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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/infiniband/sw/rxe/rxe_comp.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/infiniband/sw/rxe/rxe_comp.c')
-rw-r--r--drivers/infiniband/sw/rxe/rxe_comp.c778
1 files changed, 778 insertions, 0 deletions
diff --git a/drivers/infiniband/sw/rxe/rxe_comp.c b/drivers/infiniband/sw/rxe/rxe_comp.c
new file mode 100644
index 000000000..d2a250123
--- /dev/null
+++ b/drivers/infiniband/sw/rxe/rxe_comp.c
@@ -0,0 +1,778 @@
+// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
+/*
+ * Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
+ * Copyright (c) 2015 System Fabric Works, Inc. All rights reserved.
+ */
+
+#include <linux/skbuff.h>
+
+#include "rxe.h"
+#include "rxe_loc.h"
+#include "rxe_queue.h"
+#include "rxe_task.h"
+
+enum comp_state {
+ COMPST_GET_ACK,
+ COMPST_GET_WQE,
+ COMPST_COMP_WQE,
+ COMPST_COMP_ACK,
+ COMPST_CHECK_PSN,
+ COMPST_CHECK_ACK,
+ COMPST_READ,
+ COMPST_ATOMIC,
+ COMPST_WRITE_SEND,
+ COMPST_UPDATE_COMP,
+ COMPST_ERROR_RETRY,
+ COMPST_RNR_RETRY,
+ COMPST_ERROR,
+ COMPST_EXIT, /* We have an issue, and we want to rerun the completer */
+ COMPST_DONE, /* The completer finished successflly */
+};
+
+static char *comp_state_name[] = {
+ [COMPST_GET_ACK] = "GET ACK",
+ [COMPST_GET_WQE] = "GET WQE",
+ [COMPST_COMP_WQE] = "COMP WQE",
+ [COMPST_COMP_ACK] = "COMP ACK",
+ [COMPST_CHECK_PSN] = "CHECK PSN",
+ [COMPST_CHECK_ACK] = "CHECK ACK",
+ [COMPST_READ] = "READ",
+ [COMPST_ATOMIC] = "ATOMIC",
+ [COMPST_WRITE_SEND] = "WRITE/SEND",
+ [COMPST_UPDATE_COMP] = "UPDATE COMP",
+ [COMPST_ERROR_RETRY] = "ERROR RETRY",
+ [COMPST_RNR_RETRY] = "RNR RETRY",
+ [COMPST_ERROR] = "ERROR",
+ [COMPST_EXIT] = "EXIT",
+ [COMPST_DONE] = "DONE",
+};
+
+static unsigned long rnrnak_usec[32] = {
+ [IB_RNR_TIMER_655_36] = 655360,
+ [IB_RNR_TIMER_000_01] = 10,
+ [IB_RNR_TIMER_000_02] = 20,
+ [IB_RNR_TIMER_000_03] = 30,
+ [IB_RNR_TIMER_000_04] = 40,
+ [IB_RNR_TIMER_000_06] = 60,
+ [IB_RNR_TIMER_000_08] = 80,
+ [IB_RNR_TIMER_000_12] = 120,
+ [IB_RNR_TIMER_000_16] = 160,
+ [IB_RNR_TIMER_000_24] = 240,
+ [IB_RNR_TIMER_000_32] = 320,
+ [IB_RNR_TIMER_000_48] = 480,
+ [IB_RNR_TIMER_000_64] = 640,
+ [IB_RNR_TIMER_000_96] = 960,
+ [IB_RNR_TIMER_001_28] = 1280,
+ [IB_RNR_TIMER_001_92] = 1920,
+ [IB_RNR_TIMER_002_56] = 2560,
+ [IB_RNR_TIMER_003_84] = 3840,
+ [IB_RNR_TIMER_005_12] = 5120,
+ [IB_RNR_TIMER_007_68] = 7680,
+ [IB_RNR_TIMER_010_24] = 10240,
+ [IB_RNR_TIMER_015_36] = 15360,
+ [IB_RNR_TIMER_020_48] = 20480,
+ [IB_RNR_TIMER_030_72] = 30720,
+ [IB_RNR_TIMER_040_96] = 40960,
+ [IB_RNR_TIMER_061_44] = 61410,
+ [IB_RNR_TIMER_081_92] = 81920,
+ [IB_RNR_TIMER_122_88] = 122880,
+ [IB_RNR_TIMER_163_84] = 163840,
+ [IB_RNR_TIMER_245_76] = 245760,
+ [IB_RNR_TIMER_327_68] = 327680,
+ [IB_RNR_TIMER_491_52] = 491520,
+};
+
