/o
+ * holding the locks and blocking interrupts.
+ * XXX Yet another place that affects relaxed
+ * RDMA order since we don't want s_sge modified.
+ */
+ qp->s_len -= pmtu;
+ qp->s_last_psn = psn;
+ spin_unlock_irqrestore(&qp->s_lock, flags);
+ ipath_copy_sge(&qp->s_sge, data, pmtu);
+ goto bail;
+
+ case OP(RDMA_READ_RESPONSE_LAST):
+ /* ACKs READ req. */
+ if (unlikely(ipath_cmp24(psn, qp->s_last_psn + 1))) {
+ dev->n_rdma_seq++;
+ ipath_restart_rc(qp, qp->s_last_psn + 1, &wc);
+ goto ack_done;
+ }
+ /* FALLTHROUGH */
+ case OP(RDMA_READ_RESPONSE_ONLY):
+ if (unlikely(qp->s_state != OP(RDMA_READ_REQUEST)))
+ 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 >= 1 && <= pmtu.
+ * Remember to account for the AETH header (4) and
+ * ICRC (4).
+ */
+ if (unlikely(tlen <= (hdrsize + pad + 8))) {
+ /*
+ * XXX Need to generate an error CQ
+ * entry.
+ */
+ goto ack_done;
+ }
+ tlen -= hdrsize + pad + 8;
+ if (unlikely(tlen != qp->s_len)) {
+ /*
+ * XXX Need to generate an error CQ
+ * entry.
+ */
+ goto ack_done;
+ }
+ if (!header_in_data)
+ aeth = be32_to_cpu(ohdr->u.aeth);
+ else {
+ aeth = be32_to_cpu(((u32 *) data)[0]);
+ data += sizeof(u32);
+ }
+ ipath_copy_sge(&qp->s_sge, data, tlen);
+ if (do_rc_ack(qp, aeth, psn, OP(RDMA_READ_RESPONSE_LAST))) {
+ /*
+ * Change the state so we contimue
+ * processing new requests.
+ */
+ qp->s_state = OP(SEND_LAST);
+ }
+ goto ack_done;
+ }
+
+ack_done:
+ spin_unlock_irqrestore(&qp->s_lock, flags);
+bail:
+ return;
+}
+
+/**
+ * ipath_rc_rcv_error - process an incoming duplicate or error RC packet
+ * @dev: the device this packet came in on
+ * @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
+ * @header_in_data: true if part of the header data is in the data buffer
+ *
+ * This is called from ipath_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 and the s_lock unlocked.
+ */
+static inline int ipath_rc_rcv_error(struct ipath_ibdev *dev,
+ struct ipath_other_headers *ohdr,
+ void *data,
+ struct ipath_qp *qp,
+ u32 opcode,
+ u32 psn,
+ int diff,
+ int header_in_data)
+{
+ struct ib_reth *reth;
+
+ if (diff > 0) {
+ /*
+ * Packet sequence error.
+ * A NAK will ACK earlier sends and RDMA writes.
+ * Don't queue the NAK if a RDMA read, atomic, or
+ * NAK is pending though.
+ */
+ spin_lock(&qp->s_lock);
+ if ((qp->s_ack_state >= OP(RDMA_READ_REQUEST) &&
+ qp->s_ack_state != IB_OPCODE_ACKNOWLEDGE) ||
+ qp->s_nak_state != 0) {
+ spin_unlock(&qp->s_lock);
+ goto done;
+ }
+ qp->s_ack_state = OP(SEND_ONLY);
+ qp->s_nak_state = IB_NAK_PSN_ERROR;
+ /* Use the expected PSN. */
+ qp->s_ack_psn = qp->r_psn;
+ goto resched;
+ }
+
+ /*
+ * 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.
+ */
+ spin_lock(&qp->s_lock);
+ if (qp->s_ack_state != IB_OPCODE_ACKNOWLEDGE &&
+ ipath_cmp24(psn, qp->s_ack_psn) >= 0) {
+ if (qp->s_ack_state < IB_OPCODE_RDMA_READ_REQUEST)
+ qp->s_ack_psn = psn;
+ spin_unlock(&qp->s_lock);
+ goto done;
+ }
+ switch (opcode) {
+ case OP(RDMA_READ_REQUEST):
+ /*
+ * We have to be careful to not change s_rdma_sge
+ * while ipath_do_rc_send() is using it and not
+ * holding the s_lock.
