Re: [PATCH V7 4/6] blk-mq: introduce .get_budget and .put_budget in blk_mq_ops

From: Bart Van Assche
Date: Mon Oct 16 2017 - 12:06:42 EST


On Mon, 2017-10-16 at 13:30 +0200, Hannes Reinecke wrote:
> On Fri, Oct 13, 2017 at 05:08:52PM +0000, Bart Van Assche wrote:
> > (+Himanshu Madhani)
> >
> > Himanshu, do you perhaps know whether it is safe to increase cmd_per_lun for
> > the qla2xxx initiator driver to the scsi_host->can_queue value?
>
> '3' is just a starting point; later on it'll be adjusted via scsi_change_depth().
> Looks like it's not working correctly with blk-mq, though.

Hello Hannes,

Isn't the purpose of scsi_change_queue_depth() to change the sdev queue_depth
only? As far as I know there is only one assignment of shost->cmd_per_lun in
the SCSI core and that's the following assignment in scsi_host_alloc():

shost->cmd_per_lun = sht->cmd_per_lun;

Bart.