[IB] mthca: Don't enter QP into MCG more than once.

Avoid entering a QP as member of a multicast group multiple times.

Signed-off-by: Jack Morgenstein <jackm@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/drivers/infiniband/hw/mthca/mthca_mcg.c b/drivers/infiniband/hw/mthca/mthca_mcg.c
index 9a0612a9d304..b47ea7daf088 100644
--- a/drivers/infiniband/hw/mthca/mthca_mcg.c
+++ b/drivers/infiniband/hw/mthca/mthca_mcg.c
@@ -185,7 +185,12 @@ int mthca_multicast_attach(struct ib_qp *ibqp, union ib_gid *gid, u16 lid)
         }
 
         for (i = 0; i < MTHCA_QP_PER_MGM; ++i)
-                if (!(mgm->qp[i] & cpu_to_be32(1 << 31))) {
+                if (mgm->qp[i] == cpu_to_be32(ibqp->qp_num | (1 << 31))) {
+                        mthca_dbg(dev, "QP %06x already a member of MGM\n", 
+                                  ibqp->qp_num);
+                        err = 0;
+                        goto out;
+                } else if (!(mgm->qp[i] & cpu_to_be32(1 << 31))) {
                         mgm->qp[i] = cpu_to_be32(ibqp->qp_num | (1 << 31));
                         break;
                 }