The gup_test binary will fail showing only the output of perror("open") in
the case that /sys/kernel/debug/gup_test is not found. This will almost
always be due to CONFIG_GUP_TEST not being set, which enables
compilation of a kernel that provides this file.
Add a short error message to clarify this failure and point the user to
the solution.
Signed-off-by: Joel Savitz <jsavitz@xxxxxxxxxx>
---
tools/testing/selftests/vm/gup_test.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/vm/gup_test.c b/tools/testing/selftests/vm/gup_test.c
index cda837a14736..ac4e804d47f0 100644
--- a/tools/testing/selftests/vm/gup_test.c
+++ b/tools/testing/selftests/vm/gup_test.c
@@ -18,6 +18,8 @@
#define FOLL_WRITE 0x01 /* check pte is writable */
#define FOLL_TOUCH 0x02 /* mark page accessed */
+#define GUP_TEST_FILE "/sys/kernel/debug/gup_test"
+
static unsigned long cmd = GUP_FAST_BENCHMARK;
static int gup_fd, repeats = 1;
static unsigned long size = 128 * MB;
@@ -204,9 +206,11 @@ int main(int argc, char **argv)
if (write)
gup.gup_flags |= FOLL_WRITE;
- gup_fd = open("/sys/kernel/debug/gup_test", O_RDWR);
+ gup_fd = open(GUP_TEST_FILE, O_RDWR);
if (gup_fd == -1) {
perror("open");
+ fprintf(stderr, "Unable to open %s: check that CONFIG_GUP_TEST=y\n",
+ GUP_TEST_FILE);
exit(1);
}
--
2.27.0