+ */
+ if (qp->s_ack_state != OP(ACKNOWLEDGE) &&
+ qp->s_ack_state >= IB_OPCODE_RDMA_READ_REQUEST) {
+ spin_unlock(&qp->s_lock);
+ dev->n_rdma_dup_busy++;
+ goto done;
+ }
+ /* RETH comes after BTH */
+ if (!header_in_data)
+ reth = &ohdr->u.rc.reth;
+ else {
+ reth = (struct ib_reth *)data;
+ data += sizeof(*reth);
+ }
+ qp->s_rdma_len = be32_to_cpu(reth->length);
+ if (qp->s_rdma_len != 0) {
+ u32 rkey = be32_to_cpu(reth->rkey);
+ u64 vaddr = be64_to_cpu(reth->vaddr);
+ int ok;
+
+ /*
+ * Address range must be a subset of the
+ * original request and start on pmtu
+ * boundaries.
+ */
+ ok = ipath_rkey_ok(dev, &qp->s_rdma_sge,
+ qp->s_rdma_len, vaddr, rkey,
+ IB_ACCESS_REMOTE_READ);
+ if (unlikely(!ok))
+ goto done;
+ } else {
+ qp->s_rdma_sge.sg_list = NULL;
+ qp->s_rdma_sge.num_sge = 0;
+ qp->s_rdma_sge.sge.mr = NULL;
+ qp->s_rdma_sge.sge.vaddr = NULL;
+ qp->s_rdma_sge.sge.length = 0;
+ qp->s_rdma_sge.sge.sge_length = 0;
+ }
+ break;
+
+ case OP(COMPARE_SWAP):
+ case OP(FETCH_ADD):
+ /*
+ * Check for the PSN of the last atomic operations
+ * performed and resend the result if found.
+ */
+ if ((psn & IPS_PSN_MASK) != qp->r_atomic_psn) {
+ spin_unlock(&qp->s_lock);
+ goto done;
+ }
+ qp->s_ack_atomic = qp->r_atomic_data;
+ break;
+ }
+ qp->s_ack_state = opcode;
+ qp->s_nak_state = 0;
+ qp->s_ack_psn = psn;
+resched:
+ return 0;
+
+done:
+ return 1;
+}
+
+/**
+ * ipath_rc_rcv - process an incoming RC packet
+ * @dev: the device this packet came in on
+ * @hdr: the header of this packet
+ * @has_grh: true if the header has a GRH
+ * @data: the packet data
+ * @tlen: the packet length
+ * @qp: the QP for this packet
+ *
+ * This is called from ipath_qp_rcv() to process an incoming RC packet
+ * for the given QP.
+ * Called at interrupt level.
+ */
+void ipath_rc_rcv(struct ipath_ibdev *dev, struct ipath_ib_header *hdr,
+ int has_grh, void *data, u32 tlen, struct ipath_qp *qp)
+{
+ struct ipath_other_headers *ohdr;
+ u32 opcode;
+ u32 hdrsize;
+ u32 psn;
+ u32 pad;
+ unsigned long flags;
+ struct ib_wc wc;
+ u32 pmtu = ib_mtu_enum_to_int(qp->path_mtu);
+ int diff;
+ struct ib_reth *reth;
+ int header_in_data;
+
+ /* Check for GRH */
+ if (!has_grh) {
+ ohdr = &hdr->u.oth;
+ hdrsize = 8 + 12; /* LRH + BTH */
+ psn = be32_to_cpu(ohdr->bth[2]);
+ header_in_data = 0;
+ } else {
+ ohdr = &hdr->u.l.oth;
+ hdrsize = 8 + 40 + 12; /* LRH + GRH + BTH */
+ /*
+ * The header with GRH is 60 bytes and the
+ * core driver sets the eager header buffer
+ * size to 56 bytes so the last 4 bytes of
+ * the BTH header (PSN) is in the data buffer.
+ */
+ header_in_data =
+ ipath_layer_get_rcvhdrentsize(dev->dd) == 16;
+ if (header_in_data) {
+ psn = be32_to_cpu(((u32 *) data)[0]);
+ data += sizeof(u32);
+ } else
+ psn = be32_to_cpu(ohdr->bth[2]);
+ }
+ /*
+ * The opcode is in the low byte when its in network order
+ * (top byte when in host order).
