Re: [PATCH blktests v2 1/2] common/null_blk: introduce _have_null_blk_feature

[Bart Van Assche <bvanassche@acm.org>]

On 1/9/24 02:44, Shin'ichiro Kawasaki wrote:
> Introduce a helper function _have_null_blk_feature which checks
> /sys/kernel/config/features. It allows test cases to adapt to null_blk
> feature support status.
> 
> Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
> ---
>   common/null_blk | 15 +++++++++++++++
>   1 file changed, 15 insertions(+)
> 
> diff --git a/common/null_blk b/common/null_blk
> index 91b78d4..164125d 100644
> --- a/common/null_blk
> +++ b/common/null_blk
> @@ -10,6 +10,21 @@ _have_null_blk() {
>   	_have_driver null_blk
>   }
>   
> +_have_null_blk_feature() {
> +	# Ensure that null_blk driver is built-in or loaded
> +	if ! [[ -d /sys/module/null_blk ]]; then
> +		if ! modprobe -q null_blk; then
> +			return 1
> +		fi
> +		if [[ ! "${MODULES_TO_UNLOAD[*]}" =~ null_blk ]]; then
> +			MODULES_TO_UNLOAD+=(null_blk)
> +		fi
> +	fi
> +
> +	# Check that null_blk has the specified feature
> +	grep -qe "$1" /sys/kernel/config/nullb/features
> +}
> +
>   _remove_null_blk_devices() {
>   	if [[ -d /sys/kernel/config/nullb ]]; then
>   		find /sys/kernel/config/nullb -mindepth 1 -maxdepth 1 \

Shouldn't _have_null_blk_feature() unload the null_blk kernel module if it
loads that kernel module? That will allow to simplify the next patch in this
series.

Thanks,

Bart.