Re: [PATCH V2] block: ignore RWF_HIPRI hint for sync dio

Keith Busch
2022-05-23T22:36:10Z

On Wed, Apr 20, 2022 at 10:31:10PM +0800, Ming Lei wrote:
> So far bio is marked as REQ_POLLED if RWF_HIPRI/IOCB_HIPRI is passed
> from userspace sync io interface, then block layer tries to poll until
> the bio is completed. But the current implementation calls
> blk_io_schedule() if bio_poll() returns 0, and this way causes io hang or
> timeout easily.

Wait a second. The task's current state is TASK_RUNNING when bio_poll() returns
zero, so calling blk_io_schedule() isn't supposed to hang.