qla2xxx: Delete session if initiator is gone from FW

qla2xxx: Delete session if initiator is gone from FW

1. Initiator A is logged in with fc_id(1)/loop_id(1)
2. Initiator A re-logs in with fc_id(2)/loop_id(2)
3. Part of old session deletion async logoout for 1/1 is queued
4. Initiator B logs in with fc_id(1)/loop_id(1), starts
   passing data and creates session.
5. Async logo from 3 is processed by DPC and sent to FW

Now initiator B has the session but is logged out from FW.

This condition is detected first with CTIO error 29 at which
point we should delete current session. During session
deletion we will send LOGO to initiator to force re-login.

Under rare circumstances initiator might be logged out of FW,
not have driver session, but still think it's logged in.
E.g. the above sequence plus session deletion due to re-config.
Incoming commands will fail to create local session because
initiator is not found in FW. In this case we also issue LOGO
to initiator to force him re-login.

Finally this patch fixes exchange leak when commands where
received in logged out state. In this case loop_id must be
set to FFFF when corresponding exchange is terminated. The
patch modifies exchange termination to always use FFFF,
since in certain scenarios it's impossible to tell whether
command was received in logged in or logged out state.

Signed-off-by: Alexei Potashnik <alexei@purestorage.com>
Acked-by: Quinn Tran <quinn.tran@qlogic.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@qlogic.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>