+static inline unsigned long rnrnak_jiffies(u8 timeout)
+{
+ return max_t(unsigned long,
+ usecs_to_jiffies(rnrnak_usec[timeout]), 1);
+}
+
+static enum ib_wc_opcode wr_to_wc_opcode(enum ib_wr_opcode opcode)
+{
+ switch (opcode) {
+ case IB_WR_RDMA_WRITE: return IB_WC_RDMA_WRITE;
+ case IB_WR_RDMA_WRITE_WITH_IMM: return IB_WC_RDMA_WRITE;
+ case IB_WR_SEND: return IB_WC_SEND;
+ case IB_WR_SEND_WITH_IMM: return IB_WC_SEND;
+ case IB_WR_RDMA_READ: return IB_WC_RDMA_READ;
+ case IB_WR_ATOMIC_CMP_AND_SWP: return IB_WC_COMP_SWAP;
+ case IB_WR_ATOMIC_FETCH_AND_ADD: return IB_WC_FETCH_ADD;
+ case IB_WR_LSO: return IB_WC_LSO;
+ case IB_WR_SEND_WITH_INV: return IB_WC_SEND;
+ case IB_WR_RDMA_READ_WITH_INV: return IB_WC_RDMA_READ;
+ case IB_WR_LOCAL_INV: return IB_WC_LOCAL_INV;
+ case IB_WR_REG_MR: return IB_WC_REG_MR;
+ case IB_WR_BIND_MW: return IB_WC_BIND_MW;
+
+ default:
+ return 0xff;
+ }
+}
+
+void retransmit_timer(struct timer_list *t)
+{
+ struct rxe_qp *qp = from_timer(qp, t, retrans_timer);
+
+ pr_debug("%s: fired for qp#%d\n", __func__, qp->elem.index);
+
+ if (qp->valid) {
+ qp->comp.timeout = 1;
+ rxe_sched_task(&qp->comp.task);
+ }
+}
+
+void rxe_comp_queue_pkt(struct rxe_qp *qp, struct sk_buff *skb)
+{
+ int must_sched;
+
+ skb_queue_tail(&qp->resp_pkts, skb);
+
+ must_sched = skb_queue_len(&qp->resp_pkts) > 1;
+ if (must_sched != 0)
+ rxe_counter_inc(SKB_TO_PKT(skb)->rxe, RXE_CNT_COMPLETER_SCHED);
+
+ if (must_sched)
+ rxe_sched_task(&qp->comp.task);
+ else
+ rxe_run_task(&qp->comp.task);
+}
+
+static inline enum comp_state get_wqe(struct rxe_qp *qp,
+ struct rxe_pkt_info *pkt,
+ struct rxe_send_wqe **wqe_p)
+{
+ struct rxe_send_wqe *wqe;
+
+ /* we come here whether or not we found a response packet to see if
+ * there are any posted WQEs
+ */
+ wqe = queue_head(qp->sq.queue, QUEUE_TYPE_FROM_CLIENT);
+ *wqe_p = wqe;
+
+ /* no WQE or requester has not started it yet */
+ if (!wqe || wqe->state == wqe_state_posted)
+ return pkt ? COMPST_DONE : COMPST_EXIT;
+
+ /* WQE does not require an ack */
+ if (wqe->state == wqe_state_done)
+ return COMPST_COMP_WQE;
+
+ /* WQE caused an error */
+ if (wqe->state == wqe_state_error)
+ return COMPST_ERROR;
+
+ /* we have a WQE, if we also have an ack check its PSN */
+ return pkt ? COMPST_CHECK_PSN : COMPST_EXIT;
+}
+
+static inline void reset_retry_counters(struct rxe_qp *qp)
+{
+ qp->comp.retry_cnt = qp->attr.retry_cnt;
+ qp->comp.rnr_retry = qp->attr.rnr_retry;
+ qp->comp.started_retry = 0;
+}
+
+static inline enum comp_state check_psn(struct rxe_qp *qp,
+ struct rxe_pkt_info *pkt,
+ struct rxe_send_wqe *wqe)
+{
+ s32 diff;
+
+ /* check to see if response is past the oldest WQE. if it is, complete
+ * send/write or error read/atomic
+ */
+ diff = psn_compare(pkt->psn, wqe->last_psn);
+ if (diff > 0) {
+ if (wqe->state == wqe_state_pending) {
+ if (wqe->mask & WR_ATOMIC_OR_READ_MASK)
