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linux/drivers/infiniband/sw/rxe/rxe_comp.c
Bob Pearson 23bc06af54 RDMA/rxe: Don't call direct between tasks 
Replace calls to rxe_run_task() with rxe_sched_task().  This prevents the
tasks from all running on the same cpu.

This change slightly reduces performance for single qp send and write
benchmarks in loopback mode but greatly improves the performance with
multiple qps because if run task is used all the work tends to be
performed on one cpu. For actual on the wire benchmarks there is no
noticeable performance change.

Link: https://lore.kernel.org/r/20240329145513.35381-11-rpearsonhpe@gmail.com
Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
2024-04-22 16:54:33 -03:00

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// 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;
case IB_WR_ATOMIC_WRITE: return IB_WC_ATOMIC_WRITE;
case IB_WR_FLUSH: return IB_WC_FLUSH;
default:
return 0xff;
}
}
void retransmit_timer(struct timer_list *t)
{
struct rxe_qp *qp = from_timer(qp, t, retrans_timer);
unsigned long flags;
rxe_dbg_qp(qp, "retransmit timer fired\n");
spin_lock_irqsave(&qp->state_lock, flags);
if (qp->valid) {
qp->comp.timeout = 1;
rxe_sched_task(&qp->send_task);
}
spin_unlock_irqrestore(&qp->state_lock, flags);
}
void rxe_comp_queue_pkt(struct rxe_qp *qp, struct sk_buff *skb)
{
rxe_counter_inc(SKB_TO_PKT(skb)->rxe, RXE_CNT_SENDER_SCHED);
skb_queue_tail(&qp->resp_pkts, skb);
rxe_sched_task(&qp->send_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 if (pkt->opcode == IB_OPCODE_RC_ACKNOWLEDGE &&
(qp->comp.opcode == IB_OPCODE_RC_RDMA_READ_RESPONSE_FIRST ||
qp->comp.opcode == IB_OPCODE_RC_RDMA_READ_RESPONSE_MIDDLE))
return COMPST_CHECK_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:
/* Check NAK code to handle a remote error */
if (pkt->opcode == IB_OPCODE_RC_ACKNOWLEDGE)
break;
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;
if (wqe->wr.opcode == IB_WR_ATOMIC_WRITE)
return COMPST_WRITE_SEND;
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->wr.opcode != IB_WR_FLUSH) {
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;
qp->req.again = 1;
}
}
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:
rxe_dbg_qp(qp, "unexpected nak %x\n", syn);
wqe->status = IB_WC_REM_OP_ERR;
return COMPST_ERROR;
}
default:
return COMPST_ERROR;
}
break;
default:
rxe_dbg_qp(qp, "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;
}
} else {
if (wqe->status != IB_WC_WR_FLUSH_ERR)
rxe_err_qp(qp, "non-flush error status = %d\n",
wqe->status);
}
}
/*
* 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;
qp->req.again = 1;
}
}
static void comp_check_sq_drain_done(struct rxe_qp *qp)
{
unsigned long flags;
spin_lock_irqsave(&qp->state_lock, flags);
if (unlikely(qp_state(qp) == IB_QPS_SQD)) {
if (qp->attr.sq_draining && qp->comp.psn == qp->req.psn) {
qp->attr.sq_draining = 0;
spin_unlock_irqrestore(&qp->state_lock, flags);
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);
}
return;
}
}
spin_unlock_irqrestore(&qp->state_lock, flags);
}
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;
qp->req.again = 1;
}
}
comp_check_sq_drain_done(qp);
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;
qp->req.again = 1;
}
}
do_complete(qp, wqe);
return COMPST_GET_WQE;
}
/* drain incoming response packet queue */
static void drain_resp_pkts(struct rxe_qp *qp)
{
struct sk_buff *skb;
while ((skb = skb_dequeue(&qp->resp_pkts))) {
rxe_put(qp);
kfree_skb(skb);
ib_device_put(qp->ibqp.device);
}
}
/* complete send wqe with flush error */
static int flush_send_wqe(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;
int err;
if (qp->is_user) {
uwc->wr_id = wqe->wr.wr_id;
uwc->status = IB_WC_WR_FLUSH_ERR;
uwc->qp_num = qp->ibqp.qp_num;
} else {
wc->wr_id = wqe->wr.wr_id;
wc->status = IB_WC_WR_FLUSH_ERR;
wc->qp = &qp->ibqp;
}
err = rxe_cq_post(qp->scq, &cqe, 0);
if (err)
rxe_dbg_cq(qp->scq, "post cq failed, err = %d\n", err);
return err;
}
/* drain and optionally complete the send queue
* if unable to complete a wqe, i.e. cq is full, stop
* completing and flush the remaining wqes
*/
static void flush_send_queue(struct rxe_qp *qp, bool notify)
{
struct rxe_send_wqe *wqe;
struct rxe_queue *q = qp->sq.queue;
int err;
/* send queue never got created. nothing to do. */
if (!qp->sq.queue)
return;
while ((wqe = queue_head(q, q->type))) {
if (notify) {
err = flush_send_wqe(qp, wqe);
if (err)
notify = 0;
}
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);
}
/* reset the retry timer if
* - QP is type RC
* - 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)
* - the timeout parameter is set
* - the QP is alive
*/
static void reset_retry_timer(struct rxe_qp *qp)
{
unsigned long flags;
if (qp_type(qp) == IB_QPT_RC && qp->qp_timeout_jiffies) {
spin_lock_irqsave(&qp->state_lock, flags);
if (qp_state(qp) >= IB_QPS_RTS &&
psn_compare(qp->req.psn, qp->comp.psn) > 0)
mod_timer(&qp->retrans_timer,
jiffies + qp->qp_timeout_jiffies);
spin_unlock_irqrestore(&qp->state_lock, flags);
}
}
int rxe_completer(struct rxe_qp *qp)
{
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;
unsigned long flags;
qp->req.again = 0;
spin_lock_irqsave(&qp->state_lock, flags);
if (!qp->valid || qp_state(qp) == IB_QPS_ERR ||
qp_state(qp) == IB_QPS_RESET) {
bool notify = qp->valid && (qp_state(qp) == IB_QPS_ERR);
drain_resp_pkts(qp);
flush_send_queue(qp, notify);
spin_unlock_irqrestore(&qp->state_lock, flags);
goto exit;
}
spin_unlock_irqrestore(&qp->state_lock, flags);
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) {
rxe_dbg_qp(qp, "state = %s\n", 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;
qp->req.again = 1;
}
state = COMPST_DONE;
break;
case COMPST_DONE:
goto done;
case COMPST_EXIT:
if (qp->comp.timeout_retry && wqe) {
state = COMPST_ERROR_RETRY;
break;
}
reset_retry_timer(qp);
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;
qp->req.again = 1;
}
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;
rxe_dbg_qp(qp, "set rnr nak timer\n");
// TODO who protects from destroy_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 work item. A zero return
* will continue looping and return to rxe_completer
*/
done:
ret = 0;
goto out;
exit:
ret = (qp->req.again) ? 0 : -EAGAIN;
out:
qp->req.again = 0;
if (pkt)
free_pkt(pkt);
return ret;
}
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