selftests/mm: move read_file(), read_num() and write_num() to vm_util

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>

diff --git a/tools/testing/selftests/mm/hugepage_settings.c b/tools/testing/selftests/mm/hugepage_settings.c
index 01a557f372d16ffaf0a8dae780a33adb509099d3..2eab2110ac6a4662e6f3db29526a4b443104a163 100644 (file)
--- a/tools/testing/selftests/mm/hugepage_settings.c
+++ b/tools/testing/selftests/mm/hugepage_settings.c
@@ -48,47 +48,6 @@ static const char * const shmem_enabled_strings[] = {
        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];

diff --git a/tools/testing/selftests/mm/hugepage_settings.h b/tools/testing/selftests/mm/hugepage_settings.h
index c07722b7f102d747bf94f4757c977d7b4907b4cf..726c73c43c05ba5cecd9052265a9cd9454473cbc 100644 (file)
--- a/tools/testing/selftests/mm/hugepage_settings.h
+++ b/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);

diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c
index 412e980cce9afdc22b84d1a76dd64812ae78d499..9256bbbe38ead834cf8d0eac085c73825da0ec69 100644 (file)
--- a/tools/testing/selftests/mm/vm_util.c
+++ b/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 char *buf, size_t buflen)
                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);
+}

diff --git a/tools/testing/selftests/mm/vm_util.h b/tools/testing/selftests/mm/vm_util.h
index 195bf2e26792a1e60f4b09a24c65eb386274b82b..5fc9707f6b9a1c9561dc1979606aa8996ca625ef 100644 (file)
--- a/tools/testing/selftests/mm/vm_util.h
+++ b/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);