@@ -94,9 +94,11 @@ static int rxrpc_wait_to_be_connected(struct rxrpc_call *call, long *timeo)
*/
static bool rxrpc_check_tx_space(struct rxrpc_call *call, rxrpc_seq_t *_tx_win)
{
+ rxrpc_seq_t tx_bottom = READ_ONCE(call->tx_bottom);
+
if (_tx_win)
- *_tx_win = call->tx_bottom;
- return call->tx_prepared - call->tx_bottom < 256;
+ *_tx_win = tx_bottom;
+ return call->tx_prepared - tx_bottom < 256;
}
/*
@@ -138,7 +140,7 @@ static int rxrpc_wait_for_tx_window_waitall(struct rxrpc_sock *rx,
rtt = 2;
timeout = rtt;
- tx_start = smp_load_acquire(&call->acks_hard_ack);
+ tx_start = READ_ONCE(call->acks_hard_ack);
for (;;) {
set_current_state(TASK_UNINTERRUPTIBLE);
@@ -214,14 +214,14 @@ void rxrpc_shrink_call_tx_buffer(struct rxrpc_call *call)
while ((txb = list_first_entry_or_null(&call->tx_buffer,
struct rxrpc_txbuf, call_link))) {
- hard_ack = smp_load_acquire(&call->acks_hard_ack);
+ hard_ack = call->acks_hard_ack;
if (before(hard_ack, txb->seq))
break;
if (txb->seq != call->tx_bottom + 1)
rxrpc_see_txbuf(txb, rxrpc_txbuf_see_out_of_step);
ASSERTCMP(txb->seq, ==, call->tx_bottom + 1);
- smp_store_release(&call->tx_bottom, call->tx_bottom + 1);
+ WRITE_ONCE(call->tx_bottom, call->tx_bottom + 1);
list_del_rcu(&txb->call_link);
trace_rxrpc_txqueue(call, rxrpc_txqueue_dequeue);
We don't need a barrier for the ->tx_bottom value (which indicates the lowest sequence still in the transmission queue) and the ->acks_hard_ack value (which tracks the DATA packets hard-ack'd by the latest ACK packet received and thus indicates which DATA packets can now be discarded) as the app thread doesn't use either value as a reference to memory to access. Rather, the app thread merely uses these as a guide to how much space is available in the transmission queue Change the code to use READ/WRITE_ONCE() instead. Also, change rxrpc_check_tx_space() to use the same value for tx_bottom throughout. 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/sendmsg.c | 8 +++++--- net/rxrpc/txbuf.c | 4 ++-- 2 files changed, 7 insertions(+), 5 deletions(-)