[PATCH v2] selftests/mm: skip khugepaged file tests if mkfs.xfs is unavailable

[Jaeyeon Lee <jaeyeon.lee.dev@gmail.com>]

The XFS setup for ./khugepaged all:file checks that the kernel supports
XFS but not that mkfs.xfs is installed. When CONFIG_XFS_FS=y and
xfsprogs is missing, mkfs.xfs and mount both fail, but
SPLIT_HUGE_PAGE_TEST_XFS_PATH is assigned from mktemp -d and stays set.
The test then runs against plain tmpfs and six subtests fail.

The script already has a skip path for this test, but it never runs
because the path variable is always set. Assign
SPLIT_HUGE_PAGE_TEST_XFS_PATH only once mkfs.xfs and mount have both
succeeded, and remove the image and directory otherwise.

Suggested-by: Zi Yan <ziy@nvidia.com>
Assisted-by: LLM
Signed-off-by: Jaeyeon Lee <jaeyeon.lee.dev@gmail.com>
---
Changes in v2:
- Attempt mkfs.xfs and mount and fall back if either fails, rather than
  only checking whether mkfs.xfs exists (Zi Yan)
- Fix Assisted-by tag format

v1: https://lore.kernel.org/linux-mm/20260911124517.63714-1-jaeyeon.lee.dev@gmail.com/

 tools/testing/selftests/mm/run_vmtests.sh | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh
index d09f9f6a384e..b870d21c055a 100755
--- a/tools/testing/selftests/mm/run_vmtests.sh
+++ b/tools/testing/selftests/mm/run_vmtests.sh
@@ -417,11 +417,15 @@ if [ -z "${SPLIT_HUGE_PAGE_TEST_XFS_PATH}" ]; then
     if test_selected "thp"; then
 	if grep xfs /proc/filesystems &>/dev/null; then
 	    XFS_IMG=$(mktemp /tmp/xfs_img_XXXXXX)
-	    SPLIT_HUGE_PAGE_TEST_XFS_PATH=$(mktemp -d /tmp/xfs_dir_XXXXXX)
+	    XFS_DIR=$(mktemp -d /tmp/xfs_dir_XXXXXX)
 	    truncate -s 314572800 ${XFS_IMG}
-	    mkfs.xfs -q ${XFS_IMG}
-	    mount -o loop ${XFS_IMG} ${SPLIT_HUGE_PAGE_TEST_XFS_PATH}
-	    MOUNTED_XFS=1
+	    if mkfs.xfs -q ${XFS_IMG} && mount -t xfs -o loop ${XFS_IMG} ${XFS_DIR}; then
+	        SPLIT_HUGE_PAGE_TEST_XFS_PATH=${XFS_DIR}
+	        MOUNTED_XFS=1
+	    else
+	        rmdir ${XFS_DIR}
+	        rm -f ${XFS_IMG}
+	    fi
 	fi
     fi
 fi
-- 
2.43.0