IPoIB/cm: Use common CQ for CM send completions

Use the same CQ for CM send completions as for all other IPoIB
completions.  This means all completions are processed via the same
NAPI polling routine.  This should help reduce the number of
interrupts for bi-directional traffic (such as TCP) and fixes "driver
is hogging interrupts" errors reported for IPoIB send side, e.g.
<https://bugs.openfabrics.org/show_bug.cgi?id=508>

To do this, keep a per-interface counter of outstanding send WRs, and
stop the interface when this counter reaches the send queue size to
avoid CQ overruns.

Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 27 insertions, 19 deletions

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_ib.c b/drivers/infiniband/ulp/ipoib/ipoib_ib.c
index 6a5f9fc07fb..5063dd509ad 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_ib.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_ib.c
@@ -267,11 +267,10 @@ static void ipoib_ib_handle_tx_wc(struct net_device *dev, struct ib_wc *wc)
 
 	spin_lock_irqsave(&priv->tx_lock, flags);
 	++priv->tx_tail;
-	if (unlikely(test_bit(IPOIB_FLAG_NETIF_STOPPED, &priv->flags)) &&
-	    priv->tx_head - priv->tx_tail <= ipoib_sendq_size >> 1) {
-		clear_bit(IPOIB_FLAG_NETIF_STOPPED, &priv->flags);
+	if (unlikely(--priv->tx_outstanding == ipoib_sendq_size >> 1) &&
+	    netif_queue_stopped(dev) &&
+	    test_bit(IPOIB_FLAG_ADMIN_UP, &priv->flags))
 		netif_wake_queue(dev);
-	}
 	spin_unlock_irqrestore(&priv->tx_lock, flags);
 
 	if (wc->status != IB_WC_SUCCESS &&
@@ -301,14 +300,18 @@ poll_more:
 		for (i = 0; i < n; i++) {
 			struct ib_wc *wc = priv->ibwc + i;
 
-			if (wc->wr_id & IPOIB_CM_OP_SRQ) {
-				++done;
-				ipoib_cm_handle_rx_wc(dev, wc);
-			} else if (wc->wr_id & IPOIB_OP_RECV) {
+			if (wc->wr_id & IPOIB_OP_RECV) {
 				++done;
-				ipoib_ib_handle_rx_wc(dev, wc);
-			} else
-				ipoib_ib_handle_tx_wc(dev, wc);
+				if (wc->wr_id & IPOIB_OP_CM)
+					ipoib_cm_handle_rx_wc(dev, wc);
+				else
+					ipoib_ib_handle_rx_wc(dev, wc);
+			} else {
+				if (wc->wr_id & IPOIB_OP_CM)
+					ipoib_cm_handle_tx_wc(dev, wc);
+				else
+					ipoib_ib_handle_tx_wc(dev, wc);
+			}
 		}
 
 		if (n != t)
@@ -401,10 +404,9 @@ void ipoib_send(struct net_device *dev, struct sk_buff *skb,
 		address->last_send = priv->tx_head;
 		++priv->tx_head;
 
-		if (priv->tx_head - priv->tx_tail == ipoib_sendq_size) {
+		if (++priv->tx_outstanding == ipoib_sendq_size) {
 			ipoib_dbg(priv, "TX ring full, stopping kernel net queue\n");
 			netif_stop_queue(dev);
-			set_bit(IPOIB_FLAG_NETIF_STOPPED, &priv->flags);
 		}
 	}
 }
@@ -563,12 +565,17 @@ void ipoib_drain_cq(struct net_device *dev)
 			if (priv->ibwc[i].status == IB_WC_SUCCESS)
 				priv->ibwc[i].status = IB_WC_WR_FLUSH_ERR;
 
-			if (priv->ibwc[i].wr_id & IPOIB_CM_OP_SRQ)
-				ipoib_cm_handle_rx_wc(dev, priv->ibwc + i);
-			else if (priv->ibwc[i].wr_id & IPOIB_OP_RECV)
-				ipoib_ib_handle_rx_wc(dev, priv->ibwc + i);
-			else
-				ipoib_ib_handle_tx_wc(dev, priv->ibwc + i);
+			if (priv->ibwc[i].wr_id & IPOIB_OP_RECV) {
+				if (priv->ibwc[i].wr_id & IPOIB_OP_CM)
+					ipoib_cm_handle_rx_wc(dev, priv->ibwc + i);
+				else
+					ipoib_ib_handle_rx_wc(dev, priv->ibwc + i);
+			} else {
+				if (priv->ibwc[i].wr_id & IPOIB_OP_CM)
+					ipoib_cm_handle_tx_wc(dev, priv->ibwc + i);
+				else
+					ipoib_ib_handle_tx_wc(dev, priv->ibwc + i);
+			}
 		}
 	} while (n == IPOIB_NUM_WC);
 }
@@ -614,6 +621,7 @@ int ipoib_ib_dev_stop(struct net_device *dev, int flush)
 						    DMA_TO_DEVICE);
 				dev_kfree_skb_any(tx_req->skb);
 				++priv->tx_tail;
+				--priv->tx_outstanding;
 			}
 
 			for (i = 0; i < ipoib_recvq_size; ++i) {