1 files changed, 30 insertions, 33 deletions

diff --git a/kernel/padata.c b/kernel/padata.c
index 05316c9f32da..868f947166d7 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -154,8 +154,6 @@ EXPORT_SYMBOL(padata_do_parallel);
  * A pointer to the control struct of the next object that needs
  * serialization, if present in one of the percpu reorder queues.
  *
- * NULL, if all percpu reorder queues are empty.
- *
  * -EINPROGRESS, if the next object that needs serialization will
  *  be parallel processed by another cpu and is not yet present in
  *  the cpu's reorder queue.
@@ -182,23 +180,22 @@ static struct padata_priv *padata_get_next(struct parallel_data *pd)
 	cpu = padata_index_to_cpu(pd, next_index);
 	next_queue = per_cpu_ptr(pd->pqueue, cpu);
 
-	padata = NULL;
-
 	reorder = &next_queue->reorder;
 
+	spin_lock(&reorder->lock);
 	if (!list_empty(&reorder->list)) {
 		padata = list_entry(reorder->list.next,
 				    struct padata_priv, list);
 
-		spin_lock(&reorder->lock);
 		list_del_init(&padata->list);
 		atomic_dec(&pd->reorder_objects);
-		spin_unlock(&reorder->lock);
 
 		pd->processed++;
 
+		spin_unlock(&reorder->lock);
 		goto out;
 	}
+	spin_unlock(&reorder->lock);
 
 	if (__this_cpu_read(pd->pqueue->cpu_index) == next_queue->cpu_index) {
 		padata = ERR_PTR(-ENODATA);
@@ -234,12 +231,11 @@ static void padata_reorder(struct parallel_data *pd)
 		padata = padata_get_next(pd);
 
 		/*
-		 * All reorder queues are empty, or the next object that needs
-		 * serialization is parallel processed by another cpu and is
-		 * still on it's way to the cpu's reorder queue, nothing to
-		 * do for now.
+		 * If the next object that needs serialization is parallel
+		 * processed by another cpu and is still on it's way to the
+		 * cpu's reorder queue, nothing to do for now.
 		 */
-		if (!padata || PTR_ERR(padata) == -EINPROGRESS)
+		if (PTR_ERR(padata) == -EINPROGRESS)
 			break;
 
 		/*
@@ -353,7 +349,7 @@ static int padata_setup_cpumasks(struct parallel_data *pd,
 
 	cpumask_and(pd->cpumask.pcpu, pcpumask, cpu_online_mask);
 	if (!alloc_cpumask_var(&pd->cpumask.cbcpu, GFP_KERNEL)) {
-		free_cpumask_var(pd->cpumask.cbcpu);
+		free_cpumask_var(pd->cpumask.pcpu);
 		return -ENOMEM;
 	}
 
@@ -938,29 +934,18 @@ static struct kobj_type padata_attr_type = {
 };
 
 /**
- * padata_alloc_possible - Allocate and initialize padata instance.
- *                         Use the cpu_possible_mask for serial and
- *                         parallel workers.
- *
- * @wq: workqueue to use for the allocated padata instance
- */
-struct padata_instance *padata_alloc_possible(struct workqueue_struct *wq)
-{
-	return padata_alloc(wq, cpu_possible_mask, cpu_possible_mask);
-}
-EXPORT_SYMBOL(padata_alloc_possible);
-
-/**
  * padata_alloc - allocate and initialize a padata instance and specify
  *                cpumasks for serial and parallel workers.
  *
  * @wq: workqueue to use for the allocated padata instance
  * @pcpumask: cpumask that will be used for padata parallelization
  * @cbcpumask: cpumask that will be used for padata serialization
+ *
+ * Must be called from a cpus_read_lock() protected region
  */
-struct padata_instance *padata_alloc(struct workqueue_struct *wq,
-				     const struct cpumask *pcpumask,
-				     const struct cpumask *cbcpumask)
+static struct padata_instance *padata_alloc(struct workqueue_struct *wq,
+					    const struct cpumask *pcpumask,
+					    const struct cpumask *cbcpumask)
 {
 	struct padata_instance *pinst;
 	struct parallel_data *pd = NULL;
@@ -969,7 +954,6 @@ struct padata_instance *padata_alloc(struct workqueue_struct *wq,
 	if (!pinst)
 		goto err;
 
-	get_online_cpus();
 	if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL))
 		goto err_free_inst;
 	if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) {
@@ -993,14 +977,12 @@ struct padata_instance *padata_alloc(struct workqueue_struct *wq,
 
 	pinst->flags = 0;
 
-	put_online_cpus();
-
 	BLOCKING_INIT_NOTIFIER_HEAD(&pinst->cpumask_change_notifier);
 	kobject_init(&pinst->kobj, &padata_attr_type);
 	mutex_init(&pinst->lock);
 
 #ifdef CONFIG_HOTPLUG_CPU
-	cpuhp_state_add_instance_nocalls(hp_online, &pinst->node);
+	cpuhp_state_add_instance_nocalls_cpuslocked(hp_online, &pinst->node);
 #endif
 	return pinst;
 
@@ -1009,12 +991,27 @@ err_free_masks:
 	free_cpumask_var(pinst->cpumask.cbcpu);
 err_free_inst:
 	kfree(pinst);
-	put_online_cpus();
 err:
 	return NULL;
 }
 
 /**
+ * padata_alloc_possible - Allocate and initialize padata instance.
+ *                         Use the cpu_possible_mask for serial and
+ *                         parallel workers.
+ *
+ * @wq: workqueue to use for the allocated padata instance
+ *
+ * Must be called from a cpus_read_lock() protected region
+ */
+struct padata_instance *padata_alloc_possible(struct workqueue_struct *wq)
+{
+	lockdep_assert_cpus_held();
+	return padata_alloc(wq, cpu_possible_mask, cpu_possible_mask);
+}
+EXPORT_SYMBOL(padata_alloc_possible);
+
+/**
  * padata_free - free a padata instance
  *
  * @padata_inst: padata instance to free