Dan Aloni wrote:
Hello,
scsi_execute_async() has replaced scsi_do_req() a few versions ago,
but it also incurred a change of behavior. I noticed that over-queuing
a SCSI device using that function causes I/Os to be starved from
low-level queuing for no justified reason.
I think it makes much more sense to perserve the original behaviour
of scsi_do_req() and add the request to the tail of the queue.
As far as I'm aware the way in which scsi_do_req() was to insert at the
head of the queue, leading to projects like SCST to come up with
scsi_do_req_fifo() as queuing multiple commands using scsi_do_req() with
constant head insertion might lead to out of order execution.
Just thought I'd throw some light on the history and what others have
done in the past.
Steve
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