1 files changed, 18 insertions, 77 deletions

diff --git a/kernel/padata.c b/kernel/padata.c
index c280cb153915..47dc31ce15ac 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -167,23 +167,12 @@ EXPORT_SYMBOL(padata_do_parallel);
  */
 static struct padata_priv *padata_get_next(struct parallel_data *pd)
 {
-	int cpu, num_cpus;
-	unsigned int next_nr, next_index;
 	struct padata_parallel_queue *next_queue;
 	struct padata_priv *padata;
 	struct padata_list *reorder;
+	int cpu = pd->cpu;
 
-	num_cpus = cpumask_weight(pd->cpumask.pcpu);
-
-	/*
-	 * Calculate the percpu reorder queue and the sequence
-	 * number of the next object.
-	 */
-	next_nr = pd->processed;
-	next_index = next_nr % num_cpus;
-	cpu = padata_index_to_cpu(pd, next_index);
 	next_queue = per_cpu_ptr(pd->pqueue, cpu);
-
 	reorder = &next_queue->reorder;
 
 	spin_lock(&reorder->lock);
@@ -194,7 +183,8 @@ static struct padata_priv *padata_get_next(struct parallel_data *pd)
 		list_del_init(&padata->list);
 		atomic_dec(&pd->reorder_objects);
 
-		pd->processed++;
+		pd->cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu, -1,
+					    false);
 
 		spin_unlock(&reorder->lock);
 		goto out;
@@ -217,6 +207,7 @@ static void padata_reorder(struct parallel_data *pd)
 	struct padata_priv *padata;
 	struct padata_serial_queue *squeue;
 	struct padata_instance *pinst = pd->pinst;
+	struct padata_parallel_queue *next_queue;
 
 	/*
 	 * We need to ensure that only one cpu can work on dequeueing of
@@ -248,7 +239,6 @@ static void padata_reorder(struct parallel_data *pd)
 		 * so exit immediately.
 		 */
 		if (PTR_ERR(padata) == -ENODATA) {
-			del_timer(&pd->timer);
 			spin_unlock_bh(&pd->lock);
 			return;
 		}
@@ -267,70 +257,29 @@ static void padata_reorder(struct parallel_data *pd)
 
 	/*
 	 * The next object that needs serialization might have arrived to
-	 * the reorder queues in the meantime, we will be called again
-	 * from the timer function if no one else cares for it.
+	 * the reorder queues in the meantime.
 	 *
-	 * Ensure reorder_objects is read after pd->lock is dropped so we see
-	 * an increment from another task in padata_do_serial.  Pairs with
+	 * Ensure reorder queue is read after pd->lock is dropped so we see
+	 * new objects from another task in padata_do_serial.  Pairs with
 	 * smp_mb__after_atomic in padata_do_serial.
 	 */
 	smp_mb();
-	if (atomic_read(&pd->reorder_objects)
-			&& !(pinst->flags & PADATA_RESET))
-		mod_timer(&pd->timer, jiffies + HZ);
-	else
-		del_timer(&pd->timer);
 
-	return;
+	next_queue = per_cpu_ptr(pd->pqueue, pd->cpu);
+	if (!list_empty(&next_queue->reorder.list))
+		queue_work(pinst->wq, &pd->reorder_work);
 }
 
 static void invoke_padata_reorder(struct work_struct *work)
 {
-	struct padata_parallel_queue *pqueue;
 	struct parallel_data *pd;
 
 	local_bh_disable();
-	pqueue = container_of(work, struct padata_parallel_queue, reorder_work);
-	pd = pqueue->pd;
+	pd = container_of(work, struct parallel_data, reorder_work);
 	padata_reorder(pd);
 	local_bh_enable();
 }
 
