Revert "driver core: synchronize device shutdown"
This reverts commit 401097ea4b89846d66ac78f7f108d49c2e922d9c. The
original changelog said:
A patch series to make .shutdown execute asynchronously. Some drivers's
shutdown can take a lot of time. The patches can help save some shutdown
time. The patches use Arjan's async API.
This patch:
synchronize all tasks submitted by .shutdown
However, I'm not able to find any evidence that any other patches from
this series were applied, nor am I able to find any async tasks that are
scheduled in a .shutdown context.
On the other hand, we see occasional hangs on shutdown that appear to be
caused by the async_synchronize_full() in device_shutdown() waiting
forever for the async probing in sd if a SCSI disk shows up at just the
wrong time — the system starts the probe, but begins shutting down and
tears down too much of the SCSI driver to finish the probe.
If we had any async shutdown tasks, I guess the right fix would be to
create a "shutdown" async domain and have device_shutdown() only wait
for that domain. But since there apparently are no async shutdown
tasks, we can just revert the waiting.
Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Roland Dreier