Re: [Xen-devel] [PATCH V4 3/4] Introduce XEN scsiback module

["Nicholas A. Bellinger" <nab@xxxxxxxxxxxxxxx>]

On Thu, 2014-08-14 at 12:14 +0200, Juergen Gross wrote:
> On 08/14/2014 10:53 AM, Juergen Gross wrote:
> > Nicholas,
> >
> > just one more question (see below):
> >
> > On 08/12/2014 11:13 PM, Nicholas A. Bellinger wrote:
> >> Hi Juergen & Co,
> >>
> >> Finally had a chance to review this code.  Comments are inline below..
> >>
> >> On Fri, 2014-08-08 at 09:49 +0200, jgross@xxxxxxxx wrote:
> >
> > ...
> >
> >>> +    if (IS_ERR(tv_nexus->tvn_se_sess)) {
> >>> +        mutex_unlock(&tpg->tv_tpg_mutex);
> >>> +        kfree(tv_nexus);
> >>> +        return -ENOMEM;
> >>> +    }
> >>> +    se_sess = tv_nexus->tvn_se_sess;
> >>> +    /*
> >>> +     * Since we are running in 'demo mode' this call with generate a
> >>> +     * struct se_node_acl for the scsiback struct se_portal_group with
> >>> +     * the SCSI Initiator port name of the passed configfs group
> >>> 'name'.
> >>> +     */
> >>> +    tv_nexus->tvn_se_sess->se_node_acl =
> >>> core_tpg_check_initiator_node_acl(
> >>> +                se_tpg, (unsigned char *)name);
> >>> +    if (!tv_nexus->tvn_se_sess->se_node_acl) {
> >>> +        mutex_unlock(&tpg->tv_tpg_mutex);
> >>> +        pr_debug("core_tpg_check_initiator_node_acl() failed for %s\n",
> >>> +             name);
> >>> +        goto out;
> >>> +    }
> >
> > Can I drop the call to core_tpg_check_initiator_node_acl() as well?
> > Keeping it will result in failing to setup the nexus (which is to be
> > expected IMHO).
> 
> Obviously I can't. transport_lookup_cmd_lun() calls right at start
> spin_lock_irqsave(&se_sess->se_node_acl->device_list_lock, flags);
> resulting in a page fault...
> 
> I guess the hint to just throw away all the node_acl related stuff has
> to be adjusted somehow...
> 
> So: what is needed, what can be removed?
> 

The scsiback_make_nodeacl() + scsiback_drop_nodeacl() configfs callbacks
can be safely dropped, along with scisback_ncal->iport_[wwpn,name].

--nab


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