[PATCH 2/4] workqueue: add warning if pool->node is offline

[Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>]

Add warning if pool->node is offline.

This patch was originaly made for debug.
I think add warning here can show what may happen.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
---
 kernel/workqueue.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index f6cb357c..35f4f00 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -760,6 +760,15 @@ static bool too_many_workers(struct worker_pool *pool)
 	return nr_idle > 2 && (nr_idle - 2) * MAX_IDLE_WORKERS_RATIO >= nr_busy;
 }
 
+/* Check pool->node */
+static int pool_to_node(struct worker_pool *pool)
+{
+	if (WARN_ON_ONCE(pool->node != NUMA_NO_NODE
+                         && !node_online(pool->node)))
+		return NUMA_NO_NODE;
+	return pool->node;
+}
+
 /*
  * Wake up functions.
  */
@@ -1679,7 +1688,7 @@ static struct worker *create_worker(struct worker_pool *pool)
 	if (id < 0)
 		goto fail;
 
-	worker = alloc_worker(pool->node);
+	worker = alloc_worker(pool_to_node(pool));
 	if (!worker)
 		goto fail;
 
@@ -1692,7 +1701,8 @@ static struct worker *create_worker(struct worker_pool *pool)
 	else
 		snprintf(id_buf, sizeof(id_buf), "u%d:%d", pool->id, id);
 
-	worker->task = kthread_create_on_node(worker_thread, worker, pool->node,
+	worker->task = kthread_create_on_node(worker_thread, worker,
+					      pool_to_node(pool),
 					      "kworker/%s", id_buf);
 	if (IS_ERR(worker->task))
 		goto fail;
@@ -3651,7 +3661,7 @@ static struct pool_workqueue *alloc_unbound_pwq(struct workqueue_struct *wq,
 	if (!pool)
 		return NULL;
 
-	pwq = kmem_cache_alloc_node(pwq_cache, GFP_KERNEL, pool->node);
+	pwq = kmem_cache_alloc_node(pwq_cache, GFP_KERNEL, pool_to_node(pool));
 	if (!pwq) {
 		put_unbound_pool(pool);
 		return NULL;
-- 
1.8.3.1