+ selftests-mm-move-read_file-read_num-and-write_num-to-vm_util.patch added to mm-new branch

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

The patch titled
     Subject: selftests/mm: move read_file(), read_num() and write_num() to vm_util
has been added to the -mm mm-new branch.  Its filename is
     selftests-mm-move-read_file-read_num-and-write_num-to-vm_util.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-mm-move-read_file-read_num-and-write_num-to-vm_util.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
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

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and is updated there most days

------------------------------------------------------
From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
Subject: selftests/mm: move read_file(), read_num() and write_num() to vm_util
Date: Mon, 11 May 2026 19:28:13 +0300

These are useful helpers for writing and reading sysfs and proc files.

Make them available to the tests that don't use thp_settings.

While on it make write_num() use "%lu" instead of "%ld" to match 'unsigned
long num' argument type.

Link: https://lore.kernel.org/20260511162840.375890-30-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 tools/testing/selftests/mm/hugepage_settings.c |   41 ---------------
 tools/testing/selftests/mm/hugepage_settings.h |    4 -
 tools/testing/selftests/mm/vm_util.c           |   39 ++++++++++++++
 tools/testing/selftests/mm/vm_util.h           |    3 +
 4 files changed, 42 insertions(+), 45 deletions(-)

--- a/tools/testing/selftests/mm/hugepage_settings.c~selftests-mm-move-read_file-read_num-and-write_num-to-vm_util
+++ a/tools/testing/selftests/mm/hugepage_settings.c
@@ -48,47 +48,6 @@ static const char * const shmem_enabled_
 	NULL
 };
 
-int read_file(const char *path, char *buf, size_t buflen)
-{
-	int fd;
-	ssize_t numread;
-
-	fd = open(path, O_RDONLY);
-	if (fd == -1)
-		return 0;
-
-	numread = read(fd, buf, buflen - 1);
-	if (numread < 1) {
-		close(fd);
-		return 0;
-	}
-
-	buf[numread] = '\0';
-	close(fd);
-
-	return (unsigned int) numread;
-}
-
-unsigned long read_num(const char *path)
-{
-	char buf[21];
-
-	if (read_file(path, buf, sizeof(buf)) < 0) {
-		perror("read_file()");
-		exit(EXIT_FAILURE);
-	}
-
-	return strtoul(buf, NULL, 10);
-}
-
-void write_num(const char *path, unsigned long num)
-{
-	char buf[21];
-
-	sprintf(buf, "%ld", num);
-	write_file(path, buf, strlen(buf) + 1);
-}
-
 int thp_read_string(const char *name, const char * const strings[])
 {
 	char path[PATH_MAX];
--- a/tools/testing/selftests/mm/hugepage_settings.h~selftests-mm-move-read_file-read_num-and-write_num-to-vm_util
+++ a/tools/testing/selftests/mm/hugepage_settings.h
@@ -66,10 +66,6 @@ struct thp_settings {
 	struct shmem_hugepages_settings shmem_hugepages[NR_ORDERS];
 };
 
-int read_file(const char *path, char *buf, size_t buflen);
-unsigned long read_num(const char *path);
-void write_num(const char *path, unsigned long num);
-
 int thp_read_string(const char *name, const char * const strings[]);
 void thp_write_string(const char *name, const char *val);
 unsigned long thp_read_num(const char *name);
--- a/tools/testing/selftests/mm/vm_util.c~selftests-mm-move-read_file-read_num-and-write_num-to-vm_util
+++ a/tools/testing/selftests/mm/vm_util.c
@@ -698,6 +698,27 @@ int unpoison_memory(unsigned long pfn)
 	return ret > 0 ? 0 : -errno;
 }
 
+int read_file(const char *path, char *buf, size_t buflen)
+{
+	int fd;
+	ssize_t numread;
+
+	fd = open(path, O_RDONLY);
+	if (fd == -1)
+		return 0;
+
+	numread = read(fd, buf, buflen - 1);
+	if (numread < 1) {
+		close(fd);
+		return 0;
+	}
+
+	buf[numread] = '\0';
+	close(fd);
+
+	return (unsigned int) numread;
+}
+
 void write_file(const char *path, const char *buf, size_t buflen)
 {
 	int fd, saved_errno;
@@ -721,3 +742,21 @@ void write_file(const char *path, const
 		ksft_exit_fail_msg("%s write(%.*s) is truncated, expected %zu bytes, got %zd bytes\n",
 				path, (int)(buflen - 1), buf, buflen - 1, numwritten);
 }
+
+unsigned long read_num(const char *path)
+{
+	char buf[21];
+
+	if (read_file(path, buf, sizeof(buf)) < 0)
+		ksft_exit_fail_perror("read_file()");
+
+	return strtoul(buf, NULL, 10);
+}
+
+void write_num(const char *path, unsigned long num)
+{
+	char buf[21];
+
+	sprintf(buf, "%lu", num);
+	write_file(path, buf, strlen(buf) + 1);
+}
--- a/tools/testing/selftests/mm/vm_util.h~selftests-mm-move-read_file-read_num-and-write_num-to-vm_util
+++ a/tools/testing/selftests/mm/vm_util.h
@@ -165,3 +165,6 @@ int unpoison_memory(unsigned long pfn);
 #define PAGEMAP_PFN(ent)	((ent) & ((1ull << 55) - 1))
 
 void write_file(const char *path, const char *buf, size_t buflen);
+int read_file(const char *path, char *buf, size_t buflen);
+unsigned long read_num(const char *path);
+void write_num(const char *path, unsigned long num);
_

