diff mbox series

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

Message ID TYCP286MB232373567792ED1AC5E0849FCA189@TYCP286MB2323.JPNP286.PROD.OUTLOOK.COM (mailing list archive)
State New, archived
Headers show
Series Make remove() of any bus based driver void returned | expand

Commit Message

Dawei Li Dec. 5, 2022, 3:36 p.m. UTC
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@outlook.com>
---
 drivers/gpu/drm/hyperv/hyperv_drm_drv.c | 4 +---
 drivers/hid/hid-hyperv.c                | 4 +---
 drivers/hv/hv_balloon.c                 | 5 +----
 drivers/hv/hv_util.c                    | 4 +---
 drivers/input/serio/hyperv-keyboard.c   | 4 +---
 drivers/net/hyperv/netvsc_drv.c         | 4 +---
 drivers/pci/controller/pci-hyperv.c     | 3 +--
 drivers/scsi/storvsc_drv.c              | 4 +---
 drivers/uio/uio_hv_generic.c            | 5 ++---
 drivers/video/fbdev/hyperv_fb.c         | 5 +----
 include/linux/hyperv.h                  | 2 +-
 net/vmw_vsock/hyperv_transport.c        | 4 +---
 12 files changed, 13 insertions(+), 35 deletions(-)

Comments

Wei Liu Dec. 6, 2022, 11:37 a.m. UTC | #1
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@outlook.com>
[...]
> -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.
Dawei Li Dec. 6, 2022, 2:17 p.m. UTC | #2
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:
> > 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@outlook.com>
> [...]

Hi Wei:
Thanks for the review.

> > -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.

> 
> >  	}
> >  
> >  	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.
diff mbox series

Patch

diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
index ca127ff797f7..d117fff26d99 100644
--- a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
+++ b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
@@ -165,7 +165,7 @@  static int hyperv_vmbus_probe(struct hv_device *hdev,
 	return ret;
 }
 
-static int hyperv_vmbus_remove(struct hv_device *hdev)
+static void hyperv_vmbus_remove(struct hv_device *hdev)
 {
 	struct drm_device *dev = hv_get_drvdata(hdev);
 	struct hyperv_drm_device *hv = to_hv(dev);
@@ -176,8 +176,6 @@  static int hyperv_vmbus_remove(struct hv_device *hdev)
 	hv_set_drvdata(hdev, NULL);
 
 	vmbus_free_mmio(hv->mem->start, hv->fb_size);
-
-	return 0;
 }
 
 static int hyperv_vmbus_suspend(struct hv_device *hdev)
diff --git a/drivers/hid/hid-hyperv.c b/drivers/hid/hid-hyperv.c
index ab57b49a44ed..ef16c2a54362 100644
--- a/drivers/hid/hid-hyperv.c
+++ b/drivers/hid/hid-hyperv.c
@@ -535,7 +535,7 @@  static int mousevsc_probe(struct hv_device *device,
 }
 
 
-static int mousevsc_remove(struct hv_device *dev)
+static void mousevsc_remove(struct hv_device *dev)
 {
 	struct mousevsc_dev *input_dev = hv_get_drvdata(dev);
 
@@ -544,8 +544,6 @@  static int mousevsc_remove(struct hv_device *dev)
 	hid_hw_stop(input_dev->hid_device);
 	hid_destroy_device(input_dev->hid_device);
 	mousevsc_free_device(input_dev);
-
-	return 0;
 }
 
 static int mousevsc_suspend(struct hv_device *dev)
diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index 6c127f061f06..6bbd2e6fa3d4 100644
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -1990,7 +1990,7 @@  static int balloon_probe(struct hv_device *dev,
 	return ret;
 }
 
-static int balloon_remove(struct hv_device *dev)
+static void balloon_remove(struct hv_device *dev)
 {
 	struct hv_dynmem_device *dm = hv_get_drvdata(dev);
 	struct hv_hotadd_state *has, *tmp;
@@ -2031,8 +2031,6 @@  static int balloon_remove(struct hv_device *dev)
 		kfree(has);
 	}
 	spin_unlock_irqrestore(&dm_device.ha_lock, flags);
-
-	return 0;
 }
 
 static int balloon_suspend(struct hv_device *hv_dev)
@@ -2112,7 +2110,6 @@  static  struct hv_driver balloon_drv = {
 
 static int __init init_balloon_drv(void)
 {
-
 	return vmbus_driver_register(&balloon_drv);
 }
 
diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c
index 835e6039c186..24995ac41c86 100644
--- a/drivers/hv/hv_util.c
+++ b/drivers/hv/hv_util.c
@@ -602,7 +602,7 @@  static int util_probe(struct hv_device *dev,
 	return ret;
 }
 
-static int util_remove(struct hv_device *dev)
+static void util_remove(struct hv_device *dev)
 {
 	struct hv_util_service *srv = hv_get_drvdata(dev);
 
@@ -610,8 +610,6 @@  static int util_remove(struct hv_device *dev)
 		srv->util_deinit();
 	vmbus_close(dev->channel);
 	kfree(srv->recv_buffer);
-
-	return 0;
 }
 
