Re: [PATCH 1/3 v2] iommu/fsl: Factor out PCI specific code.

From: Alex Williamson
Date: Mon Dec 02 2013 - 16:34:04 EST


On Wed, 2013-10-16 at 16:53 +0530, Varun Sethi wrote:
> Factor out PCI specific code in the PAMU driver.
>
> Signed-off-by: Varun Sethi <Varun.Sethi@xxxxxxxxxxxxx>
> ---
> drivers/iommu/fsl_pamu_domain.c | 88 +++++++++++++++++++--------------------
> 1 file changed, 43 insertions(+), 45 deletions(-)
>
> diff --git a/drivers/iommu/fsl_pamu_domain.c b/drivers/iommu/fsl_pamu_domain.c
> index c857c30..966ae70 100644
> --- a/drivers/iommu/fsl_pamu_domain.c
> +++ b/drivers/iommu/fsl_pamu_domain.c
> @@ -677,21 +677,15 @@ static int handle_attach_device(struct fsl_dma_domain *dma_domain,
> return ret;
> }
>
> -static int fsl_pamu_attach_device(struct iommu_domain *domain,
> - struct device *dev)
> +static struct device *get_dma_device(struct device *dev)
> {
> - struct fsl_dma_domain *dma_domain = domain->priv;
> - const u32 *liodn;
> - u32 liodn_cnt;
> - int len, ret = 0;
> - struct pci_dev *pdev = NULL;
> - struct pci_controller *pci_ctl;
> + struct device *dma_dev = dev;
> +#ifdef CONFIG_PCI
>
> - /*
> - * Use LIODN of the PCI controller while attaching a
> - * PCI device.
> - */
> if (dev->bus == &pci_bus_type) {
> + struct pci_controller *pci_ctl;
> + struct pci_dev *pdev;
> +
> pdev = to_pci_dev(dev);
> pci_ctl = pci_bus_to_host(pdev->bus);
> /*
> @@ -699,17 +693,31 @@ static int fsl_pamu_attach_device(struct iommu_domain *domain,
> * so we can get the LIODN programmed by
> * u-boot.
> */
> - dev = pci_ctl->parent;
> + dma_dev = pci_ctl->parent;
> }
> +#endif
> + return dma_dev;
> +}
> +
> +static int fsl_pamu_attach_device(struct iommu_domain *domain,
> + struct device *dev)
> +{
> + struct fsl_dma_domain *dma_domain = domain->priv;
> + struct device *dma_dev;
> + const u32 *liodn;
> + u32 liodn_cnt;
> + int len, ret = 0;
> +
> + dma_dev = get_dma_device(dev);
>
> - liodn = of_get_property(dev->of_node, "fsl,liodn", &len);
> + liodn = of_get_property(dma_dev->of_node, "fsl,liodn", &len);
> if (liodn) {
> liodn_cnt = len / sizeof(u32);
> ret = handle_attach_device(dma_domain, dev,
> liodn, liodn_cnt);
> } else {
> pr_debug("missing fsl,liodn property at %s\n",
> - dev->of_node->full_name);
> + dma_dev->of_node->full_name);
> ret = -EINVAL;
> }
>
> @@ -720,32 +728,18 @@ static void fsl_pamu_detach_device(struct iommu_domain *domain,
> struct device *dev)
> {
> struct fsl_dma_domain *dma_domain = domain->priv;
> + struct device *dma_dev;
> const u32 *prop;
> int len;
> - struct pci_dev *pdev = NULL;
> - struct pci_controller *pci_ctl;
>
> - /*
> - * Use LIODN of the PCI controller while detaching a
> - * PCI device.
> - */
> - if (dev->bus == &pci_bus_type) {
> - pdev = to_pci_dev(dev);
> - pci_ctl = pci_bus_to_host(pdev->bus);
> - /*
> - * make dev point to pci controller device
> - * so we can get the LIODN programmed by
> - * u-boot.
> - */
> - dev = pci_ctl->parent;
> - }
> + dma_dev = get_dma_device(dev);
>
> - prop = of_get_property(dev->of_node, "fsl,liodn", &len);
> + prop = of_get_property(dma_dev->of_node, "fsl,liodn", &len);
> if (prop)
> detach_device(dev, dma_domain);
> else
> pr_debug("missing fsl,liodn property at %s\n",
> - dev->of_node->full_name);
> + dma_dev->of_node->full_name);
> }
>
> static int configure_domain_geometry(struct iommu_domain *domain, void *data)
> @@ -905,6 +899,7 @@ static struct iommu_group *get_device_iommu_group(struct device *dev)
> return group;
> }
>
> +#ifdef CONFIG_PCI
> static bool check_pci_ctl_endpt_part(struct pci_controller *pci_ctl)
> {
> u32 version;
> @@ -945,13 +940,18 @@ static struct iommu_group *get_shared_pci_device_group(struct pci_dev *pdev)
> return NULL;
> }
>
> -static struct iommu_group *get_pci_device_group(struct pci_dev *pdev)
> +static struct iommu_group *get_pci_device_group(struct device *dev)
> {
> struct pci_controller *pci_ctl;
> bool pci_endpt_partioning;
> struct iommu_group *group = NULL;
> - struct pci_dev *bridge, *dma_pdev = NULL;
> + struct pci_dev *bridge, *pdev;
> + struct pci_dev *dma_pdev = NULL;
>
> + pdev = to_pci_dev(dev);
> + /* Don't create device groups for virtual PCI bridges */
> + if (pdev->subordinate)
> + return NULL;
> pci_ctl = pci_bus_to_host(pdev->bus);
> pci_endpt_partioning = check_pci_ctl_endpt_part(pci_ctl);
> /* We can partition PCIe devices so assign device group to the device */
> @@ -1044,11 +1044,11 @@ root_bus:
>
> return group;
> }
> +#endif
>
> static int fsl_pamu_add_device(struct device *dev)
> {
> struct iommu_group *group = NULL;
> - struct pci_dev *pdev;
> const u32 *prop;
> int ret, len;
>
> @@ -1056,19 +1056,15 @@ static int fsl_pamu_add_device(struct device *dev)
> * For platform devices we allocate a separate group for
> * each of the devices.
> */
> - if (dev->bus == &pci_bus_type) {
> - pdev = to_pci_dev(dev);
> - /* Don't create device groups for virtual PCI bridges */
> - if (pdev->subordinate)
> - return 0;
> -
> - group = get_pci_device_group(pdev);
> -
> - } else {
> + if (dev->bus == &platform_bus_type) {
> prop = of_get_property(dev->of_node, "fsl,liodn", &len);
> if (prop)
> group = get_device_iommu_group(dev);
> }
> +#ifdef CONFIG_PCI
> + else
> + group = get_pci_device_group(dev);
> +#endif
>
> if (!group || IS_ERR(group))
> return PTR_ERR(group);

It feels like there's a bug here that group is initialized to NULL and
there are a few ways for it to remain NULL through the above code, then
we get here and return PTR_ERR(NULL), which is indistinguishable from a
successful return below. Perhaps !group is ok, but if so I'd suggest a
separate return block for it. Thanks,

Alex

> @@ -1166,7 +1162,9 @@ int pamu_domain_init()
> return ret;
>
> bus_set_iommu(&platform_bus_type, &fsl_pamu_ops);
> +#ifdef CONFIG_PCI
> bus_set_iommu(&pci_bus_type, &fsl_pamu_ops);
> +#endif
>
> return ret;
> }



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