selftests: zram: return Kselftest Skip code for skipped tests

BugLink: https://bugs.launchpad.net/bugs/1792377

[ Upstream commit 68581446 ]

When zram test is skipped because of unmet dependencies and/or
unsupported configuration, it exits with error which is treated as
a fail by the Kselftest framework. This leads to false negative result
even when the test could not be run.

Change it to return kselftest skip code when a test gets skipped to
clearly report that the test could not be run.

Kselftest framework SKIP code is 4 and the framework prints appropriate
messages to indicate that the test is skipped.
Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

tools/testing/selftests/zram/zram.sh

 #!/bin/bash
 TCID="zram.sh"
 
+# Kselftest framework requirement - SKIP code is 4.
+ksft_skip=4
+
 . ./zram_lib.sh
 
 run_zram () {
@@ -23,5 +26,5 @@ elif [ -b /dev/zram0 ]; then
 else
 	echo "$TCID : No zram.ko module or /dev/zram0 device file not found"
 	echo "$TCID : CONFIG_ZRAM is not set"
-	exit 1
+	exit $ksft_skip
 fi

tools/testing/selftests/zram/zram_lib.sh

@@ -18,6 +18,9 @@ MODULE=0
 dev_makeswap=-1
 dev_mounted=-1
 
+# Kselftest framework requirement - SKIP code is 4.
+ksft_skip=4
+
 trap INT
 
 check_prereqs()
@@ -27,7 +30,7 @@ check_prereqs()
 
 	if [ $uid -ne 0 ]; then
 		echo $msg must be run as root >&2
-		exit 0
+		exit $ksft_skip
 	fi
 }