IB/ipath: Limit # of packets sent without an ACK received

[linux-2.6-block.git] / drivers / infiniband / hw / ipath / ipath_rc.c

diff --git a/drivers/infiniband/hw/ipath/ipath_rc.c b/drivers/infiniband/hw/ipath/ipath_rc.c
index a08654042c03411db35b26c54acaf5105e4015cb..52caa2edf5a4068be02162390c4ad6952dcc3a89 100644 (file)
--- a/drivers/infiniband/hw/ipath/ipath_rc.c
+++ b/drivers/infiniband/hw/ipath/ipath_rc.c
@@ -201,6 +201,18 @@ int ipath_make_rc_req(struct ipath_qp *qp,
            qp->s_rnr_timeout)
                goto done;
 
+       /* Limit the number of packets sent without an ACK. */
+       if (ipath_cmp24(qp->s_psn, qp->s_last_psn + IPATH_PSN_CREDIT) > 0) {
+               qp->s_wait_credit = 1;
+               dev->n_rc_stalls++;
+               spin_lock(&dev->pending_lock);
+               if (list_empty(&qp->timerwait))
+                       list_add_tail(&qp->timerwait,
+                                     &dev->pending[dev->pending_index]);
+               spin_unlock(&dev->pending_lock);
+               goto done;
+       }
+
        /* header size in 32-bit words LRH+BTH = (8+12)/4. */
        hwords = 5;
        bth0 = 0;
@@ -221,7 +233,7 @@ int ipath_make_rc_req(struct ipath_qp *qp,
                        /* Check if send work queue is empty. */
                        if (qp->s_tail == qp->s_head)
                                goto done;
-                       qp->s_psn = wqe->psn = qp->s_next_psn;
+                       wqe->psn = qp->s_next_psn;
                        newreq = 1;
                }
                /*
@@ -393,12 +405,6 @@ int ipath_make_rc_req(struct ipath_qp *qp,
                ss = &qp->s_sge;
                len = qp->s_len;
                if (len > pmtu) {
-                       /*
-                        * Request an ACK every 1/2 MB to avoid retransmit
-                        * timeouts.
-                        */
-                       if (((wqe->length - len) % (512 * 1024)) == 0)
-                               bth2 |= 1 << 31;
                        len = pmtu;
                        break;
                }
@@ -435,12 +441,6 @@ int ipath_make_rc_req(struct ipath_qp *qp,
                ss = &qp->s_sge;
                len = qp->s_len;
                if (len > pmtu) {
-                       /*
-                        * Request an ACK every 1/2 MB to avoid retransmit
-                        * timeouts.
-                        */
-                       if (((wqe->length - len) % (512 * 1024)) == 0)
-                               bth2 |= 1 << 31;
                        len = pmtu;
                        break;
                }
@@ -498,6 +498,8 @@ int ipath_make_rc_req(struct ipath_qp *qp,
                 */
                goto done;
        }
+       if (ipath_cmp24(qp->s_psn, qp->s_last_psn + IPATH_PSN_CREDIT - 1) >= 0)
+               bth2 |= 1 << 31;        /* Request ACK. */
        qp->s_len -= len;
        qp->s_hdrwords = hwords;
        qp->s_cur_sge = ss;
@@ -737,6 +739,15 @@ bail:
        return;
 }
 
+static inline void update_last_psn(struct ipath_qp *qp, u32 psn)
+{
+       if (qp->s_wait_credit) {
+               qp->s_wait_credit = 0;
+               tasklet_hi_schedule(&qp->s_task);
+       }
+       qp->s_last_psn = psn;
+}
+
 /**
  * do_rc_ack - process an incoming RC ACK
  * @qp: the QP the ACK came in on
@@ -805,7 +816,7 @@ static int do_rc_ack(struct ipath_qp *qp, u32 aeth, u32 psn, int opcode)
                         * The last valid PSN seen is the previous
                         * request's.
                         */
-                       qp->s_last_psn = wqe->psn - 1;
+                       update_last_psn(qp, wqe->psn - 1);
                        /* Retry this request. */
                        ipath_restart_rc(qp, wqe->psn, &wc);
                        /*
@@ -864,7 +875,7 @@ static int do_rc_ack(struct ipath_qp *qp, u32 aeth, u32 psn, int opcode)
                ipath_get_credit(qp, aeth);
                qp->s_rnr_retry = qp->s_rnr_retry_cnt;
                qp->s_retry = qp->s_retry_cnt;
-               qp->s_last_psn = psn;
+               update_last_psn(qp, psn);
                ret = 1;
                goto bail;
 
@@ -883,7 +894,7 @@ static int do_rc_ack(struct ipath_qp *qp, u32 aeth, u32 psn, int opcode)
                        goto bail;
 
                /* The last valid PSN is the previous PSN. */
-               qp->s_last_psn = psn - 1;
+               update_last_psn(qp, psn - 1);
 
                dev->n_rc_resends += (int)qp->s_psn - (int)psn;
 
@@ -898,7 +909,7 @@ static int do_rc_ack(struct ipath_qp *qp, u32 aeth, u32 psn, int opcode)
        case 3:         /* NAK */
                /* The last valid PSN seen is the previous request's. */
                if (qp->s_last != qp->s_tail)
-                       qp->s_last_psn = wqe->psn - 1;
+                       update_last_psn(qp, wqe->psn - 1);
                switch ((aeth >> IPATH_AETH_CREDIT_SHIFT) &
                        IPATH_AETH_CREDIT_MASK) {
                case 0: /* PSN sequence error */
@@ -1071,7 +1082,7 @@ static inline void ipath_rc_rcv_resp(struct ipath_ibdev *dev,
                 * since we don't want s_sge modified.
                 */
                qp->s_len -= pmtu;
-               qp->s_last_psn = psn;
+               update_last_psn(qp, psn);
                spin_unlock_irqrestore(&qp->s_lock, flags);
                ipath_copy_sge(&qp->s_sge, data, pmtu);
                goto bail;