NFSv4.1: Ensure smooth handover of slots from one task to the next waiting

Currently, we see a lot of bouncing for the value of highest_used_slotid
due to the fact that slots are getting freed, instead of getting instantly
transmitted to the next waiting task.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/nfs4session.h b/fs/nfs/nfs4session.h
index bdd14a6..7db73937 100644
--- a/fs/nfs/nfs4session.h
+++ b/fs/nfs/nfs4session.h
@@ -94,6 +94,10 @@
 	return !!test_bit(NFS4_SESSION_DRAINING, &session->session_state);
 }
 
+bool nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
+		struct nfs4_slot *slot);
+void nfs41_wake_slot_table(struct nfs4_slot_table *tbl);
+
 /*
  * Determine if sessions are in use.
  */