v5.9-rc1 commit reliably breaks pci nvme detection

[Ahmed S. Darwish]

Hello,

Below v5.9-rc1 commit reliably breaks my boot on a Thinkpad e480
laptop. PCI nvme detection fails, and the kernel becomes not able
anymore to find the rootfs / parse "root=".

Bisecting v5.8=>v5.9-rc1 blames that commit. Reverting it *reliably*
fixes the problem and makes me able to boot v5.9-rc1.

Please advise.

commit 61f3b89630973037f67d8e25e5d26e80a51a7b37
Author: Chaitanya Kulkarni <chaitanya.kulkarni@xxxxxxx>
Date:   Wed Jun 17 10:05:13 2020 +0200

    nvme-pci: use unsigned for io queue depth
    
    The NVMe PCIe declares module parameter io_queue_depth as int. Change
    this to u16 as queue depth can never be negative. Now to reflect this
    update module parameter getter function from param_get_int() ->
    param_get_uint() and respective setter function with type of n changed
    from int to u16 with param_set_int() to param_set_ushort(). Finally
    update struct nvme_dev q_depth member to u16 and use u16 in min_t()
    when calculating dev->q_depth in the nvme_pci_enable() (since q_depth is
    now u16) and use unsigned int instead of int when calculating
    dev->tagset.queue_depth as target variable tagset->queue_depth is of type
    unsigned int in nvme_dev_add().

Thanks,

--
Ahmed S. Darwish
Linutronix GmbH