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authorDavid Howells <dhowells@redhat.com>2018-11-12 22:33:22 +0000
committerDavid S. Miller <davem@davemloft.net>2018-11-15 11:35:40 -0800
commit7150ceaacb27f7b3bf494e72cd4be4e11612dfff (patch)
treecdb1fb191dc649c0f1563045fe17ef0630690b2c /net/rxrpc
parentebcd210e93b2a984b7a7b82d45f7f0d21b7ec2d2 (diff)
downloadlinux-stericsson-7150ceaacb27f7b3bf494e72cd4be4e11612dfff.tar.gz
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 <dhowells@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/rxrpc')
-rw-r--r--net/rxrpc/af_rxrpc.c27
1 files changed, 23 insertions, 4 deletions
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
@@ -375,17 +375,36 @@ 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
* @call: The call to query