1 files changed, 24 insertions, 4 deletions

diff --git a/include/linux/tfrc.h b/include/linux/tfrc.h
index 7dab7831c3c..8a8462b4a4d 100644
--- a/include/linux/tfrc.h
+++ b/include/linux/tfrc.h
@@ -1,7 +1,8 @@
 #ifndef _LINUX_TFRC_H_
 #define _LINUX_TFRC_H_
 /*
- *  include/linux/tfrc.h
+ *  TFRC - Data Structures for the TCP-Friendly Rate Control congestion
+ *         control mechanism as specified in RFC 3448.
  *
  *  Copyright (c) 2005 The University of Waikato, Hamilton, New Zealand.
  *  Copyright (c) 2005 Ian McDonald <iam4@cs.waikato.ac.nz>
@@ -13,18 +14,37 @@
  *  the Free Software Foundation; either version 2 of the License, or
  *  (at your option) any later version.
  */
-
 #include <linux/types.h>
 
+/**     tfrc_rx_info    -    TFRC Receiver Data Structure
+ *
+ *      @tfrcrx_x_recv: receiver estimate of sending rate (3.2.2)
+ *      @tfrcrx_rtt:    round-trip-time (communicated by sender)
+ *      @tfrcrx_p:      current estimate of loss event rate (3.2.2)
+ */
 struct tfrc_rx_info {
         __u32 tfrcrx_x_recv;
         __u32 tfrcrx_rtt;
         __u32 tfrcrx_p;
 };
 
+/**     tfrc_tx_info    -    TFRC Sender Data Structure
+ *
+ *      @tfrctx_x:      computed transmit rate (4.3 (4))
+ *      @tfrctx_x_recv: receiver estimate of send rate (4.3)
+ *      @tfrctx_x_calc: return value of throughput equation (3.1)
+ *      @tfrctx_rtt:    (moving average) estimate of RTT (4.3)
+ *      @tfrctx_p:      current loss event rate (5.4)
+ *      @tfrctx_rto:    estimate of RTO, equals 4*RTT (4.3)
+ *      @tfrctx_ipi:    inter-packet interval (4.6)
+ *
+ *  Note: X and X_recv are both maintained in units of 64 * bytes/second. This
+ *        enables a finer resolution of sending rates and avoids problems with
+ *        integer arithmetic; u32 is not sufficient as scaling consumes 6 bits.
+ */
 struct tfrc_tx_info {
-        __u32 tfrctx_x;
-        __u32 tfrctx_x_recv;
+        __u64 tfrctx_x;
+        __u64 tfrctx_x_recv;
         __u32 tfrctx_x_calc;
         __u32 tfrctx_rtt;
         __u32 tfrctx_p;