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>

diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h
index 6d86ab6ec2c9792a206f8d7236e48b40f7e258b3..1549f456fb7b73f79c1c0fdead126ca0f3fed92f 100644 (file)
--- 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);