Re: problem: connection teardown is always blocked because host is busy doing work on other connections

[Mike Christie <michaelc@cs.wisc.edu>]

On 6/18/15, 8:09 PM, Minh Tran wrote:
> From: Minh Duc Tran <MinhDuc.Tran@avagotech.Com>
>
> This blocking is ok if we use software iscsi or iser where each
> connection has a separate host.  In the case of hw iscsi offload, one
> host could have hundreds of connections and some connections may have
> IOs running which makes host->host_busy is always TRUE.  Another
> problem is the host_lock taken here is disruptive to other
> connections' EH paths.  Wouldn't using target_busy a better choice
> here?
>

Do you talk to John :) I had told him to do that a couple days ago when 
you guys emailed me about this offlist.

However, I think Christoph wants to remove target_busy so you need to 
think of something else. I think you could take the session eh_mutex in 
the libiscsi session and conn teardown functions and rely on refcounting 
and state checks in the eh callouts.