Re: [PATCH v4 1/2] blktests: replace module removal with patient module removal

[Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>]

On Nov 26, 2025 / 09:11, Luis Chamberlain wrote:
[...]
> diff --git a/common/rc b/common/rc
> index ea92970..556581f 100644
> --- a/common/rc
> +++ b/common/rc
[...]
> +# Tries to wait patiently to remove a module by ensuring first
> +# the refcnt is 0 and then trying to remove the module over and over
> +# again within the time allowed. The timeout is configurable per test, just set
> +# MODPROBE_PATIENT_RM_TIMEOUT_SECONDS prior to calling this function.
> +# This applies to both cases where kmod supports the patient module remover
> +# (modprobe --wait) and where it does not.
> +#
> +# If your version of kmod supports modprobe --wait, we use that instead.
> +# Otherwise we have to implement a patient module remover ourselves.
> +_patient_rmmod()
> +{
> +	local module=$1
> +	local max_tries_max=$MODPROBE_PATIENT_RM_TIMEOUT_SECONDS
> +	local max_tries=0
> +	local mod_ret=0
> +	local refcnt_is_zero=0
> +	# Since we are looking for a directory we must adopt the
> +	# specific directory used by scripts/Makefile.lib for
> +	# KBUILD_MODNAME
> +	local module_sys=${module//-/_}
> +
> +	# Check if module is built-in or not loaded
> +	if [[ ! -d "/sys/module/$module_sys" ]]; then
> +		return 0
> +	fi
> +
> +	# Check if this is a built-in module (no refcnt file means built-in)
> +	if [[ ! -f "/sys/module/$module_sys/refcnt" ]]; then
> +		return 0
> +	fi
> +
> +	if [[ -n $MODPROBE_HAS_WAIT ]]; then
> +		local timeout_ms=$((MODPROBE_PATIENT_RM_TIMEOUT_SECONDS * 1000))
> +		modprobe -r --wait="${timeout_ms}" "$module"

While I evaluated this patch, I noticed that the modprobe command above can
return zero status code, even when it fails to remove the target module. I will
add a follow-up patch to the v5 series to check the reference count even when
the command above success to catch such cases.

Also, I will replace the short option -r with the long option --remove for
script readability and stability.

> +		mod_ret=$?
> +		if [[ $mod_ret -ne 0 ]]; then
> +			echo "kmod patient module removal for $module timed out waiting for refcnt to become 0 using timeout of $max_tries_max returned $mod_ret"
> +		fi
> +		return $mod_ret
> +	fi