linux-kernel - Re: [PATCH -next] io-wq: Remove duplicate code in io_workqueue

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Date:   Wed, 15 Sep 2021 12:12:12 -0600
From:   Jens Axboe <axboe@...nel.dk>
To:     Hao Xu <haoxu@...ux.alibaba.com>,
        Bixuan Cui <cuibixuan@...wei.com>,
        linux-kernel@...r.kernel.org, io-uring@...r.kernel.org
Cc:     asml.silence@...il.com, Joseph Qi <joseph.qi@...ux.alibaba.com>
Subject: Re: [PATCH -next] io-wq: Remove duplicate code in
 io_workqueue_create()

On 9/12/21 9:36 AM, Hao Xu wrote:
> 在 2021/9/11 下午4:58, Bixuan Cui 写道:
>> While task_work_add() in io_workqueue_create() is true,
>> then duplicate code is executed:
>>
>>    -> clear_bit_unlock(0, &worker->create_state);
>>    -> io_worker_release(worker);
>>    -> atomic_dec(&acct->nr_running);
>>    -> io_worker_ref_put(wq);
>>    -> return false;
>>
>>    -> clear_bit_unlock(0, &worker->create_state); // back to io_workqueue_create()
>>    -> io_worker_release(worker);
>>    -> kfree(worker);
>>
>> The io_worker_release() and clear_bit_unlock() are executed twice.
>>
>> Fixes: 3146cba99aa2 ("io-wq: make worker creation resilient against signals")
>> Signed-off-by: Bixuan Cui <cuibixuan@...wei.com>
>> ---
>>   fs/io-wq.c | 9 ++++-----
>>   1 file changed, 4 insertions(+), 5 deletions(-)
>>
>> diff --git a/fs/io-wq.c b/fs/io-wq.c
>> index 6c55362c1f99..95d0eaed7c00 100644
>> --- a/fs/io-wq.c
>> +++ b/fs/io-wq.c
>> @@ -329,8 +329,10 @@ static bool io_queue_worker_create(struct io_worker *worker,
>>   
>>   	init_task_work(&worker->create_work, func);
>>   	worker->create_index = acct->index;
>> -	if (!task_work_add(wq->task, &worker->create_work, TWA_SIGNAL))
>> +	if (!task_work_add(wq->task, &worker->create_work, TWA_SIGNAL)) {
>> +		clear_bit_unlock(0, &worker->create_state);
>>   		return true;
>> +	}
>>   	clear_bit_unlock(0, &worker->create_state);
>>   fail_release:
>>   	io_worker_release(worker);
>> @@ -723,11 +725,8 @@ static void io_workqueue_create(struct work_struct *work)
>>   	struct io_worker *worker = container_of(work, struct io_worker, work);
>>   	struct io_wqe_acct *acct = io_wqe_get_acct(worker);
>>   
>> -	if (!io_queue_worker_create(worker, acct, create_worker_cont)) {
>> -		clear_bit_unlock(0, &worker->create_state);
>> -		io_worker_release(worker);
>> +	if (!io_queue_worker_create(worker, acct, create_worker_cont))
>>   		kfree(worker);
>> -	}
>>   }
>>   
>>   static bool create_io_worker(struct io_wq *wq, struct io_wqe *wqe, int index)
>>
> AFAIK, this looks reasonable for me.

I took that as a reviewed-by, let me know if that isn't correct.

-- 
Jens Axboe