IB/ipath: Fix RDMA reads

The PSN used to generate the request following a RDMA read was
incorrect and some state booking wasn't maintained correctly.  This
patch fixes that.

Signed-off-by: Ralph Campbell <ralph.campbell@qlogic.com>
Signed-off-by: Bryan O'Sullivan <bryan.osullivan@qlogic.com>

1 files changed, 32 insertions, 27 deletions

diff --git a/drivers/infiniband/hw/ipath/ipath_rc.c b/drivers/infiniband/hw/ipath/ipath_rc.c
index a504cf67f272..ce6038743c5c 100644
--- a/drivers/infiniband/hw/ipath/ipath_rc.c
+++ b/drivers/infiniband/hw/ipath/ipath_rc.c
@@ -241,10 +241,7 @@ int ipath_make_rc_req(struct ipath_qp *qp,
                  * 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;
+                len = wqe->length;
                 ss = &qp->s_sge;
                 bth2 = 0;
                 switch (wqe->wr.opcode) {
@@ -368,14 +365,23 @@ int ipath_make_rc_req(struct ipath_qp *qp,
                 default:
                         goto done;
                 }
+                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 = wqe->length;
                 if (newreq) {
                         qp->s_tail++;
                         if (qp->s_tail >= qp->s_size)
                                 qp->s_tail = 0;
                 }
-                bth2 |= qp->s_psn++ & IPATH_PSN_MASK;
-                if ((int)(qp->s_psn - qp->s_next_psn) > 0)
-                        qp->s_next_psn = qp->s_psn;
+                bth2 |= qp->s_psn & IPATH_PSN_MASK;
+                if (wqe->wr.opcode == IB_WR_RDMA_READ)
+                        qp->s_psn = wqe->lpsn + 1;
+                else {
+                        qp->s_psn++;
+                        if ((int)(qp->s_psn - qp->s_next_psn) > 0)
+                                qp->s_next_psn = qp->s_psn;
+                }
                 /*
                  * Put the QP on the pending list so lost ACKs will cause
                  * a retry.  More than one request can be pending so the
@@ -690,13 +696,6 @@ 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;
 
-        /*
-         * 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;
@@ -731,8 +730,6 @@ void ipath_restart_rc(struct ipath_qp *qp, u32 psn, struct ib_wc *wc)
                 dev->n_rc_resends += (int)qp->s_psn - (int)psn;
 
         reset_psn(qp, psn);
-
-done:
         tasklet_hi_schedule(&qp->s_task);
 
 bail:
@@ -765,6 +762,7 @@ static int do_rc_ack(struct ipath_qp *qp, u32 aeth, u32 psn, int opcode)
         struct ib_wc wc;
         struct ipath_swqe *wqe;
         int ret = 0;
+        u32 ack_psn;
 
         /*
          * Remove the QP from the timeout queue (or RNR timeout queue).
@@ -777,26 +775,26 @@ static int do_rc_ack(struct ipath_qp *qp, u32 aeth, u32 psn, int opcode)
                 list_del_init(&qp->timerwait);
         spin_unlock(&dev->pending_lock);
 
+        /* Nothing is pending to ACK/NAK. */
+        if (unlikely(qp->s_last == qp->s_tail))
+                goto bail;
+
         /*
          * 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_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;
+        while (ipath_cmp24(ack_psn, wqe->lpsn) >= 0) {
                 /*
                  * If this request is a RDMA read or atomic, and the ACK is
                  * for a later operation, this ACK NAKs the RDMA read or
@@ -807,7 +805,8 @@ static int do_rc_ack(struct ipath_qp *qp, u32 aeth, u32 psn, int opcode)
                  * is sent but before the response is received.
                  */
                 if ((wqe->wr.opcode == IB_WR_RDMA_READ &&
-                     opcode != OP(RDMA_READ_RESPONSE_LAST)) ||
+                     (opcode != OP(RDMA_READ_RESPONSE_LAST) ||
+                       ipath_cmp24(ack_psn, wqe->lpsn) != 0)) ||
                     ((wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
                       wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) &&
                      (opcode != OP(ATOMIC_ACKNOWLEDGE) ||
@@ -825,6 +824,10 @@ static int do_rc_ack(struct ipath_qp *qp, u32 aeth, u32 psn, int opcode)
                          */
                         goto bail;
                 }
+                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)
+                        tasklet_hi_schedule(&qp->s_task);
                 /* 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)) {
@@ -1055,7 +1058,8 @@ static inline void ipath_rc_rcv_resp(struct ipath_ibdev *dev,
                 /* 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);
+                        if (qp->s_last != qp->s_tail)
+                                ipath_restart_rc(qp, qp->s_last_psn + 1, &wc);
                         goto ack_done;
                 }
         rdma_read:
@@ -1091,7 +1095,8 @@ static inline void ipath_rc_rcv_resp(struct ipath_ibdev *dev,
                 /* 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);
+                        if (qp->s_last != qp->s_tail)
+                                ipath_restart_rc(qp, qp->s_last_psn + 1, &wc);
                         goto ack_done;
                 }
                 /* FALLTHROUGH */