Re: [PATCH 4/4] ib_srpt: Convert acl lookup to modern get_initiator_node_acl usage

[Bart Van Assche]

On 01/08/2016 10:17 AM, Nicholas A. Bellinger wrote:
> On Fri, 2016-01-08 at 09:52 +0100, Bart Van Assche wrote:
> > On 01/08/2016 08:15 AM, Nicholas A. Bellinger wrote:
> > > @@ -2574,24 +2558,18 @@ static int srpt_cm_req_recv(struct ib_cm_id *cm_id,
> > >
> > >    	pr_debug("registering session %s\n", ch->sess_name);
> > >
> > > -	nacl = srpt_lookup_acl(sport, ch->i_port_id);
> > > -	if (!nacl) {
> > > +	se_acl = core_tpg_get_initiator_node_acl(&sport->port_tpg_1, ch->sess_name);
> > > +	if (!se_acl) {
> > >    		pr_info("Rejected login because no ACL has been"
> > >    			" configured yet for initiator %s.\n", ch->sess_name);
> > >    		rej->reason = cpu_to_be32(
> > > -			      SRP_LOGIN_REJ_CHANNEL_LIMIT_REACHED);
> > > +				SRP_LOGIN_REJ_CHANNEL_LIMIT_REACHED);
> > > +		transport_free_session(ch->sess);
> > >    		goto destroy_ib;
> > >    	}
> > > +	ch->sess->se_node_acl = se_acl;
> >
> > This is a backwards-incompatible change. Today the ib_srpt target driver
> > accepts initiator port names with and without leading "0x". With this
> > change the "0x" prefix becomes mandatory.
>
> The internally ib_srpt formatted ch->sess_name already needs to match
> se_node_acl->initiatorname for se_node_acl->acl_group configfs group
> shutdown reference..
>
> How does this patch become a backworks-incompatible change for that..?

Hello Nic,

Personally I'm not that worried about this change but I wanted to report 
it anyway. The current algorithm is as follows:
- When a directory is created in configfs for an initiator, the
  initiator name is parsed and stored in binary form in struct
  srpt_node_acl. The parsing function accepts both initiator
  names that start with a "0x" prefix and initiator names that
  do not have that prefix.
- During login the initiator port ID provided by the initiator in
  the SRP login request is compared with the binary initiator port ID
  in struct srpt_node_acl.

The patch at the start of this e-mail thread changes this behavior 
because core_tpg_get_initiator_node_acl() looks up the initiator port ID 
in a list that contains the ASCII representations of the initiator port 
ID. This means that the initiator port name will only be found by 
core_tpg_get_initiator_node_acl() if the name format used in the mkdir 
command matches the initiator name format used by the 
core_tpg_get_initiator_node_acl() caller, this means with "0x" prefix.

Bart.

Bart.