crimson: fix DynamicPerfStats usage in ClientRequest

ClientRequest::get_connection() return l_conn, which will be
null by the time PG::add_client_request_lat is called in
ClientRequest::do_process.  Modify get_connection() to
return a Connection& from whichever of l_conn or r_conn
isn't null.

Signed-off-by: Samuel Just <[email protected]>
(cherry picked from commit 794bb02)

Author: athanatos

src/crimson/osd/osd_operations/client_request.h

@@ -54,8 +54,13 @@ class ClientRequest final : public PhasedOperationT<ClientRequest> {
     static_assert(std::is_same_v<T, MOSDOp>);
     return m.get();
   }
-  const crimson::net::ConnectionRef &get_connection() const {
-    return l_conn;
+  const crimson::net::Connection &get_connection() const {
+    if (l_conn) {
+      return *l_conn;
+    } else {
+      assert(r_conn);
+      return *r_conn;
+    }
   }
 
   /**

src/osd/DynamicPerfStats.h

@@ -122,7 +122,7 @@ class DynamicPerfStats {
             break;
           case OSDPerfMetricSubKeyType::CLIENT_ADDRESS:
 #ifdef WITH_CRIMSON
-	    match_string = stringify(op.get_connection()->get_peer_addr());
+	    match_string = stringify(op.get_connection().get_peer_addr());
 #else
             match_string = stringify(m->get_connection()->get_peer_addr());
 #endif