IPoIB: Only set Q_Key once: after joining broadcast group

The current code will set the Q_Key for any join of a non-sendonly
multicast group.  The operation involves a modify QP operation, which
is fairly heavyweight, and is only really required after the join of
the broadcast group.  Fix this by adding a parameter to ipoib_mcast_attach()
to control when the Q_Key is set.

Signed-off-by: Eli Cohen <eli@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

3 files changed, 19 insertions, 15 deletions

diff --git a/drivers/infiniband/ulp/ipoib/ipoib.h b/drivers/infiniband/ulp/ipoib/ipoib.h
index b8753222c870..7b46e2d7b3c2 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib.h
+++ b/drivers/infiniband/ulp/ipoib/ipoib.h
@@ -485,7 +485,7 @@ void ipoib_path_iter_read(struct ipoib_path_iter *iter,
 #endif
 
 int ipoib_mcast_attach(struct net_device *dev, u16 mlid,
-                       union ib_gid *mgid);
+                       union ib_gid *mgid, int set_qkey);
 int ipoib_mcast_detach(struct net_device *dev, u16 mlid,
                        union ib_gid *mgid);
 
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
index 0b7d129161e1..55ebd950bf23 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
@@ -186,6 +186,7 @@ static int ipoib_mcast_join_finish(struct ipoib_mcast *mcast,
         struct ipoib_dev_priv *priv = netdev_priv(dev);
         struct ipoib_ah *ah;
         int ret;
+        int set_qkey = 0;
 
         mcast->mcmember = *mcmember;
 
@@ -200,6 +201,7 @@ static int ipoib_mcast_join_finish(struct ipoib_mcast *mcast,
                 priv->qkey = be32_to_cpu(priv->broadcast->mcmember.qkey);
                 spin_unlock_irq(&priv->lock);
                 priv->tx_wr.wr.ud.remote_qkey = priv->qkey;
+                set_qkey = 1;
         }
 
         if (!test_bit(IPOIB_MCAST_FLAG_SENDONLY, &mcast->flags)) {
@@ -212,7 +214,7 @@ static int ipoib_mcast_join_finish(struct ipoib_mcast *mcast,
                 }
 
                 ret = ipoib_mcast_attach(dev, be16_to_cpu(mcast->mcmember.mlid),
-                                         &mcast->mcmember.mgid);
+                                         &mcast->mcmember.mgid, set_qkey);
                 if (ret < 0) {
                         ipoib_warn(priv, "couldn't attach QP to multicast group "
                                    IPOIB_GID_FMT "\n",
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_verbs.c b/drivers/infiniband/ulp/ipoib/ipoib_verbs.c
index f50ebe0643ef..ba7c8868e6f7 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_verbs.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_verbs.c
@@ -33,18 +33,13 @@
 
 #include "ipoib.h"
 
-int ipoib_mcast_attach(struct net_device *dev, u16 mlid, union ib_gid *mgid)
+int ipoib_mcast_attach(struct net_device *dev, u16 mlid, union ib_gid *mgid, int set_qkey)
 {
         struct ipoib_dev_priv *priv = netdev_priv(dev);
-        struct ib_qp_attr *qp_attr;
+        struct ib_qp_attr *qp_attr = NULL;
         int ret;
         u16 pkey_index;
 
-        ret = -ENOMEM;
-        qp_attr = kmalloc(sizeof *qp_attr, GFP_KERNEL);
-        if (!qp_attr)
-                goto out;
-
         if (ib_find_pkey(priv->ca, priv->port, priv->pkey, &pkey_index)) {
                 clear_bit(IPOIB_PKEY_ASSIGNED, &priv->flags);
                 ret = -ENXIO;
@@ -52,12 +47,19 @@ int ipoib_mcast_attach(struct net_device *dev, u16 mlid, union ib_gid *mgid)
         }
         set_bit(IPOIB_PKEY_ASSIGNED, &priv->flags);
 
-        /* set correct QKey for QP */
-        qp_attr->qkey = priv->qkey;
-        ret = ib_modify_qp(priv->qp, qp_attr, IB_QP_QKEY);
-        if (ret) {
-                ipoib_warn(priv, "failed to modify QP, ret = %d\n", ret);
-                goto out;
+        if (set_qkey) {
+                ret = -ENOMEM;
+                qp_attr = kmalloc(sizeof *qp_attr, GFP_KERNEL);
+                if (!qp_attr)
+                        goto out;
+
+                /* set correct QKey for QP */
+                qp_attr->qkey = priv->qkey;
+                ret = ib_modify_qp(priv->qp, qp_attr, IB_QP_QKEY);
+                if (ret) {
+                        ipoib_warn(priv, "failed to modify QP, ret = %d\n", ret);
+                        goto out;
+                }
         }
 
         /* attach QP to multicast group */