writeback: move backing_dev_info->wb_lock and ->worklist into bdi_writeback
Currently, a bdi (backing_dev_info) embeds single wb (bdi_writeback)
and the role of the separation is unclear. For cgroup support for
writeback IOs, a bdi will be updated to host multiple wb's where each
wb serves writeback IOs of a different cgroup on the bdi. To achieve
that, a wb should carry all states necessary for servicing writeback
IOs for a cgroup independently.
This patch moves bdi->wb_lock and ->worklist into wb.
* The lock protects bdi->worklist and bdi->wb.dwork scheduling. While
moving, rename it to wb->work_lock as wb->wb_lock is confusing.
Also, move wb->dwork downwards so that it's colocated with the new
->work_lock and ->work_list fields.
* bdi_writeback_workfn() -> wb_workfn()
bdi_wakeup_thread_delayed(bdi) -> wb_wakeup_delayed(wb)
bdi_wakeup_thread(bdi) -> wb_wakeup(wb)
bdi_queue_work(bdi, ...) -> wb_queue_work(wb, ...)
__bdi_start_writeback(bdi, ...) -> __wb_start_writeback(wb, ...)
get_next_work_item(bdi) -> get_next_work_item(wb)
* bdi_wb_shutdown() is renamed to wb_shutdown() and now takes @wb.
The function contained parts which belong to the containing bdi
rather than the wb itself - testing cap_writeback_dirty and
bdi_remove_from_list() invocation. Those are moved to
bdi_unregister().
* bdi_wb_{init|exit}() are renamed to wb_{init|exit}().
Initializations of the moved bdi->wb_lock and ->work_list are
relocated from bdi_init() to wb_init().
* As there's still only one bdi_writeback per backing_dev_info, all
uses of bdi->state are mechanically replaced with bdi->wb.state
introducing no behavior changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 2ab0604..d796f49 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -52,7 +52,6 @@
unsigned long state; /* Always use atomic bitops on this */
unsigned long last_old_flush; /* last old data flush */
- struct delayed_work dwork; /* work item used for writeback */
struct list_head b_dirty; /* dirty inodes */
struct list_head b_io; /* parked for writeback */
struct list_head b_more_io; /* parked for more writeback */
@@ -78,6 +77,10 @@
struct fprop_local_percpu completions;
int dirty_exceeded;
+
+ spinlock_t work_lock; /* protects work_list & dwork scheduling */
+ struct list_head work_list;
+ struct delayed_work dwork; /* work item used for writeback */
};
struct backing_dev_info {
@@ -93,9 +96,6 @@
unsigned int max_ratio, max_prop_frac;
struct bdi_writeback wb; /* default writeback info for this bdi */
- spinlock_t wb_lock; /* protects work_list & wb.dwork scheduling */
-
- struct list_head work_list;
struct device *dev;
@@ -121,9 +121,9 @@
void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
enum wb_reason reason);
void bdi_start_background_writeback(struct backing_dev_info *bdi);
-void bdi_writeback_workfn(struct work_struct *work);
+void wb_workfn(struct work_struct *work);
int bdi_has_dirty_io(struct backing_dev_info *bdi);
-void bdi_wakeup_thread_delayed(struct backing_dev_info *bdi);
+void wb_wakeup_delayed(struct bdi_writeback *wb);
extern spinlock_t bdi_lock;
extern struct list_head bdi_list;