sunrpc: allow svc_recv() to return -ETIMEDOUT and -EBUSY

To dynamically adjust the thread count, nfsd requires some information
about how busy things are.

Change svc_recv() to take a timeout value, and then allow the wait for
work to time out if it's set. If a timeout is not defined, then the
schedule will be set to MAX_SCHEDULE_TIMEOUT. If the task waits for the
full timeout, then have it return -ETIMEDOUT to the caller.

If it wakes up, finds that there is more work and that no threads are
available, then attempt to set SP_TASK_STARTING. If wasn't already set,
have the task return -EBUSY to cue to the caller that the service could
use more threads.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
index e2a1b12272f5..dcd80c4e74c9 100644
--- a/fs/lockd/svc.c
+++ b/fs/lockd/svc.c
@@ -141,7 +141,7 @@ lockd(void *vrqstp)
 	 */
 	while (!svc_thread_should_stop(rqstp)) {
 		nlmsvc_retry_blocked(rqstp);
-		svc_recv(rqstp);
+		svc_recv(rqstp, 0);
 	}
 	if (nlmsvc_ops)
 		nlmsvc_invalidate_all();