Re: [PATCH blktests] block/049: test polled dio with user PI metadata

[Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>]

On Sep 24, 2026 / 10:55, Yang Xiuwei wrote:
> IOPOLL combined with a PI attribute used to leave iocb->private as a
> uio_meta and oops in bio_poll(). The kernel rejects that combination
> with -EOPNOTSUPP. Add a scsi_debug reproducer that expects this result.
> 
> Assisted-by: LLM
> Signed-off-by: Yang Xiuwei <yangxiuwei@kylinos.cn>
> ---
> Depends on the kernel fix that rejects IOPOLL plus user PI metadata
> with -EOPNOTSUPP. Without that fix this test oopses in bio_poll().
> 
> Link: https://lore.kernel.org/linux-block/20260923093732.1504291-1-yangxiuwei@kylinos.cn/

Thanks for the patch. I confirmed the new test case recreates the Oops, and the
kernel fix patch avoids it. Good from test run point of view.

> 
> The fix is not in mainline yet. Is an oops on kernels without it
> acceptable here, or how should the test avoid that? _have_kver after
> the fix lands would still skip a stable backport, which keeps the old
> version number. The only userspace difference is -EOPNOTSUPP versus
> the oops.

I understand the concern. My current policy is to wait for the kernel side
fix gets upstreamed to Linus master branch, then add the test case to blktests.
This way we can keep blktests runs healthy with Linus master branch. It can
cause the failure with stable kernels, but I expect it will work as the signal
to encourage backport of the fix. So, let's wait for the kernel side fix to
get settled on Linus master branch.

Also, please find my inline comments below.

...

> diff --git a/src/metadata-iopoll.c b/src/metadata-iopoll.c
> new file mode 100644
> index 0000000..95e2bc9
> --- /dev/null
> +++ b/src/metadata-iopoll.c
> @@ -0,0 +1,101 @@
> +// SPDX-License-Identifier: GPL-3.0+

Your copyright is missing here.

> +#include <errno.h>
> +#include <fcntl.h>
> +#include <signal.h>
> +#include <stdio.h>

...

> diff --git a/tests/block/049 b/tests/block/049
> new file mode 100755
> index 0000000..b932414
> --- /dev/null
> +++ b/tests/block/049
> @@ -0,0 +1,46 @@
> +#!/bin/bash
> +# SPDX-License-Identifier: GPL-3.0+
> +# Copyright (C) 2026 Yang Xiuwei <yangxiuwei@kylinos.cn>
> +#
> +# IOPOLL combined with a PI attribute used to oops in bio_poll(). The kernel
> +# rejects that combination with -EOPNOTSUPP.
> +
> +. tests/block/rc
> +. common/scsi_debug
> +
> +DESCRIPTION="iopoll dio with user PI metadata returns -EOPNOTSUPP"
> +QUICK=1
> +
> +requires() {
> +	_have_kernel_option IO_URING
> +	_have_kernel_option BLK_DEV_INTEGRITY
> +	_have_module scsi_debug

I recommend _have_loadable_scsi_debug instead of "_have_module scsi_debug".
It will do some more check for the scsi_dubug module status.