diff --git a/include/linux/padata.h b/include/linux/padata.h
index 3bfa503503ac5..b0affa466a841 100644
--- a/include/linux/padata.h
+++ b/include/linux/padata.h
@@ -4,6 +4,9 @@
  *
  * Copyright (C) 2008, 2009 secunet Security Networks AG
  * Copyright (C) 2008, 2009 Steffen Klassert <steffen.klassert@secunet.com>
+ *
+ * Copyright (c) 2020 Oracle and/or its affiliates.
+ * Author: Daniel Jordan <daniel.m.jordan@oracle.com>
  */
 
 #ifndef PADATA_H
@@ -130,6 +133,31 @@ struct padata_shell {
 	struct list_head		list;
 };
 
+/**
+ * struct padata_mt_job - represents one multithreaded job
+ *
+ * @thread_fn: Called for each chunk of work that a padata thread does.
+ * @fn_arg: The thread function argument.
+ * @start: The start of the job (units are job-specific).
+ * @size: size of this node's work (units are job-specific).
+ * @align: Ranges passed to the thread function fall on this boundary, with the
+ *         possible exceptions of the beginning and end of the job.
+ * @min_chunk: The minimum chunk size in job-specific units.  This allows
+ *             the client to communicate the minimum amount of work that's
+ *             appropriate for one worker thread to do at once.
+ * @max_threads: Max threads to use for the job, actual number may be less
+ *               depending on task size and minimum chunk size.
+ */
+struct padata_mt_job {
+	void (*thread_fn)(unsigned long start, unsigned long end, void *arg);
+	void			*fn_arg;
+	unsigned long		start;
+	unsigned long		size;
+	unsigned long		align;
+	unsigned long		min_chunk;
+	int			max_threads;
+};
+
 /**
  * struct padata_instance - The overall control structure.
  *
@@ -171,6 +199,7 @@ extern void padata_free_shell(struct padata_shell *ps);
 extern int padata_do_parallel(struct padata_shell *ps,
 			      struct padata_priv *padata, int *cb_cpu);
 extern void padata_do_serial(struct padata_priv *padata);
+extern void __init padata_do_multithreaded(struct padata_mt_job *job);
 extern int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
 			      cpumask_var_t cpumask);
 extern int padata_start(struct padata_instance *pinst);
diff --git a/kernel/padata.c b/kernel/padata.c
index 78ff9aa529204..e78f57d9aef90 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -7,6 +7,9 @@
  * Copyright (C) 2008, 2009 secunet Security Networks AG
  * Copyright (C) 2008, 2009 Steffen Klassert <steffen.klassert@secunet.com>
  *
+ * Copyright (c) 2020 Oracle and/or its affiliates.
+ * Author: Daniel Jordan <daniel.m.jordan@oracle.com>
+ *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
  * version 2, as published by the Free Software Foundation.
@@ -21,6 +24,7 @@
  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
+#include <linux/completion.h>
 #include <linux/export.h>
 #include <linux/cpumask.h>
 #include <linux/err.h>
@@ -32,6 +36,8 @@
 #include <linux/sysfs.h>
 #include <linux/rcupdate.h>
 
+#define	PADATA_WORK_ONSTACK	1	/* Work's memory is on stack */
+
 struct padata_work {
 	struct work_struct	pw_work;
 	struct list_head	pw_list;  /* padata_free_works linkage */
@@ -42,7 +48,17 @@ static DEFINE_SPINLOCK(padata_works_lock);
 static struct padata_work *padata_works;
 static LIST_HEAD(padata_free_works);
 
+struct padata_mt_job_state {
+	spinlock_t		lock;
+	struct completion	completion;
+	struct padata_mt_job	*job;
+	int			nworks;
+	int			nworks_fini;
+	unsigned long		chunk_size;
+};
+
 static void padata_free_pd(struct parallel_data *pd);
+static void __init padata_mt_helper(struct work_struct *work);
 
 static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index)
 {
@@ -81,18 +97,56 @@ static struct padata_work *padata_work_alloc(void)
 }
 
 static void padata_work_init(struct padata_work *pw, work_func_t work_fn,
-			     void *data)
+			     void *data, int flags)
 {
-	INIT_WORK(&pw->pw_work, work_fn);
+	if (flags & PADATA_WORK_ONSTACK)
+		INIT_WORK_ONSTACK(&pw->pw_work, work_fn);
+	else
+		INIT_WORK(&pw->pw_work, work_fn);
 	pw->pw_data = data;
 }
 
+static int __init padata_work_alloc_mt(int nworks, void *data,
+				       struct list_head *head)
+{
+	int i;
+
+	spin_lock(&padata_works_lock);
+	/* Start at 1 because the current task participates in the job. */
+	for (i = 1; i < nworks; ++i) {
+		struct padata_work *pw = padata_work_alloc();
+
+		if (!pw)
+			break;
+		padata_work_init(pw, padata_mt_helper, data, 0);
+		list_add(&pw->pw_list, head);
+	}
+	spin_unlock(&padata_works_lock);
+
+	return i;
+}
+
 static void padata_work_free(struct padata_work *pw)
 {
 	lockdep_assert_held(&padata_works_lock);
 	list_add(&pw->pw_list, &padata_free_works);
 }
 
