3 files changed, 33 insertions, 15 deletions

diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index ec299c627f77..7f9ed3a60b9a 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -622,13 +622,14 @@ static void rxrpc_input_requested_ack(struct rxrpc_call *call,
                 if (!skb)
                         continue;
 
+                sent_at = skb->tstamp;
+                smp_rmb(); /* Read timestamp before serial. */
                 sp = rxrpc_skb(skb);
                 if (sp->hdr.serial != orig_serial)
                         continue;
-                smp_rmb();
-                sent_at = skb->tstamp;
                 goto found;
         }
+
         return;
 
 found:
@@ -1143,6 +1144,9 @@ void rxrpc_data_ready(struct sock *udp_sk)
                 return;
         }
 
+        if (skb->tstamp == 0)
+                skb->tstamp = ktime_get_real();
+
         rxrpc_new_skb(skb, rxrpc_skb_rx_received);
 
         _net("recv skb %p", skb);
diff --git a/net/rxrpc/local_object.c b/net/rxrpc/local_object.c
index 777c3ed4cfc0..81de7d889ffa 100644
--- a/net/rxrpc/local_object.c
+++ b/net/rxrpc/local_object.c
@@ -173,6 +173,15 @@ static int rxrpc_open_socket(struct rxrpc_local *local, struct net *net)
                         _debug("setsockopt failed");
                         goto error;
                 }
+
+                /* We want receive timestamps. */
+                opt = 1;
+                ret = kernel_setsockopt(local->socket, SOL_SOCKET, SO_TIMESTAMPNS,
+                                        (char *)&opt, sizeof(opt));
+                if (ret < 0) {
+                        _debug("setsockopt failed");
+                        goto error;
+                }
                 break;
 
         default:
diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index ccf5de160444..8a4da3fe96df 100644
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -124,7 +124,6 @@ int rxrpc_send_ack_packet(struct rxrpc_call *call, bool ping,
         struct kvec iov[2];
         rxrpc_serial_t serial;
         rxrpc_seq_t hard_ack, top;
-        ktime_t now;
         size_t len, n;
         int ret;
         u8 reason;
@@ -196,9 +195,7 @@ int rxrpc_send_ack_packet(struct rxrpc_call *call, bool ping,
                 /* We need to stick a time in before we send the packet in case
                  * the reply gets back before kernel_sendmsg() completes - but
                  * asking UDP to send the packet can take a relatively long
-                 * time, so we update the time after, on the assumption that
-                 * the packet transmission is more likely to happen towards the
-                 * end of the kernel_sendmsg() call.
+                 * time.
                  */
                 call->ping_time = ktime_get_real();
                 set_bit(RXRPC_CALL_PINGING, &call->flags);
@@ -206,9 +203,6 @@ int rxrpc_send_ack_packet(struct rxrpc_call *call, bool ping,
         }
 
         ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
-        now = ktime_get_real();
-        if (ping)
-                call->ping_time = now;
         conn->params.peer->last_tx_at = ktime_get_seconds();
         if (ret < 0)
                 trace_rxrpc_tx_fail(call->debug_id, serial, ret,
@@ -363,8 +357,14 @@ int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb,
 
         /* If our RTT cache needs working on, request an ACK.  Also request
          * ACKs if a DATA packet appears to have been lost.
+         *
+         * However, we mustn't request an ACK on the last reply packet of a
+         * service call, lest OpenAFS incorrectly send us an ACK with some
+         * soft-ACKs in it and then never follow up with a proper hard ACK.
          */
-        if (!(sp->hdr.flags & RXRPC_LAST_PACKET) &&
+        if ((!(sp->hdr.flags & RXRPC_LAST_PACKET) ||
+             rxrpc_to_server(sp)
+             ) &&
             (test_and_clear_bit(RXRPC_CALL_EV_ACK_LOST, &call->events) ||
              retrans ||
              call->cong_mode == RXRPC_CALL_SLOW_START ||
@@ -390,6 +390,11 @@ int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb,
                 goto send_fragmentable;
 
         down_read(&conn->params.local->defrag_sem);
+
+        sp->hdr.serial = serial;
+        smp_wmb(); /* Set serial before timestamp */
+        skb->tstamp = ktime_get_real();
+
         /* send the packet by UDP
          * - returns -EMSGSIZE if UDP would have to fragment the packet
          *   to go out of the interface
@@ -413,12 +418,8 @@ done:
         trace_rxrpc_tx_data(call, sp->hdr.seq, serial, whdr.flags,
                             retrans, lost);
         if (ret >= 0) {
-                ktime_t now = ktime_get_real();
-                skb->tstamp = now;
-                smp_wmb();
-                sp->hdr.serial = serial;
                 if (whdr.flags & RXRPC_REQUEST_ACK) {
-                        call->peer->rtt_last_req = now;
+                        call->peer->rtt_last_req = skb->tstamp;
                         trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_data, serial);
                         if (call->peer->rtt_usage > 1) {
                                 unsigned long nowj = jiffies, ack_lost_at;
@@ -457,6 +458,10 @@ send_fragmentable:
 
         down_write(&conn->params.local->defrag_sem);
 
+        sp->hdr.serial = serial;
+        smp_wmb(); /* Set serial before timestamp */
+        skb->tstamp = ktime_get_real();
+
         switch (conn->params.local->srx.transport.family) {
         case AF_INET:
                 opt = IP_PMTUDISC_DONT;