Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull RCU updates from Ingo Molnar:

 - updates to the handling of expedited grace periods

 - updates to reduce lock contention in the rcu_node combining tree

   [ These are in preparation for the consolidation of RCU-bh,
     RCU-preempt, and RCU-sched into a single flavor, which was
     requested by Linus in response to a security flaw whose root cause
     included confusion between the multiple flavors of RCU ]

 - torture-test updates that save their users some time and effort

 - miscellaneous fixes

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (44 commits)
  rcu/x86: Provide early rcu_cpu_starting() callback
  torture: Make kvm-find-errors.sh find build warnings
  rcutorture: Abbreviate kvm.sh summary lines
  rcutorture: Print end-of-test state in kvm.sh summary
  rcutorture: Print end-of-test state
  torture: Fold parse-torture.sh into parse-console.sh
  torture: Add a script to edit output from failed runs
  rcu: Update list of rcu_future_grace_period() trace events
  rcu: Drop early GP request check from rcu_gp_kthread()
  rcu: Simplify and inline cpu_needs_another_gp()
  rcu: The rcu_gp_cleanup() function does not need cpu_needs_another_gp()
  rcu: Make rcu_start_this_gp() check for out-of-range requests
  rcu: Add funnel locking to rcu_start_this_gp()
  rcu: Make rcu_start_future_gp() caller select grace period
  rcu: Inline rcu_start_gp_advanced() into rcu_start_future_gp()
  rcu: Clear request other than RCU_GP_FLAG_INIT at GP end
  rcu: Cleanup, don't put ->completed into an int
  rcu: Switch __rcu_process_callbacks() to rcu_accelerate_cbs()
  rcu: Avoid __call_rcu_core() root rcu_node ->lock acquisition
  rcu: Make rcu_migrate_callbacks wake GP kthread when needed
  ...

1 files changed, 9 insertions, 3 deletions

diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index 7a693e31184a..40cea6735c2d 100644
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -270,6 +270,12 @@ static inline void rcu_init_levelspread(int *levelspread, const int *levelcnt)
 	}
 }
 
+/* Returns first leaf rcu_node of the specified RCU flavor. */
+#define rcu_first_leaf_node(rsp) ((rsp)->level[rcu_num_lvls - 1])
+
+/* Is this rcu_node a leaf? */
+#define rcu_is_leaf_node(rnp) ((rnp)->level == rcu_num_lvls - 1)
+
 /*
  * Do a full breadth-first scan of the rcu_node structures for the
  * specified rcu_state structure.
@@ -284,8 +290,7 @@ static inline void rcu_init_levelspread(int *levelspread, const int *levelcnt)
  * rcu_node tree with but one rcu_node structure, this loop is a no-op.
  */
 #define rcu_for_each_nonleaf_node_breadth_first(rsp, rnp) \
-	for ((rnp) = &(rsp)->node[0]; \
-	     (rnp) < (rsp)->level[rcu_num_lvls - 1]; (rnp)++)
+	for ((rnp) = &(rsp)->node[0]; !rcu_is_leaf_node(rsp, rnp); (rnp)++)
 
 /*
  * Scan the leaves of the rcu_node hierarchy for the specified rcu_state
@@ -294,7 +299,7 @@ static inline void rcu_init_levelspread(int *levelspread, const int *levelcnt)
  * It is still a leaf node, even if it is also the root node.
  */
 #define rcu_for_each_leaf_node(rsp, rnp) \
-	for ((rnp) = (rsp)->level[rcu_num_lvls - 1]; \
+	for ((rnp) = rcu_first_leaf_node(rsp); \
 	     (rnp) < &(rsp)->node[rcu_num_nodes]; (rnp)++)
 
 /*
@@ -486,6 +491,7 @@ void rcu_force_quiescent_state(void);
 void rcu_bh_force_quiescent_state(void);
 void rcu_sched_force_quiescent_state(void);
 extern struct workqueue_struct *rcu_gp_wq;
+extern struct workqueue_struct *rcu_par_gp_wq;
 #endif /* #else #ifdef CONFIG_TINY_RCU */
 
 #ifdef CONFIG_RCU_NOCB_CPU