1 files changed, 26 insertions, 58 deletions

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index b043af7b0212..618ec9152e5e 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3379,29 +3379,26 @@ static void kfree_rcu_work(struct work_struct *work)
 }
 
 /*
- * Schedule the kfree batch RCU work to run in workqueue context after a GP.
- *
- * This function is invoked by kfree_rcu_monitor() when the KFREE_DRAIN_JIFFIES
- * timeout has been reached.
+ * This function is invoked after the KFREE_DRAIN_JIFFIES timeout.
  */
-static inline bool queue_kfree_rcu_work(struct kfree_rcu_cpu *krcp)
+static void kfree_rcu_monitor(struct work_struct *work)
 {
-	struct kfree_rcu_cpu_work *krwp;
-	bool repeat = false;
+	struct kfree_rcu_cpu *krcp = container_of(work,
+		struct kfree_rcu_cpu, monitor_work.work);
+	unsigned long flags;
 	int i, j;
 
-	lockdep_assert_held(&krcp->lock);
+	raw_spin_lock_irqsave(&krcp->lock, flags);
 
+	// Attempt to start a new batch.
 	for (i = 0; i < KFREE_N_BATCHES; i++) {
-		krwp = &(krcp->krw_arr[i]);
+		struct kfree_rcu_cpu_work *krwp = &(krcp->krw_arr[i]);
 
-		/*
-		 * Try to detach bkvhead or head and attach it over any
-		 * available corresponding free channel. It can be that
-		 * a previous RCU batch is in progress, it means that
-		 * immediately to queue another one is not possible so
-		 * return false to tell caller to retry.
-		 */
+		// Try to detach bkvhead or head and attach it over any
+		// available corresponding free channel. It can be that
+		// a previous RCU batch is in progress, it means that
+		// immediately to queue another one is not possible so
+		// in that case the monitor work is rearmed.
 		if ((krcp->bkvhead[0] && !krwp->bkvhead_free[0]) ||
 			(krcp->bkvhead[1] && !krwp->bkvhead_free[1]) ||
 				(krcp->head && !krwp->head_free)) {
@@ -3423,57 +3420,28 @@ static inline bool queue_kfree_rcu_work(struct kfree_rcu_cpu *krcp)
 
 			WRITE_ONCE(krcp->count, 0);
 
-			/*
-			 * One work is per one batch, so there are three
-			 * "free channels", the batch can handle. It can
-			 * be that the work is in the pending state when
-			 * channels have been detached following by each
-			 * other.
-			 */
+			// One work is per one batch, so there are three
+			// "free channels", the batch can handle. It can
+			// be that the work is in the pending state when
+			// channels have been detached following by each
+			// other.
 			queue_rcu_work(system_wq, &krwp->rcu_work);
 		}
-
-		// Repeat if any "free" corresponding channel is still busy.
-		if (krcp->bkvhead[0] || krcp->bkvhead[1] || krcp->head)
-			repeat = true;
 	}
 
-	return !repeat;
-}
-
-static inline void kfree_rcu_drain_unlock(struct kfree_rcu_cpu *krcp,
-					  unsigned long flags)
-{
-	// Attempt to start a new batch.
-	if (queue_kfree_rcu_work(krcp)) {
-		// Success! Our job is done here.
+	// If there is nothing to detach, it means that our job is
+	// successfully done here. In case of having at least one
+	// of the channels that is still busy we should rearm the
+	// work to repeat an attempt. Because previous batches are
+	// still in progress.
+	if (!krcp->bkvhead[0] && !krcp->bkvhead[1] && !krcp->head)
 		krcp->monitor_todo = false;
-		raw_spin_unlock_irqrestore(&krcp->lock, flags);
-		return;
-	}
+	else
+		schedule_delayed_work(&krcp->monitor_work, KFREE_DRAIN_JIFFIES);
 
-	// Previous RCU batch still in progress, try again later.
-	schedule_delayed_work(&krcp->monitor_work, KFREE_DRAIN_JIFFIES);
 	raw_spin_unlock_irqrestore(&krcp->lock, flags);
 }
 
-/*
- * This function is invoked after the KFREE_DRAIN_JIFFIES timeout.
- * It invokes kfree_rcu_drain_unlock() to attempt to start another batch.
- */
-static void kfree_rcu_monitor(struct work_struct *work)
-{
-	unsigned long flags;
-	struct kfree_rcu_cpu *krcp = container_of(work, struct kfree_rcu_cpu,
-						 monitor_work.work);
-
-	raw_spin_lock_irqsave(&krcp->lock, flags);
-	if (krcp->monitor_todo)
-		kfree_rcu_drain_unlock(krcp, flags);
-	else
-		raw_spin_unlock_irqrestore(&krcp->lock, flags);
-}
-
 static enum hrtimer_restart
 schedule_page_work_fn(struct hrtimer *t)
 {