[PATCH 3/3] mm: Rework setup_transparent_hugepage()

[PATCH 3/3] mm: Rework setup_transparent_hugepage()

[Gavin Shan]

This reworks setup_transparent_hugepage() to used the declared arrays
(enabled_{strings,bits}[]).

Signed-off-by: Gavin Shan <gshan@redhat.com>
---
 mm/huge_memory.c | 49 ++++++++++++++++++++++++------------------------
 1 file changed, 24 insertions(+), 25 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 26b47ce8ea17..228349f4f937 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -159,7 +159,6 @@ static struct shrinker huge_zero_page_shrinker = {
 	.seeks = DEFAULT_SEEKS,
 };
 
-#ifdef CONFIG_SYSFS
 static const char * const enabled_strings[] = {
 	"always", "madvise", "never"
 };
@@ -169,6 +168,7 @@ static unsigned int enabled_bits[] = {
 	UINT_MAX
 };
 
+#ifdef CONFIG_SYSFS
 static ssize_t enabled_show(struct kobject *kobj,
 			    struct kobj_attribute *attr, char *buf)
 {
@@ -495,32 +495,31 @@ subsys_initcall(hugepage_init);
 
 static int __init setup_transparent_hugepage(char *str)
 {
-	int ret = 0;
+	int i;
+
 	if (!str)
-		goto out;
-	if (!strcmp(str, "always")) {
-		set_bit(TRANSPARENT_HUGEPAGE_FLAG,
-			&transparent_hugepage_flags);
-		clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
-			  &transparent_hugepage_flags);
-		ret = 1;
-	} else if (!strcmp(str, "madvise")) {
-		clear_bit(TRANSPARENT_HUGEPAGE_FLAG,
-			  &transparent_hugepage_flags);
-		set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
-			&transparent_hugepage_flags);
-		ret = 1;
-	} else if (!strcmp(str, "never")) {
-		clear_bit(TRANSPARENT_HUGEPAGE_FLAG,
-			  &transparent_hugepage_flags);
-		clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
-			  &transparent_hugepage_flags);
-		ret = 1;
+		goto error;
+
+	for (i = 0; i < ARRAY_SIZE(enabled_strings); i++) {
+		if (!strcmp(str, enabled_strings[i]))
+			break;
 	}
-out:
-	if (!ret)
-		pr_warn("transparent_hugepage= cannot parse, ignored\n");
-	return ret;
+
+	if (i >= ARRAY_SIZE(enabled_strings))
+		goto error;
+
+	clear_bit(TRANSPARENT_HUGEPAGE_FLAG,
+		  &transparent_hugepage_flags);
+	clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
+		  &transparent_hugepage_flags);
+	if (enabled_bits[i] != UINT_MAX)
+		set_bit(enabled_bits[i], &transparent_hugepage_flags);
+
+	return 1;
+
+error:
+	pr_warn("transparent_hugepage= cannot parse, ignored\n");
+	return 0;
 }
 __setup("transparent_hugepage=", setup_transparent_hugepage);
 
-- 
2.23.0