rcu: Push lock release to rcu_start_gp()'s callers

If CPUs are to give prior notice of needed grace periods, it will be
necessary to invoke rcu_start_gp() without dropping the root rcu_node
structure's ->lock.  This commit takes a second step in this direction
by moving the release of this lock to rcu_start_gp()'s callers.

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

1 files changed, 2 insertions, 3 deletions

diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index df50502eca2c..073ded26e259 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -2174,7 +2174,6 @@ static void rcu_nocb_wait_gp(struct rcu_data *rdp)
         unsigned long c;
         bool d;
         unsigned long flags;
-        unsigned long flags1;
         struct rcu_node *rnp = rdp->mynode;
         struct rcu_node *rnp_root = rcu_get_root(rdp->rsp);
 
@@ -2236,8 +2235,8 @@ static void rcu_nocb_wait_gp(struct rcu_data *rdp)
                                                       c, rnp->level,
                                                       rnp->grplo, rnp->grphi,
                                                       "Startedroot");
-                        local_save_flags(flags1);
-                        rcu_start_gp(rdp->rsp, flags1); /* Rlses ->lock. */
+                        rcu_start_gp(rdp->rsp);
+                        raw_spin_unlock(&rnp->lock);
                 }
 
                 /* Clean up locking and irq state. */