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* [PATCH -next] io-wq: Remove duplicate code in io_workqueue_create()
@ 2021-09-11  8:58 Bixuan Cui
  2021-09-12 15:36 ` Hao Xu
  0 siblings, 1 reply; 3+ messages in thread
From: Bixuan Cui @ 2021-09-11  8:58 UTC (permalink / raw)
  To: linux-kernel, io-uring; +Cc: axboe, asml.silence

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@huawei.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)
-- 
2.17.1


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH -next] io-wq: Remove duplicate code in io_workqueue_create()
  2021-09-11  8:58 [PATCH -next] io-wq: Remove duplicate code in io_workqueue_create() Bixuan Cui
@ 2021-09-12 15:36 ` Hao Xu
  2021-09-15 18:12   ` Jens Axboe
  0 siblings, 1 reply; 3+ messages in thread
From: Hao Xu @ 2021-09-12 15:36 UTC (permalink / raw)
  To: Bixuan Cui, linux-kernel, io-uring; +Cc: axboe, asml.silence, Joseph Qi

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@huawei.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.


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH -next] io-wq: Remove duplicate code in io_workqueue_create()
  2021-09-12 15:36 ` Hao Xu
@ 2021-09-15 18:12   ` Jens Axboe
  0 siblings, 0 replies; 3+ messages in thread
From: Jens Axboe @ 2021-09-15 18:12 UTC (permalink / raw)
  To: Hao Xu, Bixuan Cui, linux-kernel, io-uring; +Cc: asml.silence, Joseph Qi

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@huawei.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


^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2021-09-15 18:12 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2021-09-11  8:58 [PATCH -next] io-wq: Remove duplicate code in io_workqueue_create() Bixuan Cui
2021-09-12 15:36 ` Hao Xu
2021-09-15 18:12   ` Jens Axboe

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