+ return COMPST_ERROR_RETRY;
+
+ reset_retry_counters(qp);
+ return COMPST_COMP_WQE;
+ } else {
+ return COMPST_DONE;
+ }
+ }
+
+ /* compare response packet to expected response */
+ diff = psn_compare(pkt->psn, qp->comp.psn);
+ if (diff < 0) {
+ /* response is most likely a retried packet if it matches an
+ * uncompleted WQE go complete it else ignore it
+ */
+ if (pkt->psn == wqe->last_psn)
+ return COMPST_COMP_ACK;
+ else
+ return COMPST_DONE;
+ } else if ((diff > 0) && (wqe->mask & WR_ATOMIC_OR_READ_MASK)) {
+ return COMPST_DONE;
+ } else {
+ return COMPST_CHECK_ACK;
+ }
+}
+
+static inline enum comp_state check_ack(struct rxe_qp *qp,
+ struct rxe_pkt_info *pkt,
+ struct rxe_send_wqe *wqe)
+{
+ unsigned int mask = pkt->mask;
+ u8 syn;
+ struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
+
+ /* Check the sequence only */
+ switch (qp->comp.opcode) {
+ case -1:
+ /* Will catch all *_ONLY cases. */
+ if (!(mask & RXE_START_MASK))
+ return COMPST_ERROR;
+
+ break;
+
+ case IB_OPCODE_RC_RDMA_READ_RESPONSE_FIRST:
+ case IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE:
+ if (pkt->opcode != IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE &&
+ pkt->opcode != IB_OPCODE_RC_RDMA_READ_RESPONSE_LAST) {
+ /* read retries of partial data may restart from
+ * read response first or response only.
+ */
+ if ((pkt->psn == wqe->first_psn &&
+ pkt->opcode ==
+ IB_OPCODE_RC_RDMA_READ_RESPONSE_FIRST) ||
+ (wqe->first_psn == wqe->last_psn &&
+ pkt->opcode ==
+ IB_OPCODE_RC_RDMA_READ_RESPONSE_ONLY))
+ break;
+
+ return COMPST_ERROR;
+ }
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ }
+
+ /* Check operation validity. */
+ switch (pkt->opcode) {
+ case IB_OPCODE_RC_RDMA_READ_RESPONSE_FIRST:
+ case IB_OPCODE_RC_RDMA_READ_RESPONSE_LAST:
+ case IB_OPCODE_RC_RDMA_READ_RESPONSE_ONLY:
+ syn = aeth_syn(pkt);
+
+ if ((syn & AETH_TYPE_MASK) != AETH_ACK)
+ return COMPST_ERROR;
+
+ fallthrough;
+ /* (IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE doesn't have an AETH)
+ */
+ case IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE:
+ if (wqe->wr.opcode != IB_WR_RDMA_READ &&
+ wqe->wr.opcode != IB_WR_RDMA_READ_WITH_INV) {
+ wqe->status = IB_WC_FATAL_ERR;
+ return COMPST_ERROR;
+ }
+ reset_retry_counters(qp);
+ return COMPST_READ;
+
+ case IB_OPCODE_RC_ATOMIC_ACKNOWLEDGE:
+ syn = aeth_syn(pkt);
+
+ if ((syn & AETH_TYPE_MASK) != AETH_ACK)
+ return COMPST_ERROR;
+
+ if (wqe->wr.opcode != IB_WR_ATOMIC_CMP_AND_SWP &&
+ wqe->wr.opcode != IB_WR_ATOMIC_FETCH_AND_ADD)
+ return COMPST_ERROR;
+ reset_retry_counters(qp);
+ return COMPST_ATOMIC;
+
+ case IB_OPCODE_RC_ACKNOWLEDGE:
+ syn = aeth_syn(pkt);
+ switch (syn & AETH_TYPE_MASK) {
+ case AETH_ACK:
+ reset_retry_counters(qp);
+ return COMPST_WRITE_SEND;
+
+ case AETH_RNR_NAK:
+ rxe_counter_inc(rxe, RXE_CNT_RCV_RNR);
+ return COMPST_RNR_RETRY;
+
+ case AETH_NAK:
+ switch (syn) {
