mm/thp: use conventional format for boolean attributes

The conventional format for boolean attributes in sysfs is numeric ("0" or
"1" followed by new-line).  Any boolean attribute can then be read and
written using a generic function.  Using the strings "yes [no]", "[yes]
no" (read), "yes" and "no" (write) will frustrate this.

[[email protected]: use kstrtoul()]
[[email protected]: test_bit() doesn't return 1/0, per Neil]
Signed-off-by: Ben Hutchings <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Hugh Dickins <[email protected]>
Tested-by: David Rientjes <[email protected]>
Cc: NeilBrown <[email protected]>
Cc: <[email protected]> 	[2.6.38.x]
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

mm/huge_memory.c

@@ -244,24 +244,28 @@ static ssize_t single_flag_show(struct kobject *kobj,
 				struct kobj_attribute *attr, char *buf,
 				enum transparent_hugepage_flag flag)
 {
-	if (test_bit(flag, &transparent_hugepage_flags))
-		return sprintf(buf, "[yes] no\n");
-	else
-		return sprintf(buf, "yes [no]\n");
+	return sprintf(buf, "%d\n",
+		       !!test_bit(flag, &transparent_hugepage_flags));
 }
+
 static ssize_t single_flag_store(struct kobject *kobj,
 				 struct kobj_attribute *attr,
 				 const char *buf, size_t count,
 				 enum transparent_hugepage_flag flag)
 {
-	if (!memcmp("yes", buf,
-		    min(sizeof("yes")-1, count))) {
+	unsigned long value;
+	int ret;
+
+	ret = kstrtoul(buf, 10, &value);
+	if (ret < 0)
+		return ret;
+	if (value > 1)
+		return -EINVAL;
+
+	if (value)
 		set_bit(flag, &transparent_hugepage_flags);
-	} else if (!memcmp("no", buf,
-			   min(sizeof("no")-1, count))) {
+	else
 		clear_bit(flag, &transparent_hugepage_flags);
-	} else
-		return -EINVAL;
 
 	return count;
 }