Re: [PATCH 6/7] cxlflash: Fix to avoid unnecessary scan with internal LUNs

[Uma Krishnan <ukrishn@linux.vnet.ibm.com>]

On 3/4/2016 3:55 PM, Uma Krishnan wrote:
> From: "Manoj N. Kumar" <manoj@linux.vnet.ibm.com>
>
> When switching to the internal LUN defined on the
> IBM CXL flash adapter, there is an unnecessary
> scan occurring on the second port. This scan leads
> to the following extra lines in the log:
>
> Dec 17 10:09:00 tul83p1 kernel: [ 3708.561134] cxlflash 0008:00:00.0: cxlflash_queuecommand: (scp=c0000000fc1f0f00) 11/1/0/0 cdb=(A0000000-00000000-10000000-00000000)
> Dec 17 10:09:00 tul83p1 kernel: [ 3708.561147] process_cmd_err: cmd failed afu_rc=32 scsi_rc=0 fc_rc=0 afu_extra=0xE, scsi_extra=0x0, fc_extra=0x0
>
> By definition, both of the internal LUNs are on the first port/channel.
>
> When the lun_mode is switched to internal LUN the
> same value for host->max_channel is retained. This
> causes an unnecessary scan over the second port/channel.
>
> This fix alters the host->max_channel to 0 (1 port), if internal
> LUNs are configured and switches it back to 1 (2 ports) while
> going back to external LUNs.
>
> Signed-off-by: Manoj N. Kumar <manoj@linux.vnet.ibm.com>

Reviewed-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>