[PATCH] i2c: diolan-u2c: drop redundant device reference

[PATCH] i2c: diolan-u2c: drop redundant device reference

[Johan Hovold]

Driver core holds a reference to the USB interface and its parent USB
device while the interface is bound to a driver and there is no need to
take additional references unless the structures are needed after
disconnect.

Drop the redundant device reference to reduce cargo culting, make it
easier to spot drivers where an extra reference is needed, and reduce
the risk of memory leaks when drivers fail to release it.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/i2c/busses/i2c-diolan-u2c.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/drivers/i2c/busses/i2c-diolan-u2c.c b/drivers/i2c/busses/i2c-diolan-u2c.c
index 077b093ba834..d502f6e4732f 100644
--- a/drivers/i2c/busses/i2c-diolan-u2c.c
+++ b/drivers/i2c/busses/i2c-diolan-u2c.c
@@ -427,12 +427,6 @@ static const struct usb_device_id diolan_u2c_table[] = {
 
 MODULE_DEVICE_TABLE(usb, diolan_u2c_table);
 
-static void diolan_u2c_free(struct i2c_diolan_u2c *dev)
-{
-	usb_put_dev(dev->usb_dev);
-	kfree(dev);
-}
-
 static int diolan_u2c_probe(struct usb_interface *interface,
 			    const struct usb_device_id *id)
 {
@@ -453,7 +447,7 @@ static int diolan_u2c_probe(struct usb_interface *interface,
 	dev->ep_out = hostif->endpoint[0].desc.bEndpointAddress;
 	dev->ep_in = hostif->endpoint[1].desc.bEndpointAddress;
 
-	dev->usb_dev = usb_get_dev(interface_to_usbdev(interface));
+	dev->usb_dev = interface_to_usbdev(interface);
 	dev->interface = interface;
 
 	/* save our data pointer in this interface device */
@@ -488,7 +482,7 @@ static int diolan_u2c_probe(struct usb_interface *interface,
 
 error_free:
 	usb_set_intfdata(interface, NULL);
-	diolan_u2c_free(dev);
+	kfree(dev);
 error:
 	return ret;
 }
@@ -499,7 +493,7 @@ static void diolan_u2c_disconnect(struct usb_interface *interface)
 
 	i2c_del_adapter(&dev->adapter);
 	usb_set_intfdata(interface, NULL);
-	diolan_u2c_free(dev);
+	kfree(dev);
 
 	dev_dbg(&interface->dev, "disconnected\n");
 }
-- 
2.52.0

Re: [PATCH] i2c: diolan-u2c: drop redundant device reference

[Wolfram Sang]

On Thu, Mar 05, 2026 at 01:52:21PM +0100, Johan Hovold wrote:
> Driver core holds a reference to the USB interface and its parent USB
> device while the interface is bound to a driver and there is no need to
> take additional references unless the structures are needed after
> disconnect.
> 
> Drop the redundant device reference to reduce cargo culting, make it
> easier to spot drivers where an extra reference is needed, and reduce
> the risk of memory leaks when drivers fail to release it.
> 
> Signed-off-by: Johan Hovold <johan@kernel.org>

Applied to for-next, thanks!