+ selftests-mm-pagemap_scan-ioctl-add-pfn-zero-test-cases.patch added to mm-new branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: selftests/mm: pagemap_scan ioctl: add PFN ZERO test cases
has been added to the -mm mm-new branch.  Its filename is
     selftests-mm-pagemap_scan-ioctl-add-pfn-zero-test-cases.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-mm-pagemap_scan-ioctl-add-pfn-zero-test-cases.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
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------------------------------------------------------
From: Muhammad Usama Anjum <usama.anjum@collabora.com>
Subject: selftests/mm: pagemap_scan ioctl: add PFN ZERO test cases
Date: Mon, 30 Jun 2025 15:24:42 +0500

Add test cases to test the correctness of PFN ZERO flag of pagemap_scan
ioctl.  Test with normal pages backed memory and huge pages backed memory.

Link: https://lkml.kernel.org/r/20250630102443.137809-1-usama.anjum@collabora.com
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 tools/testing/selftests/mm/pagemap_ioctl.c |   57 ++++++++++++++++++-
 1 file changed, 56 insertions(+), 1 deletion(-)

--- a/tools/testing/selftests/mm/pagemap_ioctl.c~selftests-mm-pagemap_scan-ioctl-add-pfn-zero-test-cases
+++ a/tools/testing/selftests/mm/pagemap_ioctl.c
@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0
+
 #define _GNU_SOURCE
 #include <stdio.h>
 #include <fcntl.h>
@@ -1480,6 +1481,57 @@ static void transact_test(int page_size)
 			      extra_thread_faults);
 }
 
+void zeropfn_tests(void)
+{
+	unsigned long long mem_size;
+	struct page_region vec;
+	int i, ret;
+	char *mem;
+
+	/* Test with page backed memory */
+	mem_size = 10 * page_size;
+	mem = mmap(NULL, mem_size, PROT_READ, MAP_PRIVATE | MAP_ANON, -1, 0);
+	if (mem == MAP_FAILED)
+		ksft_exit_fail_msg("error nomem\n");
+
+	/* Touch each page to ensure it's mapped */
+	for (i = 0; i < mem_size; i += page_size)
+		(void)((volatile char *)mem)[i];
+
+	ret = pagemap_ioctl(mem, mem_size, &vec, 1, 0,
+			    (mem_size / page_size), PAGE_IS_PFNZERO, 0, 0, PAGE_IS_PFNZERO);
+	if (ret < 0)
+		ksft_exit_fail_msg("error %d %d %s\n", ret, errno, strerror(errno));
+
+	ksft_test_result(ret == 1 && LEN(vec) == (mem_size / page_size),
+			 "%s all pages must have PFNZERO set\n", __func__);
+
+	munmap(mem, mem_size);
+
+	/* Test with huge page */
+	mem_size = 10 * hpage_size;
+	mem = memalign(hpage_size, mem_size);
+	if (!mem)
+		ksft_exit_fail_msg("error nomem\n");
+
+	ret = madvise(mem, mem_size, MADV_HUGEPAGE);
+	if (ret)
+		ksft_exit_fail_msg("madvise failed %d %s\n", errno, strerror(errno));
+
+	for (i = 0; i < mem_size; i += hpage_size)
+		(void)((volatile char *)mem)[i];
+
+	ret = pagemap_ioctl(mem, mem_size, &vec, 1, 0,
+			    (mem_size / page_size), PAGE_IS_PFNZERO, 0, 0, PAGE_IS_PFNZERO);
+	if (ret < 0)
+		ksft_exit_fail_msg("error %d %d %s\n", ret, errno, strerror(errno));
+
+	ksft_test_result(ret == 1 && LEN(vec) == (mem_size / page_size),
+			 "%s all huge pages must have PFNZERO set\n", __func__);
+
+	free(mem);
+}
+
 int main(int __attribute__((unused)) argc, char *argv[])
 {
 	int shmid, buf_size, fd, i, ret;
@@ -1494,7 +1546,7 @@ int main(int __attribute__((unused)) arg
 	if (init_uffd())
 		ksft_exit_pass();
 
-	ksft_set_plan(115);
+	ksft_set_plan(117);
 
 	page_size = getpagesize();
 	hpage_size = read_pmd_pagesize();
@@ -1669,6 +1721,9 @@ int main(int __attribute__((unused)) arg
 	/* 16. Userfaultfd tests */
 	userfaultfd_tests();
 
+	/* 17. ZEROPFN tests */
+	zeropfn_tests();
+
 	close(pagemap_fd);
 	ksft_exit_pass();
 }
_

Patches currently in -mm which might be from usama.anjum@collabora.com are

selftests-mm-pagemap_scan-ioctl-add-pfn-zero-test-cases.patch