2008-06-30 22:39:55

by Chuck Lever III

[permalink] [raw]
Subject: [PATCH 5/7] SUNRPC: introduce new rpc_task flag that fails requests on xprt disconnect

Introduce a new RPC client capability that allows RPC consumers to specify
that if a connection cannot be established to the remote RPC service, a
submitted request should fail immediately.

Useful for in-kernel RPC applications that want to connect and do just one
or a handful of idempotent requests, but don't want any long waits if the
remote service is not available.

No, Tom, I'm not going to call it "squishy." :-)

Note that because the UDP transport uses an unconnected socket, this new
flag is a no-op for UDP.

Signed-off-by: Chuck Lever <[email protected]>

include/linux/sunrpc/sched.h | 2 ++
net/sunrpc/clnt.c | 2 ++
2 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h
index 64981a2..dcbdb60 100644
--- a/include/linux/sunrpc/sched.h
+++ b/include/linux/sunrpc/sched.h
@@ -130,12 +130,14 @@ struct rpc_task_setup {
#define RPC_TASK_DYNAMIC 0x0080 /* task was kmalloc'ed */
#define RPC_TASK_KILLED 0x0100 /* task was killed */
#define RPC_TASK_SOFT 0x0200 /* Use soft timeouts */
+#define RPC_TASK_ONESHOT 0x0400 /* fail if can't connect */

#define RPC_IS_ASYNC(t) ((t)->tk_flags & RPC_TASK_ASYNC)
#define RPC_IS_SWAPPER(t) ((t)->tk_flags & RPC_TASK_SWAPPER)
#define RPC_DO_ROOTOVERRIDE(t) ((t)->tk_flags & RPC_TASK_ROOTCREDS)
#define RPC_ASSASSINATED(t) ((t)->tk_flags & RPC_TASK_KILLED)
#define RPC_IS_SOFT(t) ((t)->tk_flags & RPC_TASK_SOFT)
+#define RPC_IS_ONESHOT(t) ((t)->tk_flags & RPC_TASK_ONESHOT)

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 09631f6..171d53c 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -1029,6 +1029,8 @@ call_connect_status(struct rpc_task *task)

switch (status) {
+ if (RPC_IS_ONESHOT(task))
+ break;
case -EAGAIN:
task->tk_action = call_bind;
if (!RPC_IS_SOFT(task))