On Tue, Dec 06, 2022 at 11:37:26AM +0000, Wei Liu wrote:

On Mon, Dec 05, 2022 at 11:36:39PM +0800, Dawei Li wrote:

quoted

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 <redacted>

[...]

Hi Wei:
Thanks for the review.

quoted

-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.

Nice catch, will fix it.

quoted

 	}
 
 	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.

Sorry about the confusion.
In short, the point of this commit is making remove() of _driver_ void returned.

For bus-based driver, device removal is implemented as:
1 device_remove() =>
  2 bus->remove() =>
    3 driver->remove()

1 is void. 
For 2, commit fc7a6209d571 ("bus: Make remove callback return void") forces
bus_type::remove be void-returned, which applies for hv_bus(vmbus) too.
So it doesn't make sense for 3(driver->remove) to return non-void, in this case it's hv_driver. 

Thanks,
      Dawei

Thanks,
Wei.