diff --git a/lib/nghttp2_frame.h b/lib/nghttp2_frame.h
index 719e1f64..25bfa797 100644
--- a/lib/nghttp2_frame.h
+++ b/lib/nghttp2_frame.h
@@ -52,7 +52,7 @@
   (NGHTTP2_FRAME_HDLEN + 2 + NGHTTP2_MAX_PAYLOADLEN)
 
 /* The maximum length of DATA frame payload. */
-#define NGHTTP2_DATA_PAYLOAD_LENGTH 4096
+#define NGHTTP2_DATA_PAYLOADLEN 4096
 
 /* The number of bytes for each SETTINGS entry */
 #define NGHTTP2_FRAME_SETTINGS_ENTRY_LENGTH 5
diff --git a/lib/nghttp2_session.c b/lib/nghttp2_session.c
index 10f0f9c0..8b312da8 100644
--- a/lib/nghttp2_session.c
+++ b/lib/nghttp2_session.c
@@ -1331,7 +1331,7 @@ static int nghttp2_session_predicate_settings_send(nghttp2_session *session,
 static size_t nghttp2_session_next_data_read(nghttp2_session *session,
                                              nghttp2_stream *stream)
 {
-  int32_t window_size = NGHTTP2_DATA_PAYLOAD_LENGTH;
+  int32_t window_size = NGHTTP2_DATA_PAYLOADLEN;
 
   DEBUGF(fprintf(stderr,
                  "send: remote windowsize connection=%d, "
diff --git a/tests/nghttp2_session_test.c b/tests/nghttp2_session_test.c
index accdfdbd..9cd2bc90 100644
--- a/tests/nghttp2_session_test.c
+++ b/tests/nghttp2_session_test.c
@@ -2645,7 +2645,7 @@ void test_nghttp2_submit_data(void)
   callbacks.send_callback = block_count_send_callback;
 
   data_prd.read_callback = fixed_length_data_source_read_callback;
-  ud.data_source_length = NGHTTP2_DATA_PAYLOAD_LENGTH * 2;
+  ud.data_source_length = NGHTTP2_DATA_PAYLOADLEN * 2;
   CU_ASSERT(0 == nghttp2_session_client_new(&session, &callbacks, &ud));
   aob = &session->aob;
   framebufs = &aob->framebufs;
@@ -3884,7 +3884,7 @@ void test_nghttp2_session_stop_data_with_rst_stream(void)
   data_prd.read_callback = fixed_length_data_source_read_callback;
 
   ud.frame_send_cb_called = 0;
-  ud.data_source_length = NGHTTP2_DATA_PAYLOAD_LENGTH * 4;
+  ud.data_source_length = NGHTTP2_DATA_PAYLOADLEN * 4;
 
   nghttp2_session_server_new(&session, &callbacks, &ud);
   nghttp2_session_open_stream(session, 1, NGHTTP2_STREAM_FLAG_NONE,
@@ -3897,7 +3897,7 @@ void test_nghttp2_session_stop_data_with_rst_stream(void)
   CU_ASSERT(0 == nghttp2_session_send(session));
   CU_ASSERT(NGHTTP2_DATA == ud.sent_frame_type);
   /* data for DATA[1] is read from data_prd but it is not sent */
-  CU_ASSERT(ud.data_source_length == NGHTTP2_DATA_PAYLOAD_LENGTH * 2);
+  CU_ASSERT(ud.data_source_length == NGHTTP2_DATA_PAYLOADLEN * 2);
 
   nghttp2_frame_rst_stream_init(&frame.rst_stream, 1, NGHTTP2_CANCEL);
   CU_ASSERT(0 == nghttp2_session_on_rst_stream_received(session, &frame));
@@ -3909,7 +3909,7 @@ void test_nghttp2_session_stop_data_with_rst_stream(void)
   CU_ASSERT(0 == nghttp2_session_send(session));
   /* With RST_STREAM, stream is canceled and further DATA on that
      stream are not sent. */
-  CU_ASSERT(ud.data_source_length == NGHTTP2_DATA_PAYLOAD_LENGTH * 2);
+  CU_ASSERT(ud.data_source_length == NGHTTP2_DATA_PAYLOADLEN * 2);
 
   CU_ASSERT(NULL == nghttp2_session_get_stream(session, 1));
 
