#!/bin/bash
#
# Takes a list of modules and unloads them and all dependent modules.
# If a module cannot be unloaded (e.g. it's in use), an error is
# returned.
###############################################################################

# Unload all modules dependent on $1 (exclude removal of $1)
unload_dep_modules_exclusive() {
	local MODULE=$1
	local DEPS="$(lsmod | awk '($1 == "'$MODULE'") { print $4 }')"
	for SUBMOD in $(echo $DEPS | tr ',' ' '); do
		unload_dep_modules_inclusive $SUBMOD || return 1
	done
	return 0
}

# Unload all modules dependent on $1 (include removal of $1)
unload_dep_modules_inclusive() {
	local MODULE=$1

	# if $MODULE not loaded, return 0
	lsmod | egrep -q "^\<$MODULE\>" || return 0
	unload_dep_modules_exclusive $MODULE || return 1
	rmmod $MODULE || return 1
	return 0
}

modules="$@"

# To maintain backwards compatibility, ldiskfs and libcfs must be
# unloaded if no parameters are given, or if only the ldiskfs parameter
# is given. It's ugly, but is needed to emulate the prior functionality
if [ -z "$modules" ] || [ "$modules" = "ldiskfs" ]; then
	modules="ptlrpc lnet_selftest ldiskfs libcfs"
fi

if [ -f /sys/kernel/debug/kmemleak ] ; then
	cat /proc/modules >/tmp/kmemleak-modules-list.txt
	echo scan > /sys/kernel/debug/kmemleak
	cat /sys/kernel/debug/kmemleak > /tmp/kmemleak-before-unload.txt
	test -s /tmp/kmemleak-before-unload.txt && logger -t leak-pre -f /tmp/kmemleak-before-unload.txt
	rm /tmp/kmemleak-before-unload.txt
	# Clear everything here so that only new leaks show up
	# after module unload
	echo clear > /sys/kernel/debug/kmemleak
fi

for mod in $modules; do
	unload_dep_modules_inclusive $mod || exit 1
done

if [ -f /sys/kernel/debug/kmemleak ] ; then
	echo scan > /sys/kernel/debug/kmemleak
	cat /sys/kernel/debug/kmemleak > /tmp/kmemleak-after-unload.txt
	test -s /tmp/kmemleak-after-unload.txt && logger -t leak-mods -f /tmp/kmemleak-modules-list.txt && logger -t leak-post -f /tmp/kmemleak-after-unload.txt
	rm -f /tmp/kmemleak-after-unload.txt /tmp/kmemleak-modules-list.txt
fi

exit 0