|author||David Howells <email@example.com>||2017-10-18 11:07:31 +0100|
|committer||David Howells <firstname.lastname@example.org>||2017-10-18 11:42:48 +0100|
rxrpc: Provide functions for allowing cleaner handling of signals
Provide a couple of functions to allow cleaner handling of signals in a kernel service. They are: (1) rxrpc_kernel_get_rtt() This allows the kernel service to find out the RTT time for a call, so as to better judge how large a timeout to employ. Note, though, that whilst this returns a value in nanoseconds, the timeouts can only actually be in jiffies. (2) rxrpc_kernel_check_life() This returns a number that is updated when ACKs are received from the peer (notably including PING RESPONSE ACKs which we can elicit by sending PING ACKs to see if the call still exists on the server). The caller should compare the numbers of two calls to see if the call is still alive. These can be used to provide an extending timeout rather than returning immediately in the case that a signal occurs that would otherwise abort an RPC operation. The timeout would be extended if the server is still responsive and the call is still apparently alive on the server. For most operations this isn't that necessary - but for FS.StoreData it is: OpenAFS writes the data to storage as it comes in without making a backup, so if we immediately abort it when partially complete on a CTRL+C, say, we have no idea of the state of the file after the abort. Signed-off-by: David Howells <email@example.com>
Diffstat (limited to 'net/rxrpc/peer_object.c')
1 files changed, 13 insertions, 0 deletions
diff --git a/net/rxrpc/peer_object.c b/net/rxrpc/peer_object.c
index 5787f97f5330..d02a99f37f5f 100644
@@ -411,3 +411,16 @@ void rxrpc_kernel_get_peer(struct socket *sock, struct rxrpc_call *call,
*_srx = call->peer->srx;
+ * rxrpc_kernel_get_rtt - Get a call's peer RTT
+ * @sock: The socket on which the call is in progress.
+ * @call: The call to query
+ * Get the call's peer RTT.
+u64 rxrpc_kernel_get_rtt(struct socket *sock, struct rxrpc_call *call)
+ return call->peer->rtt;