selftests/mm: use generic read_sysfs in thuge-gen test

As generic read_sysfs is available in vm_utils, let's use is in thuge-gen
test.

Link: https://lkml.kernel.org/r/20250611100106.1331197-1-pulehui@huaweicloud.com
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 10 insertions, 28 deletions

diff --git a/tools/testing/selftests/mm/thuge-gen.c b/tools/testing/selftests/mm/thuge-gen.c
index 95b6f043a3cb..8e2b08dc5762 100644
--- a/tools/testing/selftests/mm/thuge-gen.c
+++ b/tools/testing/selftests/mm/thuge-gen.c
@@ -77,40 +77,20 @@ void show(unsigned long ps)
 	system(buf);
 }
 
-unsigned long thuge_read_sysfs(int warn, char *fmt, ...)
+unsigned long read_free(unsigned long ps)
 {
-	char *line = NULL;
-	size_t linelen = 0;
-	char buf[100];
-	FILE *f;
-	va_list ap;
 	unsigned long val = 0;
+	char buf[100];
 
-	va_start(ap, fmt);
-	vsnprintf(buf, sizeof buf, fmt, ap);
-	va_end(ap);
+	snprintf(buf, sizeof(buf),
+		 "/sys/kernel/mm/hugepages/hugepages-%lukB/free_hugepages",
+		 ps >> 10);
+	if (read_sysfs(buf, &val) && ps != getpagesize())
+		ksft_print_msg("missing %s\n", buf);
 
-	f = fopen(buf, "r");
-	if (!f) {
-		if (warn)
-			ksft_print_msg("missing %s\n", buf);
-		return 0;
-	}
-	if (getline(&line, &linelen, f) > 0) {
-		sscanf(line, "%lu", &val);
-	}
-	fclose(f);
-	free(line);
 	return val;
 }
 
-unsigned long read_free(unsigned long ps)
-{
-	return thuge_read_sysfs(ps != getpagesize(),
-			  "/sys/kernel/mm/hugepages/hugepages-%lukB/free_hugepages",
-			  ps >> 10);
-}
-
 void test_mmap(unsigned long size, unsigned flags)
 {
 	char *map;
@@ -173,6 +153,7 @@ void test_shmget(unsigned long size, unsigned flags)
 void find_pagesizes(void)
 {
 	unsigned long largest = getpagesize();
+	unsigned long shmmax_val = 0;
 	int i;
 	glob_t g;
 
@@ -195,7 +176,8 @@ void find_pagesizes(void)
 	}
 	globfree(&g);
 
-	if (thuge_read_sysfs(0, "/proc/sys/kernel/shmmax") < NUM_PAGES * largest)
+	read_sysfs("/proc/sys/kernel/shmmax", &shmmax_val);
+	if (shmmax_val < NUM_PAGES * largest)
 		ksft_exit_fail_msg("Please do echo %lu > /proc/sys/kernel/shmmax",
 				   largest * NUM_PAGES);