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

Jason Wang
2020-03-26T05:51:24Z

On 2020/3/25 下午8:34, 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

>