4.9-stable review patch. If anyone has any objections, please let me know.
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From: David Howells dhowells@redhat.com
[ Upstream commit 702f2ac87a9a8da23bf8506466bc70175fc970b2 ]
The RxRPC ACK packet may contain an extension that includes the peer's current Rx window size for this call. We adjust the local Tx window size to match. However, the transmitter can stall if the receive window is reduced to 0 by the peer and then reopened.
This is because the normal way that the transmitter is re-energised is by dropping something out of our Tx queue and thus making space. When a single gap is made, the transmitter is woken up. However, because there's nothing in the Tx queue at this point, this doesn't happen.
To fix this, perform a wake_up() any time we see the peer's Rx window size increasing.
The observable symptom is that calls start failing on ETIMEDOUT and the following:
kAFS: SERVER DEAD state=-62
appears in dmesg.
Signed-off-by: David Howells dhowells@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/rxrpc/input.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)
--- a/net/rxrpc/input.c +++ b/net/rxrpc/input.c @@ -649,6 +649,7 @@ static void rxrpc_input_ackinfo(struct r struct rxrpc_skb_priv *sp = rxrpc_skb(skb); struct rxrpc_peer *peer; unsigned int mtu; + bool wake = false; u32 rwind = ntohl(ackinfo->rwind);
_proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }", @@ -656,9 +657,14 @@ static void rxrpc_input_ackinfo(struct r ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU), rwind, ntohl(ackinfo->jumbo_max));
- if (rwind > RXRPC_RXTX_BUFF_SIZE - 1) - rwind = RXRPC_RXTX_BUFF_SIZE - 1; - call->tx_winsize = rwind; + if (call->tx_winsize != rwind) { + if (rwind > RXRPC_RXTX_BUFF_SIZE - 1) + rwind = RXRPC_RXTX_BUFF_SIZE - 1; + if (rwind > call->tx_winsize) + wake = true; + call->tx_winsize = rwind; + } + if (call->cong_ssthresh > rwind) call->cong_ssthresh = rwind;
@@ -672,6 +678,9 @@ static void rxrpc_input_ackinfo(struct r spin_unlock_bh(&peer->lock); _net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata); } + + if (wake) + wake_up(&call->waitq); }
/*