Re: [PATCH 5/8] io_uring: don't try io-wq polling if not supported

[Hao Xu <haoxu@linux.alibaba.com>]

在 2021/10/23 下午7:13, Pavel Begunkov 写道:
> If an opcode doesn't support polling, just let it be executed
> synchronously in iowq, otherwise it will do a nonblock attempt just to
> fail in io_arm_poll_handler() and return back to blocking execution.
> 
> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
> ---
Reviewed-by: Hao Xu <haoxu@linux.alibaba.com>
>   fs/io_uring.c | 8 ++++++--
>   1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index bff911f951ed..c6f32fcf387b 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -6741,9 +6741,13 @@ static void io_wq_submit_work(struct io_wq_work *work)
>   	}
>   
>   	if (req->flags & REQ_F_FORCE_ASYNC) {
> -		needs_poll = req->file && file_can_poll(req->file);
> -		if (needs_poll)
> +		const struct io_op_def *def = &io_op_defs[req->opcode];
> +		bool opcode_poll = def->pollin || def->pollout;
> +
> +		if (opcode_poll && file_can_poll(req->file)) {
> +			needs_poll = true;
>   			issue_flags |= IO_URING_F_NONBLOCK;
> +		}
>   	}
>   
>   	do {
>