Messages in this thread | | | Date | Thu, 4 Apr 2013 07:03:27 -0700 | From | Tejun Heo <> | Subject | Re: [PATCH] blk: start bypass mode in blk_unregister_queue |
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On Thu, Apr 04, 2013 at 10:01:14PM +0800, Aaron Lu wrote: > In blk_register_queue, we will end bypass mode for the queue; but in > blk_unregister_queue, we didn't start bypass mode for it. This would > cause the WARN_ON_ONCE(q->bypass_depth < 0) to trigger if the queue gets > registered, unregistered and then again registered, e.g. unload scsi > cdrom module driver sr_mod and then reload it will trigger such a > warning. > > Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Is this something which actually happens? Why would an unregistered queue registered again? Do we even support that?
Starting a bypass mode can be very expensive and some drivers create and destroy a lot of queues during probing. We don't want a call to blk_queue_bypass_start() on every queue creation / destruction cycle.
Thanks.
-- tejun
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