rcu: Consolidate expedited grace period machinery

The functions synchronize_rcu_expedited() and synchronize_sched_expedited()
have nearly identical code.  This commit therefore consolidates this code
into a new _synchronize_rcu_expedited() function.

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

1 files changed, 29 insertions, 33 deletions

diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h
index 6d86ab6ec2c9..1549f456fb7b 100644
--- a/kernel/rcu/tree_exp.h
+++ b/kernel/rcu/tree_exp.h
@@ -516,6 +516,33 @@ static void rcu_exp_wait_wake(struct rcu_state *rsp, unsigned long s)
         mutex_unlock(&rsp->exp_wake_mutex);
 }
 
+/*
+ * Given an rcu_state pointer and a smp_call_function() handler, kick
+ * off the specified flavor of expedited grace period.
+ */
+static void _synchronize_rcu_expedited(struct rcu_state *rsp,
+                                       smp_call_func_t func)
+{
+        unsigned long s;
+
+        /* If expedited grace periods are prohibited, fall back to normal. */
+        if (rcu_gp_is_normal()) {
+                wait_rcu_gp(rsp->call);
+                return;
+        }
+
+        /* Take a snapshot of the sequence number.  */
+        s = rcu_exp_gp_seq_snap(rsp);
+        if (exp_funnel_lock(rsp, s))
+                return;  /* Someone else did our work for us. */
+
+        /* Initialize the rcu_node tree in preparation for the wait. */
+        sync_rcu_exp_select_cpus(rsp, func);
+
+        /* Wait and clean up, including waking everyone. */
+        rcu_exp_wait_wake(rsp, s);
+}
+
 /**
  * synchronize_sched_expedited - Brute-force RCU-sched grace period
  *
@@ -534,29 +561,13 @@ static void rcu_exp_wait_wake(struct rcu_state *rsp, unsigned long s)
  */
 void synchronize_sched_expedited(void)
 {
-        unsigned long s;
         struct rcu_state *rsp = &rcu_sched_state;
 
         /* If only one CPU, this is automatically a grace period. */
         if (rcu_blocking_is_gp())
                 return;
 
-        /* If expedited grace periods are prohibited, fall back to normal. */
-        if (rcu_gp_is_normal()) {
-                wait_rcu_gp(call_rcu_sched);
-                return;
-        }
-
-        /* Take a snapshot of the sequence number.  */
-        s = rcu_exp_gp_seq_snap(rsp);
-        if (exp_funnel_lock(rsp, s))
-                return;  /* Someone else did our work for us. */
-
-        /* Initialize the rcu_node tree in preparation for the wait. */
-        sync_rcu_exp_select_cpus(rsp, sync_sched_exp_handler);
-
-        /* Wait and clean up, including waking everyone. */
-        rcu_exp_wait_wake(rsp, s);
+        _synchronize_rcu_expedited(rsp, sync_sched_exp_handler);
 }
 EXPORT_SYMBOL_GPL(synchronize_sched_expedited);
 
@@ -620,23 +631,8 @@ static void sync_rcu_exp_handler(void *info)
 void synchronize_rcu_expedited(void)
 {
         struct rcu_state *rsp = rcu_state_p;
-        unsigned long s;
 
-        /* If expedited grace periods are prohibited, fall back to normal. */
-        if (rcu_gp_is_normal()) {
-                wait_rcu_gp(call_rcu);
-                return;
-        }
-
-        s = rcu_exp_gp_seq_snap(rsp);
-        if (exp_funnel_lock(rsp, s))
-                return;  /* Someone else did our work for us. */
-
-        /* Initialize the rcu_node tree in preparation for the wait. */
-        sync_rcu_exp_select_cpus(rsp, sync_rcu_exp_handler);
-
-        /* Wait for ->blkd_tasks lists to drain, then wake everyone up. */
-        rcu_exp_wait_wake(rsp, s);
+        _synchronize_rcu_expedited(rsp, sync_rcu_exp_handler);
 }
 EXPORT_SYMBOL_GPL(synchronize_rcu_expedited);