Re: question about drivers/scsi/scsi_transport_fc.c

[Christof Schmitt <christof.schmitt@de.ibm.com>]

On Sat, Aug 28, 2010 at 07:11:12PM +0200, Julia Lawall wrote:
> The function fc_bsg_goose_queue in the file drivers/scsi/scsi_transport_fc.c
> contains the following code:
> 
>         flagset = test_bit(QUEUE_FLAG_REENTER, &rport->rqst_q->queue_flags) &&
>                   !test_bit(QUEUE_FLAG_REENTER, &rport->rqst_q->queue_flags);
> 
> I have the impression that this is always 0.  QUEUE_FLAG_REENTER is 
> defined with quite a lot of other constants, so I don't really have a 
> guess as to what was intended.

I just came across the code in scsi_run_queue in
drivers/scsi/scsi_lib.c. It looks like the check of QUEUE_FLAG_REENTER
in fc_bsg_goose_queue is modeled after the check in scsi_run_queue.

The check in scsi_run_queue has been introduced with this commit,
maybe this helps understanding the code:

commit 04846f25920d4b05d6040c531cc601049260db52
Author: Andreas Herrmann <aherrman@de.ibm.com>
Date:   Wed Aug 9 17:31:16 2006 +0200

    [SCSI] limit recursion when flushing shost->starved_list

--
Christof