writeback: separate starting of sync vs opportunistic writeback

bdi_start_writeback() is currently split into two paths, one for
WB_SYNC_NONE and one for WB_SYNC_ALL. Add bdi_sync_writeback()
for WB_SYNC_ALL writeback and let bdi_start_writeback() handle
only WB_SYNC_NONE.

Push down the writeback_control allocation and only accept the
parameters that make sense for each function. This cleans up
the API considerably.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

2 files changed, 3 insertions, 3 deletions

diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 859e797f4576..0ee33c2e6129 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -101,7 +101,7 @@ int bdi_register(struct backing_dev_info *bdi, struct device *parent,
                 const char *fmt, ...);
 int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev);
 void bdi_unregister(struct backing_dev_info *bdi);
-void bdi_start_writeback(struct writeback_control *wbc);
+void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages);
 int bdi_writeback_task(struct bdi_writeback *wb);
 int bdi_has_dirty_io(struct backing_dev_info *bdi);
 
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index 48a054e2b716..75cf58666ff9 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -68,8 +68,8 @@ struct writeback_control {
  */     
 struct bdi_writeback;
 int inode_wait(void *);
-long writeback_inodes_sb(struct super_block *);
-long sync_inodes_sb(struct super_block *);
+void writeback_inodes_sb(struct super_block *);
+void sync_inodes_sb(struct super_block *);
 void writeback_inodes_wbc(struct writeback_control *wbc);
 long wb_do_writeback(struct bdi_writeback *wb, int force_wait);
 void wakeup_flusher_threads(long nr_pages);