From: David Howells <dhowells@redhat.com>
Date: Fri, 23 Sep 2016 12:17:33 +0000 (+0100)
Subject: rxrpc: Preset timestamp on Tx sk_buffs
X-Git-Tag: v4.9-rc1~127^2~76^2~14
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=b24d2891cfb0a7975b0039743439c98fe7b7dea7;p=linux.git

rxrpc: Preset timestamp on Tx sk_buffs

Set the timestamp on sk_buffs holding packets to be transmitted before
queueing them because the moment the packet is on the queue it can be seen
by the retransmission algorithm - which may see a completely random
timestamp.

If the retransmission algorithm sees such a timestamp, it may retransmit
the packet and, in future, tell the congestion management algorithm that
the retransmit timer expired.

Signed-off-by: David Howells <dhowells@redhat.com>
---

diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c
index ca7c3be60ad2..ca3811bfbd17 100644
--- a/net/rxrpc/sendmsg.c
+++ b/net/rxrpc/sendmsg.c
@@ -99,6 +99,11 @@ static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb,
 
 	ASSERTCMP(seq, ==, call->tx_top + 1);
 
+	/* We have to set the timestamp before queueing as the retransmit
+	 * algorithm can see the packet as soon as we queue it.
+	 */
+	skb->tstamp = ktime_get_real();
+
 	ix = seq & RXRPC_RXTX_BUFF_MASK;
 	rxrpc_get_skb(skb, rxrpc_skb_tx_got);
 	call->rxtx_annotations[ix] = RXRPC_TX_ANNO_UNACK;