writeback: move backing_dev_info->state 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->state into wb.
* enum bdi_state is renamed to wb_state and the prefix of all enums is
changed from BDI_ to WB_.
* Explicit zeroing of bdi->state is removed without adding zeoring of
wb->state as the whole data structure is zeroed on init anyway.
* 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>
Cc: drbd-dev@lists.linbit.com
Cc: Neil Brown <neilb@suse.de>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 6dc4580..b23cf0e 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -96,7 +96,7 @@
nr_io,
nr_more_io,
nr_dirty_time,
- !list_empty(&bdi->bdi_list), bdi->state);
+ !list_empty(&bdi->bdi_list), bdi->wb.state);
#undef K
return 0;
@@ -280,7 +280,7 @@
timeout = msecs_to_jiffies(dirty_writeback_interval * 10);
spin_lock_bh(&bdi->wb_lock);
- if (test_bit(BDI_registered, &bdi->state))
+ if (test_bit(WB_registered, &bdi->wb.state))
queue_delayed_work(bdi_wq, &bdi->wb.dwork, timeout);
spin_unlock_bh(&bdi->wb_lock);
}
@@ -315,7 +315,7 @@
bdi->dev = dev;
bdi_debug_register(bdi, dev_name(dev));
- set_bit(BDI_registered, &bdi->state);
+ set_bit(WB_registered, &bdi->wb.state);
spin_lock_bh(&bdi_lock);
list_add_tail_rcu(&bdi->bdi_list, &bdi_list);
@@ -339,7 +339,7 @@
{
/* Make sure nobody queues further work */
spin_lock_bh(&bdi->wb_lock);
- if (!test_and_clear_bit(BDI_registered, &bdi->state)) {
+ if (!test_and_clear_bit(WB_registered, &bdi->wb.state)) {
spin_unlock_bh(&bdi->wb_lock);
return;
}
@@ -492,11 +492,11 @@
void clear_bdi_congested(struct backing_dev_info *bdi, int sync)
{
- enum bdi_state bit;
+ enum wb_state bit;
wait_queue_head_t *wqh = &congestion_wqh[sync];
- bit = sync ? BDI_sync_congested : BDI_async_congested;
- if (test_and_clear_bit(bit, &bdi->state))
+ bit = sync ? WB_sync_congested : WB_async_congested;
+ if (test_and_clear_bit(bit, &bdi->wb.state))
atomic_dec(&nr_bdi_congested[sync]);
smp_mb__after_atomic();
if (waitqueue_active(wqh))
@@ -506,10 +506,10 @@
void set_bdi_congested(struct backing_dev_info *bdi, int sync)
{
- enum bdi_state bit;
+ enum wb_state bit;
- bit = sync ? BDI_sync_congested : BDI_async_congested;
- if (!test_and_set_bit(bit, &bdi->state))
+ bit = sync ? WB_sync_congested : WB_async_congested;
+ if (!test_and_set_bit(bit, &bdi->wb.state))
atomic_inc(&nr_bdi_congested[sync]);
}
EXPORT_SYMBOL(set_bdi_congested);