1 files changed, 42 insertions, 1 deletions

diff --git a/kernel/padata.c b/kernel/padata.c
index 1b9b4bac4a9b..b4066147bce4 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -275,11 +275,51 @@ static void padata_reorder(struct parallel_data *pd)
 	return;
 }
 
+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;
+	padata_reorder(pd);
+	local_bh_enable();
+}
+
 static void padata_reorder_timer(unsigned long arg)
 {
 	struct parallel_data *pd = (struct parallel_data *)arg;
+	unsigned int weight;
+	int target_cpu, cpu;
 
-	padata_reorder(pd);
+	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+	 * it doesn't matter if we're off to the next one by using an outdated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)
@@ -399,6 +439,7 @@ static void padata_init_pqueues(struct parallel_data *pd)
 		__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);
 	}
 }