mm: update uffd-stress to handle EINVAL for unset config features

Conflicts: Missing a number of commits that add new test cases.

commit a47a7af
Author: Audra Mitchell <audra@redhat.com>
Date:   Wed Jun 26 09:05:12 2024 -0400

    mm: update uffd-stress to handle EINVAL for unset config features

    Now that we have updated userfaultfd_api to correctly return EINVAL 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.

    Link: https://lkml.kernel.org/r/20240626130513.120193-2-audra@redhat.com
    Signed-off-by: Audra Mitchell <audra@redhat.com>
    Cc: Al Viro <viro@zeniv.linux.org.uk>
    Cc: Andrea Arcangeli <aarcange@redhat.com>
    Cc: Christian Brauner <brauner@kernel.org>
    Cc: Jan Kara <jack@suse.cz>
    Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
    Cc: Peter Xu <peterx@redhat.com>
    Cc: Rafael Aquini <raquini@redhat.com>
    Cc: Shaohua Li <shli@fb.com>
    Cc: Shuah Khan <shuah@kernel.org>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

JIRA: https://issues.redhat.com/browse/RHEL-39306
Signed-off-by: Nico Pache <npache@redhat.com>

Author: PacheNico

tools/testing/selftests/mm/uffd-stress.c

@@ -37,6 +37,7 @@
 #include "uffd-common.h"
 
 #ifdef __NR_userfaultfd
+uint64_t features;
 
 #define BOUNCE_RANDOM		(1<<0)
 #define BOUNCE_RACINGFAULTS	(1<<1)
@@ -249,8 +250,12 @@ 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;
 
-	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))
@@ -382,8 +387,6 @@ 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)
@@ -406,8 +409,8 @@ 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);