+ */
+ opcode = be32_to_cpu(ohdr->bth[0]) >> 24;
+
+ /*
+ * 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)) {
+ ipath_rc_rcv_resp(dev, ohdr, data, tlen, qp, opcode, psn,
+ hdrsize, pmtu, header_in_data);
+ goto bail;
+ }
+
+ spin_lock_irqsave(&qp->r_rq.lock, flags);
+
+ /* Compute 24 bits worth of difference. */
+ diff = ipath_cmp24(psn, qp->r_psn);
+ if (unlikely(diff)) {
+ if (ipath_rc_rcv_error(dev, ohdr, data, qp, opcode,
+ psn, diff, header_in_data))
+ goto done;
+ goto resched;
+ }
+
+ /* 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;
+ nack_inv:
+ /*
+ * A NAK will ACK earlier sends and RDMA writes.
+ * Don't queue the NAK if a RDMA read, atomic, or
+ * NAK is pending though.
+ */
+ spin_lock(&qp->s_lock);
+ if (qp->s_ack_state >= OP(RDMA_READ_REQUEST) &&
+ qp->s_ack_state != IB_OPCODE_ACKNOWLEDGE) {
+ spin_unlock(&qp->s_lock);
+ goto done;
+ }
+ /* XXX Flush WQEs */
+ qp->state = IB_QPS_ERR;
+ qp->s_ack_state = OP(SEND_ONLY);
+ qp->s_nak_state = IB_NAK_INVALID_REQUEST;
+ qp->s_ack_psn = qp->r_psn;
+ goto resched;
+
+ 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;
+
+ case OP(RDMA_READ_REQUEST):
+ case OP(COMPARE_SWAP):
+ case OP(FETCH_ADD):
+ /*
+ * Drop all new requests until a response has been sent.
+ * A new request then ACKs the RDMA response we sent.
+ * Relaxed ordering would allow new requests to be
+ * processed but we would need to keep a queue
+ * of rwqe's for all that are in progress.
+ * Note that we can't RNR NAK this request since the RDMA
+ * READ or atomic response is already queued to be sent
+ * (unless we implement a response send queue).
+ */
+ goto done;
+
+ 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;
+ break;
+ }
+
+ wc.imm_data = 0;
+ wc.wc_flags = 0;
+
+ /* OK, process the packet. */
+ switch (opcode) {
+ case OP(SEND_FIRST):
+ if (!ipath_get_rwqe(qp, 0)) {
+ rnr_nak:
+ /*
+ * A RNR NAK will ACK earlier sends and RDMA writes.
+ * Don't queue the NAK if a RDMA read or atomic
+ * is pending though.
+ */
+ spin_lock(&qp->s_lock);
+ if (qp->s_ack_state >=
+ OP(RDMA_READ_REQUEST) &&
+ qp->s_ack_state != IB_OPCODE_ACKNOWLEDGE) {
+ spin_unlock(&qp->s_lock);
+ goto done;
+ }
+ qp->s_ack_state = OP(SEND_ONLY);
+ qp->s_nak_state = IB_RNR_NAK | qp->s_min_rnr_timer;
+ qp->s_ack_psn = qp->r_psn;
+ goto resched;
+ }
+ 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;
+ ipath_copy_sge(&qp->r_sge, data, pmtu);
+ break;
+
+ case OP(RDMA_WRITE_LAST_WITH_IMMEDIATE):
+ /* consume RWQE */
+ if (!ipath_get_rwqe(qp, 1))
+ goto rnr_nak;
+ goto send_last_imm;
+
+ case OP(SEND_ONLY):
+ case OP(SEND_ONLY_WITH_IMMEDIATE):
+ if (!ipath_get_rwqe(qp, 0))
+ goto rnr_nak;
+ qp->r_rcv_len = 0;
+ if (opcode == OP(SEND_ONLY))
+ goto send_last;
+ /* FALLTHROUGH */
+ case OP(SEND_LAST_WITH_IMMEDIATE):
+ send_last_imm:
+ if (header_in_data) {
+ wc.imm_data = *(u32 *) data;
+ data += sizeof(u32);
+ } else {
+ /* Immediate data comes after BTH */
+ wc.imm_data = ohdr->u.imm_data;
+ }
+ hdrsize += 4;
+ wc.wc_flags = IB_WC_WITH_IMM;
+ /* FALLTHROUGH */
+ case OP(SEND_LAST):
+ case OP(RDMA_WRITE_LAST):
+ send_last:
