On Fri 22-05-15 17:13:58, Tejun Heo wrote:
> If the completion of a wb_writeback_work can be waited upon by setting
> its ->done to a struct completion and waiting on it; however, for
> cgroup writeback support, it's necessary to issue multiple work items
> to multiple bdi_writebacks and wait for the completion of all.
>
> This patch implements wb_completion which can wait for multiple work
> items and replaces the struct completion with it. It can be defined
> using DEFINE_WB_COMPLETION_ONSTACK(), used for multiple work items and
> waited for by wb_wait_for_completion().
>
> Nobody currently issues multiple work items and this patch doesn't
> introduce any behavior changes.
One more thing...
> @@ -161,17 +178,34 @@ static void wb_queue_work(struct bdi_writeback *wb,
> trace_writeback_queue(wb->bdi, work);
>
> spin_lock_bh(&wb->work_lock);
> - if (!test_bit(WB_registered, &wb->state)) {
> - if (work->done)
> - complete(work->done);
> + if (!test_bit(WB_registered, &wb->state))
> goto out_unlock;
This seems like a change in behavior. Previously unregistered wbs just
completed the work->done, now you don't complete them. Is that intentional?
Honza
--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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