Re: [PATCH V8 9/9] virtio: Intel IFC VF driver for VDPA

[Jason Wang]

On 2020/3/25 äå8:34, Jason Gunthorpe wrote:
> On Wed, Mar 25, 2020 at 04:27:11PM +0800, Jason Wang wrote:
> > +static int ifcvf_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> > +{
> > +	struct device *dev = &pdev->dev;
> > +	struct ifcvf_adapter *adapter;
> > +	struct ifcvf_hw *vf;
> > +	int ret, i;
> > +
> > +	ret = pci_enable_device(pdev);
> > +	if (ret) {
> > +		IFCVF_ERR(&pdev->dev, "Failed to enable device\n");
> > +		goto err_enable;
> > +	}
> > +
> > +	ret = pci_request_regions(pdev, IFCVF_DRIVER_NAME);
> > +	if (ret) {
> > +		IFCVF_ERR(&pdev->dev, "Failed to request MMIO region\n");
> > +		goto err_regions;
> > +	}
> > +
> > +	ret = pci_alloc_irq_vectors(pdev, IFCVF_MAX_INTR,
> > +				    IFCVF_MAX_INTR, PCI_IRQ_MSIX);
> > +	if (ret < 0) {
> > +		IFCVF_ERR(&pdev->dev, "Failed to alloc irq vectors\n");
> > +		goto err_vectors;
> > +	}
> > +
> > +	adapter = vdpa_alloc_device(ifcvf_adapter, vdpa, dev, &ifc_vdpa_ops);
> > +	if (adapter == NULL) {
> > +		IFCVF_ERR(&pdev->dev, "Failed to allocate vDPA structure");
> > +		ret = -ENOMEM;
> > +		goto err_alloc;
> > +	}
> > +
> > +	adapter->dev = dev;
> > +	pci_set_master(pdev);
> > +	pci_set_drvdata(pdev, adapter);
> > +
> > +	ret = ifcvf_request_irq(adapter);
> > +	if (ret) {
> > +		IFCVF_ERR(&pdev->dev, "Failed to request MSI-X irq\n");
> > +		goto err_msix;
> > +	}
> > +
> > +	vf = &adapter->vf;
> > +	for (i = 0; i < IFCVF_PCI_MAX_RESOURCE; i++) {
> > +		vf->mem_resource[i].phys_addr = pci_resource_start(pdev, i);
> > +		vf->mem_resource[i].len = pci_resource_len(pdev, i);
> > +		if (!vf->mem_resource[i].len)
> > +			continue;
> > +
> > +		vf->mem_resource[i].addr = pci_iomap_range(pdev, i, 0,
> > +				vf->mem_resource[i].len);
> > +		if (!vf->mem_resource[i].addr) {
> > +			IFCVF_ERR(&pdev->dev,
> > +				  "Failed to map IO resource %d\n", i);
> > +			ret = -EINVAL;
> > +			goto err_msix;
> > +		}
> > +	}
> > +
> > +	if (ifcvf_init_hw(vf, pdev) < 0) {
> > +		ret = -EINVAL;
> > +		goto err_msix;
> > +	}
> > +
> > +	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
> > +	if (ret)
> > +		ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
> > +
> > +	if (ret) {
> > +		IFCVF_ERR(adapter->dev, "No usable DMA confiugration\n");
> > +		ret = -EINVAL;
> > +		goto err_msix;
> > +	}
> > +
> > +	adapter->vdpa.dma_dev = dev;
> > +	ret = vdpa_register_device(&adapter->vdpa);
> > +	if (ret) {
> > +		IFCVF_ERR(adapter->dev, "Failed to register ifcvf to vdpa bus");
> > +		goto err_msix;
> > +	}
> > +
> > +	return 0;
> > +
> > +err_msix:
> > +	put_device(&adapter->vdpa.dev);
> > +	return ret;
> > +err_alloc:
> > +	pci_free_irq_vectors(pdev);
> > +err_vectors:
> > +	pci_release_regions(pdev);
> > +err_regions:
> > +	pci_disable_device(pdev);
> > +err_enable:
> > +	return ret;
> > +}
> I personally don't like seeing goto unwinds with multiple returns, and
> here I think it is actually a tiny bug.
>
> All touches to the PCI device must stop before the driver core
> remove() returns - so these pci function cannot be in the kref put
> release function anyhow.


I'm not sure I get here. IFCVF held refcnt of its PCI parent, so it 
looks to me it's safe to free PCI resources in vDPA free callback?


> Suggest to use the devm versions of the above instead, and then you
> can reorder things so the allocation is done first.
>
> Jason


Using devm looks nice, but if it's possible I prefer to tweak on top.

Thanks


>