-static void padata_reorder_timer(struct timer_list *t)
-{
-	struct parallel_data *pd = from_timer(pd, t, timer);
-	unsigned int weight;
-	int target_cpu, cpu;
-
-	cpu = get_cpu();
-
-	/* We don't lock pd here to not interfere with parallel processing
-	 * padata_reorder() calls on other CPUs. We just need any CPU out of
-	 * the cpumask.pcpu set. It would be nice if it's the right one but
-	 * it doesn't matter if we're off to the next one by using an outdated
-	 * pd->processed value.
-	 */
-	weight = cpumask_weight(pd->cpumask.pcpu);
-	target_cpu = padata_index_to_cpu(pd, pd->processed % weight);
-
-	/* ensure to call the reorder callback on the correct CPU */
-	if (cpu != target_cpu) {
-		struct padata_parallel_queue *pqueue;
-		struct padata_instance *pinst;
-
-		/* The timer function is serialized wrt itself -- no locking
-		 * needed.
-		 */
-		pinst = pd->pinst;
-		pqueue = per_cpu_ptr(pd->pqueue, target_cpu);
-		queue_work_on(target_cpu, pinst->wq, &pqueue->reorder_work);
-	} else {
-		padata_reorder(pd);
-	}
-
-	put_cpu();
-}
-
 static void padata_serial_worker(struct work_struct *serial_work)
 {
 	struct padata_serial_queue *squeue;
@@ -384,9 +333,8 @@ void padata_do_serial(struct padata_priv *padata)
 
 	cpu = get_cpu();
 
-	/* We need to run on the same CPU padata_do_parallel(.., padata, ..)
-	 * was called on -- or, at least, enqueue the padata object into the
-	 * correct per-cpu queue.
+	/* We need to enqueue the padata object into the correct
+	 * per-cpu queue.
 	 */
 	if (cpu != padata->cpu) {
 		reorder_via_wq = 1;
@@ -396,12 +344,12 @@ void padata_do_serial(struct padata_priv *padata)
 	pqueue = per_cpu_ptr(pd->pqueue, cpu);
 
 	spin_lock(&pqueue->reorder.lock);
-	atomic_inc(&pd->reorder_objects);
 	list_add_tail(&padata->list, &pqueue->reorder.list);
+	atomic_inc(&pd->reorder_objects);
 	spin_unlock(&pqueue->reorder.lock);
 
 	/*
-	 * Ensure the atomic_inc of reorder_objects above is ordered correctly
+	 * Ensure the addition to the reorder list is ordered correctly
 	 * with the trylock of pd->lock in padata_reorder.  Pairs with smp_mb
 	 * in padata_reorder.
 	 */
@@ -409,13 +357,7 @@ void padata_do_serial(struct padata_priv *padata)
 
 	put_cpu();
 
-	/* If we're running on the wrong CPU, call padata_reorder() via a
-	 * kernel worker.
-	 */
-	if (reorder_via_wq)
-		queue_work_on(cpu, pd->pinst->wq, &pqueue->reorder_work);
-	else
-		padata_reorder(pd);
+	padata_reorder(pd);
 }
 EXPORT_SYMBOL(padata_do_serial);
 
@@ -471,14 +413,12 @@ static void padata_init_pqueues(struct parallel_data *pd)
 			continue;
 		}
 
-		pqueue->pd = pd;
 		pqueue->cpu_index = cpu_index;
 		cpu_index++;
 
 		__padata_list_init(&pqueue->reorder);
 		__padata_list_init(&pqueue->parallel);
 		INIT_WORK(&pqueue->work, padata_parallel_worker);
-		INIT_WORK(&pqueue->reorder_work, invoke_padata_reorder);
 		atomic_set(&pqueue->num_obj, 0);
 	}
 }
@@ -506,12 +446,13 @@ static struct parallel_data *padata_alloc_pd(struct padata_instance *pinst,
 
 	padata_init_pqueues(pd);
 	padata_init_squeues(pd);
-	timer_setup(&pd->timer, padata_reorder_timer, 0);
 	atomic_set(&pd->seq_nr, -1);
 	atomic_set(&pd->reorder_objects, 0);
 	atomic_set(&pd->refcnt, 1);
 	pd->pinst = pinst;
 	spin_lock_init(&pd->lock);
+	pd->cpu = cpumask_first(pcpumask);
+	INIT_WORK(&pd->reorder_work, invoke_padata_reorder);
 
 	return pd;