/* Schedule writeback for all backing devices. This does WB_SYNC_NONE writeback, for integrity writeback see bdi_sync_writeback().  */
static void bdi_writeback_all(struct super_block *sb, long nr_pages)
/* Schedule writeback for all backing devices. This does WB_SYNC_NONE writeback, for integrity writeback see bdi_sync_writeback().  */
static void bdi_writeback_all(struct super_block *sb, long nr_pages)
{
	struct wb_writeback_args args = {
		.sb		= sb,
		.nr_pages	= nr_pages,
		.sync_mode	= WB_SYNC_NONE,
	};
	struct backing_dev_info *bdi;
	rcu_read_lock();
	list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) {
		if (!bdi_has_dirty_io(bdi))
			continue;
		bdi_alloc_queue_work(bdi, &args);
	}
	rcu_read_unlock();
}