+ case AETH_NAK_PSN_SEQ_ERROR:
+ /* a nak implicitly acks all packets with psns
+ * before
+ */
+ if (psn_compare(pkt->psn, qp->comp.psn) > 0) {
+ rxe_counter_inc(rxe,
+ RXE_CNT_RCV_SEQ_ERR);
+ qp->comp.psn = pkt->psn;
+ if (qp->req.wait_psn) {
+ qp->req.wait_psn = 0;
+ rxe_run_task(&qp->req.task);
+ }
+ }
+ return COMPST_ERROR_RETRY;
+
+ case AETH_NAK_INVALID_REQ:
+ wqe->status = IB_WC_REM_INV_REQ_ERR;
+ return COMPST_ERROR;
+
+ case AETH_NAK_REM_ACC_ERR:
+ wqe->status = IB_WC_REM_ACCESS_ERR;
+ return COMPST_ERROR;
+
+ case AETH_NAK_REM_OP_ERR:
+ wqe->status = IB_WC_REM_OP_ERR;
+ return COMPST_ERROR;
+
+ default:
+ pr_warn("unexpected nak %x\n", syn);
+ wqe->status = IB_WC_REM_OP_ERR;
+ return COMPST_ERROR;
+ }
+
+ default:
+ return COMPST_ERROR;
+ }
+ break;
+
+ default:
+ pr_warn("unexpected opcode\n");
+ }
+
+ return COMPST_ERROR;
+}
+
+static inline enum comp_state do_read(struct rxe_qp *qp,
+ struct rxe_pkt_info *pkt,
+ struct rxe_send_wqe *wqe)
+{
+ int ret;
+
+ ret = copy_data(qp->pd, IB_ACCESS_LOCAL_WRITE,
+ &wqe->dma, payload_addr(pkt),
+ payload_size(pkt), RXE_TO_MR_OBJ);
+ if (ret) {
+ wqe->status = IB_WC_LOC_PROT_ERR;
+ return COMPST_ERROR;
+ }
+
+ if (wqe->dma.resid == 0 && (pkt->mask & RXE_END_MASK))
+ return COMPST_COMP_ACK;
+
+ return COMPST_UPDATE_COMP;
+}
+
+static inline enum comp_state do_atomic(struct rxe_qp *qp,
+ struct rxe_pkt_info *pkt,
+ struct rxe_send_wqe *wqe)
+{
+ int ret;
+
+ u64 atomic_orig = atmack_orig(pkt);
+
+ ret = copy_data(qp->pd, IB_ACCESS_LOCAL_WRITE,
+ &wqe->dma, &atomic_orig,
+ sizeof(u64), RXE_TO_MR_OBJ);
+ if (ret) {
+ wqe->status = IB_WC_LOC_PROT_ERR;
+ return COMPST_ERROR;
+ }
+
+ return COMPST_COMP_ACK;
+}
+
+static void make_send_cqe(struct rxe_qp *qp, struct rxe_send_wqe *wqe,
+ struct rxe_cqe *cqe)
+{
+ struct ib_wc *wc = &cqe->ibwc;
+ struct ib_uverbs_wc *uwc = &cqe->uibwc;
+
+ memset(cqe, 0, sizeof(*cqe));
+
+ if (!qp->is_user) {
+ wc->wr_id = wqe->wr.wr_id;
+ wc->status = wqe->status;
+ wc->qp = &qp->ibqp;
+ } else {
+ uwc->wr_id = wqe->wr.wr_id;
+ uwc->status = wqe->status;
+ uwc->qp_num = qp->ibqp.qp_num;
+ }
+
+ if (wqe->status == IB_WC_SUCCESS) {
+ if (!qp->is_user) {
+ wc->opcode = wr_to_wc_opcode(wqe->wr.opcode);
+ if (wqe->wr.opcode == IB_WR_RDMA_WRITE_WITH_IMM ||
+ wqe->wr.opcode == IB_WR_SEND_WITH_IMM)
+ wc->wc_flags = IB_WC_WITH_IMM;
+ wc->byte_len = wqe->dma.length;
+ } else {
+ uwc->opcode = wr_to_wc_opcode(wqe->wr.opcode);
+ if (wqe->wr.opcode == IB_WR_RDMA_WRITE_WITH_IMM ||
+ wqe->wr.opcode == IB_WR_SEND_WITH_IMM)
+ uwc->wc_flags = IB_WC_WITH_IMM;
+ uwc->byte_len = wqe->dma.length;
+ }
+ }
+}
+
+/*
+ * IBA Spec. Section 10.7.3.1 SIGNALED COMPLETIONS
+ * ---------8<---------8<-------------
+ * ...Note that if a completion error occurs, a Work Completion
+ * will always be generated, even if the signaling
+ * indicator requests an Unsignaled Completion.
