Merge branch 'tcp-coalesce-merge-timestamps'

Martin KaFai Lau says:

====================
tcp: Merge timestamp info when coalescing skbs

This series is separated from the RFC series related to
tcp_sendmsg(MSG_EOR) and it is targeting for the net branch.
This patchset is focusing on fixing cases where TCP
timestamp could be lost after coalescing skbs.

A BPF prog is used to kprobe to sock_queue_err_skb()
and print out the value of serr->ee.ee_data.  The BPF
prog (run-able from bcc) is attached here:

BPF prog used for testing:
~~~~~

from __future__ import print_function
from bcc import BPF

bpf_text = """

int trace_err_skb(struct pt_regs *ctx)
{
	struct sk_buff *skb = (struct sk_buff *)ctx->si;
	struct sock *sk = (struct sock *)ctx->di;
	struct sock_exterr_skb *serr;
	u32 ee_data = 0;

	if (!sk || !skb)
		return 0;

	serr = SKB_EXT_ERR(skb);
	bpf_probe_read(&ee_data, sizeof(ee_data), &serr->ee.ee_data);
	bpf_trace_printk("ee_data:%u\\n", ee_data);

	return 0;
};
"""

b = BPF(text=bpf_text)
b.attach_kprobe(event="sock_queue_err_skb", fn_name="trace_err_skb")
print("Attached to kprobe")
b.trace_print()
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 0 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 0edb07185c25..c124c3c12f7c 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1309,6 +1309,7 @@ static bool tcp_shifted_skb(struct sock *sk, struct sk_buff *skb,
 	if (skb == tcp_highest_sack(sk))
 		tcp_advance_highest_sack(sk, skb);
 
+	tcp_skb_collapse_tstamp(prev, skb);
 	tcp_unlink_write_queue(skb, sk);
 	sk_wmem_free_skb(sk, skb);