Merge git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc-merge

[linux-2.6] / kernel / rcupdate.c

diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index 30b0bba0385978b0220b562f33ce4fb5468293e3..ccc45d49ce71c6180d91418584be5fc948c6b862 100644 (file)
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -429,6 +429,36 @@ static void rcu_process_callbacks(unsigned long unused)
                                &__get_cpu_var(rcu_bh_data));
 }
 
+static int __rcu_pending(struct rcu_ctrlblk *rcp, struct rcu_data *rdp)
+{
+       /* This cpu has pending rcu entries and the grace period
+        * for them has completed.
+        */
+       if (rdp->curlist && !rcu_batch_before(rcp->completed, rdp->batch))
+               return 1;
+
+       /* This cpu has no pending entries, but there are new entries */
+       if (!rdp->curlist && rdp->nxtlist)
+               return 1;
+
+       /* This cpu has finished callbacks to invoke */
+       if (rdp->donelist)
+               return 1;
+
+       /* The rcu core waits for a quiescent state from the cpu */
+       if (rdp->quiescbatch != rcp->cur || rdp->qs_pending)
+               return 1;
+
+       /* nothing to do */
+       return 0;
+}
+
+int rcu_pending(int cpu)
+{
+       return __rcu_pending(&rcu_ctrlblk, &per_cpu(rcu_data, cpu)) ||
+               __rcu_pending(&rcu_bh_ctrlblk, &per_cpu(rcu_bh_data, cpu));
+}
+
 void rcu_check_callbacks(int cpu, int user)
 {
        if (user ||