Re: [PATCH 2/8] driver-core: add asynchronous probing support for drivers

From	Dmitry Torokhov <dmitry.torokhov@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 2/8] driver-core: add asynchronous probing support for drivers
Date	2015-07-09 03:00 +0200
Message-ID	<pK8lX-1Lr-5@gated-at.bofh.it> (permalink)
References	<pIO5X-W8-11@gated-at.bofh.it> <pJo9s-6oK-3@gated-at.bofh.it> <pK8ch-1HX-9@gated-at.bofh.it> <pK8lX-1Lr-3@gated-at.bofh.it> <pK8lX-1Lr-1@gated-at.bofh.it>
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On Wed, Jul 08, 2015 at 05:54:26PM -0700, Dan Williams wrote:
> On Wed, Jul 8, 2015 at 5:52 PM, Dmitry Torokhov
> <dmitry.torokhov@gmail.com> wrote:
> > On Wed, Jul 08, 2015 at 05:43:23PM -0700, Dan Williams wrote:
> >> On Mon, Jul 6, 2015 at 4:38 PM, Dmitry Torokhov
> >> <dmitry.torokhov@gmail.com> wrote:
> >> > On Sat, Jul 04, 2015 at 07:09:19AM -0700, Dan Williams wrote:
> >> >> The problem I ran into was needing to remove devices that still had
> >> >> yet to be probed and not being able to use registration completion vs
> >> >> the device_lock() to effectively synchronize the sub-system.
> >> >
> >> > Why do you need to "synchronize the sub-system"? The asynchronous
> >> > probing should be transparent to the driver. Just unregister the device
> >> > (or the driver) and driver core will ensure that probe() is not in
> >> > flight.
> >>
> >> Async registration is indeed transparent to the driver.  The primary
> >> need to "flush registration" is the case of "region" devices that
> >> reference a set of NVDIMM devices.  A region device requires all
> >> related NVDIMMs to be active before the region can be enabled.
> >
> > Sounds like you need to call into the subsystem to let it know that the
> > device is active and activate region devices when they are ready. Could
> > be either explicit call or you can try using bus notifiers for
> > bind/unbind events.
> >
> > BTW, do you handle bind/unbind via sysfs (everyone forgets about this
> > mechanism)?
> 
> bind/unbind via systs is central to how libnvdimm operates.  It's
> covered by our unit tests.

Ah, excellent then.

-- 
Dmitry
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Thread

Re: [PATCH 2/8] driver-core: add asynchronous probing support for drivers Dan Williams <dan.j.williams@intel.com> - 2015-07-05 11:10 +0200
  Re: [PATCH 2/8] driver-core: add asynchronous probing support for drivers Dan Williams <dan.j.williams@intel.com> - 2015-07-09 02:40 +0200
    Re: [PATCH 2/8] driver-core: add asynchronous probing support for  drivers Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2015-07-09 02:50 +0200
      Re: [PATCH 2/8] driver-core: add asynchronous probing support for drivers Dan Williams <dan.j.williams@intel.com> - 2015-07-09 03:10 +0200
  Re: [PATCH 2/8] driver-core: add asynchronous probing support for drivers Dan Williams <dan.j.williams@intel.com> - 2015-07-09 02:50 +0200
    Re: [PATCH 2/8] driver-core: add asynchronous probing support for drivers Dan Williams <dan.j.williams@intel.com> - 2015-07-09 03:00 +0200
      Re: [PATCH 2/8] driver-core: add asynchronous probing support for  drivers Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2015-07-09 03:00 +0200
    Re: [PATCH 2/8] driver-core: add asynchronous probing support for  drivers Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2015-07-09 03:00 +0200

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