IB/ipath: Fix RDMA read response sequence checking

If an out of sequence RDMA read response middle or last packet is
received, we should only resend the RDMA read request on the first
out of sequence packet and drop subsequent out of sequence packets
otherwise, we get "too many retries".

Signed-off-by: Ralph Campbell <ralph.campbell@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

2 files changed, 8 insertions, 0 deletions

diff --git a/drivers/infiniband/hw/ipath/ipath_rc.c b/drivers/infiniband/hw/ipath/ipath_rc.c
index 5b5276a270bc..108df667d2ee 100644
--- a/drivers/infiniband/hw/ipath/ipath_rc.c
+++ b/drivers/infiniband/hw/ipath/ipath_rc.c
@@ -1189,6 +1189,7 @@ static inline void ipath_rc_rcv_resp(struct ipath_ibdev *dev,
                 wqe = get_swqe_ptr(qp, qp->s_last);
                 if (unlikely(wqe->wr.opcode != IB_WR_RDMA_READ))
                         goto ack_op_err;
+                qp->r_flags &= ~IPATH_R_RDMAR_SEQ;
                 /*
                  * If this is a response to a resent RDMA read, we
                  * have to be careful to copy the data to the right
@@ -1202,6 +1203,9 @@ 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++;
+                        if (qp->r_flags & IPATH_R_RDMAR_SEQ)
+                                goto ack_done;
+                        qp->r_flags |= IPATH_R_RDMAR_SEQ;
                         ipath_restart_rc(qp, qp->s_last_psn + 1);
                         goto ack_done;
                 }
@@ -1263,6 +1267,9 @@ 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++;
+                        if (qp->r_flags & IPATH_R_RDMAR_SEQ)
+                                goto ack_done;
+                        qp->r_flags |= IPATH_R_RDMAR_SEQ;
                         ipath_restart_rc(qp, qp->s_last_psn + 1);
                         goto ack_done;
                 }
diff --git a/drivers/infiniband/hw/ipath/ipath_verbs.h b/drivers/infiniband/hw/ipath/ipath_verbs.h
index deee02ca7ca4..9d12ae8a778e 100644
--- a/drivers/infiniband/hw/ipath/ipath_verbs.h
+++ b/drivers/infiniband/hw/ipath/ipath_verbs.h
@@ -444,6 +444,7 @@ struct ipath_qp {
  * Bit definitions for r_flags.
  */
 #define IPATH_R_REUSE_SGE       0x01
+#define IPATH_R_RDMAR_SEQ       0x02
 
 /*
  * Bit definitions for s_flags.