On 02/06/2020 04:16, Xiaoguang Wang wrote:
> hi Jens, Pavel,
>
> Will you have a look at this V5 version? Or we hold on this patchset, and
> do the refactoring work related io_wq_work firstly.
It's entirely up to Jens, but frankly, I think it'll bring more bugs than
merits in the current state of things.
>
>
>> Basically IORING_OP_POLL_ADD command and async armed poll handlers
>> for regular commands don't touch io_wq_work, so only REQ_F_WORK_INITIALIZED
>> is set, can we do io_wq_work copy and restore.
>>
>> Signed-off-by: Xiaoguang Wang <xiaoguang.wang@xxxxxxxxxxxxxxxxx>
>> ---
>> V3:
>> drop the REQ_F_WORK_NEED_RESTORE flag introduced in V2 patch, just
>> use REQ_F_WORK_INITIALIZED to control whether to do io_wq_work copy
>> and restore.
>> ---
>> fs/io_uring.c | 13 +++++++++----
>> 1 file changed, 9 insertions(+), 4 deletions(-)
>>
>> diff --git a/fs/io_uring.c b/fs/io_uring.c
>> index 8e022d0f0c86..b761ef7366f9 100644
>> --- a/fs/io_uring.c
>> +++ b/fs/io_uring.c
>> @@ -4527,7 +4527,8 @@ static void io_async_task_func(struct callback_head *cb)
>> spin_unlock_irq(&ctx->completion_lock);
>> /* restore ->work in case we need to retry again */
>> - memcpy(&req->work, &apoll->work, sizeof(req->work));
>> + if (req->flags & REQ_F_WORK_INITIALIZED)
>> + memcpy(&req->work, &apoll->work, sizeof(req->work));
>> kfree(apoll);
>> if (!canceled) {
>> @@ -4624,7 +4625,8 @@ static bool io_arm_poll_handler(struct io_kiocb *req)
>> return false;
>> req->flags |= REQ_F_POLLED;
>> - memcpy(&apoll->work, &req->work, sizeof(req->work));
>> + if (req->flags & REQ_F_WORK_INITIALIZED)
>> + memcpy(&apoll->work, &req->work, sizeof(req->work));
>> had_io = req->io != NULL;
>> get_task_struct(current);
>> @@ -4649,7 +4651,8 @@ static bool io_arm_poll_handler(struct io_kiocb *req)
>> if (!had_io)
>> io_poll_remove_double(req);
>> spin_unlock_irq(&ctx->completion_lock);
>> - memcpy(&req->work, &apoll->work, sizeof(req->work));
>> + if (req->flags & REQ_F_WORK_INITIALIZED)
>> + memcpy(&req->work, &apoll->work, sizeof(req->work));
>> kfree(apoll);
>> return false;
>> }
>> @@ -4694,7 +4697,9 @@ static bool io_poll_remove_one(struct io_kiocb *req)
>> * io_req_work_drop_env below when dropping the
>> * final reference.
>> */
>> - memcpy(&req->work, &apoll->work, sizeof(req->work));
>> + if (req->flags & REQ_F_WORK_INITIALIZED)
>> + memcpy(&req->work, &apoll->work,
>> + sizeof(req->work));
>> kfree(apoll);
>> }
>> }
>>
--
Pavel Begunkov
