| Message ID | 20220502224942.995427-1-jsavitz@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | selftests: clarify common error when running gup_test | expand |
On Mon, 2 May 2022 18:49:42 -0400 Joel Savitz <jsavitz@redhat.com> wrote: > > 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. > > --- 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); > } > Sidhartha did a similar thing: https://lkml.kernel.org/r/20220405214809.3351223-1-sidhartha.kumar@oracle.com (Which is now in mm-stable at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm) Although in retroreview, it should have printed that to stderr rather than to stdout.
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); }
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@redhat.com> --- tools/testing/selftests/vm/gup_test.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)