Re: [dpdk-dev] [PATCH v6 4/4] kernel/linux/kni: add IOVA support in kni module

[Stephen Hemminger <stephen@networkplumber.org>]

On Tue, 25 Jun 2019 09:27:00 +0530
<vattunuru@marvell.com> wrote:

> diff --git a/kernel/linux/kni/kni_misc.c b/kernel/linux/kni/kni_misc.c
> index 1fc5eeb..b70c827 100644
> --- a/kernel/linux/kni/kni_misc.c
> +++ b/kernel/linux/kni/kni_misc.c
> @@ -294,6 +294,9 @@ kni_ioctl_create(struct net *net, uint32_t ioctl_num,
>  	struct rte_kni_device_info dev_info;
>  	struct net_device *net_dev = NULL;
>  	struct kni_dev *kni, *dev, *n;
> +	struct pci_dev *pci = NULL;
> +	struct iommu_domain *domain = NULL;

Please don't do unnecessary initailization. It defeats the purpose
of compiler and static checkers.

> +	phys_addr_t phys_addr;
>  
>  	pr_info("Creating kni...\n");
>  	/* Check the buffer size, to avoid warning */
> @@ -351,15 +354,56 @@ kni_ioctl_create(struct net *net, uint32_t ioctl_num,
>  	strncpy(kni->name, dev_info.name, RTE_KNI_NAMESIZE);
>  
>  	/* Translate user space info into kernel space info */
> -	kni->tx_q = phys_to_virt(dev_info.tx_phys);
> -	kni->rx_q = phys_to_virt(dev_info.rx_phys);
> -	kni->alloc_q = phys_to_virt(dev_info.alloc_phys);
> -	kni->free_q = phys_to_virt(dev_info.free_phys);
> -
> -	kni->req_q = phys_to_virt(dev_info.req_phys);
> -	kni->resp_q = phys_to_virt(dev_info.resp_phys);
> -	kni->sync_va = dev_info.sync_va;
> -	kni->sync_kva = phys_to_virt(dev_info.sync_phys);
> +	if (dev_info.iova_mode) {
> +#if KERNEL_VERSION(4, 4, 0) > LINUX_VERSION_CODE
> +		(void)pci;
> +		pr_err("Kernel version is not supported\n");
> +		return -EINVAL;
> +#else
> +		pci = pci_get_device(dev_info.vendor_id,
> +				     dev_info.device_id, NULL);
> +		while (pci) {
> +			if ((pci->bus->number == dev_info.bus) &&
> +			    (PCI_SLOT(pci->devfn) == dev_info.devid) &&
> +			    (PCI_FUNC(pci->devfn) == dev_info.function)) {
> +				domain = iommu_get_domain_for_dev(&pci->dev);
> +				break;
> +			}
> +			pci = pci_get_device(dev_info.vendor_id,
> +					     dev_info.device_id, pci);
> +		}
> +#endif

Why not move the variable pci inside the if() statement, then (void)pci
is unnecessary.