+static void __init padata_works_free(struct list_head *works)
+{
+	struct padata_work *cur, *next;
+
+	if (list_empty(works))
+		return;
+
+	spin_lock(&padata_works_lock);
+	list_for_each_entry_safe(cur, next, works, pw_list) {
+		list_del(&cur->pw_list);
+		padata_work_free(cur);
+	}
+	spin_unlock(&padata_works_lock);
+}
+
 static void padata_parallel_worker(struct work_struct *parallel_work)
 {
 	struct padata_work *pw = container_of(parallel_work, struct padata_work,
@@ -168,7 +222,7 @@ int padata_do_parallel(struct padata_shell *ps,
 	pw = padata_work_alloc();
 	spin_unlock(&padata_works_lock);
 	if (pw) {
-		padata_work_init(pw, padata_parallel_worker, padata);
+		padata_work_init(pw, padata_parallel_worker, padata, 0);
 		queue_work(pinst->parallel_wq, &pw->pw_work);
 	} else {
 		/* Maximum works limit exceeded, run in the current task. */
@@ -409,6 +463,98 @@ static int pd_setup_cpumasks(struct parallel_data *pd,
 	return err;
 }
 
+static void __init padata_mt_helper(struct work_struct *w)
+{
+	struct padata_work *pw = container_of(w, struct padata_work, pw_work);
+	struct padata_mt_job_state *ps = pw->pw_data;
+	struct padata_mt_job *job = ps->job;
+	bool done;
+
+	spin_lock(&ps->lock);
+
+	while (job->size > 0) {
+		unsigned long start, size, end;
+
+		start = job->start;
+		/* So end is chunk size aligned if enough work remains. */
+		size = roundup(start + 1, ps->chunk_size) - start;
+		size = min(size, job->size);
+		end = start + size;
+
+		job->start = end;
+		job->size -= size;
+
+		spin_unlock(&ps->lock);
+		job->thread_fn(start, end, job->fn_arg);
+		spin_lock(&ps->lock);
+	}
+
+	++ps->nworks_fini;
+	done = (ps->nworks_fini == ps->nworks);
+	spin_unlock(&ps->lock);
+
+	if (done)
+		complete(&ps->completion);
+}
+
+/**
+ * padata_do_multithreaded - run a multithreaded job
+ * @job: Description of the job.
+ *
+ * See the definition of struct padata_mt_job for more details.
+ */
+void __init padata_do_multithreaded(struct padata_mt_job *job)
+{
+	/* In case threads finish at different times. */
+	static const unsigned long load_balance_factor = 4;
+	struct padata_work my_work, *pw;
+	struct padata_mt_job_state ps;
+	LIST_HEAD(works);
+	int nworks;
+
+	if (job->size == 0)
+		return;
+
+	/* Ensure at least one thread when size < min_chunk. */
+	nworks = max(job->size / job->min_chunk, 1ul);
+	nworks = min(nworks, job->max_threads);
+
+	if (nworks == 1) {
+		/* Single thread, no coordination needed, cut to the chase. */
+		job->thread_fn(job->start, job->start + job->size, job->fn_arg);
+		return;
+	}
+
+	spin_lock_init(&ps.lock);
+	init_completion(&ps.completion);
+	ps.job	       = job;
+	ps.nworks      = padata_work_alloc_mt(nworks, &ps, &works);
+	ps.nworks_fini = 0;
+
+	/*
+	 * Chunk size is the amount of work a helper does per call to the
+	 * thread function.  Load balance large jobs between threads by
+	 * increasing the number of chunks, guarantee at least the minimum
+	 * chunk size from the caller, and honor the caller's alignment.
+	 */
+	ps.chunk_size = job->size / (ps.nworks * load_balance_factor);
+	ps.chunk_size = max(ps.chunk_size, job->min_chunk);
+	ps.chunk_size = roundup(ps.chunk_size, job->align);
+
+	list_for_each_entry(pw, &works, pw_list)
+		queue_work(system_unbound_wq, &pw->pw_work);
+
+	/* Use the current thread, which saves starting a workqueue worker. */
+	padata_work_init(&my_work, padata_mt_helper, &ps, PADATA_WORK_ONSTACK);
+	padata_mt_helper(&my_work.pw_work);
+
+	/* Wait for all the helpers to finish. */
+	wait_for_completion(&ps.completion);
+
+	destroy_work_on_stack(&my_work.pw_work);
+	padata_works_free(&works);
+}
+
 static void __padata_list_init(struct padata_list *pd_list)
 {
 	INIT_LIST_HEAD(&pd_list->list);
