Re: [PATCH 01/37] PCI/MSI: Add Devres managed IRQ vectors allocation

Philipp Stanner
2026-02-24T08:33:22Z

On Tue, 2026-02-24 at 16:21 +0800, Shawn Lin wrote:
> 在 2026/02/24 星期二 15:47, Philipp Stanner 写道:
> > On Tue, 2026-02-24 at 10:08 +0800, Shawn Lin wrote:
> > > 在 2026/02/24 星期二 8:04, Jakub Kicinski 写道:
> > > > On Mon, 23 Feb 2026 23:29:40 +0800 Shawn Lin wrote:
> > > > > pcim_alloc_irq_vectors() and pcim_alloc_irq_vectors_affinity() are created for
> > > > > pci device drivers which rely on the devres machinery to help cleanup the IRQ
> > > > > vectors.
> > > >
> > > > If you can please add this API with just a few users, and then convert
> > > > remaining users via the subsystem trees in the next cycle.
> > > > There's no need to risk wasting maintainer time on conflicts with
> > > > conversions like this.
> > >
> > > Thanks for the suggestion, Jakub. I have little experience with
> > > cross-subsystem cleanups like this, so your suggestion is very helpful.
> >
> >
> > When I removed the hybrid nature of pci_request_region() et al., I
> > concluded that there were so few users that doing them all in one run
> > was sufficient.
> >
> > For larger reworks, like removing pcim_iomap_table(), a slower step-by-
> > step strategy is necessary for the reasons that Jakub details.
> >
> > It is then smart to omit an easy to port subsystem / driver for the
> > ultimate patch series where one then removes the hybrid behavior from
> > PCI itself, after porting the last driver.
> >
> > In general,  as Jakub details, those step-by-step cleanups are a bit
> > safer, since you can proof valid behavior early on and in case of an
> > explosion they are very easy to revert.
> >
>
> Thank you, Philipp. I wish I had attended your talk at FOSDEM 2025 on
> removing pcim_iomap_table earlier. This first version was perhaps a bit
> too aggressive.

No worries at all, it's very cool that you pick this work up!

> For v2, I think the plan should start with addressing
> the switchtec and vmd drivers, since both of those, along with the new
> API additions, can be handled entirely within the PCI subsystem scope.

Sounds reasonable to me.

Regards
Philipp