+ * ---------8<---------8<-------------
+ */
+static void do_complete(struct rxe_qp *qp, struct rxe_send_wqe *wqe)
+{
+ struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
+ struct rxe_cqe cqe;
+ bool post;
+
+ /* do we need to post a completion */
+ post = ((qp->sq_sig_type == IB_SIGNAL_ALL_WR) ||
+ (wqe->wr.send_flags & IB_SEND_SIGNALED) ||
+ wqe->status != IB_WC_SUCCESS);
+
+ if (post)
+ make_send_cqe(qp, wqe, &cqe);
+
+ queue_advance_consumer(qp->sq.queue, QUEUE_TYPE_FROM_CLIENT);
+
+ if (post)
+ rxe_cq_post(qp->scq, &cqe, 0);
+
+ if (wqe->wr.opcode == IB_WR_SEND ||
+ wqe->wr.opcode == IB_WR_SEND_WITH_IMM ||
+ wqe->wr.opcode == IB_WR_SEND_WITH_INV)
+ rxe_counter_inc(rxe, RXE_CNT_RDMA_SEND);
+
+ /*
+ * we completed something so let req run again
+ * if it is trying to fence
+ */
+ if (qp->req.wait_fence) {
+ qp->req.wait_fence = 0;
+ rxe_run_task(&qp->req.task);
+ }
+}
+
+static inline enum comp_state complete_ack(struct rxe_qp *qp,
+ struct rxe_pkt_info *pkt,
+ struct rxe_send_wqe *wqe)
+{
+ if (wqe->has_rd_atomic) {
+ wqe->has_rd_atomic = 0;
+ atomic_inc(&qp->req.rd_atomic);
+ if (qp->req.need_rd_atomic) {
+ qp->comp.timeout_retry = 0;
+ qp->req.need_rd_atomic = 0;
+ rxe_run_task(&qp->req.task);
+ }
+ }
+
+ if (unlikely(qp->req.state == QP_STATE_DRAIN)) {
+ /* state_lock used by requester & completer */
+ spin_lock_bh(&qp->state_lock);
+ if ((qp->req.state == QP_STATE_DRAIN) &&
+ (qp->comp.psn == qp->req.psn)) {
+ qp->req.state = QP_STATE_DRAINED;
+ spin_unlock_bh(&qp->state_lock);
+
+ if (qp->ibqp.event_handler) {
+ struct ib_event ev;
+
+ ev.device = qp->ibqp.device;
+ ev.element.qp = &qp->ibqp;
+ ev.event = IB_EVENT_SQ_DRAINED;
+ qp->ibqp.event_handler(&ev,
+ qp->ibqp.qp_context);
+ }
+ } else {
+ spin_unlock_bh(&qp->state_lock);
+ }
+ }
+
+ do_complete(qp, wqe);
+
+ if (psn_compare(pkt->psn, qp->comp.psn) >= 0)
+ return COMPST_UPDATE_COMP;
+ else
+ return COMPST_DONE;
+}
+
+static inline enum comp_state complete_wqe(struct rxe_qp *qp,
+ struct rxe_pkt_info *pkt,
+ struct rxe_send_wqe *wqe)
+{
+ if (pkt && wqe->state == wqe_state_pending) {
+ if (psn_compare(wqe->last_psn, qp->comp.psn) >= 0) {
+ qp->comp.psn = (wqe->last_psn + 1) & BTH_PSN_MASK;
+ qp->comp.opcode = -1;
+ }
+
+ if (qp->req.wait_psn) {
+ qp->req.wait_psn = 0;
+ rxe_sched_task(&qp->req.task);
+ }
+ }
+
+ do_complete(qp, wqe);
+
+ return COMPST_GET_WQE;
+}
+
+static void rxe_drain_resp_pkts(struct rxe_qp *qp, bool notify)
+{
+ struct sk_buff *skb;
+ struct rxe_send_wqe *wqe;
+ struct rxe_queue *q = qp->sq.queue;
+
+ while ((skb = skb_dequeue(&qp->resp_pkts))) {
+ rxe_put(qp);
+ kfree_skb(skb);
+ ib_device_put(qp->ibqp.device);
