IB/mad: Return error response for unsupported MADs

Set up a response with appropriate error status and send it for MADs
that are not supported by a specific class/version.

Reviewed-by: Hal Rosenstock <hal@mellanox.com>
Signed-off-by: Swapna Thete <swapna.thete@qlogic.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/drivers/infiniband/core/mad.c b/drivers/infiniband/core/mad.c
index 2fe428bba54c..426bb7617ec6 100644
--- a/drivers/infiniband/core/mad.c
+++ b/drivers/infiniband/core/mad.c
@@ -1842,6 +1842,24 @@ static void ib_mad_complete_recv(struct ib_mad_agent_private *mad_agent_priv,
         }
 }
 
+static bool generate_unmatched_resp(struct ib_mad_private *recv,
+                                    struct ib_mad_private *response)
+{
+        if (recv->mad.mad.mad_hdr.method == IB_MGMT_METHOD_GET ||
+            recv->mad.mad.mad_hdr.method == IB_MGMT_METHOD_SET) {
+                memcpy(response, recv, sizeof *response);
+                response->header.recv_wc.wc = &response->header.wc;
+                response->header.recv_wc.recv_buf.mad = &response->mad.mad;
+                response->header.recv_wc.recv_buf.grh = &response->grh;
+                response->mad.mad.mad_hdr.method = IB_MGMT_METHOD_GET_RESP;
+                response->mad.mad.mad_hdr.status =
+                        cpu_to_be16(IB_MGMT_MAD_STATUS_UNSUPPORTED_METHOD_ATTRIB);
+
+                return true;
+        } else {
+                return false;
+        }
+}
 static void ib_mad_recv_done_handler(struct ib_mad_port_private *port_priv,
                                      struct ib_wc *wc)
 {
@@ -1963,6 +1981,9 @@ local:
                  * or via recv_handler in ib_mad_complete_recv()
                  */
                 recv = NULL;
+        } else if (generate_unmatched_resp(recv, response)) {
+                agent_send_response(&response->mad.mad, &recv->grh, wc,
+                                    port_priv->device, port_num, qp_info->qp->qp_num);
         }
 
 out: