[PATCH net-next v3 05/21] rxrpc: Strip barriers and atomics off of timer tracking

David Howells
2024-03-06T00:07:16Z

Strip the atomic ops and barriering off of the call timer tracking as this
is handled solely within the I/O thread, except for expect_term_by which is
set by sendmsg().

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: "David S. Miller" <davem@davemloft.net>
cc: Eric Dumazet <edumazet@google.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: linux-afs@lists.infradead.org
cc: netdev@vger.kernel.org
---
net/rxrpc/call_event.c | 32 ++++++++++++++++----------------
net/rxrpc/conn_client.c | 4 ++--
net/rxrpc/input.c | 15 ++++++---------
net/rxrpc/output.c | 18 ++++++++----------
4 files changed, 32 insertions(+), 37 deletions(-)

diff --git a/net/rxrpc/call_event.c b/net/rxrpc/call_event.c
index 77eacbfc5d45..84eedbb49fcb 100644
--- a/net/rxrpc/call_event.c
+++ b/net/rxrpc/call_event.c
@@ -27,7 +27,7 @@ void rxrpc_propose_ping(struct rxrpc_call *call, u32 serial,
unsigned long ping_at = now + rxrpc_idle_ack_delay;

if (time_before(ping_at, call->ping_at)) {
- WRITE_ONCE(call->ping_at, ping_at);
+ call->ping_at = ping_at;
rxrpc_reduce_call_timer(call, ping_at, now,
rxrpc_timer_set_for_ping);
trace_rxrpc_propose_ack(call, why, RXRPC_ACK_PING, serial);
@@ -53,7 +53,7 @@ void rxrpc_propose_delay_ACK(struct rxrpc_call *call, rxrpc_serial_t serial,
ack_at += READ_ONCE(call->tx_backoff);
ack_at += now;
if (time_before(ack_at, call->delay_ack_at)) {
- WRITE_ONCE(call->delay_ack_at, ack_at);
+ call->delay_ack_at = ack_at;
rxrpc_reduce_call_timer(call, ack_at, now,
rxrpc_timer_set_for_ack);
}
@@ -220,7 +220,7 @@ void rxrpc_resend(struct rxrpc_call *call, struct sk_buff *ack_skb)
resend_at = nsecs_to_jiffies(ktime_to_ns(ktime_sub(now, oldest)));
resend_at += jiffies + rxrpc_get_rto_backoff(call->peer,
!list_empty(&retrans_queue));
- WRITE_ONCE(call->resend_at, resend_at);
+ call->resend_at = resend_at;

if (unacked)
rxrpc_congestion_timeout(call);
@@ -260,7 +260,7 @@ static void rxrpc_begin_service_reply(struct rxrpc_call *call)
unsigned long now = jiffies;

rxrpc_set_call_state(call, RXRPC_CALL_SERVER_SEND_REPLY);
- WRITE_ONCE(call->delay_ack_at, now + MAX_JIFFY_OFFSET);
+ call->delay_ack_at = now + MAX_JIFFY_OFFSET;
if (call->ackr_reason == RXRPC_ACK_DELAY)
call->ackr_reason = 0;
trace_rxrpc_timer(call, rxrpc_timer_init_for_send_reply, now);
@@ -399,13 +399,13 @@ bool rxrpc_input_call_event(struct rxrpc_call *call, struct sk_buff *skb)

/* If we see our async-event poke, check for timeout trippage. */
now = jiffies;
- t = READ_ONCE(call->expect_rx_by);
+ t = call->expect_rx_by;
if (time_after_eq(now, t)) {
trace_rxrpc_timer(call, rxrpc_timer_exp_normal, now);
expired = true;
}

- t = READ_ONCE(call->expect_req_by);
+ t = call->expect_req_by;
if (__rxrpc_call_state(call) == RXRPC_CALL_SERVER_RECV_REQUEST &&
time_after_eq(now, t)) {
trace_rxrpc_timer(call, rxrpc_timer_exp_idle, now);
@@ -418,41 +418,41 @@ bool rxrpc_input_call_event(struct rxrpc_call *call, struct sk_buff *skb)
expired = true;
}