+ /* Get the number of bytes the message was padded by. */
+ pad = (be32_to_cpu(ohdr->bth[0]) >> 20) & 3;
+ /* Check for invalid length. */
+ /* XXX LAST len should be >= 1 */
+ if (unlikely(tlen < (hdrsize + pad + 4)))
+ goto 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;
+ ipath_copy_sge(&qp->r_sge, data, tlen);
+ atomic_inc(&qp->msn);
+ if (opcode == OP(RDMA_WRITE_LAST) ||
+ opcode == OP(RDMA_WRITE_ONLY))
+ break;
+ wc.wr_id = qp->r_wr_id;
+ wc.status = IB_WC_SUCCESS;
+ wc.opcode = IB_WC_RECV;
+ wc.vendor_err = 0;
+ wc.qp_num = qp->ibqp.qp_num;
+ wc.src_qp = qp->remote_qpn;
+ wc.pkey_index = 0;
+ wc.slid = qp->remote_ah_attr.dlid;
+ wc.sl = qp->remote_ah_attr.sl;
+ wc.dlid_path_bits = 0;
+ wc.port_num = 0;
+ /* Signal completion event if the solicited bit is set. */
+ ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
+ ohdr->bth[0] &
+ __constant_cpu_to_be32(1 << 23));
+ break;
+
+ case OP(RDMA_WRITE_FIRST):
+ case OP(RDMA_WRITE_ONLY):
+ case OP(RDMA_WRITE_ONLY_WITH_IMMEDIATE):
+ /* consume RWQE */
+ /* RETH comes after BTH */
+ if (!header_in_data)
+ reth = &ohdr->u.rc.reth;
+ else {
+ reth = (struct ib_reth *)data;
+ data += sizeof(*reth);
+ }
+ hdrsize += sizeof(*reth);
+ qp->r_len = be32_to_cpu(reth->length);
+ qp->r_rcv_len = 0;
+ 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 = ipath_rkey_ok(dev, &qp->r_sge,
+ qp->r_len, vaddr, rkey,
+ IB_ACCESS_REMOTE_WRITE);
+ if (unlikely(!ok)) {
+ nack_acc:
+ /*
+ * A NAK will ACK earlier sends and RDMA
+ * writes. Don't queue the NAK if a RDMA
+ * read, atomic, or NAK is pending though.
+ */
+ spin_lock(&qp->s_lock);
+ if (qp->s_ack_state >=
+ OP(RDMA_READ_REQUEST) &&
+ qp->s_ack_state !=
+ IB_OPCODE_ACKNOWLEDGE) {
+ spin_unlock(&qp->s_lock);
+ goto done;
+ }
+ /* XXX Flush WQEs */
+ qp->state = IB_QPS_ERR;
+ qp->s_ack_state = OP(RDMA_WRITE_ONLY);
+ qp->s_nak_state =
+ IB_NAK_REMOTE_ACCESS_ERROR;
+ qp->s_ack_psn = qp->r_psn;
+ goto resched;
+ }
+ } else {
+ qp->r_sge.sg_list = NULL;
+ 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 (unlikely(!(qp->qp_access_flags &
+ IB_ACCESS_REMOTE_WRITE)))
+ goto nack_acc;
+ if (opcode == OP(RDMA_WRITE_FIRST))
+ goto send_middle;
+ else if (opcode == OP(RDMA_WRITE_ONLY))
+ goto send_last;
+ if (!ipath_get_rwqe(qp, 1))
+ goto rnr_nak;
+ goto send_last_imm;
+
+ case OP(RDMA_READ_REQUEST):
+ /* RETH comes after BTH */
+ if (!header_in_data)
+ reth = &ohdr->u.rc.reth;
+ else {
+ reth = (struct ib_reth *)data;
+ data += sizeof(*reth);
+ }
+ spin_lock(&qp->s_lock);
+ if (qp->s_ack_state != OP(ACKNOWLEDGE) &&
+ qp->s_ack_state >= IB_OPCODE_RDMA_READ_REQUEST) {
+ spin_unlock(&qp->s_lock);
+ goto done;
+ }
+ qp->s_rdma_len = be32_to_cpu(reth->length);
+ if (qp->s_rdma_len != 0) {
+ u32 rkey = be32_to_cpu(reth->rkey);
+ u64 vaddr = be64_to_cpu(reth->vaddr);
+ int ok;
+
+ /* Check rkey & NAK */
+ ok = ipath_rkey_ok(dev, &qp->s_rdma_sge,
+ qp->s_rdma_len, vaddr, rkey,
+ IB_ACCESS_REMOTE_READ);
+ if (unlikely(!ok)) {
+ spin_unlock(&qp->s_lock);
+ goto nack_acc;
+ }
+ /*
+ * Update the next expected PSN. We add 1 later
+ * below, so only add the remainder here.
