From 17de1e559cf1eb01d5d90afd3064d5a280060f6f Mon Sep 17 00:00:00 2001
From: Joel Savitz <jsavitz@redhat.com>
Date: Mon, 9 May 2022 18:20:47 -0700
Subject: [PATCH] selftests: clarify common error when running gup_test
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.
Link: https://lkml.kernel.org/r/20220502224942.995427-1-jsavitz@redhat.com
Signed-off-by: Joel Savitz <jsavitz@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
tools/testing/selftests/vm/gup_test.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/tools/testing/selftests/vm/gup_test.c b/tools/testing/selftests/vm/gup_test.c
index 593262555e18c..6bb36ca71cb50 100644
--- a/tools/testing/selftests/vm/gup_test.c
+++ b/tools/testing/selftests/vm/gup_test.c
@@ -21,6 +21,8 @@
#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;
--
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