[PATCH v2 2/3] Update uffd-stress to handle EINVAL for unset config features

[Audra Mitchell <audra@redhat.com>]

Now that we have updated userfaultfd_api to correctly return
EIVAL when a feature is requested but not available, let's fix
the uffd-stress test to only set the UFFD_FEATURE_WP_UNPOPULATED
feature when the config is set. In addition, still run the test if
the CONFIG_PTE_MARKER_UFFD_WP is not set, just dont use the corresponding
UFFD_FEATURE_WP_UNPOPULATED feature.

Signed-off-by: Audra Mitchell <audra@redhat.com>
---
 tools/testing/selftests/mm/uffd-stress.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/tools/testing/selftests/mm/uffd-stress.c b/tools/testing/selftests/mm/uffd-stress.c
index f78bab0f3d45..b9b6d858eab8 100644
--- a/tools/testing/selftests/mm/uffd-stress.c
+++ b/tools/testing/selftests/mm/uffd-stress.c
@@ -38,6 +38,8 @@
 
 #ifdef __NR_userfaultfd
 
+uint64_t features;
+
 #define BOUNCE_RANDOM		(1<<0)
 #define BOUNCE_RACINGFAULTS	(1<<1)
 #define BOUNCE_VERIFY		(1<<2)
@@ -247,10 +249,14 @@ static int userfaultfd_stress(void)
 	unsigned long nr;
 	struct uffd_args args[nr_cpus];
 	uint64_t mem_size = nr_pages * page_size;
+	int flags = 0;
 
 	memset(args, 0, sizeof(struct uffd_args) * nr_cpus);
 
-	if (uffd_test_ctx_init(UFFD_FEATURE_WP_UNPOPULATED, NULL))
+	if (features & UFFD_FEATURE_WP_UNPOPULATED && test_type == TEST_ANON)
+		flags = UFFD_FEATURE_WP_UNPOPULATED;
+
+	if (uffd_test_ctx_init(flags, NULL))
 		err("context init failed");
 
 	if (posix_memalign(&area, page_size, page_size))
@@ -385,8 +391,6 @@ static void set_test_type(const char *type)
 
 static void parse_test_type_arg(const char *raw_type)
 {
-	uint64_t features = UFFD_API_FEATURES;
-
 	set_test_type(raw_type);
 
 	if (!test_type)
@@ -409,8 +413,8 @@ static void parse_test_type_arg(const char *raw_type)
 	 * feature.
 	 */
 
-	if (userfaultfd_open(&features))
-		err("Userfaultfd open failed");
+	if (uffd_get_features(&features))
+		err("failed to get available features");
 
 	test_uffdio_wp = test_uffdio_wp &&
 		(features & UFFD_FEATURE_PAGEFAULT_FLAG_WP);
-- 
2.44.0