This is a note to let you know that I've just added the patch titled rxrpc: Make rxrpc_kernel_get_srtt() indicate validity to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: rxrpc-make-rxrpc_kernel_get_srtt-indicate-validity.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 0b647ba3c11fbf8f44fcb34b7e4a11e0d7d16660 Author: David Howells <dhowells@xxxxxxxxxx> Date: Thu Aug 20 15:13:00 2020 +0100 rxrpc: Make rxrpc_kernel_get_srtt() indicate validity [ Upstream commit 1d4adfaf65746203861c72d9d78de349eb97d528 ] Fix rxrpc_kernel_get_srtt() to indicate the validity of the returned smoothed RTT. If we haven't had any valid samples yet, the SRTT isn't useful. Fixes: c410bf01933e ("rxrpc: Fix the excessive initial retransmission timeout") Signed-off-by: David Howells <dhowells@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/fs/afs/fs_probe.c b/fs/afs/fs_probe.c index 02e976ca5732f..51ee3dd79700f 100644 --- a/fs/afs/fs_probe.c +++ b/fs/afs/fs_probe.c @@ -92,8 +92,8 @@ responded: } } - rtt_us = rxrpc_kernel_get_srtt(call->net->socket, call->rxcall); - if (rtt_us < server->probe.rtt) { + if (rxrpc_kernel_get_srtt(call->net->socket, call->rxcall, &rtt_us) && + rtt_us < server->probe.rtt) { server->probe.rtt = rtt_us; alist->preferred = index; have_result = true; diff --git a/fs/afs/vl_probe.c b/fs/afs/vl_probe.c index e3aa013c21779..081b7e5b13f58 100644 --- a/fs/afs/vl_probe.c +++ b/fs/afs/vl_probe.c @@ -92,8 +92,8 @@ responded: } } - rtt_us = rxrpc_kernel_get_srtt(call->net->socket, call->rxcall); - if (rtt_us < server->probe.rtt) { + if (rxrpc_kernel_get_srtt(call->net->socket, call->rxcall, &rtt_us) && + rtt_us < server->probe.rtt) { server->probe.rtt = rtt_us; alist->preferred = index; have_result = true; diff --git a/include/net/af_rxrpc.h b/include/net/af_rxrpc.h index ab988940bf045..55b980b21f4b4 100644 --- a/include/net/af_rxrpc.h +++ b/include/net/af_rxrpc.h @@ -59,7 +59,7 @@ bool rxrpc_kernel_abort_call(struct socket *, struct rxrpc_call *, void rxrpc_kernel_end_call(struct socket *, struct rxrpc_call *); void rxrpc_kernel_get_peer(struct socket *, struct rxrpc_call *, struct sockaddr_rxrpc *); -u32 rxrpc_kernel_get_srtt(struct socket *, struct rxrpc_call *); +bool rxrpc_kernel_get_srtt(struct socket *, struct rxrpc_call *, u32 *); int rxrpc_kernel_charge_accept(struct socket *, rxrpc_notify_rx_t, rxrpc_user_attach_call_t, unsigned long, gfp_t, unsigned int); diff --git a/net/rxrpc/peer_object.c b/net/rxrpc/peer_object.c index efce27802a74f..e011594adcd13 100644 --- a/net/rxrpc/peer_object.c +++ b/net/rxrpc/peer_object.c @@ -500,11 +500,21 @@ EXPORT_SYMBOL(rxrpc_kernel_get_peer); * rxrpc_kernel_get_srtt - Get a call's peer smoothed RTT * @sock: The socket on which the call is in progress. * @call: The call to query + * @_srtt: Where to store the SRTT value. * - * Get the call's peer smoothed RTT. + * Get the call's peer smoothed RTT in uS. */ -u32 rxrpc_kernel_get_srtt(struct socket *sock, struct rxrpc_call *call) +bool rxrpc_kernel_get_srtt(struct socket *sock, struct rxrpc_call *call, + u32 *_srtt) { - return call->peer->srtt_us >> 3; + struct rxrpc_peer *peer = call->peer; + + if (peer->rtt_count == 0) { + *_srtt = 1000000; /* 1S */ + return false; + } + + *_srtt = call->peer->srtt_us >> 3; + return true; } EXPORT_SYMBOL(rxrpc_kernel_get_srtt);