Patches currently in -mm which might be from rppt@kernel.org are

maintainers-add-tree-for-kdump-and-kexec.patch
maintainers-add-kexec-list-to-live-update-entry.patch
sh-fix-fallout-from-zero_page-consolidation.patch
selftests-mm-hugetlb-read-hwpoison-add-sigbus-handler.patch
selftests-mm-migration-dont-assume-huge-page-is-twomeg.patch
selftests-mm-migration-make-nthreads-represent-number-of-working-threads.patch
selftests-mm-migration-properly-cleanup-forked-processes.patch
selftests-mm-run_vmtestssh-dont-gate-thp-and-ksm-tests-on-have_hugepages.patch
selftests-mm-merge-map_hugetlb-into-hugepage-mmap.patch
selftests-mm-rename-hugepage-tests-to-hugetlb.patch
selftests-mm-hugetlb-shm-use-kselftest-framework.patch
selftests-mm-hugetlb-vmemmap-use-kselftest-framework.patch
selftests-mm-hugetlb-madvise-use-kselftest-framework.patch
selftests-mm-hugetlb_madv_vs_map-use-kselftest-framework.patch
selftests-mm-hugetlb-read-hwpoison-use-kselftest-framework.patch
selftests-mm-khugepaged-group-tests-in-an-array.patch
selftests-mm-khugepaged-use-ksefltest-framework.patch
selftests-mm-ksm_tests-use-kselftest-framework.patch
selftests-mm-protection_keys-use-descriptive-test-names-in-the-output.patch
selftests-mm-protection_keys-use-kselftest-framework.patch
selftests-mm-uffd-common-use-kselftest-framework.patch
selftests-mm-uffd-stress-use-kselftest-framework.patch
selftests-mm-uffd-unit-tests-use-kselftest-framework.patch
selftests-mm-va_high_addr_switch-use-kselftest-framework.patch
selftests-mm-add-atexit-and-signal-handlers-to-thp_settings.patch
selftests-mm-rename-thp_settings-to-hugepage_settings.patch
selftests-mm-move-hugetlb-helpers-to-hugepage_settings.patch
selftests-mm-hugepage_settings-use-unsigned-long-in-detect_hugetlb_page_size.patch
selftests-mm-hugepage_settings-add-apis-to-get-and-set-nr_hugepages.patch
selftests-mm-hugepage_settings-rename-and-rework-get_free_hugepages.patch
selftests-mm-hugepage_settings-add-apis-for-hugetlb-setup-and-teardown.patch
selftests-mm-move-read_file-read_num-and-write_num-to-vm_util.patch
selftests-mm-vm_util-add-helpers-to-set-and-restore-shm-limits.patch
selftests-mm-compaction_test-use-hugetlb-helpers.patch
selftests-mm-cow-add-setup-of-hugetlb-pages.patch
selftests-mm-gup_longterm-add-setup-of-hugetlb-pages.patch
selftests-mm-gup_test-add-setup-of-hugetlb-pages.patch
selftests-mm-hmm-tests-add-setup-of-hugetlb-pages.patch
selftests-mm-hugepage_dio-add-setup-of-hugetlb-pages.patch
selftests-mm-hugetlb_fault_after_madv-add-setup-of-hugetlb-pages.patch
selftests-mm-hugetlb-madvise-add-setup-of-hugetlb-pages.patch
selftests-mm-hugetlb_madv_vs_map-add-setup-of-hugetlb-pages.patch
selftests-mm-hugetlb-mmap-add-setup-of-hugetlb-pages.patch
selftests-mm-hugetlb-mremap-add-setup-of-hugetlb-pages.patch
selftests-mm-hugetlb-shm-add-setup-of-hugetlb-pages.patch
selftests-mm-hugetlb-soft-offline-add-setup-of-hugetlb-pages.patch
selftests-mm-hugetlb-vmemmap-add-setup-of-hugetlb-pages.patch
selftests-mm-migration-add-setup-of-hugetlb-pages.patch
selftests-mm-pagemap_ioctl-add-setup-of-hugetlb-pages.patch
selftests-mm-protection_keys-use-library-code-for-hugetlb-setup.patch
selftests-mm-thuge-gen-add-setup-of-hugetlb-pages.patch
selftests-mm-uffd-stress-use-hugetlb_save-and-alloc-huge-pages.patch
selftests-mm-uffd-unit-tests-add-setup-of-hugetlb-pages.patch
selftests-mm-uffd-wp-mremap-add-setup-of-hugetlb-pages.patch
selftests-mm-va_high_addr_switch-add-setup-of-hugetlb-pages.patch
selftests-mm-va_high_addr_switchsh-drop-huge-pages-setup.patch
selftests-mm-run_vmtestssh-free-memory-if-available-memory-is-low.patch
selftests-mm-run_vmtestssh-drop-detection-and-setup-of-hugetlb.patch