ib_srpt: always set response for task management

The SRP specification requires:

  "Response data shall be provided in any SRP_RSP response that is sent in
   response to an SRP_TSK_MGMT request (see 6.7). The information in the
   RSP_CODE field (see table 24) shall indicate the completion status of
   the task management function."

So fix this to avoid the SRP initiator interprets task management functions
that succeeded as failed.
Signed-off-by: Jack Wang <jinpu.wang@profitbricks.com>
Cc: stable@vger.kernel.org # 3.3+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/infiniband/ulp/srpt/ib_srpt.c

@@ -1588,7 +1588,7 @@ static int srpt_build_tskmgmt_rsp(struct srpt_rdma_ch *ch,
 	int resp_data_len;
 	int resp_len;
 
-	resp_data_len = (rsp_code == SRP_TSK_MGMT_SUCCESS) ? 0 : 4;
+	resp_data_len = 4;
 	resp_len = sizeof(*srp_rsp) + resp_data_len;
 
 	srp_rsp = ioctx->ioctx.buf;
@@ -1600,11 +1600,9 @@ static int srpt_build_tskmgmt_rsp(struct srpt_rdma_ch *ch,
 				    + atomic_xchg(&ch->req_lim_delta, 0));
 	srp_rsp->tag = tag;
 
-	if (rsp_code != SRP_TSK_MGMT_SUCCESS) {
 	srp_rsp->flags |= SRP_RSP_FLAG_RSPVALID;
 	srp_rsp->resp_data_len = cpu_to_be32(resp_data_len);
 	srp_rsp->data[3] = rsp_code;
-	}
 
 	return resp_len;
 }