staging/rdma/hfi1: use mod_timer when appropriate

Use new timer API to optimize maintenance of
timers during ACK processing.

When we are still expecting ACKs, mod the timer
to avoid a heavyweight delete/add. Otherwise, insure
do_rc_ack() maintains the timer as it had.

Reviewed-by: Jubin John <jubin.john@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

diff --git a/drivers/staging/rdma/hfi1/rc.c b/drivers/staging/rdma/hfi1/rc.c
index 5c32182dbf179b8f20687d0cfd356cf26f5c49d7..700d84942afe23e95a410ea4fc19e94327a821bc 100644 (file)
--- a/drivers/staging/rdma/hfi1/rc.c
+++ b/drivers/staging/rdma/hfi1/rc.c
@@ -1266,9 +1266,6 @@ static int do_rc_ack(struct rvt_qp *qp, u32 aeth, u32 psn, int opcode,
        int diff;
        unsigned long to;
 
-       /* Remove QP from retry timer */
-       hfi1_stop_rc_timers(qp);
-
        /*
         * Note that NAKs implicitly ACK outstanding SEND and RDMA write
         * requests and implicitly NAK RDMA read and atomic requests issued
@@ -1296,7 +1293,7 @@ static int do_rc_ack(struct rvt_qp *qp, u32 aeth, u32 psn, int opcode,
                    opcode == OP(RDMA_READ_RESPONSE_ONLY) &&
                    diff == 0) {
                        ret = 1;
-                       goto bail;
+                       goto bail_stop;
                }
                /*
                 * If this request is a RDMA read or atomic, and the ACK is
@@ -1327,7 +1324,7 @@ static int do_rc_ack(struct rvt_qp *qp, u32 aeth, u32 psn, int opcode,
                         * No need to process the ACK/NAK since we are
                         * restarting an earlier request.
                         */
-                       goto bail;
+                       goto bail_stop;
                }
                if (wqe->wr.opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
                    wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD) {
@@ -1362,18 +1359,22 @@ static int do_rc_ack(struct rvt_qp *qp, u32 aeth, u32 psn, int opcode,
                if (qp->s_acked != qp->s_tail) {
                        /*
                         * We are expecting more ACKs so
-                        * reset the re-transmit timer.
+                        * mod the retry timer.
                         */
-                       hfi1_add_retry_timer(qp);
+                       hfi1_mod_retry_timer(qp);
                        /*
                         * We can stop re-sending the earlier packets and
                         * continue with the next packet the receiver wants.
                         */
                        if (cmp_psn(qp->s_psn, psn) <= 0)
                                reset_psn(qp, psn + 1);
-               } else if (cmp_psn(qp->s_psn, psn) <= 0) {
-                       qp->s_state = OP(SEND_LAST);
-                       qp->s_psn = psn + 1;
+               } else {
+                       /* No more acks - kill all timers */
+                       hfi1_stop_rc_timers(qp);
+                       if (cmp_psn(qp->s_psn, psn) <= 0) {
+                               qp->s_state = OP(SEND_LAST);
+                               qp->s_psn = psn + 1;
+                       }
                }
                if (qp->s_flags & RVT_S_WAIT_ACK) {
                        qp->s_flags &= ~RVT_S_WAIT_ACK;
@@ -1383,15 +1384,14 @@ static int do_rc_ack(struct rvt_qp *qp, u32 aeth, u32 psn, int opcode,
                qp->s_rnr_retry = qp->s_rnr_retry_cnt;
                qp->s_retry = qp->s_retry_cnt;
                update_last_psn(qp, psn);
-               ret = 1;
-               goto bail;
+               return 1;
 
        case 1:         /* RNR NAK */
                ibp->rvp.n_rnr_naks++;
                if (qp->s_acked == qp->s_tail)
-                       goto bail;
+                       goto bail_stop;
                if (qp->s_flags & RVT_S_WAIT_RNR)
-                       goto bail;
+                       goto bail_stop;
                if (qp->s_rnr_retry == 0) {
                        status = IB_WC_RNR_RETRY_EXC_ERR;
                        goto class_b;
@@ -1407,15 +1407,16 @@ static int do_rc_ack(struct rvt_qp *qp, u32 aeth, u32 psn, int opcode,
                reset_psn(qp, psn);
 
                qp->s_flags &= ~(RVT_S_WAIT_SSN_CREDIT | RVT_S_WAIT_ACK);
+               hfi1_stop_rc_timers(qp);
                to =
                        ib_hfi1_rnr_table[(aeth >> HFI1_AETH_CREDIT_SHIFT) &
                                           HFI1_AETH_CREDIT_MASK];
                hfi1_add_rnr_timer(qp, to);
-               goto bail;
+               return 0;
 
        case 3:         /* NAK */
                if (qp->s_acked == qp->s_tail)
-                       goto bail;
+                       goto bail_stop;
                /* The last valid PSN is the previous PSN. */
                update_last_psn(qp, psn - 1);
                switch ((aeth >> HFI1_AETH_CREDIT_SHIFT) &
@@ -1458,15 +1459,16 @@ class_b:
                }
                qp->s_retry = qp->s_retry_cnt;
                qp->s_rnr_retry = qp->s_rnr_retry_cnt;
-               goto bail;
+               goto bail_stop;
 
        default:                /* 2: reserved */
 reserved:
                /* Ignore reserved NAK codes. */
-               goto bail;
+               goto bail_stop;
        }
-
-bail:
+       return ret;
+bail_stop:
+       hfi1_stop_rc_timers(qp);
        return ret;
 }