[PATCH v2] selftests/filesystems/mount-notify: fix unused unused result warning

[Chen Linxuan]

When running `make kselftest`, the following compilation warning was 
encountered:

mount-notify_test.c: In function ‘fanotify_rmdir’:
mount-notify_test.c:490:17: warning: ignoring return value of ‘chdir’ declared 
with attribute ‘warn_unused_result’ [-Wunused-result]
  490 |                 chdir("/");
      |                 ^~~~~~~~~~

Signed-off-by: Chen Linxuan <chenlinx...@uniontech.com>
---
Changes in v2:
- Apply changes suggested by Shuah Khan
- Link to v1: 
https://lore.kernel.org/all/20250610020758.2798787-2-chenlinx...@uniontech.com/
---
 .../filesystems/mount-notify/mount-notify_test.c  | 15 ++++++++++-----
 .../mount-notify/mount-notify_test_ns.c           | 15 ++++++++++-----
 2 files changed, 20 insertions(+), 10 deletions(-)

diff --git 
a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c 
b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
index 5a3b0ace1a88c..f8e0c6b06e2d9 100644
--- a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
+++ b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c
@@ -458,12 +458,17 @@ TEST_F(fanotify, rmdir)
        ASSERT_GE(ret, 0);
 
        if (ret == 0) {
-               chdir("/");
-               unshare(CLONE_NEWNS);
-               mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL);
-               umount2("/a", MNT_DETACH);
+               if (chdir("/"))
+                       exit(-1);
+               if (unshare(CLONE_NEWNS))
+                       exit(-1);
+               if (mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL))
+                       exit(-1);
+               if (umount2("/a", MNT_DETACH))
+                       exit(-1);
                // This triggers a detach in the other namespace
-               rmdir("/a");
+               if (rmdir("/a"))
+                       exit(-1);
                exit(0);
        }
        wait(NULL);
diff --git 
a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c 
b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c
index d91946e69591a..d6a6a7ee87028 100644
--- a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c
+++ b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c
@@ -486,12 +486,17 @@ TEST_F(fanotify, rmdir)
        ASSERT_GE(ret, 0);
 
        if (ret == 0) {
-               chdir("/");
-               unshare(CLONE_NEWNS);
-               mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL);
-               umount2("/a", MNT_DETACH);
+               if (chdir("/"))
+                       exit(-1);
+               if (unshare(CLONE_NEWNS))
+                       exit(-1);
+               if (mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL))
+                       exit(-1);
+               if (umount2("/a", MNT_DETACH))
+                       exit(-1);
                // This triggers a detach in the other namespace
-               rmdir("/a");
+               if (rmdir("/a"))
+                       exit(-1);
                exit(0);
        }
        wait(NULL);
-- 
2.43.0