Re: [PATCH] PCI: Stop waiting for link status after config read failure

["Yury M." <yurypm@arista.com>]

On 9/5/26 11:06, Lukas Wunner wrote:
> It's repetitive because pcie_capability_read_word() already checks
> internally for pci_dev_is_disconnected():
>
>    pcie_capability_read_word()
>      pci_read_config_word()
>        pci_dev_is_disconnected()
>
> I just thought that since you specifically want to bail out in the
> hot-removal case, it might be clearer to check pci_dev_is_disconnected()
> in pcie_wait_for_link_status() before performing the config space read.
>
> But I don't feel strongly either way and checking the return value of
> pcie_capability_read_word() is a viable approach as well.

I've sent v3 of the patch, returning to validating the 
|pcie_capability_read_word()| return value.

Reasoning:

 1.

    I don't see any benefit to using |pci_dev_is_disconnected()|, other
    than your point that it makes the code clearer or more readable.

 2.

    I checked how we set |pci_dev_is_disconnected()| now, and it looks
    like failed reads don't guarantee that the device will immediately
    be marked as disconnected. I assume that eventually we will receive
    a link-status-changed interrupt and the device will then be marked
    as disconnected.

 3.

    On the other hand, |pcie_capability_read_word()| internally performs
    a |pci_dev_is_disconnected()| check. So in our context, validating
    the |pcie_capability_read_word()| return value is more robust,
    allowing us to react to device disappearance (for any reason) faster
    and more reliably.

  Thanks