On Tue, Sep 23, 2025 at 11:30:41AM -0600, Alex Williamson wrote: > On Tue, 23 Sep 2025 12:04:14 -0300 > Jason Gunthorpe <jgg@xxxxxxxxxx> wrote: > > > On Mon, Sep 22, 2025 at 03:00:32PM -0600, Alex Williamson wrote: > > > But then later in patch 8/ and again in 10/ why exactly do we cache > > > the provider on the vfio_pci_core_device rather than ask for it on > > > demand from the p2pdma? > > > > It makes the most sense if the P2P is activated once during probe(), > > it is just a cheap memory allocation, so no reason not to. > > > > If you try to do it on-demand then it will require more locking. > > I'm only wondering about splitting to an "initialize/setup" function > where providers for each BAR are setup, and a "get provider" interface, > which doesn't really seem to be a hot path anyway. Batching could > still be done to setup all BAR providers at once. I agree it is a weird interface, but it is close to the existing weird interface :\ > However, the setup isn't really once per probe(), even in the case of a > new driver probing we re-use the previously setup providers. It uses devm to call pci_p2pdma_release() which NULL's pdev->p2pdma. Jason