+ }
+
+ while ((wqe = queue_head(q, q->type))) {
+ if (notify) {
+ wqe->status = IB_WC_WR_FLUSH_ERR;
+ do_complete(qp, wqe);
+ } else {
+ queue_advance_consumer(q, q->type);
+ }
+ }
+}
+
+static void free_pkt(struct rxe_pkt_info *pkt)
+{
+ struct sk_buff *skb = PKT_TO_SKB(pkt);
+ struct rxe_qp *qp = pkt->qp;
+ struct ib_device *dev = qp->ibqp.device;
+
+ kfree_skb(skb);
+ rxe_put(qp);
+ ib_device_put(dev);
+}
+
+int rxe_completer(void *arg)
+{
+ struct rxe_qp *qp = (struct rxe_qp *)arg;
+ struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
+ struct rxe_send_wqe *wqe = NULL;
+ struct sk_buff *skb = NULL;
+ struct rxe_pkt_info *pkt = NULL;
+ enum comp_state state;
+ int ret;
+
+ if (!rxe_get(qp))
+ return -EAGAIN;
+
+ if (!qp->valid || qp->comp.state == QP_STATE_ERROR ||
+ qp->comp.state == QP_STATE_RESET) {
+ rxe_drain_resp_pkts(qp, qp->valid &&
+ qp->comp.state == QP_STATE_ERROR);
+ goto exit;
+ }
+
+ if (qp->comp.timeout) {
+ qp->comp.timeout_retry = 1;
+ qp->comp.timeout = 0;
+ } else {
+ qp->comp.timeout_retry = 0;
+ }
+
+ if (qp->req.need_retry)
+ goto exit;
+
+ state = COMPST_GET_ACK;
+
+ while (1) {
+ pr_debug("qp#%d state = %s\n", qp_num(qp),
+ comp_state_name[state]);
+ switch (state) {
+ case COMPST_GET_ACK:
+ skb = skb_dequeue(&qp->resp_pkts);
+ if (skb) {
+ pkt = SKB_TO_PKT(skb);
+ qp->comp.timeout_retry = 0;
+ }
+ state = COMPST_GET_WQE;
+ break;
+
+ case COMPST_GET_WQE:
+ state = get_wqe(qp, pkt, &wqe);
+ break;
+
+ case COMPST_CHECK_PSN:
+ state = check_psn(qp, pkt, wqe);
+ break;
+
+ case COMPST_CHECK_ACK:
+ state = check_ack(qp, pkt, wqe);
+ break;
+
+ case COMPST_READ:
+ state = do_read(qp, pkt, wqe);
+ break;
+
+ case COMPST_ATOMIC:
+ state = do_atomic(qp, pkt, wqe);
+ break;
+
+ case COMPST_WRITE_SEND:
+ if (wqe->state == wqe_state_pending &&
+ wqe->last_psn == pkt->psn)
+ state = COMPST_COMP_ACK;
+ else
+ state = COMPST_UPDATE_COMP;
+ break;
+
+ case COMPST_COMP_ACK:
+ state = complete_ack(qp, pkt, wqe);
+ break;
+
+ case COMPST_COMP_WQE:
+ state = complete_wqe(qp, pkt, wqe);
+ break;
+
+ case COMPST_UPDATE_COMP:
+ if (pkt->mask & RXE_END_MASK)
+ qp->comp.opcode = -1;
+ else
+ qp->comp.opcode = pkt->opcode;
+
+ if (psn_compare(pkt->psn, qp->comp.psn) >= 0)
+ qp->comp.psn = (pkt->psn + 1) & BTH_PSN_MASK;
+
+ if (qp->req.wait_psn) {
+ qp->req.wait_psn = 0;
+ rxe_sched_task(&qp->req.task);
+ }
+
+ state = COMPST_DONE;
+ break;
+
+ case COMPST_DONE:
+ goto done;
+
+ case COMPST_EXIT:
+ if (qp->comp.timeout_retry && wqe) {
+ state = COMPST_ERROR_RETRY;
+ break;
+ }
+
+ /* re reset the timeout counter if
+ * (1) QP is type RC
+ * (2) the QP is alive
