On Wed, Jul 17, 2019 at 06:07:53PM -0700, Dan Williams wrote:
> The libnvdimm subsystem arranges for devices to be destroyed as a result
> of a sysfs operation. Since device_unregister() cannot be called from
> an actively running sysfs attribute of the same device libnvdimm
> arranges for device_unregister() to be performed in an out-of-line async
> context.
>
> The driver core maintains a 'dead' state for coordinating its own racing
> async registration / de-registration requests. Rather than add local
> 'dead' state tracking infrastructure to libnvdimm device objects, export
> the existing state tracking via a new kill_device() helper.
>
> The kill_device() helper simply marks the device as dead, i.e. that it
> is on its way to device_del(), or returns that the device was already
> dead. This can be used in advance of calling device_unregister() for
> subsystems like libnvdimm that might need to handle multiple user
> threads racing to delete a device.
>
> This refactoring does not change any behavior, but it is a pre-requisite
> for follow-on fixes and therefore marked for -stable.
>
> Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
> Cc: "Rafael J. Wysocki" <raf...@kernel.org>
> Fixes: 4d88a97aa9e8 ("libnvdimm, nvdimm: dimm driver and base libnvdimm
> device-driver...")
> Cc: <sta...@vger.kernel.org>
> Tested-by: Jane Chu <jane....@oracle.com>
> Signed-off-by: Dan Williams <dan.j.willi...@intel.com>
Reviewed-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
