[PATCH v2] writeback: remove the unused function parameter

[Wang Long]

The parameter `struct bdi_writeback *wb` is not been used in the function
body. so we just remove it.

Signed-off-by: Wang Long <wanglong19@xxxxxxxxxxx>
---
 include/linux/backing-dev.h | 2 +-
 mm/page-writeback.c         | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 1662157..186a2e7 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -95,7 +95,7 @@ static inline s64 wb_stat_sum(struct bdi_writeback *wb, enum wb_stat_item item)
 /*
  * maximal error of a stat counter.
  */
-static inline unsigned long wb_stat_error(struct bdi_writeback *wb)
+static inline unsigned long wb_stat_error(void)
 {
 #ifdef CONFIG_SMP
 	return nr_cpu_ids * WB_STAT_BATCH;
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 0b9c5cb..9287466 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1543,7 +1543,7 @@ static inline void wb_dirty_limits(struct dirty_throttle_control *dtc)
 	 * actually dirty; with m+n sitting in the percpu
 	 * deltas.
 	 */
-	if (dtc->wb_thresh < 2 * wb_stat_error(wb)) {
+	if (dtc->wb_thresh < 2 * wb_stat_error()) {
 		wb_reclaimable = wb_stat_sum(wb, WB_RECLAIMABLE);
 		dtc->wb_dirty = wb_reclaimable + wb_stat_sum(wb, WB_WRITEBACK);
 	} else {
@@ -1802,7 +1802,7 @@ static void balance_dirty_pages(struct address_space *mapping,
 		 * more page. However wb_dirty has accounting errors.  So use
 		 * the larger and more IO friendly wb_stat_error.
 		 */
-		if (sdtc->wb_dirty <= wb_stat_error(wb))
+		if (sdtc->wb_dirty <= wb_stat_error())
 			break;
 
 		if (fatal_signal_pending(current))
-- 
1.8.3.1