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Diffstat (limited to 'net/dccp/ccids/ccid3.h')
-rw-r--r--net/dccp/ccids/ccid3.h18
1 files changed, 13 insertions, 5 deletions
diff --git a/net/dccp/ccids/ccid3.h b/net/dccp/ccids/ccid3.h
index b7e569c22f36..4a00174a97dd 100644
--- a/net/dccp/ccids/ccid3.h
+++ b/net/dccp/ccids/ccid3.h
@@ -45,12 +45,22 @@
 /* Two seconds as per RFC 5348, 4.2 */
 #define TFRC_INITIAL_TIMEOUT	   (2 * USEC_PER_SEC)
 
-/* In usecs - half the scheduling granularity as per RFC3448 4.6 */
-#define TFRC_OPSYS_HALF_TIME_GRAN  (USEC_PER_SEC / (2 * HZ))
-
 /* Parameter t_mbi from [RFC 3448, 4.3]: backoff interval in seconds */
 #define TFRC_T_MBI		   64
 
+/*
+ * The t_delta parameter (RFC 5348, 8.3): delays of less than %USEC_PER_MSEC are
+ * rounded down to 0, since sk_reset_timer() here uses millisecond granularity.
+ * Hence we can use a constant t_delta = %USEC_PER_MSEC when HZ >= 500. A coarse
+ * resolution of HZ < 500 means that the error is below one timer tick (t_gran)
+ * when using the constant t_delta  =  t_gran / 2  =  %USEC_PER_SEC / (2 * HZ).
+ */
+#if (HZ >= 500)
+# define TFRC_T_DELTA		   USEC_PER_MSEC
+#else
+# define TFRC_T_DELTA		   (USEC_PER_SEC / (2 * HZ))
+#endif
+
 enum ccid3_options {
 	TFRC_OPT_LOSS_EVENT_RATE = 192,
 	TFRC_OPT_LOSS_INTERVALS	 = 193,
@@ -90,7 +100,6 @@ enum ccid3_hc_tx_states {
  * @tx_no_feedback_timer: Handle to no feedback timer
  * @tx_t_ld:		  Time last doubled during slow start
  * @tx_t_nom:		  Nominal send time of next packet
- * @tx_delta:		  Send timer delta (RFC 3448, 4.6) in usecs
  * @tx_hist:		  Packet history
  * @tx_options_received:  Parsed set of retrieved options
  */
@@ -109,7 +118,6 @@ struct ccid3_hc_tx_sock {
 	struct timer_list		tx_no_feedback_timer;
 	ktime_t				tx_t_ld;
 	ktime_t				tx_t_nom;
-	u32				tx_delta;
 	struct tfrc_tx_hist_entry	*tx_hist;
 	struct ccid3_options_received	tx_options_received;
 };