From 7150ceaacb27f7b3bf494e72cd4be4e11612dfff Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 12 Nov 2018 22:33:22 +0000 Subject: rxrpc: Fix life check The life-checking function, which is used by kAFS to make sure that a call is still live in the event of a pending signal, only samples the received packet serial number counter; it doesn't actually provoke a change in the counter, rather relying on the server to happen to give us a packet in the time window. Fix this by adding a function to force a ping to be transmitted. kAFS then keeps track of whether there's been a stall, and if so, uses the new function to ping the server, resetting the timeout to allow the reply to come back. If there's a stall, a ping and the call is *still* stalled in the same place after another period, then the call will be aborted. Fixes: bc5e3a546d55 ("rxrpc: Use MSG_WAITALL to tell sendmsg() to temporarily ignore signals") Fixes: f4d15fb6f99a ("rxrpc: Provide functions for allowing cleaner handling of signals") Signed-off-by: David Howells Signed-off-by: David S. Miller --- net/rxrpc/af_rxrpc.c | 27 +++++++++++++++++++++++---- 1 file changed, 23 insertions(+), 4 deletions(-) (limited to 'net') diff --git a/net/rxrpc/af_rxrpc.c b/net/rxrpc/af_rxrpc.c index 64362d078da8..a2522f9d71e2 100644 --- a/net/rxrpc/af_rxrpc.c +++ b/net/rxrpc/af_rxrpc.c @@ -375,16 +375,35 @@ EXPORT_SYMBOL(rxrpc_kernel_end_call); * getting ACKs from the server. Returns a number representing the life state * which can be compared to that returned by a previous call. * - * If this is a client call, ping ACKs will be sent to the server to find out - * whether it's still responsive and whether the call is still alive on the - * server. + * If the life state stalls, rxrpc_kernel_probe_life() should be called and + * then 2RTT waited. */ -u32 rxrpc_kernel_check_life(struct socket *sock, struct rxrpc_call *call) +u32 rxrpc_kernel_check_life(const struct socket *sock, + const struct rxrpc_call *call) { return call->acks_latest; } EXPORT_SYMBOL(rxrpc_kernel_check_life); +/** + * rxrpc_kernel_probe_life - Poke the peer to see if it's still alive + * @sock: The socket the call is on + * @call: The call to check + * + * In conjunction with rxrpc_kernel_check_life(), allow a kernel service to + * find out whether a call is still alive by pinging it. This should cause the + * life state to be bumped in about 2*RTT. + * + * The must be called in TASK_RUNNING state on pain of might_sleep() objecting. + */ +void rxrpc_kernel_probe_life(struct socket *sock, struct rxrpc_call *call) +{ + rxrpc_propose_ACK(call, RXRPC_ACK_PING, 0, 0, true, false, + rxrpc_propose_ack_ping_for_check_life); + rxrpc_send_ack_packet(call, true, NULL); +} +EXPORT_SYMBOL(rxrpc_kernel_probe_life); + /** * rxrpc_kernel_get_epoch - Retrieve the epoch value from a call. * @sock: The socket the call is on -- cgit v1.2.3