rxrpc: Fix loss of PING RESPONSE ACK production due to PING ACKs

[cascardo/linux.git] / net / rxrpc / call_event.c

diff --git a/net/rxrpc/call_event.c b/net/rxrpc/call_event.c
index e313099..eeea960 100644 (file)
--- a/net/rxrpc/call_event.c
+++ b/net/rxrpc/call_event.c
@@ -54,6 +54,14 @@ void rxrpc_set_timer(struct rxrpc_call *call, enum rxrpc_timer_trace why,
                        t = call->ack_at;
                }
 
+               if (!ktime_after(call->ping_at, now)) {
+                       call->ping_at = call->expire_at;
+                       if (!test_and_set_bit(RXRPC_CALL_EV_PING, &call->events))
+                               queue = true;
+               } else if (ktime_before(call->ping_at, t)) {
+                       t = call->ping_at;
+               }
+
                t_j = nsecs_to_jiffies(ktime_to_ns(ktime_sub(t, now)));
                t_j += jiffies;
 
@@ -77,6 +85,27 @@ out:
        read_unlock_bh(&call->state_lock);
 }
 
+/*
+ * Propose a PING ACK be sent.
+ */
+static void rxrpc_propose_ping(struct rxrpc_call *call,
+                              bool immediate, bool background)
+{
+       if (immediate) {
+               if (background &&
+                   !test_and_set_bit(RXRPC_CALL_EV_PING, &call->events))
+                       rxrpc_queue_call(call);
+       } else {
+               ktime_t now = ktime_get_real();
+               ktime_t ping_at = ktime_add_ms(now, rxrpc_idle_ack_delay);
+
+               if (ktime_before(ping_at, call->ping_at)) {
+                       call->ping_at = ping_at;
+                       rxrpc_set_timer(call, rxrpc_timer_set_for_ping, now);
+               }
+       }
+}
+
 /*
  * propose an ACK be sent
  */
@@ -90,6 +119,14 @@ static void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
        ktime_t now, ack_at;
        s8 prior = rxrpc_ack_priority[ack_reason];
 
+       /* Pings are handled specially because we don't want to accidentally
+        * lose a ping response by subsuming it into a ping.
+        */
+       if (ack_reason == RXRPC_ACK_PING) {
+               rxrpc_propose_ping(call, immediate, background);
+               goto trace;
+       }
+
        /* Update DELAY, IDLE, REQUESTED and PING_RESPONSE ACK serial
         * numbers, but we don't alter the timeout.
         */
@@ -125,7 +162,6 @@ static void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
                        expiry = rxrpc_soft_ack_delay;
                break;
 
-       case RXRPC_ACK_PING:
        case RXRPC_ACK_IDLE:
                if (rxrpc_idle_ack_delay < expiry)
                        expiry = rxrpc_idle_ack_delay;
@@ -253,7 +289,7 @@ static void rxrpc_resend(struct rxrpc_call *call, ktime_t now)
                        goto out;
                rxrpc_propose_ACK(call, RXRPC_ACK_PING, 0, 0, true, false,
                                  rxrpc_propose_ack_ping_for_lost_ack);
-               rxrpc_send_ack_packet(call);
+               rxrpc_send_ack_packet(call, true);
                goto out;
        }
 
@@ -345,13 +381,17 @@ recheck_state:
        }
 
        if (test_and_clear_bit(RXRPC_CALL_EV_ACK, &call->events)) {
-               call->ack_at = call->expire_at;
                if (call->ackr_reason) {
-                       rxrpc_send_ack_packet(call);
+                       rxrpc_send_ack_packet(call, false);
                        goto recheck_state;
                }
        }
 
+       if (test_and_clear_bit(RXRPC_CALL_EV_PING, &call->events)) {
+               rxrpc_send_ack_packet(call, true);
+               goto recheck_state;
+       }
+
        if (test_and_clear_bit(RXRPC_CALL_EV_RESEND, &call->events)) {
                rxrpc_resend(call, now);
                goto recheck_state;