Re: [PATCH 2/5] scsi: improved eh timeout handler

[Hannes Reinecke <hare@suse.de>]

On 02/11/2014 03:01 PM, Christoph Hellwig wrote:
> Hi Hannes,
> 
> I'll need a little reminder how we came to the conclusion that the
> cancel_delayed_work in scsi_put_command was safe and we didn't need
> a cancel_delayed_work_sync or flush_delayed_work.  I remember we had
> that discussion, but it seems that same doesn't apply to the equivalent
> call in the blk-mq codepath in my tree.  If you remember anything that
> might make my life debugging this a bit easier.
> 

Well, _actually_ the cancel_delayed_work should be pointless; I've
just added it as a terminal measure here.
(It'd actually be an idea to insert a BUG_ON() here ...)

Thing is whenever the eh_timeout thingie kicks in we most definitely
know there's a command in flight, and hence scsi_command_put()
should _never_ be called.
Only after eh_abort has finished the command will be returned via
scsi_command_put(), but then eh_abort is done for, too, and no item
should remain in the workqueue.

HTH.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@suse.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
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