- t = READ_ONCE(call->delay_ack_at);
+ t = call->delay_ack_at;
if (time_after_eq(now, t)) {
trace_rxrpc_timer(call, rxrpc_timer_exp_ack, now);
- cmpxchg(&call->delay_ack_at, t, now + MAX_JIFFY_OFFSET);
+ call->delay_ack_at = now + MAX_JIFFY_OFFSET;
rxrpc_send_ACK(call, RXRPC_ACK_DELAY, 0,
rxrpc_propose_ack_ping_for_lost_ack);
}

- t = READ_ONCE(call->ack_lost_at);
+ t = call->ack_lost_at;
if (time_after_eq(now, t)) {
trace_rxrpc_timer(call, rxrpc_timer_exp_lost_ack, now);
- cmpxchg(&call->ack_lost_at, t, now + MAX_JIFFY_OFFSET);
+ call->ack_lost_at = now + MAX_JIFFY_OFFSET;
set_bit(RXRPC_CALL_EV_ACK_LOST, &call->events);
}

- t = READ_ONCE(call->keepalive_at);
+ t = call->keepalive_at;
if (time_after_eq(now, t)) {
trace_rxrpc_timer(call, rxrpc_timer_exp_keepalive, now);
- cmpxchg(&call->keepalive_at, t, now + MAX_JIFFY_OFFSET);
+ call->keepalive_at = now + MAX_JIFFY_OFFSET;
rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
rxrpc_propose_ack_ping_for_keepalive);
}

- t = READ_ONCE(call->ping_at);
+ t = call->ping_at;
if (time_after_eq(now, t)) {
trace_rxrpc_timer(call, rxrpc_timer_exp_ping, now);
- cmpxchg(&call->ping_at, t, now + MAX_JIFFY_OFFSET);
+ call->ping_at = now + MAX_JIFFY_OFFSET;
rxrpc_send_ACK(call, RXRPC_ACK_PING, 0,
rxrpc_propose_ack_ping_for_keepalive);
}

- t = READ_ONCE(call->resend_at);
+ t = call->resend_at;
if (time_after_eq(now, t)) {
trace_rxrpc_timer(call, rxrpc_timer_exp_resend, now);
- cmpxchg(&call->resend_at, t, now + MAX_JIFFY_OFFSET);
+ call->resend_at = now + MAX_JIFFY_OFFSET;
resend = true;
}

diff --git a/net/rxrpc/conn_client.c b/net/rxrpc/conn_client.c
index 3b9b267a4431..d25bf1cf3670 100644
--- a/net/rxrpc/conn_client.c
+++ b/net/rxrpc/conn_client.c
@@ -636,7 +636,7 @@ void rxrpc_disconnect_client_call(struct rxrpc_bundle *bundle, struct rxrpc_call
test_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
unsigned long final_ack_at = jiffies + 2;

- WRITE_ONCE(chan->final_ack_at, final_ack_at);
+ chan->final_ack_at = final_ack_at;
smp_wmb(); /* vs rxrpc_process_delayed_final_acks() */
set_bit(RXRPC_CONN_FINAL_ACK_0 + channel, &conn->flags);
rxrpc_reduce_conn_timer(conn, final_ack_at);
@@ -770,7 +770,7 @@ void rxrpc_discard_expired_client_conns(struct rxrpc_local *local)

conn_expires_at = conn->idle_timestamp + expiry;

- now = READ_ONCE(jiffies);
+ now = jiffies;
if (time_after(conn_expires_at, now))
goto not_yet_expired;
}
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index ea2df62e05e7..e53a49accc16 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -288,14 +288,12 @@ static void rxrpc_end_tx_phase(struct rxrpc_call *call, bool reply_begun,
static bool rxrpc_receiving_reply(struct rxrpc_call *call)
{
struct rxrpc_ack_summary summary = { 0 };
- unsigned long now, timo;
+ unsigned long now;
rxrpc_seq_t top = READ_ONCE(call->tx_top);

if (call->ackr_reason) {
now = jiffies;
- timo = now + MAX_JIFFY_OFFSET;
-
- WRITE_ONCE(call->delay_ack_at, timo);
+ call->delay_ack_at = now + MAX_JIFFY_OFFSET;
trace_rxrpc_timer(call, rxrpc_timer_init_for_reply, now);
}

