From 4ee4c2f82b81c088d1514b04c28c84c15e98ba1a Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 4 Dec 2024 07:47:06 +0000 Subject: [PATCH] rxrpc: Fix request for an ACK when cwnd is minimum rxrpc_prepare_data_subpacket() sets the REQUEST-ACK flag on the outgoing DATA packet under a number of circumstances, including, theoretically, when the cwnd is at minimum (or less). However, the minimum in this function is hard-coded as 2, but the actual minimum is RXRPC_MIN_CWND (which is currently 4) and so this never occurs. Without this, we will miss the request of some ACKs, potentially leading to a transmission stall until a timeout occurs on one side or the other that leads to an ACK being generated. Fix the function to use RXRPC_MIN_CWND rather than a hard-coded number. Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org Signed-off-by: Jakub Kicinski --- net/rxrpc/output.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c index ecaf3becee40..f934551a9b1c 100644 --- a/net/rxrpc/output.c +++ b/net/rxrpc/output.c @@ -469,7 +469,7 @@ static size_t rxrpc_prepare_data_subpacket(struct rxrpc_call *call, why = rxrpc_reqack_ack_lost; else if (txb->flags & RXRPC_TXBUF_RESENT) why = rxrpc_reqack_retrans; - else if (call->cong_ca_state == RXRPC_CA_SLOW_START && call->cong_cwnd <= 2) + else if (call->cong_ca_state == RXRPC_CA_SLOW_START && call->cong_cwnd <= RXRPC_MIN_CWND) why = rxrpc_reqack_slow_start; else if (call->tx_winsize <= 2) why = rxrpc_reqack_small_txwin; -- 2.25.1