Merge branch 'writeback-for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux

Pull writeback fixes from Fengguang Wu:
 "Three trivial writeback fixes"

* 'writeback-for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux:
  CPU hotplug, writeback: Don't call writeback_set_ratelimit() too often during hotplug
  writeback: correct comment for move_expired_inodes()
  backing-dev: use kstrto* in preference to simple_strtoul

fs/fs-writeback.c

@@ -249,7 +249,7 @@ static bool inode_dirtied_after(struct inode *inode, unsigned long t)
 }
 
 /*
- * Move expired (dirtied after work->older_than_this) dirty inodes from
+ * Move expired (dirtied before work->older_than_this) dirty inodes from
  * @delaying_queue to @dispatch_queue.
  */
 static int move_expired_inodes(struct list_head *delaying_queue,

mm/backing-dev.c

@@ -158,16 +158,16 @@ static ssize_t read_ahead_kb_store(struct device *dev,
 				  const char *buf, size_t count)
 {
 	struct backing_dev_info *bdi = dev_get_drvdata(dev);
-	char *end;
 	unsigned long read_ahead_kb;
-	ssize_t ret = -EINVAL;
+	ssize_t ret;
 
-	read_ahead_kb = simple_strtoul(buf, &end, 10);
-	if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) {
-		bdi->ra_pages = read_ahead_kb >> (PAGE_SHIFT - 10);
-		ret = count;
-	}
-	return ret;
+	ret = kstrtoul(buf, 10, &read_ahead_kb);
+	if (ret < 0)
+		return ret;
+
+	bdi->ra_pages = read_ahead_kb >> (PAGE_SHIFT - 10);
+
+	return count;
 }
 
 #define K(pages) ((pages) << (PAGE_SHIFT - 10))
@@ -187,16 +187,17 @@ static ssize_t min_ratio_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t count)
 {
 	struct backing_dev_info *bdi = dev_get_drvdata(dev);
-	char *end;
 	unsigned int ratio;
-	ssize_t ret = -EINVAL;
+	ssize_t ret;
+
+	ret = kstrtouint(buf, 10, &ratio);
+	if (ret < 0)
+		return ret;
+
+	ret = bdi_set_min_ratio(bdi, ratio);
+	if (!ret)
+		ret = count;
 
-	ratio = simple_strtoul(buf, &end, 10);
-	if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) {
-		ret = bdi_set_min_ratio(bdi, ratio);
-		if (!ret)
-			ret = count;
-	}
 	return ret;
 }
 BDI_SHOW(min_ratio, bdi->min_ratio)
@@ -205,16 +206,17 @@ static ssize_t max_ratio_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t count)
 {
 	struct backing_dev_info *bdi = dev_get_drvdata(dev);
-	char *end;
 	unsigned int ratio;
-	ssize_t ret = -EINVAL;
+	ssize_t ret;
+
+	ret = kstrtouint(buf, 10, &ratio);
+	if (ret < 0)
+		return ret;
+
+	ret = bdi_set_max_ratio(bdi, ratio);
+	if (!ret)
+		ret = count;
 
-	ratio = simple_strtoul(buf, &end, 10);
-	if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) {
-		ret = bdi_set_max_ratio(bdi, ratio);
-		if (!ret)
-			ret = count;
-	}
 	return ret;
 }
 BDI_SHOW(max_ratio, bdi->max_ratio)

mm/page-writeback.c

@@ -1602,10 +1602,18 @@ void writeback_set_ratelimit(void)
 }
 
 static int __cpuinit
-ratelimit_handler(struct notifier_block *self, unsigned long u, void *v)
+ratelimit_handler(struct notifier_block *self, unsigned long action,
+		  void *hcpu)
 {
-	writeback_set_ratelimit();
-	return NOTIFY_DONE;
+
+	switch (action & ~CPU_TASKS_FROZEN) {
+	case CPU_ONLINE:
+	case CPU_DEAD:
+		writeback_set_ratelimit();
+		return NOTIFY_OK;
+	default:
+		return NOTIFY_DONE;
+	}
 }
 
 static struct notifier_block __cpuinitdata ratelimit_nb = {