updates for CFQ oops fix

- add a comment to the device structure that the device_busy field
  is now protected by the request_queue->queue_lock
- null out sdev->request_queue after the queue is released to trap
  any (and there shouldn't be any) use after the queue is freed.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2 files changed