+ */
+ if (qp->s_rdma_len > pmtu)
+ qp->r_psn += (qp->s_rdma_len - 1) / pmtu;
+ } else {
+ qp->s_rdma_sge.sg_list = NULL;
+ qp->s_rdma_sge.num_sge = 0;
+ qp->s_rdma_sge.sge.mr = NULL;
+ qp->s_rdma_sge.sge.vaddr = NULL;
+ qp->s_rdma_sge.sge.length = 0;
+ qp->s_rdma_sge.sge.sge_length = 0;
+ }
+ if (unlikely(!(qp->qp_access_flags &
+ IB_ACCESS_REMOTE_READ)))
+ goto nack_acc;
+ /*
+ * 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.
+ */
+ atomic_inc(&qp->msn);
+ qp->s_ack_state = opcode;
+ qp->s_nak_state = 0;
+ qp->s_ack_psn = psn;
+ qp->r_psn++;
+ qp->r_state = opcode;
+ goto rdmadone;
+
+ case OP(COMPARE_SWAP):
+ case OP(FETCH_ADD): {
+ struct ib_atomic_eth *ateth;
+ u64 vaddr;
+ u64 sdata;
+ u32 rkey;
+
+ if (!header_in_data)
+ ateth = &ohdr->u.atomic_eth;
+ else {
+ ateth = (struct ib_atomic_eth *)data;
+ data += sizeof(*ateth);
+ }
+ vaddr = be64_to_cpu(ateth->vaddr);
+ if (unlikely(vaddr & (sizeof(u64) - 1)))
+ goto nack_inv;
+ rkey = be32_to_cpu(ateth->rkey);
+ /* Check rkey & NAK */
+ if (unlikely(!ipath_rkey_ok(dev, &qp->r_sge,
+ sizeof(u64), vaddr, rkey,
+ IB_ACCESS_REMOTE_ATOMIC)))
+ goto nack_acc;
+ if (unlikely(!(qp->qp_access_flags &
+ IB_ACCESS_REMOTE_ATOMIC)))
+ goto nack_acc;
+ /* Perform atomic OP and save result. */
+ sdata = be64_to_cpu(ateth->swap_data);
+ spin_lock(&dev->pending_lock);
+ qp->r_atomic_data = *(u64 *) qp->r_sge.sge.vaddr;
+ if (opcode == OP(FETCH_ADD))
+ *(u64 *) qp->r_sge.sge.vaddr =
+ qp->r_atomic_data + sdata;
+ else if (qp->r_atomic_data ==
+ be64_to_cpu(ateth->compare_data))
+ *(u64 *) qp->r_sge.sge.vaddr = sdata;
+ spin_unlock(&dev->pending_lock);
+ atomic_inc(&qp->msn);
+ qp->r_atomic_psn = psn & IPS_PSN_MASK;
+ psn |= 1 << 31;
+ break;
+ }
+
+ default:
+ /* Drop packet for unknown opcodes. */
+ goto done;
+ }
+ qp->r_psn++;
+ qp->r_state = opcode;
+ /* Send an ACK if requested or required. */
+ if (psn & (1 << 31)) {
+ /*
+ * Coalesce ACKs unless there is a RDMA READ or
+ * ATOMIC pending.
+ */
+ spin_lock(&qp->s_lock);
+ if (qp->s_ack_state == OP(ACKNOWLEDGE) ||
+ qp->s_ack_state < IB_OPCODE_RDMA_READ_REQUEST) {
+ qp->s_ack_state = opcode;
+ qp->s_nak_state = 0;
+ qp->s_ack_psn = psn;
+ qp->s_ack_atomic = qp->r_atomic_data;
+ goto resched;
+ }
+ spin_unlock(&qp->s_lock);
+ }
+done:
+ spin_unlock_irqrestore(&qp->r_rq.lock, flags);
+ goto bail;
+
+resched:
+ /*
+ * Try to send ACK right away but not if ipath_do_rc_send() is
+ * active.
+ */
+ if (qp->s_hdrwords == 0 &&
+ (qp->s_ack_state < IB_OPCODE_RDMA_READ_REQUEST ||
+ qp->s_ack_state >= IB_OPCODE_COMPARE_SWAP))
+ send_rc_ack(qp);
+
+rdmadone:
+ spin_unlock(&qp->s_lock);
+ spin_unlock_irqrestore(&qp->r_rq.lock, flags);
+
+ /* Call ipath_do_rc_send() in another thread. */
+ tasklet_hi_schedule(&qp->s_task);
+
+bail:
+ return;
+}
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