IB/mlx4: Fix leaks in __mlx4_ib_modify_qp

Temporarily allocated struct mlx4_qp_context *context is leaked by
several error paths.  The patch takes advantage of the return value
'err' being preinitialized to -EINVAL.

Spotted by Coverity (CID 1768).
Signed-off-by: Florin Malita <fmalita@gmail.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/mlx4/qp.c

@@ -742,7 +742,7 @@ static int __mlx4_ib_modify_qp(struct ib_qp *ibqp,
 		if (attr->path_mtu < IB_MTU_256 || attr->path_mtu > IB_MTU_4096) {
 			printk(KERN_ERR "path MTU (%u) is invalid\n",
 			       attr->path_mtu);
-			return -EINVAL;
+			goto out;
 		}
 		context->mtu_msgmax = (attr->path_mtu << 5) | 31;
 	}
@@ -781,10 +781,8 @@ static int __mlx4_ib_modify_qp(struct ib_qp *ibqp,
 
 	if (attr_mask & IB_QP_AV) {
 		if (mlx4_set_path(dev, &attr->ah_attr, &context->pri_path,
-				  attr_mask & IB_QP_PORT ? attr->port_num : qp->port)) {
-			err = -EINVAL;
+				  attr_mask & IB_QP_PORT ? attr->port_num : qp->port))
 			goto out;
-		}
 
 		optpar |= (MLX4_QP_OPTPAR_PRIMARY_ADDR_PATH |
 			   MLX4_QP_OPTPAR_SCHED_QUEUE);
@@ -798,15 +796,15 @@ static int __mlx4_ib_modify_qp(struct ib_qp *ibqp,
 	if (attr_mask & IB_QP_ALT_PATH) {
 		if (attr->alt_port_num == 0 ||
 		    attr->alt_port_num > dev->dev->caps.num_ports)
-			return -EINVAL;
+			goto out;
 
 		if (attr->alt_pkey_index >=
 		    dev->dev->caps.pkey_table_len[attr->alt_port_num])
-			return -EINVAL;
+			goto out;
 
 		if (mlx4_set_path(dev, &attr->alt_ah_attr, &context->alt_path,
 				  attr->alt_port_num))
-			return -EINVAL;
+			goto out;
 
 		context->alt_path.pkey_index = attr->alt_pkey_index;
 		context->alt_path.ackto = attr->alt_timeout << 3;