Re: [PATCH v2] PCI hotplug Eq v2

[Bjorn Helgaas]

On Thu, Aug 30, 2018 at 04:11:59PM -0600, Jon Derrick wrote:
> Hi Bjorn,
> 
> Sorry for the delay on this one and pushing it after RC1.
> Feel free to queue it up for 4.20 if it looks fine.
> 
> I've added comments to the git log and source explaining why
> calculate_iosize was left unchanged. Basically I could not
> synthesize a condition where it would have affected the topology.

In other words, the only reason you didn't change the
calculate_iosize() path was because you couldn't test it?

I appreciate your desire to avoid untested changes, but I think it's
very important to preserve and even improve the symmetry between
calculate_memsize() and calculate_iosize().  For example, it's not
obvious why the order is different here:

  calculate_iosize():
    size = ALIGN(size + size1, align);
    if (size < old_size)
      size = old_size;

  calculate_memsize():
    if (size < old_size)
      size = old_size;
    size = ALIGN(size + size1, align);

So I don't want to diverge them further unless there's a real
functional reason why we need to handle I/O port space differently
than MMIO space.

You've tested the MMIO path, and I'm willing to take the risk of
doing the same thing in the I/O port path.

Bjorn