Re: [PATCH 01/12] target: Convert se_node_acl->device_list[] to RCU hlist

[Nicholas A. Bellinger]

On Sun, 2015-05-17 at 18:51 +0200, Christoph Hellwig wrote:
> On Wed, May 13, 2015 at 01:46:11AM -0700, Nicholas A. Bellinger wrote:
> > Updated to use a mirror lun->lun_rtpi, with the assignment from sep_rtpi
> > occuring in core_dev_export() code.
> 
> From looking at your current tree I suspect freeing the se_port structure
> using kfree_rcu might be a better idea.  Together with dropping the references
> to the se_device from call_rcu context this basically means all pointers
> in struct se_lun are rcu protected which is much safer if you want
> to access struct se_lun under rcu protection, as this avoids having to
> deal with special cases.  Additionally that basically allows you to
> replace lun_sep_lock with rcu_read_lock for anything remotely like
> a fast path.

Here's a first pass at this along with kref + completion conversion for
the special case PR ALL_TGT_PT=1 pointer dereference.

Thanks HCH.