rcu: Consolidate expedited GP code into rcu_exp_wait_wake()

Currently, synchronize_rcu_expedited() and rcu_sched_expedited() have
significant duplicate code.  This commit therefore consolidates some of
this code into rcu_exp_wake(), which is now renamed to rcu_exp_wait_wake()
in recognition of its added responsibilities.

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

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 892a140..fd86eca 100644 (file)
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3839,14 +3839,18 @@ static void synchronize_sched_expedited_wait(struct rcu_state *rsp)
 }
 
 /*
- * Wake up everyone who piggybacked on the just-completed expedited
+ * Wait for the current expedited grace period to complete, and then
+ * wake up everyone who piggybacked on the just-completed expedited
  * grace period.  Also update all the ->exp_seq_rq counters as needed
  * in order to avoid counter-wrap problems.
  */
-static void rcu_exp_wake(struct rcu_state *rsp, unsigned long s)
+static void rcu_exp_wait_wake(struct rcu_state *rsp, unsigned long s)
 {
        struct rcu_node *rnp;
 
+       synchronize_sched_expedited_wait(rsp);
+       rcu_exp_gp_seq_end(rsp);
+       trace_rcu_exp_grace_period(rsp->name, s, TPS("end"));
        rcu_for_each_node_breadth_first(rsp, rnp) {
                if (ULONG_CMP_LT(READ_ONCE(rnp->exp_seq_rq), s)) {
                        spin_lock(&rnp->exp_lock);
@@ -3857,6 +3861,8 @@ static void rcu_exp_wake(struct rcu_state *rsp, unsigned long s)
                }
                wake_up_all(&rnp->exp_wq[(rsp->expedited_sequence >> 1) & 0x1]);
        }
+       trace_rcu_exp_grace_period(rsp->name, s, TPS("endwake"));
+       mutex_unlock(&rsp->exp_mutex);
 }
 
 /**
@@ -3904,13 +3910,7 @@ void synchronize_sched_expedited(void)
        sync_rcu_exp_select_cpus(rsp, sync_sched_exp_handler);
 
        /* Wait and clean up, including waking everyone. */
-       synchronize_sched_expedited_wait(rsp);
-       rcu_exp_gp_seq_end(rsp);
-       trace_rcu_exp_grace_period(rsp->name, s, TPS("end"));
-       rcu_exp_wake(rsp, s);
-
-       trace_rcu_exp_grace_period(rsp->name, s, TPS("endwake"));
-       mutex_unlock(&rsp->exp_mutex);
+       rcu_exp_wait_wake(rsp, s);
 }
 EXPORT_SYMBOL_GPL(synchronize_sched_expedited);
 

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index c82c364..b6d5dde 100644 (file)
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -759,14 +759,8 @@ void synchronize_rcu_expedited(void)
        /* Initialize the rcu_node tree in preparation for the wait. */
        sync_rcu_exp_select_cpus(rsp, sync_rcu_exp_handler);
 
-       /* Wait for snapshotted ->blkd_tasks lists to drain. */
-       synchronize_sched_expedited_wait(rsp);
-       rcu_exp_gp_seq_end(rsp);
-       trace_rcu_exp_grace_period(rsp->name, s, TPS("end"));
-       rcu_exp_wake(rsp, s);
-
-       trace_rcu_exp_grace_period(rsp->name, s, TPS("endwake"));
-       mutex_unlock(&rsp->exp_mutex);
+       /* Wait for ->blkd_tasks lists to drain, then wake everyone up. */
+       rcu_exp_wait_wake(rsp, s);
 }
 EXPORT_SYMBOL_GPL(synchronize_rcu_expedited);