rcu: Move rcu_nocb_gp_get() to ->gp_seq

This commit makes rcu_try_advance_all_cbs() use ->gp_seq.  It uses
rcu_seq_ctr() in order to shift away the state bits, so that the
low-order bits of the result may safely be used to index ->nocb_gp_wq[].

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index d893899b72f495c84b4fa83139e30d879ccb8707..5b10904669c57b425ef77e25d7215df354dcc3aa 100644 (file)
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1852,7 +1852,7 @@ static void rcu_nocb_gp_cleanup(struct swait_queue_head *sq)
 
 static struct swait_queue_head *rcu_nocb_gp_get(struct rcu_node *rnp)
 {
-       return &rnp->nocb_gp_wq[rnp->completed & 0x1];
+       return &rnp->nocb_gp_wq[rcu_seq_ctr(rnp->gp_seq) & 0x1];
 }
 
 static void rcu_init_one_nocb(struct rcu_node *rnp)