Patch "tcp_bbr: introduce bbr_bw_to_pacing_rate() helper" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

tcp_bbr: introduce bbr_bw_to_pacing_rate() helper

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
tcp_bbr-introduce-bbr_bw_to_pacing_rate-helper.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Neal Cardwell <[email protected]>
Date: Fri, 14 Jul 2017 17:49:22 -0400
Subject: tcp_bbr: introduce bbr_bw_to_pacing_rate() helper

From: Neal Cardwell <[email protected]>

[ Upstream commit f19fd62dafaf1ed6cf615dba655b82fa9df59074 ]

Introduce a helper to convert a BBR bandwidth and gain factor to a pacing rate in bytes per second. This is a pure refactor, but is needed for two following fixes.

---
 net/ipv4/tcp_bbr.c |   14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

@@ -182,6 +182,16 @@ static u64 bbr_rate_bytes_per_sec(struct
 	return rate >> BW_SCALE;
 }
 
+/* Convert a BBR bw and gain factor to a pacing rate in bytes per second. */
+static u32 bbr_bw_to_pacing_rate(struct sock *sk, u32 bw, int gain)
+{
+	u64 rate = bw;
+
+	rate = bbr_rate_bytes_per_sec(sk, rate, gain);
+	rate = min_t(u64, rate, sk->sk_max_pacing_rate);
+	return rate;
+}
+
 /* Pace using current bw estimate and a gain factor. In order to help drive the
  * network toward lower queues while maintaining high utilization and low
  * latency, the average pacing rate aims to be slightly (~1%) lower than the

@@ -191,10 +201,8 @@ static u64 bbr_rate_bytes_per_sec(struct
  */
 static void bbr_set_pacing_rate(struct sock *sk, u32 bw, int gain)
 {
-	u64 rate = bw;
+	u32 rate = bbr_bw_to_pacing_rate(sk, bw, gain);
 
-	rate = bbr_rate_bytes_per_sec(sk, rate, gain);
-	rate = min_t(u64, rate, sk->sk_max_pacing_rate);
 	if (bbr_full_bw_reached(sk) || rate > sk->sk_pacing_rate)
 		sk->sk_pacing_rate = rate;
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/tcp_bbr-remove-sk_pacing_rate-0-transient-during-init.patch queue-4.9/tcp_bbr-introduce-bbr_bw_to_pacing_rate-helper.patch queue-4.9/tcp_bbr-introduce-bbr_init_pacing_rate_from_rtt-helper.patch queue-4.9/tcp_bbr-init-pacing-rate-on-first-rtt-sample.patch queue-4.9/tcp_bbr-cut-pacing-rate-only-if-filled-pipe.patch