@@ -3930,7 +3930,7 @@ void test_nghttp2_session_defer_data(void)
   data_prd.read_callback = defer_data_source_read_callback;
 
   ud.frame_send_cb_called = 0;
-  ud.data_source_length = NGHTTP2_DATA_PAYLOAD_LENGTH * 4;
+  ud.data_source_length = NGHTTP2_DATA_PAYLOADLEN * 4;
 
   nghttp2_session_server_new(&session, &callbacks, &ud);
   nghttp2_session_open_stream(session, 1, NGHTTP2_STREAM_FLAG_NONE,
@@ -3943,7 +3943,7 @@ void test_nghttp2_session_defer_data(void)
   CU_ASSERT(0 == nghttp2_session_send(session));
   CU_ASSERT(NGHTTP2_HEADERS == ud.sent_frame_type);
   /* No data is read */
-  CU_ASSERT(ud.data_source_length == NGHTTP2_DATA_PAYLOAD_LENGTH * 4);
+  CU_ASSERT(ud.data_source_length == NGHTTP2_DATA_PAYLOADLEN * 4);
 
   ud.block_count = 1;
   nghttp2_submit_ping(session, NGHTTP2_FLAG_NONE, NULL);
@@ -3959,7 +3959,7 @@ void test_nghttp2_session_defer_data(void)
   ud.block_count = 1;
   /* Reads 2 DATA chunks */
   CU_ASSERT(0 == nghttp2_session_send(session));
-  CU_ASSERT(ud.data_source_length == NGHTTP2_DATA_PAYLOAD_LENGTH * 2);
+  CU_ASSERT(ud.data_source_length == NGHTTP2_DATA_PAYLOADLEN * 2);
 
   /* Deferred again */
   OB_DATA(item)->data_prd.read_callback = defer_data_source_read_callback;
@@ -3967,7 +3967,7 @@ void test_nghttp2_session_defer_data(void)
      sent. No read_callback invocation. */
   ud.block_count = 1;
   CU_ASSERT(0 == nghttp2_session_send(session));
-  CU_ASSERT(ud.data_source_length == NGHTTP2_DATA_PAYLOAD_LENGTH * 2);
+  CU_ASSERT(ud.data_source_length == NGHTTP2_DATA_PAYLOADLEN * 2);
 
   /* Resume deferred DATA */
 
@@ -4528,7 +4528,7 @@ void test_nghttp2_session_data_backoff_by_high_pri_frame(void)
   data_prd.read_callback = fixed_length_data_source_read_callback;
 
   ud.frame_send_cb_called = 0;
-  ud.data_source_length = NGHTTP2_DATA_PAYLOAD_LENGTH * 4;
+  ud.data_source_length = NGHTTP2_DATA_PAYLOADLEN * 4;
 
   nghttp2_session_client_new(&session, &callbacks, &ud);
   nghttp2_submit_request(session, NULL, NULL, 0, &data_prd, NULL);
@@ -4538,7 +4538,7 @@ void test_nghttp2_session_data_backoff_by_high_pri_frame(void)
   CU_ASSERT(0 == nghttp2_session_send(session));
   CU_ASSERT(NGHTTP2_DATA == ud.sent_frame_type);
   /* data for DATA[1] is read from data_prd but it is not sent */
-  CU_ASSERT(ud.data_source_length == NGHTTP2_DATA_PAYLOAD_LENGTH * 2);
+  CU_ASSERT(ud.data_source_length == NGHTTP2_DATA_PAYLOADLEN * 2);
 
   nghttp2_submit_ping(session, NGHTTP2_FLAG_NONE, NULL);
   ud.block_count = 2;
@@ -4546,7 +4546,7 @@ void test_nghttp2_session_data_backoff_by_high_pri_frame(void)
   CU_ASSERT(0 == nghttp2_session_send(session));
   CU_ASSERT(NGHTTP2_PING == ud.sent_frame_type);
   /* data for DATA[2] is read from data_prd but it is not sent */
-  CU_ASSERT(ud.data_source_length == NGHTTP2_DATA_PAYLOAD_LENGTH);
+  CU_ASSERT(ud.data_source_length == NGHTTP2_DATA_PAYLOADLEN);
 
   ud.block_count = 2;
   /* Sends DATA[2..3] */