Re: [PATCH 1/6] hyperv: Make remove callback of hyperv driver void returned

From: Wei Liu
Date: Tue Dec 06 2022 - 06:37:56 EST


On Mon, Dec 05, 2022 at 11:36:39PM +0800, Dawei Li wrote:
> Since commit fc7a6209d571 ("bus: Make remove callback return
> void") forces bus_type::remove be void-returned, it doesn't
> make much sense for any bus based driver implementing remove
> callbalk to return non-void to its caller.
>
> This change is for hyperv bus based drivers.
>
> Signed-off-by: Dawei Li <set_pte_at@xxxxxxxxxxx>
[...]
> -static int netvsc_remove(struct hv_device *dev)
> +static void netvsc_remove(struct hv_device *dev)
> {
> struct net_device_context *ndev_ctx;
> struct net_device *vf_netdev, *net;
> @@ -2603,7 +2603,6 @@ static int netvsc_remove(struct hv_device *dev)
> net = hv_get_drvdata(dev);
> if (net == NULL) {
> dev_err(&dev->device, "No net device to remove\n");
> - return 0;

This is wrong. You are introducing a NULL pointer dereference.

> }
>
> ndev_ctx = netdev_priv(net);
> @@ -2637,7 +2636,6 @@ static int netvsc_remove(struct hv_device *dev)
>
> free_percpu(ndev_ctx->vf_stats);
> free_netdev(net);
> - return 0;
> }
>
> static int netvsc_suspend(struct hv_device *dev)
> diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
> index ba64284eaf9f..3a09de70d6ea 100644
> --- a/drivers/pci/controller/pci-hyperv.c
> +++ b/drivers/pci/controller/pci-hyperv.c
> @@ -3756,7 +3756,7 @@ static int hv_pci_bus_exit(struct hv_device *hdev, bool keep_devs)
> *
> * Return: 0 on success, -errno on failure
> */

This comment is no longer needed in the new world.

But, are you sure you're modifying the correct piece of code?

hv_pci_remove is not a hook in the base bus type. It is used in struct
hv_driver.

The same comment applies to all other modifications.

Thanks,
Wei.