diff options
Diffstat (limited to 'fs/fs-writeback.c')
-rw-r--r-- | fs/fs-writeback.c | 31 |
1 files changed, 22 insertions, 9 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index d0da306..29e4599 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -778,19 +778,24 @@ static void bdi_split_work_to_wbs(struct backing_dev_info *bdi, struct wb_writeback_work *base_work, bool skip_if_busy) { - int next_memcg_id = 0; - struct bdi_writeback *wb; - struct wb_iter iter; + struct bdi_writeback *last_wb = NULL; + struct bdi_writeback *wb = list_entry_rcu(&bdi->wb_list, + struct bdi_writeback, bdi_node); might_sleep(); restart: rcu_read_lock(); - bdi_for_each_wb(wb, bdi, &iter, next_memcg_id) { + list_for_each_entry_continue_rcu(wb, &bdi->wb_list, bdi_node) { DEFINE_WB_COMPLETION_ONSTACK(fallback_work_done); struct wb_writeback_work fallback_work; struct wb_writeback_work *work; long nr_pages; + if (last_wb) { + wb_put(last_wb); + last_wb = NULL; + } + /* SYNC_ALL writes out I_DIRTY_TIME too */ if (!wb_has_dirty_io(wb) && (base_work->sync_mode == WB_SYNC_NONE || @@ -819,12 +824,22 @@ restart: wb_queue_work(wb, work); - next_memcg_id = wb->memcg_css->id + 1; + /* + * Pin @wb so that it stays on @bdi->wb_list. This allows + * continuing iteration from @wb after dropping and + * regrabbing rcu read lock. + */ + wb_get(wb); + last_wb = wb; + rcu_read_unlock(); wb_wait_for_completion(bdi, &fallback_work_done); goto restart; } rcu_read_unlock(); + + if (last_wb) + wb_put(last_wb); } #else /* CONFIG_CGROUP_WRITEBACK */ @@ -1857,12 +1872,11 @@ void wakeup_flusher_threads(long nr_pages, enum wb_reason reason) rcu_read_lock(); list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) { struct bdi_writeback *wb; - struct wb_iter iter; if (!bdi_has_dirty_io(bdi)) continue; - bdi_for_each_wb(wb, bdi, &iter, 0) + list_for_each_entry_rcu(wb, &bdi->wb_list, bdi_node) wb_start_writeback(wb, wb_split_bdi_pages(wb, nr_pages), false, reason); } @@ -1894,9 +1908,8 @@ static void wakeup_dirtytime_writeback(struct work_struct *w) rcu_read_lock(); list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) { struct bdi_writeback *wb; - struct wb_iter iter; - bdi_for_each_wb(wb, bdi, &iter, 0) + list_for_each_entry_rcu(wb, &bdi->wb_list, bdi_node) if (!list_empty(&wb->b_dirty_time)) wb_wakeup(wb); } |