diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index e060ff2bc20c..46381490f496 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -282,9 +282,18 @@ static inline int __next_wq_cpu(int cpu, const struct cpumask *mask,
  * for_each_pool - iterate through all worker_pools in the system
  * @pool: iteration cursor
  * @id: integer used for iteration
+ *
+ * This must be called either with workqueue_lock held or sched RCU read
+ * locked.  If the pool needs to be used beyond the locking in effect, the
+ * caller is responsible for guaranteeing that the pool stays online.
+ *
+ * The if/else clause exists only for the lockdep assertion and can be
+ * ignored.
  */
 #define for_each_pool(pool, id)						\
-	idr_for_each_entry(&worker_pool_idr, pool, id)
+	idr_for_each_entry(&worker_pool_idr, pool, id)			\
+		if (({ assert_rcu_or_wq_lock(); false; })) { }		\
+		else
 
 /**
  * for_each_pwq - iterate through all pool_workqueues of the specified workqueue
@@ -432,8 +441,10 @@ static DEFINE_PER_CPU_SHARED_ALIGNED(struct worker_pool [NR_STD_WORKER_POOLS],
 				     cpu_std_worker_pools);
 static struct worker_pool unbound_std_worker_pools[NR_STD_WORKER_POOLS];
 
-/* idr of all pools */
-static DEFINE_MUTEX(worker_pool_idr_mutex);
+/*
+ * idr of all pools.  Modifications are protected by workqueue_lock.  Read
+ * accesses are protected by sched-RCU protected.
+ */
 static DEFINE_IDR(worker_pool_idr);
 
 static int worker_thread(void *__worker);
@@ -456,23 +467,18 @@ static int worker_pool_assign_id(struct worker_pool *pool)
 {
 	int ret;
 
-	mutex_lock(&worker_pool_idr_mutex);
-	idr_pre_get(&worker_pool_idr, GFP_KERNEL);
-	ret = idr_get_new(&worker_pool_idr, pool, &pool->id);
-	mutex_unlock(&worker_pool_idr_mutex);
+	do {
+		if (!idr_pre_get(&worker_pool_idr, GFP_KERNEL))
+			return -ENOMEM;
+
+		spin_lock_irq(&workqueue_lock);
+		ret = idr_get_new(&worker_pool_idr, pool, &pool->id);
+		spin_unlock_irq(&workqueue_lock);
+	} while (ret == -EAGAIN);
 
 	return ret;
 }
 
-/*
- * Lookup worker_pool by id.  The idr currently is built during boot and
- * never modified.  Don't worry about locking for now.
- */
-static struct worker_pool *worker_pool_by_id(int pool_id)
-{
-	return idr_find(&worker_pool_idr, pool_id);
-}
-
 static struct worker_pool *get_std_worker_pool(int cpu, bool highpri)
 {
 	struct worker_pool *pools = std_worker_pools(cpu);
@@ -586,13 +592,23 @@ static struct pool_workqueue *get_work_pwq(struct work_struct *work)
  * @work: the work item of interest
  *
  * Return the worker_pool @work was last associated with.  %NULL if none.
+ *
+ * Pools are created and destroyed under workqueue_lock, and allows read
+ * access under sched-RCU read lock.  As such, this function should be
+ * called under workqueue_lock or with preemption disabled.
+ *
+ * All fields of the returned pool are accessible as long as the above
+ * mentioned locking is in effect.  If the returned pool needs to be used
+ * beyond the critical section, the caller is responsible for ensuring the
+ * returned pool is and stays online.
  */
 static struct worker_pool *get_work_pool(struct work_struct *work)
 {
 	unsigned long data = atomic_long_read(&work->data);
-	struct worker_pool *pool;
 	int pool_id;
 
+	assert_rcu_or_wq_lock();
+
 	if (data & WORK_STRUCT_PWQ)
 		return ((struct pool_workqueue *)
 			(data & WORK_STRUCT_WQ_DATA_MASK))->pool;
@@ -601,9 +617,7 @@ static struct worker_pool *get_work_pool(struct work_struct *work)
 	if (pool_id == WORK_OFFQ_POOL_NONE)
 		return NULL;
 
-	pool = worker_pool_by_id(pool_id);
-	WARN_ON_ONCE(!pool);
-	return pool;
+	return idr_find(&worker_pool_idr, pool_id);
 }
 
 /**
@@ -2767,11 +2781,15 @@ static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr)
 	struct pool_workqueue *pwq;
 
 	might_sleep();
-	pool = get_work_pool(work);
-	if (!pool)
-		return false;
 
-	spin_lock_irq(&pool->lock);
+	local_irq_disable();
+	pool = get_work_pool(work);
+	if (!pool) {
+		local_irq_enable();
+		return false;
+	}
+
+	spin_lock(&pool->lock);
 	/* see the comment in try_to_grab_pending() with the same code */
 	pwq = get_work_pwq(work);
 	if (pwq) {
@@ -3414,19 +3432,22 @@ EXPORT_SYMBOL_GPL(workqueue_congested);
  */
 unsigned int work_busy(struct work_struct *work)
 {
-	struct worker_pool *pool = get_work_pool(work);
+	struct worker_pool *pool;
 	unsigned long flags;
 	unsigned int ret = 0;
 
 	if (work_pending(work))
 		ret |= WORK_BUSY_PENDING;
 
+	local_irq_save(flags);
+	pool = get_work_pool(work);
 	if (pool) {
-		spin_lock_irqsave(&pool->lock, flags);
+		spin_lock(&pool->lock);
 		if (find_worker_executing_work(pool, work))
 			ret |= WORK_BUSY_RUNNING;
-		spin_unlock_irqrestore(&pool->lock, flags);
+		spin_unlock(&pool->lock);
 	}
+	local_irq_restore(flags);
 
 	return ret;
 }