writeback: add bg_threshold parameter to __bdi_update_bandwidth()

No behavior change.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 04cf3b9..2807656 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -675,7 +675,7 @@
 static void wb_update_bandwidth(struct bdi_writeback *wb,
 				unsigned long start_time)
 {
-	__bdi_update_bandwidth(wb->bdi, 0, 0, 0, 0, start_time);
+	__bdi_update_bandwidth(wb->bdi, 0, 0, 0, 0, 0, start_time);
 }
 
 /*
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index 2b8963f..ddb4652 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -143,6 +143,7 @@
 
 void __bdi_update_bandwidth(struct backing_dev_info *bdi,
 			    unsigned long thresh,
+			    unsigned long bg_thresh,
 			    unsigned long dirty,
 			    unsigned long bdi_thresh,
 			    unsigned long bdi_dirty,
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index c16ddd8..4b954c9 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -779,6 +779,7 @@
 
 void __bdi_update_bandwidth(struct backing_dev_info *bdi,
 			    unsigned long thresh,
+			    unsigned long bg_thresh,
 			    unsigned long dirty,
 			    unsigned long bdi_thresh,
 			    unsigned long bdi_dirty,
@@ -815,6 +816,7 @@
 
 static void bdi_update_bandwidth(struct backing_dev_info *bdi,
 				 unsigned long thresh,
+				 unsigned long bg_thresh,
 				 unsigned long dirty,
 				 unsigned long bdi_thresh,
 				 unsigned long bdi_dirty,
@@ -823,8 +825,8 @@
 	if (time_is_after_eq_jiffies(bdi->bw_time_stamp + BANDWIDTH_INTERVAL))
 		return;
 	spin_lock(&bdi->wb.list_lock);
-	__bdi_update_bandwidth(bdi, thresh, dirty, bdi_thresh, bdi_dirty,
-			       start_time);
+	__bdi_update_bandwidth(bdi, thresh, bg_thresh, dirty,
+			       bdi_thresh, bdi_dirty, start_time);
 	spin_unlock(&bdi->wb.list_lock);
 }
 
@@ -912,8 +914,9 @@
 		if (!bdi->dirty_exceeded)
 			bdi->dirty_exceeded = 1;
 
-		bdi_update_bandwidth(bdi, dirty_thresh, nr_dirty,
-				     bdi_thresh, bdi_dirty, start_time);
+		bdi_update_bandwidth(bdi, dirty_thresh, background_thresh,
+				     nr_dirty, bdi_thresh, bdi_dirty,
+				     start_time);
 
 		/* Note: nr_reclaimable denotes nr_dirty + nr_unstable.
 		 * Unstable writes are a feature of certain networked