xen-balloon: fix up sysfs issues

1. Set the class so it doesn't clash with the normal memory class
2. Fix up the sysfs show functions to match the new prototype
3. Clean up use of memparse

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: "viets@work.de" <viets@work.de>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

drivers/xen/balloon.c

@@ -60,7 +60,7 @@
 
 #define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10))
 
-#define BALLOON_CLASS_NAME "memory"
+#define BALLOON_CLASS_NAME "xen_memory"
 
 struct balloon_stats {
 	/* We aim for 'current allocation' == 'target allocation'. */
@@ -588,12 +588,13 @@ static void balloon_release_driver_page(struct page *page)
 }
 
 
-#define BALLOON_SHOW(name, format, args...)			\
-	static ssize_t show_##name(struct sys_device *dev,	\
-				   char *buf)			\
-	{							\
-		return sprintf(buf, format, ##args);		\
-	}							\
+#define BALLOON_SHOW(name, format, args...)				\
+	static ssize_t show_##name(struct sys_device *dev,		\
+				   struct sysdev_attribute *attr,	\
+				   char *buf)				\
+	{								\
+		return sprintf(buf, format, ##args);			\
+	}								\
 	static SYSDEV_ATTR(name, S_IRUGO, show_##name, NULL)
 
 BALLOON_SHOW(current_kb, "%lu\n", PAGES2KB(balloon_stats.current_pages));
@@ -604,7 +605,8 @@ BALLOON_SHOW(hard_limit_kb,
 	     (balloon_stats.hard_limit!=~0UL) ? PAGES2KB(balloon_stats.hard_limit) : 0);
 BALLOON_SHOW(driver_kb, "%lu\n", PAGES2KB(balloon_stats.driver_pages));
 
-static ssize_t show_target_kb(struct sys_device *dev, char *buf)
+static ssize_t show_target_kb(struct sys_device *dev, struct sysdev_attribute *attr,
+			      char *buf)
 {
 	return sprintf(buf, "%lu\n", PAGES2KB(balloon_stats.target_pages));
 }
@@ -614,19 +616,14 @@ static ssize_t store_target_kb(struct sys_device *dev,
 			       const char *buf,
 			       size_t count)
 {
-	char memstring[64], *endchar;
+	char *endchar;
 	unsigned long long target_bytes;
 
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
 
-	if (count <= 1)
-		return -EBADMSG; /* runt */
-	if (count > sizeof(memstring))
-		return -EFBIG;   /* too long */
-	strcpy(memstring, buf);
+	target_bytes = memparse(buf, &endchar);
 
-	target_bytes = memparse(memstring, &endchar);
 	balloon_set_new_target(target_bytes >> PAGE_SHIFT);
 
 	return count;