[PATCH v2 2/2] mm: huge_memory: refactor thpsize_shmem_enabled_show() with helper arrays

[ranxiaokai627]

From: Ran Xiaokai <ran.xiaokai@xxxxxxxxxx>

Replace the hardcoded if/else chain of test_bit() calls and string
literals in thpsize_shmem_enabled_show() with a loop over
huge_shmem_orders_by_mode[] and huge_shmem_enabled_mode_strings[] arrays.

This makes thpsize_shmem_enabled_show() consistent with
thpsize_shmem_enabled_store() and eliminates duplicated mode name strings.

Signed-off-by: Ran Xiaokai <ran.xiaokai@xxxxxxxxxx>
---
 mm/shmem.c | 36 +++++++++++++++++++++++-------------
 1 file changed, 23 insertions(+), 13 deletions(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index 60cb10854f11..086762e6de71 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -5553,20 +5553,30 @@ static ssize_t thpsize_shmem_enabled_show(struct kobject *kobj,
 					  struct kobj_attribute *attr, char *buf)
 {
 	int order = to_thpsize(kobj)->order;
-	const char *output;
-
-	if (test_bit(order, &huge_shmem_orders_always))
-		output = "[always] inherit within_size advise never";
-	else if (test_bit(order, &huge_shmem_orders_inherit))
-		output = "always [inherit] within_size advise never";
-	else if (test_bit(order, &huge_shmem_orders_within_size))
-		output = "always inherit [within_size] advise never";
-	else if (test_bit(order, &huge_shmem_orders_madvise))
-		output = "always inherit within_size [advise] never";
-	else
-		output = "always inherit within_size advise [never]";
+	int active = HUGE_SHMEM_ENABLED_NEVER;
+	int len = 0;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(huge_shmem_orders_by_mode); i++) {
+		if (test_bit(order, huge_shmem_orders_by_mode[i])) {
+			active = i;
+			break;
+		}
+	}
+
+	for (i = 0; i < ARRAY_SIZE(huge_shmem_enabled_mode_strings); i++) {
+		if (i == active)
+			len += sysfs_emit_at(buf, len, "[%s] ",
+						huge_shmem_enabled_mode_strings[i]);
+		else
+			len += sysfs_emit_at(buf, len, "%s ",
+						huge_shmem_enabled_mode_strings[i]);
+	}
+
+	/* Replace trailing space with newline */
+	buf[len - 1] = '\n';
 
-	return sysfs_emit(buf, "%s\n", output);
+	return len;
 }
 
 static ssize_t thpsize_shmem_enabled_store(struct kobject *kobj,
-- 
2.25.1