RE: [smartpqi updates PATCH V2 09/11] smartpqi: fix duplicate device nodes for tape changers

Don.Brace
2021-10-05T20:23:30Z

From: Paul Menzel [mailto:pmenzel@molgen.mpg.de]

Subject: Re: [smartpqi updates PATCH V2 09/11] smartpqi: fix duplicate device nodes for tape changers

Dear Kevin, dear Don,
> Our controller FW lists both LUNs in the RPL results.

Please document the firmware version (and controller) you tested with in the commit message.

DON: Done in V3, thanks for your review.

Shortly describing the implementation (new struct member ignore_device) would be nice.
DON: Don in V3, thanks for your review.

> u8 rescan : 1;
> + u8 ignore_device : 1;

Why not type bool?
Don: They both take the same amount of memory and since the other members are also u8, the new member was also u8 for consistency.

> - device->lun = sdev->lun;
> - device->target_lun_valid = true;

Off topic, with `u8 target_lun_valid : 1`, why is `true` used.
Don: Has the same behavior, and carried forward from other member fields.

> + if (device->target_lun_valid) {
> + device->ignore_device = true;
> + } else {
> + device->target = sdev_id(sdev);
> + device->lun = sdev->lun;
> + device->target_lun_valid = true;
> + }

If the LUN should be ignored, is it actually valid? Why not extend target_lun_valid and add a third option (enums?) to ignore it?

Don: The reason is that it takes advantage of the order the devices are added and how slave_alloc and slave_configure fit into this order.

> + return device->devtype == TYPE_TAPE || device->devtype ==
> +TYPE_MEDIUM_CHANGER;

Why also check for TYPE_TAPE? The function name should be updated then?
Don: Because out tape changer consisted of the changer and one or more tape units and both were duplicated.

> static int pqi_slave_configure(struct scsi_device *sdev)
> + if (pqi_is_tape_changer_device(device) && device->ignore_device) {
> + rc = -ENXIO;
> + device->ignore_device = false;

I’d add a `return -ENXIO` here, and remove the variable.
Don: This works in conjunction with slave_alloc and is needed.

>

Kind regards,
Paul

Thanks for your review. Appreciate the inspection.
Don and Kevin