Re: [PATCH 2/2] fs: Add aio priority support for block_dev

[Christoph Hellwig]

> --- a/fs/aio.c
> +++ b/fs/aio.c
> @@ -1603,6 +1603,15 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
>  		goto out_put_req;
>  	}
>  
> +	if (req->common.ki_flags & IOCB_IOPRIO)
> +		/*
> +		 * The IOCB_IOPRIO flag is set when the user supplied iocb
> +		 * aio_rw_flag field has the RWF_IOPRIO flag set. If so,
> +		 * aio_reqprio is interpreted as a I/O scheduling class and
> +		 * priority.
> +		 */
> +		req->common.ki_ioprio = iocb->aio_reqprio;

Do we need any validation of the field here?

The only other thing I am a bit worried about is bloating struct kiocb
with a field for a relatively uncommon feature, but I can't really
see any much better way to pass it.