RE: [PATCH] PCI: hv: Only reuse existing IRTE allocation for Multi-MSI

From: Dexuan Cui
Date: Tue Aug 16 2022 - 17:13:39 EST


> From: Bjorn Helgaas <helgaas@xxxxxxxxxx>
> Sent: Tuesday, August 16, 2022 8:51 AM
> To: Dexuan Cui <decui@xxxxxxxxxxxxx>
>
> This has only observations with no explanations, and I don't see how
> it will be useful to future readers of the git history.
Please see the below.

> I assume you bisected the problem to b4b77778ecc5?
Yes.

> Can you just revert that? A revert requires no more explanation than
> "this broke something."

It's better to not revert b4b77778ecc5, which is required by Jeff's
Multi-MSI device, which doesn't seem to be affected by the interrupt
issue I described.

> I guess this is a fine distinction, but I really don't like random
> code changes that "seem to avoid a problem but we don't know how."
> A revert at least has the advantage that we can cover our eyes and
> pretend the commit never happened. This patch feels like future
> readers will have to try to understand the code even though we
> clearly don't understand why it makes a difference.

I just replied to Lorenzo's email with more details. FYI, this is the link
to my reply:
https://lwn.net/ml/linux-kernel/SA1PR21MB1335D08F987BBAE08EADF010BF6B9@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/

I just felt the commit message might be too long if I had put all the
details there. :-) Can we add a Links: tag?

Thanks,
-- Dexuan