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, 17 insertions, 13 deletions

diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index fb560fca9ef4..b4123d7a2cec 100644
--- a/kernel/rcu/srcutree.c
+++ b/kernel/rcu/srcutree.c
@@ -366,24 +366,28 @@ static unsigned long srcu_get_delay(struct srcu_struct *sp)
 	return SRCU_INTERVAL;
 }
 
-/**
- * cleanup_srcu_struct - deconstruct a sleep-RCU structure
- * @sp: structure to clean up.
- *
- * Must invoke this after you are finished using a given srcu_struct that
- * was initialized via init_srcu_struct(), else you leak memory.
- */
-void cleanup_srcu_struct(struct srcu_struct *sp)
+/* Helper for cleanup_srcu_struct() and cleanup_srcu_struct_quiesced(). */
+void _cleanup_srcu_struct(struct srcu_struct *sp, bool quiesced)
 {
 	int cpu;
 
 	if (WARN_ON(!srcu_get_delay(sp)))
-		return; /* Leakage unless caller handles error. */
+		return; /* Just leak it! */
 	if (WARN_ON(srcu_readers_active(sp)))
-		return; /* Leakage unless caller handles error. */
-	flush_delayed_work(&sp->work);
+		return; /* Just leak it! */
+	if (quiesced) {
+		if (WARN_ON(delayed_work_pending(&sp->work)))
+			return; /* Just leak it! */
+	} else {
+		flush_delayed_work(&sp->work);
+	}
 	for_each_possible_cpu(cpu)
-		flush_delayed_work(&per_cpu_ptr(sp->sda, cpu)->work);
+		if (quiesced) {
+			if (WARN_ON(delayed_work_pending(&per_cpu_ptr(sp->sda, cpu)->work)))
+				return; /* Just leak it! */
+		} else {
+			flush_delayed_work(&per_cpu_ptr(sp->sda, cpu)->work);
+		}
 	if (WARN_ON(rcu_seq_state(READ_ONCE(sp->srcu_gp_seq)) != SRCU_STATE_IDLE) ||
 	    WARN_ON(srcu_readers_active(sp))) {
 		pr_info("%s: Active srcu_struct %p state: %d\n", __func__, sp, rcu_seq_state(READ_ONCE(sp->srcu_gp_seq)));
@@ -392,7 +396,7 @@ void cleanup_srcu_struct(struct srcu_struct *sp)
 	free_percpu(sp->sda);
 	sp->sda = NULL;
 }
-EXPORT_SYMBOL_GPL(cleanup_srcu_struct);
+EXPORT_SYMBOL_GPL(_cleanup_srcu_struct);
 
 /*
  * Counts the new reader in the appropriate per-CPU element of the