Re: [PATCH v2 7/7] driver-core: add preferred async probe option for built-in and modules

[Tejun Heo <tj@kernel.org>]

Hello,

On Tue, Oct 07, 2014 at 01:10:46AM +0200, Luis R. Rodriguez wrote:
> On Mon, Oct 06, 2014 at 05:01:18PM -0400, Tejun Heo wrote:
> > For in-kernel stuff, we already have a clear
> > synchronization point where we already synchronize all async calls.
> > Shouldn't we be flushing these async probes there too?
> 
> This seems to be addressing if what I meant by prepared, "ready", so let
> me address this as I do think its important.
> 
> By async calls do you mean users of async_schedule()? I see it

Yes.

> also uses system_unbound_wq as well but I do not see anyone calling
> flush_workqueue(system_unbound_wq) on the kernel. We do use
> async_synchronize_full() on kernel_init() but that just waits.

But you can create a new workqueue and queue all the async probing
work items there and flush the workqueue right after
async_synchronize_full().

...
> bus.enable_kern_async=1 would still also serve as a helper for the driver core
> to figure out if it should use async probe then on modules if prefer_async_probe
> was enabled. Let me know if you figure out a way to avoid it.

Why do we need the choice at all?  It always should, no?

Thanks.

-- 
tejun