selftets/damon: prepare for monitor_on file renaming

Following change will rename 'monitor_on' DAMON debugfs file to
'monitor_on_DEPRECATED', to make the deprecation unignorable in runtime. 
Since it could make DAMON selftests fail and disturb future bisects,
update DAMON selftests to support the change.

Link: https://lkml.kernel.org/r/20240130013549.89538-7-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Alex Shi <alexs@kernel.org>
Cc: Hu Haowen <2023002089@link.tyut.edu.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

tools/testing/selftests/damon/_chk_dependency.sh

@@ -18,7 +18,14 @@ then
 	exit $ksft_skip
 fi
 
-for f in attrs target_ids monitor_on
+if [ -f "$DBGFS/monitor_on_DEPRECATED" ]
+then
+	monitor_on_file="monitor_on_DEPRECATED"
+else
+	monitor_on_file="monitor_on"
+fi
+
+for f in attrs target_ids "$monitor_on_file"
 do
 	if [ ! -f "$DBGFS/$f" ]
 	then
@@ -28,7 +35,7 @@ do
 done
 
 permission_error="Operation not permitted"
-for f in attrs target_ids monitor_on
+for f in attrs target_ids "$monitor_on_file"
 do
 	status=$( cat "$DBGFS/$f" 2>&1 )
 	if [ "${status#*$permission_error}" != "$status" ]; then

tools/testing/selftests/damon/_debugfs_common.sh

@@ -45,6 +45,13 @@ test_content() {
 source ./_chk_dependency.sh
 
 damon_onoff="$DBGFS/monitor_on"
+if [ -f "$DBGFS/monitor_on_DEPRECATED" ]
+then
+	damon_onoff="$DBGFS/monitor_on_DEPRECATED"
+else
+	damon_onoff="$DBGFS/monitor_on"
+fi
+
 if [ $(cat "$damon_onoff") = "on" ]
 then
 	echo "monitoring is on"

tools/testing/selftests/damon/debugfs_empty_targets.sh

@@ -8,6 +8,14 @@ source _debugfs_common.sh
 
 orig_target_ids=$(cat "$DBGFS/target_ids")
 echo "" > "$DBGFS/target_ids"
-orig_monitor_on=$(cat "$DBGFS/monitor_on")
-test_write_fail "$DBGFS/monitor_on" "on" "orig_monitor_on" "empty target ids"
+
+if [ -f "$DBGFS/monitor_on_DEPRECATED" ]
+then
+	monitor_on_file="$DBGFS/monitor_on_DEPRECATED"
+else
+	monitor_on_file="$DBGFS/monitor_on"
+fi
+
+orig_monitor_on=$(cat "$monitor_on_file")
+test_write_fail "$monitor_on_file" "on" "orig_monitor_on" "empty target ids"
 echo "$orig_target_ids" > "$DBGFS/target_ids"