[PATCH 36/49] writeback: remove bdi_start_writeback()

Tejun Heo
2015-04-06T20:00:26Z

bdi_start_writeback() is a thin wrapper on top of
__wb_start_writeback() which is used only by laptop_mode_timer_fn().
This patches removes bdi_start_writeback(), renames
__wb_start_writeback() to wb_start_writeback() and makes
laptop_mode_timer_fn() use it instead.

This doesn't cause any functional difference and will ease making
laptop_mode_timer_fn() cgroup writeback aware.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jan Kara <jack@suse.cz>
---
fs/fs-writeback.c | 68 +++++++++++++++++----------------------------
include/linux/backing-dev.h | 4 +--
mm/page-writeback.c | 4 +--
3 files changed, 29 insertions(+), 47 deletions(-)

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 6720af9..de309fa 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -172,33 +172,6 @@ out_unlock:
spin_unlock_bh(&wb->work_lock);
}

-static void __wb_start_writeback(struct bdi_writeback *wb, long nr_pages,
- bool range_cyclic, enum wb_reason reason)
-{
- struct wb_writeback_work *work;
-
- if (!wb_has_dirty_io(wb))
- return;
-
- /*
- * This is WB_SYNC_NONE writeback, so if allocation fails just
- * wakeup the thread for old dirty data writeback
- */
- work = kzalloc(sizeof(*work), GFP_ATOMIC);
- if (!work) {
- trace_writeback_nowork(wb->bdi);
- wb_wakeup(wb);
- return;
- }
-
- work->sync_mode = WB_SYNC_NONE;
- work->nr_pages = nr_pages;
- work->range_cyclic = range_cyclic;
- work->reason = reason;
-
- wb_queue_work(wb, work);
-}
-
#ifdef CONFIG_CGROUP_WRITEBACK

/**
@@ -228,22 +201,31 @@ EXPORT_SYMBOL_GPL(inode_congested);

#endif /* CONFIG_CGROUP_WRITEBACK */

-/**
- * bdi_start_writeback - start writeback
- * @bdi: the backing device to write from
- * @nr_pages: the number of pages to write
- * @reason: reason why some writeback work was initiated
- *
- * Description:
- * This does WB_SYNC_NONE opportunistic writeback. The IO is only
- * started when this function returns, we make no guarantees on
- * completion. Caller need not hold sb s_umount semaphore.
- *
- */
-void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
- enum wb_reason reason)
+void wb_start_writeback(struct bdi_writeback *wb, long nr_pages,
+ bool range_cyclic, enum wb_reason reason)
{
- __wb_start_writeback(&bdi->wb, nr_pages, true, reason);
+ struct wb_writeback_work *work;
+
+ if (!wb_has_dirty_io(wb))
+ return;
+
+ /*
+ * This is WB_SYNC_NONE writeback, so if allocation fails just
+ * wakeup the thread for old dirty data writeback
+ */
+ work = kzalloc(sizeof(*work), GFP_ATOMIC);
+ if (!work) {
+ trace_writeback_nowork(wb->bdi);
+ wb_wakeup(wb);
+ return;
+ }
+
+ work->sync_mode = WB_SYNC_NONE;
+ work->nr_pages = nr_pages;
+ work->range_cyclic = range_cyclic;
+ work->reason = reason;
+
+ wb_queue_work(wb, work);
}

/**
@@ -1201,7 +1183,7 @@ void wakeup_flusher_threads(long nr_pages, enum wb_reason reason)

rcu_read_lock();
list_for_each_entry_rcu(bdi, &bdi_list, bdi_list)
- __wb_start_writeback(&bdi->wb, nr_pages, false, reason);
+ wb_start_writeback(&bdi->wb, nr_pages, false, reason);
rcu_read_unlock();
}

diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index c797980..0ff40c2 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -25,8 +25,8 @@ int bdi_register(struct backing_dev_info *bdi, struct device *parent,
int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev);
void bdi_unregister(struct backing_dev_info *bdi);
int __must_check bdi_setup_and_register(struct backing_dev_info *, char *);
-void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
- enum wb_reason reason);
+void wb_start_writeback(struct bdi_writeback *wb, long nr_pages,
+ bool range_cyclic, enum wb_reason reason);
void bdi_start_background_writeback(struct backing_dev_info *bdi);
void wb_workfn(struct work_struct *work);
void wb_wakeup_delayed(struct bdi_writeback *wb);
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 8755f80..3b6d79a 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1729,8 +1729,8 @@ void laptop_mode_timer_fn(unsigned long data)
* threshold
*/
if (bdi_has_dirty_io(&q->backing_dev_info))
- bdi_start_writeback(&q->backing_dev_info, nr_pages,
- WB_REASON_LAPTOP_TIMER);
+ wb_start_writeback(&q->backing_dev_info.wb, nr_pages, true,
+ WB_REASON_LAPTOP_TIMER);
}

/*
--
2.1.0