[PATCH] IB/ipath: rC receive interrupt performance changes

This patch separates QP state used for sending and receiving RC packets so the
processing in the receive interrupt handler can be done mostly without locks
being held.  ACK packets are now sent without requiring synchronization with
the send tasklet.

Signed-off-by: Ralph Campbell <ralph.campbell@qlogic.com>
Signed-off-by: Bryan O'Sullivan <bryan.osullivan@qlogic.com>
Cc: "Michael S. Tsirkin" <mst@mellanox.co.il>
Cc: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 15 insertions, 28 deletions

diff --git a/drivers/infiniband/hw/ipath/ipath_qp.c b/drivers/infiniband/hw/ipath/ipath_qp.c
index 83b9a6a5e2c6..68f01513214f 100644
--- a/drivers/infiniband/hw/ipath/ipath_qp.c
+++ b/drivers/infiniband/hw/ipath/ipath_qp.c
@@ -333,10 +333,11 @@ static void ipath_reset_qp(struct ipath_qp *qp)
         qp->remote_qpn = 0;
         qp->qkey = 0;
         qp->qp_access_flags = 0;
+        clear_bit(IPATH_S_BUSY, &qp->s_flags);
         qp->s_hdrwords = 0;
         qp->s_psn = 0;
         qp->r_psn = 0;
-        atomic_set(&qp->msn, 0);
+        qp->r_msn = 0;
         if (qp->ibqp.qp_type == IB_QPT_RC) {
                 qp->s_state = IB_OPCODE_RC_SEND_LAST;
                 qp->r_state = IB_OPCODE_RC_SEND_LAST;
@@ -345,7 +346,8 @@ static void ipath_reset_qp(struct ipath_qp *qp)
                 qp->r_state = IB_OPCODE_UC_SEND_LAST;
         }
         qp->s_ack_state = IB_OPCODE_RC_ACKNOWLEDGE;
-        qp->s_nak_state = 0;
+        qp->r_ack_state = IB_OPCODE_RC_ACKNOWLEDGE;
+        qp->r_nak_state = 0;
         qp->s_rnr_timeout = 0;
         qp->s_head = 0;
         qp->s_tail = 0;
@@ -363,10 +365,10 @@ static void ipath_reset_qp(struct ipath_qp *qp)
  * @qp: the QP to put into an error state
  *
  * Flushes both send and receive work queues.
- * QP r_rq.lock and s_lock should be held.
+ * QP s_lock should be held and interrupts disabled.
  */
 
-static void ipath_error_qp(struct ipath_qp *qp)
+void ipath_error_qp(struct ipath_qp *qp)
 {
         struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
         struct ib_wc wc;
@@ -409,12 +411,14 @@ static void ipath_error_qp(struct ipath_qp *qp)
         qp->s_ack_state = IB_OPCODE_RC_ACKNOWLEDGE;
 
         wc.opcode = IB_WC_RECV;
+        spin_lock(&qp->r_rq.lock);
         while (qp->r_rq.tail != qp->r_rq.head) {
                 wc.wr_id = get_rwqe_ptr(&qp->r_rq, qp->r_rq.tail)->wr_id;
                 if (++qp->r_rq.tail >= qp->r_rq.size)
                         qp->r_rq.tail = 0;
                 ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc, 1);
         }
+        spin_unlock(&qp->r_rq.lock);
 }
 
 /**
@@ -434,8 +438,7 @@ int ipath_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr,
         unsigned long flags;
         int ret;
 
-        spin_lock_irqsave(&qp->r_rq.lock, flags);
-        spin_lock(&qp->s_lock);
+        spin_lock_irqsave(&qp->s_lock, flags);
 
         cur_state = attr_mask & IB_QP_CUR_STATE ?
                 attr->cur_qp_state : qp->state;
@@ -506,31 +509,19 @@ int ipath_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr,
         }
 
         if (attr_mask & IB_QP_MIN_RNR_TIMER)
-                qp->s_min_rnr_timer = attr->min_rnr_timer;
+                qp->r_min_rnr_timer = attr->min_rnr_timer;
 
         if (attr_mask & IB_QP_QKEY)
                 qp->qkey = attr->qkey;
 
         qp->state = new_state;
-        spin_unlock(&qp->s_lock);
-        spin_unlock_irqrestore(&qp->r_rq.lock, flags);
-
-        /*
-         * If QP1 changed to the RTS state, try to move to the link to INIT
-         * even if it was ACTIVE so the SM will reinitialize the SMA's
-         * state.
-         */
-        if (qp->ibqp.qp_num == 1 && new_state == IB_QPS_RTS) {
-                struct ipath_ibdev *dev = to_idev(ibqp->device);
+        spin_unlock_irqrestore(&qp->s_lock, flags);
 
-                ipath_layer_set_linkstate(dev->dd, IPATH_IB_LINKDOWN);
-        }
         ret = 0;
         goto bail;
 
 inval:
-        spin_unlock(&qp->s_lock);
-        spin_unlock_irqrestore(&qp->r_rq.lock, flags);
+        spin_unlock_irqrestore(&qp->s_lock, flags);
         ret = -EINVAL;
 
 bail:
@@ -564,7 +555,7 @@ int ipath_query_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr,
         attr->sq_draining = 0;
         attr->max_rd_atomic = 1;
         attr->max_dest_rd_atomic = 1;
-        attr->min_rnr_timer = qp->s_min_rnr_timer;
+        attr->min_rnr_timer = qp->r_min_rnr_timer;
         attr->port_num = 1;
         attr->timeout = 0;
         attr->retry_cnt = qp->s_retry_cnt;
@@ -591,16 +582,12 @@ int ipath_query_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr,
  * @qp: the queue pair to compute the AETH for
  *
  * Returns the AETH.
- *
- * The QP s_lock should be held.
  */
 __be32 ipath_compute_aeth(struct ipath_qp *qp)
 {
-        u32 aeth = atomic_read(&qp->msn) & IPS_MSN_MASK;
+        u32 aeth = qp->r_msn & IPS_MSN_MASK;
 
-        if (qp->s_nak_state) {
-                aeth |= qp->s_nak_state << IPS_AETH_CREDIT_SHIFT;
-        } else if (qp->ibqp.srq) {
+        if (qp->ibqp.srq) {
                 /*
                  * Shared receive queues don't generate credits.
                  * Set the credit field to the invalid value.