nvmecontrol: Fix condition when print number of Firmware Slots and Firmware Slot1 Readonly.

[wanpengqian_gmail.com]

Summary

When print Number of Firmware Slots and Firmware Slot1 Readonly,
The condition is fw_num_slots != 0 instead of fw != 0 (the controller supports the Firmware Commit and Firmware
Image Download commands.)

ref: D32659

Signed-off-by: Wanpeng Qian <[e-mail]>

Test Plan

Within bhyve virtual machine, fire a nvmecontrol identify nvme0
to check the output.

before

Number of Firmware Slots:    N/A
Firmware Slot 1 Read-Only:   N/A

after

Number of Firmware Slots:    1
Firmware Slot 1 Read-Only:   Yes

[wanpengqian_gmail.com]

Since D32659 is committed. Can we give a go for this? @imp

[corvink]

LGTM @manu

[manu]

In D34700#848038, @corvink wrote:

LGTM @manu

Approved.

[chuck]

The existing code isn't quite right, but I'm not quite sure what to do here. The number of firmware slots should not ever be zero (i.e., "This field shall specify a value from one to seven"), and my guess is, for most drives, this condition will always be true. Perhaps removing the check and unconditionally printing the slot count and RO status makes more sense as the field description (e.g., "Number of Firmware Slots") are always present.

[wanpengqian_gmail.com]

unconditionally print fw_num_slots.

[wanpengqian_gmail.com]

I think Chuck is right. output fw_num_slots unconditionally, but for Firmware Slot 1 Read-Only, we have to make sure the fw_num_slots is bigger than zero. othersize it is meaningless. Although the NVMe controller should at least have one firmware slot.

[corvink]

In D34700#848607, @wanpengqian_gmail.com wrote:

I think Chuck is right. output fw_num_slots unconditionally, but for Firmware Slot 1 Read-Only, we have to make sure the fw_num_slots is bigger than zero. othersize it is meaningless. Although the NVMe controller should at least have one firmware slot.

I agree with chuck. fw_num_slots can't be zero. If it's zero, your controller will be broken and you can't rely on any of these values. So, I think it makes no sense to keep the if.

[wanpengqian_gmail.com]

unconditionly print fw_slot1_ro.

[wanpengqian_gmail.com]

I agree with chuck. fw_num_slots can't be zero. If it's zero, your controller will be broken and you can't rely on any of these values. So, I think it makes no sense to keep the if.

alright, here it is.