two SCSI HBAs having same host no in Linux 2.4 kernel

Hi,
In 2.4 kernel ,a scsi HBA driver gets it's host no after scsi_register() call
returns.
The call to scsi_register is made from the driver's 'detect' routine. scsi_register_host calls the driver's 'detect' routine.

The following is an excerpt from scsi_register_host which does the above job.
-----------------------------------------------------------------------------

if (tpnt->use_new_eh_code) {
                spin_lock_irqsave(&io_request_lock, flags);
                tpnt->present = tpnt->detect(tpnt);
                spin_unlock_irqrestore(&io_request_lock, flags);
        } else
                tpnt->present = tpnt->detect(tpnt);

-----------------------------------------------------------------------------
In case of drivers which do not support new_eh_code, 'detect' is called without any locks. Is this SMP safe?

We were testing our iSCSI driver on an SMP machine which had a FC HBA as well. Both iSCSI driver and FC HBA had the same host no allocated. The behaviour could not be reproduced consistently though.

Please let me know in case I am missing something.

Thanx
N.C.Krishna Murthy

... why aren't you using the new_eh_code?

I suspect the answer is that this is part of the transition; that old drivers were expected to have their own lock inside ->detect and new ones don't. But I wasn't around for that, so I'm not sure.

"Next the statesmen will invent cheap lies, putting the blame upon 
the nation that is attacked, and every man will be glad of those
conscience-soothing falsities, and will diligently study them, and refuse
to examine any refutations of them; and thus he will by and by convince 
himself that the war is just, and will thank God for the better sleep 
he enjoys after this process of grotesque self-deception." -- Mark Twain

Hi,
Our iSCSI driver does use new_eh_code.
Thanx
N.C.Krishna Murthy