Re: [PATCH]qla4xxx:Add support for Async Message PDUs [REPOST with fixes]

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

Mike Christie wrote:
> David C Somayajulu wrote:
>> +        }
>> +        if (sshdr.asc == 0x3f && sshdr.ascq == 0x0e) {
>> +            /* induce rescan */
>> +            iscsi_block_session(ddb_entry->sess);
>> +            iscsi_unblock_session(ddb_entry->sess);
>> +        }
> 
> I think I was wrong off list. We could actually just call 
> iscsi_unblock_session, but we do not know the state of the session do 
> we? If we got a event that indicated the session was failed could we 
> have a block queued up and this would reverse it by accident?
> 
> I was thinking that because qla4xxx_process_aen is called before this we 
> could just check the ddb state, but we can call iscsi_block_session from 
> the interrupt handler to queue up a block so I think that could race 
> with the unblock call here.

Maybe to handle the race we do not want to call qla4xxx_mark_device_busy 
when we get SCS_TIMEOUT. If we get a ddb aen then could we just wait for 
that and all those events would be serialized through the dpc thread?

What does SCS_TIMEOUT mean?