RE: [PATCH hyperv-next v5 09/11] Drivers: hv: vmbus: Introduce hv_get_vmbus_root_device()

Michael Kelley
2025-03-10T23:12:23Z

From: Roman Kisel <romank@linux.microsoft.com> Sent: Friday, March 7, 2025 2:03 PM
>
> The ARM64 PCI code for hyperv needs to know the VMBus root
> device, and it is private.
>
> Provide a function that returns it. Rename it from "hv_dev"
> as "hv_dev" as a symbol is very overloaded. No functional
> changes.
>
> Signed-off-by: Roman Kisel <romank@linux.microsoft.com>

Reviewed-by: Michael Kelley <mhklinux@outlook.com>

> ---
> drivers/hv/vmbus_drv.c | 23 +++++++++++++++--------
> include/linux/hyperv.h | 2 ++
> 2 files changed, 17 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index c8474b48dcd2..7bfafe702963 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -45,7 +45,8 @@ struct vmbus_dynid {
> struct hv_vmbus_device_id id;
> };
>
> -static struct device *hv_dev;
> +/* VMBus Root Device */
> +static struct device *vmbus_root_device;
>
> static int hyperv_cpuhp_online;
>
> @@ -80,9 +81,15 @@ static struct resource *fb_mmio;
> static struct resource *hyperv_mmio;
> static DEFINE_MUTEX(hyperv_mmio_lock);
>
> +struct device *hv_get_vmbus_root_device(void)
> +{
> + return vmbus_root_device;
> +}
> +EXPORT_SYMBOL_GPL(hv_get_vmbus_root_device);
> +
> static int vmbus_exists(void)
> {
> - if (hv_dev == NULL)
> + if (vmbus_root_device == NULL)
> return -ENODEV;
>
> return 0;
> @@ -861,7 +868,7 @@ static int vmbus_dma_configure(struct device *child_device)
> * On x86/x64 coherence is assumed and these calls have no effect.
> */
> hv_setup_dma_ops(child_device,
> - device_get_dma_attr(hv_dev) == DEV_DMA_COHERENT);
> + device_get_dma_attr(vmbus_root_device) == DEV_DMA_COHERENT);
> return 0;
> }
>
> @@ -1930,7 +1937,7 @@ int vmbus_device_register(struct hv_device *child_device_obj)
> &child_device_obj->channel->offermsg.offer.if_instance);
>
> child_device_obj->device.bus = &hv_bus;
> - child_device_obj->device.parent = hv_dev;
> + child_device_obj->device.parent = vmbus_root_device;
> child_device_obj->device.release = vmbus_device_release;
>
> child_device_obj->device.dma_parms = &child_device_obj->dma_parms;
> @@ -2292,7 +2299,7 @@ static int vmbus_acpi_add(struct platform_device *pdev)
> struct acpi_device *ancestor;
> struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
>
> - hv_dev = &device->dev;
> + vmbus_root_device = &device->dev;
>
> /*
> * Older versions of Hyper-V for ARM64 fail to include the _CCA
> @@ -2383,7 +2390,7 @@ static int vmbus_device_add(struct platform_device *pdev)
> struct device_node *np = pdev->dev.of_node;
> int ret;
>
> - hv_dev = &pdev->dev;
> + vmbus_root_device = &pdev->dev;
>
> ret = of_range_parser_init(&parser, np);
> if (ret)
> @@ -2702,7 +2709,7 @@ static int __init hv_acpi_init(void)
> if (ret)
> return ret;
>
> - if (!hv_dev) {
> + if (!vmbus_root_device) {
> ret = -ENODEV;
> goto cleanup;
> }
> @@ -2733,7 +2740,7 @@ static int __init hv_acpi_init(void)
>
> cleanup:
> platform_driver_unregister(&vmbus_platform_driver);
> - hv_dev = NULL;
> + vmbus_root_device = NULL;
> return ret;
> }
>
> diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
> index 7f4f8d8bdf43..1f0851fde041 100644
> --- a/include/linux/hyperv.h
> +++ b/include/linux/hyperv.h
> @@ -1333,6 +1333,8 @@ static inline void *hv_get_drvdata(struct hv_device *dev)
> return dev_get_drvdata(&dev->device);
> }
>
> +struct device *hv_get_vmbus_root_device(void);
> +
> struct hv_ring_buffer_debug_info {
> u32 current_interrupt_mask;
> u32 current_read_index;
> --
> 2.43.0
>