[PATCH 2/3] io-wq: fix lack of acct->nr_workers < acct->max_workers judgement

[Hao Xu <haoxu@linux.alibaba.com>]

There should be this judgement before we create an io-worker

Fixes: 685fe7feedb9 ("io-wq: eliminate the need for a manager thread")
Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
---
 fs/io-wq.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/fs/io-wq.c b/fs/io-wq.c
index 6788666c65de..d8684b4d0654 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -281,10 +281,26 @@ static void create_worker_cb(struct callback_head *cb)
 {
 	struct create_worker_data *cwd;
 	struct io_wq *wq;
+	struct io_wqe *wqe;
+	struct io_wqe_acct *acct;
+	bool need_create = false;
 
 	cwd = container_of(cb, struct create_worker_data, work);
-	wq = cwd->wqe->wq;
-	create_io_worker(wq, cwd->wqe, cwd->index);
+	wqe = cwd->wqe;
+	wq = wqe->wq;
+	acct = &wqe->acct[cwd->index];
+	raw_spin_lock_irq(&wqe->lock);
+	if (acct->nr_workers < acct->max_workers) {
+		acct->nr_workers++;
+		need_create = true;
+	}
+	raw_spin_unlock_irq(&wqe->lock);
+	if (need_create) {
+		create_io_worker(wq, wqe, cwd->index);
+	} else {
+		atomic_dec(&acct->nr_running);
+		io_worker_ref_put(wq);
+	}
 	kfree(cwd);
 }
 
-- 
2.24.4