[PATCH 2/2] selftests/mm: check that PAGEMAP_SCAN returns correct categories

[Andrei Vagin]

Right now, tests read page flags from /proc/pid/pagemap files. With this
change, tests will check that PAGEMAP_SCAN return correct information
too.

Reviewed-by: Muhammad Usama Anjum <usama.anjum@xxxxxxxxxxxxx>
Tested-by: Muhammad Usama Anjum <usama.anjum@xxxxxxxxxxxxx>
Signed-off-by: Andrei Vagin <avagin@xxxxxxxxxx>
---
 tools/testing/selftests/mm/vm_util.c | 53 ++++++++++++++++++++++++++--
 1 file changed, 50 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c
index 3082b40492dd..ec3478b96e4c 100644
--- a/tools/testing/selftests/mm/vm_util.c
+++ b/tools/testing/selftests/mm/vm_util.c
@@ -4,6 +4,7 @@
 #include <dirent.h>
 #include <sys/ioctl.h>
 #include <linux/userfaultfd.h>
+#include <linux/fs.h>
 #include <sys/syscall.h>
 #include <unistd.h>
 #include "../kselftest.h"
@@ -28,19 +29,65 @@ uint64_t pagemap_get_entry(int fd, char *start)
 	return entry;
 }
 
+static uint64_t pagemap_scan_get_categories(int fd, char *start)
+{
+	struct pm_scan_arg arg;
+	struct page_region r;
+	long ret;
+
+	arg.start = (uintptr_t)start;
+	arg.end = (uintptr_t)(start + psize());
+	arg.vec = (uintptr_t)&r;
+	arg.vec_len = 1;
+	arg.flags = 0;
+	arg.size = sizeof(struct pm_scan_arg);
+	arg.max_pages = 0;
+	arg.category_inverted = 0;
+	arg.category_mask = 0;
+	arg.category_anyof_mask = PAGE_IS_WPALLOWED | PAGE_IS_WRITTEN | PAGE_IS_FILE |
+				  PAGE_IS_PRESENT | PAGE_IS_SWAPPED | PAGE_IS_PFNZERO |
+				  PAGE_IS_HUGE | PAGE_IS_SOFT_DIRTY;
+	arg.return_mask = arg.category_anyof_mask;
+
+	ret = ioctl(fd, PAGEMAP_SCAN, &arg);
+	if (ret < 0)
+		ksft_exit_fail_msg("PAGEMAP_SCAN failed: %s\n", strerror(errno));
+	if (ret == 0)
+		return 0;
+	return r.categories;
+}
+
+static bool page_entry_is(int fd, char *start, char *desc,
+			  uint64_t pagemap_flags, uint64_t pagescan_flags)
+{
+	bool m, s;
+
+	m = pagemap_get_entry(fd, start) & pagemap_flags;
+	s = pagemap_scan_get_categories(fd, start) & pagescan_flags;
+	if (m == s)
+		return m;
+
+	ksft_exit_fail_msg(
+		"read and ioctl return unmatched results for %s: %d %d", desc, m, s);
+	return m;
+}
+
 bool pagemap_is_softdirty(int fd, char *start)
 {
-	return pagemap_get_entry(fd, start) & PM_SOFT_DIRTY;
+	return page_entry_is(fd, start, "soft-dirty",
+				PM_SOFT_DIRTY, PAGE_IS_SOFT_DIRTY);
 }
 
 bool pagemap_is_swapped(int fd, char *start)
 {
-	return pagemap_get_entry(fd, start) & PM_SWAP;
+	return page_entry_is(fd, start, "swap", PM_SWAP, PAGE_IS_SWAPPED);
 }
 
 bool pagemap_is_populated(int fd, char *start)
 {
-	return pagemap_get_entry(fd, start) & (PM_PRESENT | PM_SWAP);
+	return page_entry_is(fd, start, "populated",
+				PM_PRESENT | PM_SWAP,
+				PAGE_IS_PRESENT | PAGE_IS_SWAPPED);
 }
 
 unsigned long pagemap_get_pfn(int fd, char *start)
-- 
2.42.0.869.gea05f2083d-goog