Re: [PATCH v2 3/3] common/rc: notrun if io_uring is disabled by sysctl

["Darrick J. Wong" <djwong@kernel.org>]

On Tue, Mar 12, 2024 at 12:20:29AM +0800, Zorro Lang wrote:
> If kernel supports io_uring, userspace still can/might disable that
> supporting by set /proc/sys/kernel/io_uring_disabled=2. Let's notrun
> if io_uring is disabled by that way.
> 
> Signed-off-by: Zorro Lang <zlang@kernel.org>

Looks fine to me,
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> ---
>  README        |  6 ++++++
>  common/rc     | 10 ++++++++++
>  src/feature.c | 19 ++++++++++++-------
>  3 files changed, 28 insertions(+), 7 deletions(-)
> 
> diff --git a/README b/README
> index c46690c4..477136de 100644
> --- a/README
> +++ b/README
> @@ -142,6 +142,12 @@ Setup Environment
>     https://www.lscdweb.com/registered/udf_verifier.html, then copy the udf_test
>     binary to xfstests/src/.
>  
> +8. (optional) To do io_uring related testing, please make sure below 3 things:
> +     1) kernel is built with CONFIG_IO_URING=y
> +     2) sysctl -w kernel.io_uring_disabled=0 (or set it to 2 to disable io_uring
> +        testing dynamically if kernel supports)
> +     3) install liburing development package contains liburing.h before building
> +        fstests
>  
>  For example, to run the tests with loopback partitions:
>  
> diff --git a/common/rc b/common/rc
> index 50dde313..1406d8d9 100644
> --- a/common/rc
> +++ b/common/rc
> @@ -2317,6 +2317,8 @@ _require_aiodio()
>  # this test requires that the kernel supports IO_URING
>  _require_io_uring()
>  {
> +	local n
> +
>  	$here/src/feature -R
>  	case $? in
>  	0)
> @@ -2324,6 +2326,14 @@ _require_io_uring()
>  	1)
>  		_notrun "kernel does not support IO_URING"
>  		;;
> +	2)
> +		n=$(sysctl -n kernel.io_uring_disabled 2>/dev/null)
> +		if [ "$n" != "0" ];then
> +			_notrun "io_uring isn't enabled totally by admin"
> +		else
> +			_fail "unexpected EPERM error, please check selinux or something else"
> +		fi
> +		;;
>  	*)
>  		_fail "unexpected error testing for IO_URING support"
>  		;;
> diff --git a/src/feature.c b/src/feature.c
> index 941f96fb..7e474ce5 100644
> --- a/src/feature.c
> +++ b/src/feature.c
> @@ -232,15 +232,20 @@ check_uring_support(void)
>  	int err;
>  
>  	err = io_uring_queue_init(1, &ring, 0);
> -	if (err == 0)
> +	switch (err) {
> +	case 0:
>  		return 0;
> -
> -	if (err == -ENOSYS) /* CONFIG_IO_URING=n */
> +	case -ENOSYS:
> +		/* CONFIG_IO_URING=n */
>  		return 1;
> -
> -	fprintf(stderr, "unexpected error from io_uring_queue_init(): %s\n",
> -		strerror(-err));
> -	return 2;
> +	case -EPERM:
> +		/* Might be due to sysctl io_uring_disabled isn't 0 */
> +		return 2;
> +	default:
> +		fprintf(stderr, "unexpected error from io_uring_queue_init(): %s\n",
> +			strerror(-err));
> +		return 100;
> +	}
>  #else
>  	/* liburing is unavailable, assume IO_URING is unsupported */
>  	return 1;
> -- 
> 2.43.0
> 
>