 /*
diff --git a/drivers/input/serio/hyperv-keyboard.c b/drivers/input/serio/hyperv-keyboard.c
index d62aefb2e245..31def6ce5157 100644
--- a/drivers/input/serio/hyperv-keyboard.c
+++ b/drivers/input/serio/hyperv-keyboard.c
@@ -369,7 +369,7 @@  static int hv_kbd_probe(struct hv_device *hv_dev,
 	return error;
 }
 
-static int hv_kbd_remove(struct hv_device *hv_dev)
+static void hv_kbd_remove(struct hv_device *hv_dev)
 {
 	struct hv_kbd_dev *kbd_dev = hv_get_drvdata(hv_dev);
 
@@ -378,8 +378,6 @@  static int hv_kbd_remove(struct hv_device *hv_dev)
 	kfree(kbd_dev);
 
 	hv_set_drvdata(hv_dev, NULL);
-
-	return 0;
 }
 
 static int hv_kbd_suspend(struct hv_device *hv_dev)
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 89eb4f179a3c..50c20e4d4147 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -2594,7 +2594,7 @@  static int netvsc_probe(struct hv_device *dev,
 	return ret;
 }
 
-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;
 	}
 
 	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
  */
-static int hv_pci_remove(struct hv_device *hdev)
+static void hv_pci_remove(struct hv_device *hdev)
 {
 	struct hv_pcibus_device *hbus;
 	int ret;
@@ -3795,7 +3795,6 @@  static int hv_pci_remove(struct hv_device *hdev)
 	hv_put_dom_num(hbus->bridge->domain_nr);
 
 	kfree(hbus);
-	return ret;
 }
 
 static int hv_pci_suspend(struct hv_device *hdev)
diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index bc46721aa01c..d253e7d5959d 100644
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -2093,7 +2093,7 @@  static int storvsc_change_queue_depth(struct scsi_device *sdev, int queue_depth)
 	return scsi_change_queue_depth(sdev, queue_depth);
 }
 
-static int storvsc_remove(struct hv_device *dev)
+static void storvsc_remove(struct hv_device *dev)
 {
 	struct storvsc_device *stor_device = hv_get_drvdata(dev);
 	struct Scsi_Host *host = stor_device->host;
@@ -2109,8 +2109,6 @@  static int storvsc_remove(struct hv_device *dev)
 	scsi_remove_host(host);
 	storvsc_dev_remove(dev);
 	scsi_host_put(host);
-
-	return 0;
 }
 
 static int storvsc_suspend(struct hv_device *hv_dev)
diff --git a/drivers/uio/uio_hv_generic.c b/drivers/uio/uio_hv_generic.c
index c08a6cfd119f..20d9762331bd 100644
--- a/drivers/uio/uio_hv_generic.c
+++ b/drivers/uio/uio_hv_generic.c
@@ -355,20 +355,19 @@  hv_uio_probe(struct hv_device *dev,
 	return ret;
 }
 
-static int
+static void
 hv_uio_remove(struct hv_device *dev)
 {
 	struct hv_uio_private_data *pdata = hv_get_drvdata(dev);
 
 	if (!pdata)
-		return 0;
+		return;
 
 	sysfs_remove_bin_file(&dev->channel->kobj, &ring_buffer_bin_attr);
 	uio_unregister_device(&pdata->info);
 	hv_uio_cleanup(dev, pdata);
 
 	vmbus_free_ring(dev->channel);
-	return 0;
 }
 
 static struct hv_driver hv_uio_drv = {
diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c
index 072ce07ba9e0..721b7c34a99e 100644
--- a/drivers/video/fbdev/hyperv_fb.c
+++ b/drivers/video/fbdev/hyperv_fb.c
@@ -1226,8 +1226,7 @@  static int hvfb_probe(struct hv_device *hdev,
 	return ret;
 }
 
-
-static int hvfb_remove(struct hv_device *hdev)
+static void hvfb_remove(struct hv_device *hdev)
 {
 	struct fb_info *info = hv_get_drvdata(hdev);
 	struct hvfb_par *par = info->par;
@@ -1248,8 +1247,6 @@  static int hvfb_remove(struct hv_device *hdev)
 
 	hvfb_putmem(hdev, info);
 	framebuffer_release(info);
-
-	return 0;
 }
 
 static int hvfb_suspend(struct hv_device *hdev)
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 3b42264333ef..1f128f28a487 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1273,7 +1273,7 @@  struct hv_driver {
 	} dynids;
 
 	int (*probe)(struct hv_device *, const struct hv_vmbus_device_id *);
-	int (*remove)(struct hv_device *);
+	void (*remove)(struct hv_device *dev);
 	void (*shutdown)(struct hv_device *);
 
 	int (*suspend)(struct hv_device *);
diff --git a/net/vmw_vsock/hyperv_transport.c b/net/vmw_vsock/hyperv_transport.c
index 59c3e2697069..7cb1a9d2cdb4 100644
--- a/net/vmw_vsock/hyperv_transport.c
+++ b/net/vmw_vsock/hyperv_transport.c
@@ -879,13 +879,11 @@  static int hvs_probe(struct hv_device *hdev,
 	return 0;
 }
 
-static int hvs_remove(struct hv_device *hdev)
+static void hvs_remove(struct hv_device *hdev)
 {
 	struct vmbus_channel *chan = hdev->channel;
 
 	vmbus_close(chan);
-
-	return 0;
 }
 
 /* hv_sock connections can not persist across hibernation, and all the hv_sock