@@ -594,7 +592,7 @@ static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb)
if (timo) {
now = jiffies;
expect_req_by = now + timo;
- WRITE_ONCE(call->expect_req_by, expect_req_by);
+ call->expect_req_by = now + timo;
rxrpc_reduce_call_timer(call, expect_req_by, now,
rxrpc_timer_set_for_idle);
}
@@ -1048,11 +1046,10 @@ void rxrpc_input_call_packet(struct rxrpc_call *call, struct sk_buff *skb)

timo = READ_ONCE(call->next_rx_timo);
if (timo) {
- unsigned long now = jiffies, expect_rx_by;
+ unsigned long now = jiffies;

- expect_rx_by = now + timo;
- WRITE_ONCE(call->expect_rx_by, expect_rx_by);
- rxrpc_reduce_call_timer(call, expect_rx_by, now,
+ call->expect_rx_by = now + timo;
+ rxrpc_reduce_call_timer(call, call->expect_rx_by, now,
rxrpc_timer_set_for_normal);
}

diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index 3803bf900a46..2386b01b2231 100644
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -67,11 +67,10 @@ static void rxrpc_tx_backoff(struct rxrpc_call *call, int ret)
*/
static void rxrpc_set_keepalive(struct rxrpc_call *call)
{
- unsigned long now = jiffies, keepalive_at = call->next_rx_timo / 6;
+ unsigned long now = jiffies;

- keepalive_at += now;
- WRITE_ONCE(call->keepalive_at, keepalive_at);
- rxrpc_reduce_call_timer(call, keepalive_at, now,
+ call->keepalive_at = now + call->next_rx_timo / 6;
+ rxrpc_reduce_call_timer(call, call->keepalive_at, now,
rxrpc_timer_set_for_keepalive);
}

@@ -449,7 +448,7 @@ int rxrpc_send_data_packet(struct rxrpc_call *call, struct rxrpc_txbuf *txb)

ack_lost_at = rxrpc_get_rto_backoff(call->peer, false);
ack_lost_at += nowj;
- WRITE_ONCE(call->ack_lost_at, ack_lost_at);
+ call->ack_lost_at = ack_lost_at;
rxrpc_reduce_call_timer(call, ack_lost_at, nowj,
rxrpc_timer_set_for_lost_ack);
}
@@ -458,11 +457,10 @@ int rxrpc_send_data_packet(struct rxrpc_call *call, struct rxrpc_txbuf *txb)
if (txb->seq == 1 &&
!test_and_set_bit(RXRPC_CALL_BEGAN_RX_TIMER,
&call->flags)) {
- unsigned long nowj = jiffies, expect_rx_by;
+ unsigned long nowj = jiffies;

- expect_rx_by = nowj + call->next_rx_timo;
- WRITE_ONCE(call->expect_rx_by, expect_rx_by);
- rxrpc_reduce_call_timer(call, expect_rx_by, nowj,
+ call->expect_rx_by = nowj + call->next_rx_timo;
+ rxrpc_reduce_call_timer(call, call->expect_rx_by, nowj,
rxrpc_timer_set_for_normal);
}

@@ -724,7 +722,7 @@ void rxrpc_transmit_one(struct rxrpc_call *call, struct rxrpc_txbuf *txb)
unsigned long now = jiffies;
unsigned long resend_at = now + call->peer->rto_j;

- WRITE_ONCE(call->resend_at, resend_at);
+ call->resend_at = resend_at;
rxrpc_reduce_call_timer(call, resend_at, now,
rxrpc_timer_set_for_send);
}