[PATCH] selftests/mount: output error messages when mount test fail

[Zhang Zhen <zhenzhang.zhang-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>]

Without this patch, if /proc/self/uid_map is not exist,
the mount test case will fail and no any prompting.

After applied this patch, the case will prompt why it fail.
Just as follows:
root@kernel-host:/opt/kernel> make -C tools/testing/selftests TARGETS=mount run_tests
make: Entering directory `/opt/kernel/tools/testing/selftests'
for TARGET in mount; do \
                make -C $TARGET; \
        done;
make[1]: Entering directory `/opt/kernel/tools/testing/selftests/mount'
make[1]: Nothing to be done for `all'.
make[1]: Leaving directory `/opt/kernel/tools/testing/selftests/mount'
for TARGET in mount; do \
                make -C $TARGET run_tests; \
        done;
make[1]: Entering directory `/opt/kernel/tools/testing/selftests/mount'
ERROR: No /proc/self/uid_map exist
make[1]: Leaving directory `/opt/kernel/tools/testing/selftests/mount'
make: Leaving directory `/opt/kernel/tools/testing/selftests'

Signed-off-by: Zhang Zhen <zhenzhang.zhang-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
---
 tools/testing/selftests/mount/Makefile | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/mount/Makefile b/tools/testing/selftests/mount/Makefile
index a5b367f..b3266db 100644
--- a/tools/testing/selftests/mount/Makefile
+++ b/tools/testing/selftests/mount/Makefile
@@ -8,7 +8,12 @@ unprivileged-remount-test: unprivileged-remount-test.c
 include ../lib.mk

 TEST_PROGS := unprivileged-remount-test
-override RUN_TESTS := if [ -f /proc/self/uid_map ] ; then ./unprivileged-remount-test ; fi
+override RUN_TESTS :=  @if [ -f /proc/self/uid_map ] ; \
+			then	\
+				./unprivileged-remount-test ; \
+			else	\
+				echo "ERROR: No /proc/self/uid_map exist" ; \
+			fi
 override EMIT_TESTS := echo "$(RUN_TESTS)"

 clean:
-- 
1.8.5.5


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