IB/mlx4: Fix race when detaching a QP from a multicast group

[safe/jmp/linux-2.6] / drivers / net / mlx4 / mcg.c

diff --git a/drivers/net/mlx4/mcg.c b/drivers/net/mlx4/mcg.c
index a99e772..57f7f1f 100644 (file)
--- a/drivers/net/mlx4/mcg.c
+++ b/drivers/net/mlx4/mcg.c
@@ -190,10 +190,6 @@ int mlx4_multicast_attach(struct mlx4_dev *dev, struct mlx4_qp *qp, u8 gid[16])
                }
                index += dev->caps.num_mgms;
 
-               err = mlx4_READ_MCG(dev, index, mailbox);
-               if (err)
-                       goto out;
-
                memset(mgm, 0, sizeof *mgm);
                memcpy(mgm->gid, gid, 16);
        }
@@ -301,12 +297,10 @@ int mlx4_multicast_detach(struct mlx4_dev *dev, struct mlx4_qp *qp, u8 gid[16])
        mgm->qp[loc]       = mgm->qp[i - 1];
        mgm->qp[i - 1]     = 0;
 
-       err = mlx4_WRITE_MCG(dev, index, mailbox);
-       if (err)
-               goto out;
-
-       if (i != 1)
+       if (i != 1) {
+               err = mlx4_WRITE_MCG(dev, index, mailbox);
                goto out;
+       }
 
        if (prev == -1) {
                /* Remove entry from MGM */