[PATCH 1/2] io-wq: fix bug of creating io-wokers unconditionally

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

The former patch to add check between nr_workers and max_workers has a
bug, which will cause unconditionally creating io-workers. That's
because the result of the check doesn't affect the call of
create_io_worker(), fix it by bringing in a boolean value for it.

Fixes: 21698274da5b ("io-wq: fix lack of acct->nr_workers < acct->max_workers judgement")
Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
---
 fs/io-wq.c | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/fs/io-wq.c b/fs/io-wq.c
index 12fc19353bb0..5536b2a008d1 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -252,14 +252,15 @@ static void io_wqe_wake_worker(struct io_wqe *wqe, struct io_wqe_acct *acct)
 
 		raw_spin_lock_irq(&wqe->lock);
 		if (acct->nr_workers < acct->max_workers) {
-			atomic_inc(&acct->nr_running);
-			atomic_inc(&wqe->wq->worker_refs);
 			acct->nr_workers++;
 			do_create = true;
 		}
 		raw_spin_unlock_irq(&wqe->lock);
-		if (do_create)
+		if (do_create) {
+			atomic_inc(&acct->nr_running);
+			atomic_inc(&wqe->wq->worker_refs);
 			create_io_worker(wqe->wq, wqe, acct->index);
+		}
 	}
 }
 
@@ -282,16 +283,24 @@ static void create_worker_cb(struct callback_head *cb)
 	struct io_wq *wq;
 	struct io_wqe *wqe;
 	struct io_wqe_acct *acct;
+	bool do_create = false;
 
 	cwd = container_of(cb, struct create_worker_data, work);
 	wqe = cwd->wqe;
 	wq = wqe->wq;
 	acct = &wqe->acct[cwd->index];
 	raw_spin_lock_irq(&wqe->lock);
-	if (acct->nr_workers < acct->max_workers)
+	if (acct->nr_workers < acct->max_workers) {
 		acct->nr_workers++;
+		do_create = true;
+	}
 	raw_spin_unlock_irq(&wqe->lock);
-	create_io_worker(wq, cwd->wqe, cwd->index);
+	if (do_create) {
+		create_io_worker(wq, cwd->wqe, cwd->index);
+	} else {
+		atomic_dec(&acct->nr_running);
+		io_worker_ref_put(wq);
+	}
 	kfree(cwd);
 }
 
-- 
2.24.4