+ * (3) there is a packet sent by the requester that
+ * might be acked (we still might get spurious
+ * timeouts but try to keep them as few as possible)
+ * (4) the timeout parameter is set
+ */
+ if ((qp_type(qp) == IB_QPT_RC) &&
+ (qp->req.state == QP_STATE_READY) &&
+ (psn_compare(qp->req.psn, qp->comp.psn) > 0) &&
+ qp->qp_timeout_jiffies)
+ mod_timer(&qp->retrans_timer,
+ jiffies + qp->qp_timeout_jiffies);
+ goto exit;
+
+ case COMPST_ERROR_RETRY:
+ /* we come here if the retry timer fired and we did
+ * not receive a response packet. try to retry the send
+ * queue if that makes sense and the limits have not
+ * been exceeded. remember that some timeouts are
+ * spurious since we do not reset the timer but kick
+ * it down the road or let it expire
+ */
+
+ /* there is nothing to retry in this case */
+ if (!wqe || (wqe->state == wqe_state_posted))
+ goto exit;
+
+ /* if we've started a retry, don't start another
+ * retry sequence, unless this is a timeout.
+ */
+ if (qp->comp.started_retry &&
+ !qp->comp.timeout_retry)
+ goto done;
+
+ if (qp->comp.retry_cnt > 0) {
+ if (qp->comp.retry_cnt != 7)
+ qp->comp.retry_cnt--;
+
+ /* no point in retrying if we have already
+ * seen the last ack that the requester could
+ * have caused
+ */
+ if (psn_compare(qp->req.psn,
+ qp->comp.psn) > 0) {
+ /* tell the requester to retry the
+ * send queue next time around
+ */
+ rxe_counter_inc(rxe,
+ RXE_CNT_COMP_RETRY);
+ qp->req.need_retry = 1;
+ qp->comp.started_retry = 1;
+ rxe_run_task(&qp->req.task);
+ }
+ goto done;
+
+ } else {
+ rxe_counter_inc(rxe, RXE_CNT_RETRY_EXCEEDED);
+ wqe->status = IB_WC_RETRY_EXC_ERR;
+ state = COMPST_ERROR;
+ }
+ break;
+
+ case COMPST_RNR_RETRY:
+ /* we come here if we received an RNR NAK */
+ if (qp->comp.rnr_retry > 0) {
+ if (qp->comp.rnr_retry != 7)
+ qp->comp.rnr_retry--;
+
+ /* don't start a retry flow until the
+ * rnr timer has fired
+ */
+ qp->req.wait_for_rnr_timer = 1;
+ pr_debug("qp#%d set rnr nak timer\n",
+ qp_num(qp));
+ mod_timer(&qp->rnr_nak_timer,
+ jiffies + rnrnak_jiffies(aeth_syn(pkt)
+ & ~AETH_TYPE_MASK));
+ goto exit;
+ } else {
+ rxe_counter_inc(rxe,
+ RXE_CNT_RNR_RETRY_EXCEEDED);
+ wqe->status = IB_WC_RNR_RETRY_EXC_ERR;
+ state = COMPST_ERROR;
+ }
+ break;
+
+ case COMPST_ERROR:
+ WARN_ON_ONCE(wqe->status == IB_WC_SUCCESS);
+ do_complete(qp, wqe);
+ rxe_qp_error(qp);
+ goto exit;
+ }
+ }
+
+ /* A non-zero return value will cause rxe_do_task to
+ * exit its loop and end the tasklet. A zero return
+ * will continue looping and return to rxe_completer
+ */
+done:
+ ret = 0;
+ goto out;
+exit:
+ ret = -EAGAIN;
+out:
+ if (pkt)
+ free_pkt(pkt);
+ rxe_put(qp);
+
+ return ret;
+}