[PATCH v3 2/4] userfaultfd: selftest: Skip test if userfaultfd() syscall not supported

Thiago Jung Bauermann
2018-08-28T17:26:37Z

Since there's no point in doing anything in this case, immediately exit the
process.

And take the opportunity to improve the error message.

Before:

# ./userfaultfd shmem 10 10
nr_pages: 160, nr_pages_per_cpu: 40
userfaultfd syscall not available in this kernel
# echo $?
1

After:

# ./userfaultfd shmem 10 10
nr_pages: 160, nr_pages_per_cpu: 40
userfaultfd syscall not available in this kernel: Function not implemented
# echo $?
4

Suggested-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Acked-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
---
tools/testing/selftests/vm/userfaultfd.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c
index e4099afe7557..d728bd1cb33c 100644
--- a/tools/testing/selftests/vm/userfaultfd.c
+++ b/tools/testing/selftests/vm/userfaultfd.c
@@ -636,9 +636,11 @@ static int userfaultfd_open(int features)

uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
if (uffd < 0) {
- fprintf(stderr,
- "userfaultfd syscall not available in this kernel\n");
- return 1;
+ int errnum = errno;
+
+ perror("userfaultfd syscall not available in this kernel");
+
+ exit(errnum == ENOSYS ? KSFT_SKIP : 1);
}
uffd_flags = fcntl(uffd, F_GETFD, NULL);