On Fri, Sep 26, 2025 at 08:13:50AM -0600, Alex Williamson wrote: > On Thu, 25 Sep 2025 20:02:36 -0300 > Jason Gunthorpe <[email protected]> wrote: > > > On Thu, Sep 25, 2025 at 04:31:31PM -0600, Alex Williamson wrote: > > > On Thu, 25 Sep 2025 08:53:08 -0300 > > > Jason Gunthorpe <[email protected]> wrote: > > > > > > > On Thu, Sep 25, 2025 at 10:03:14AM +0300, Leon Romanovsky wrote: > > > > > > > > > > It would at least make sense to me then to store the provider on the > > > > > > vfio_pci_dma_buf object at the time of the get feature call rather > > > > > > than > > > > > > vfio_pci_core_init_dev() though. That would eliminate patch 08/ and > > > > > > the inline #ifdefs. > > > > > > > > > > I'll change it now. If "enable" function goes to be "get" function, we > > > > > won't need to store anything in vfio_pci_dma_buf too. At the end, we > > > > > have exactly two lines "provider = priv->vdev->provider[priv->bar];", > > > > > which can easily be changed to be "provider = > > > > > pcim_p2pdma_provider(priv->vdev->pdev, priv->bar)" > > > > > > > > Not without some kind of locking change. I'd keep the > > > > priv->vdev->provider[priv->bar] because setup during probe doesn't > > > > need special locking. > > > > > > Why do we need to store the provider on the vfio_pci_core_device at > > > probe though, we can get it later via pcim_p2pdma_provider(). > > > > Because you'd need some new locking to prevent races. > > The race is avoided if we simply call pcim_p2pdma_provider() during > probe. We don't need to save the returned provider. That's where it > seems like pulling the setup out to a separate function would eliminate > this annoying BAR# arg. > > > Besides, the model here should be to call the function once during > > probe and get back the allocated provider. The fact internally it is > > kind of nutzo still shouldn't leak out as a property of the ABI. > > > > I would like to remove this weird behavior where it caches things > > inside the struct device. That's not normal for an API to do that, it > > is only done for the genalloc path that this doesn't use. > > My goal in caching the provider on the vfio p2pdma object was to avoid > caching it on the vfio_pci_core_device, but now we're storing it on the > struct device, the vfio_pci_core_device, AND the vfio p2pdma object. > Given the current state that it's stored on the struct device, I think > we only need a setup call during probe (that could be stubbed out > rather than #ifdef'd), then cache the provider on the vfio p2pdma > object when a dmabuf is configured. Thanks,
I can do it. Thanks > > Alex >
