Currently the in-kernel RPC server uses an unconnected UDP socket to
contact the local user-space portmapper daemon because UDP is less
overhead than TCP. However, attempting to register or unregister a
local RPC service with a portmapper that isn't listening for requests
results in a long timeout wait (35 seconds per request, by my
calculations).
Using TCP, the absence of a listener results in an immediate ECONNREFUSED.
Setting the ONESHOT flag causes the RPC client to fail RPC requests as soon
as this occurs.
Therefore, this patch changes rpcb_register() to use TCP to contact the
local portmapper. Starting up in-kernel RPC services should no longer
hang if there is no local portmapper listening for requests.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
net/sunrpc/rpcb_clnt.c | 22 ++++++++++++++++++++--
1 files changed, 20 insertions(+), 2 deletions(-)
diff --git a/net/sunrpc/rpcb_clnt.c b/net/sunrpc/rpcb_clnt.c
index eb2bffe..4a85bf5 100644
--- a/net/sunrpc/rpcb_clnt.c
+++ b/net/sunrpc/rpcb_clnt.c
@@ -67,6 +67,12 @@ enum {
#define RPCB_OWNER_STRING "rpcb"
#define RPCB_MAXOWNERLEN sizeof(RPCB_OWNER_STRING)
+/*
+ * Number of seconds before timing out a registration request
+ * to our local user space rpcbind daemon.
+ */
+#define RPCB_REGISTER_TO_SECS (10UL)
+
static void rpcb_getport_done(struct rpc_task *, void *);
static struct rpc_program rpcb_program;
@@ -118,14 +124,26 @@ static const struct sockaddr_in rpcb_inaddr_loopback = {
.sin_port = htons(RPCBIND_PORT),
};
+/*
+ * TCP is always used to contact the local rpcbind daemon because we
+ * get an immediate indication of whether there is a remote listener
+ * when a connection is attempted.
+ */
+static const struct rpc_timeout rpcb_local_tcp_timeout = {
+ .to_initval = RPCB_REGISTER_TO_SECS * HZ,
+ .to_maxval = RPCB_REGISTER_TO_SECS * HZ,
+ .to_retries = 0,
+};
+
static struct rpc_clnt *rpcb_create_local(struct sockaddr *addr,
size_t addrlen, u32 version)
{
struct rpc_create_args args = {
- .protocol = XPRT_TRANSPORT_UDP,
+ .protocol = XPRT_TRANSPORT_TCP,
.address = addr,
.addrsize = addrlen,
.servername = "localhost",
+ .timeout = &rpcb_local_tcp_timeout,
.program = &rpcb_program,
.version = version,
.authflavor = RPC_AUTH_UNIX,
@@ -175,7 +193,7 @@ static int rpcb_register_call(struct sockaddr *addr, size_t addrlen,
rpcb_clnt = rpcb_create_local(addr, addrlen, version);
if (!IS_ERR(rpcb_clnt)) {
- error = rpc_call_sync(rpcb_clnt, msg, 0);
+ error = rpc_call_sync(rpcb_clnt, msg, RPC_TASK_ONESHOT);
rpc_shutdown_client(rpcb_clnt);
} else
error = PTR_ERR(rpcb_clnt);
--
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