io_uring/io-wq: don't grab wq->lock for worker activation

The worker free list is RCU protected, and checks for workers going away
when iterating it. There's no need to hold the wq->lock around the
lookup.

Reviewed-by: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/io_uring/io-wq.c b/io_uring/io-wq.c
index 399e9a1..3e7025b 100644 (file)
--- a/io_uring/io-wq.c
+++ b/io_uring/io-wq.c
@@ -909,13 +909,10 @@ void io_wq_enqueue(struct io_wq *wq, struct io_wq_work *work)
        clear_bit(IO_ACCT_STALLED_BIT, &acct->flags);
        raw_spin_unlock(&acct->lock);
 
-       raw_spin_lock(&wq->lock);
        rcu_read_lock();
        do_create = !io_wq_activate_free_worker(wq, acct);
        rcu_read_unlock();
 
-       raw_spin_unlock(&wq->lock);
-
        if (do_create && ((work_flags & IO_WQ_WORK_CONCURRENT) ||
            !atomic_read(&acct->nr_running))) {
                bool did_create;