[PATCH] gpio: mpsse: drop redundant device reference

[PATCH] gpio: mpsse: 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/gpio/gpio-mpsse.c | 13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

diff --git a/drivers/gpio/gpio-mpsse.c b/drivers/gpio/gpio-mpsse.c
index 12191aeb6566..a859deab2bca 100644
--- a/drivers/gpio/gpio-mpsse.c
+++ b/drivers/gpio/gpio-mpsse.c
@@ -548,13 +548,6 @@ static void gpio_mpsse_ida_remove(void *data)
 	ida_free(&gpio_mpsse_ida, priv->id);
 }
 
-static void gpio_mpsse_usb_put_dev(void *data)
-{
-	struct mpsse_priv *priv = data;
-
-	usb_put_dev(priv->udev);
-}
-
 static int mpsse_init_valid_mask(struct gpio_chip *chip,
 				 unsigned long *valid_mask,
 				 unsigned int ngpios)
@@ -598,11 +591,7 @@ static int gpio_mpsse_probe(struct usb_interface *interface,
 
 	INIT_LIST_HEAD(&priv->workers);
 
-	priv->udev = usb_get_dev(interface_to_usbdev(interface));
-	err = devm_add_action_or_reset(dev, gpio_mpsse_usb_put_dev, priv);
-	if (err)
-		return err;
-
+	priv->udev = interface_to_usbdev(interface);
 	priv->intf = interface;
 	priv->intf_id = interface->cur_altsetting->desc.bInterfaceNumber;
 
-- 
2.52.0

Re: [PATCH] gpio: mpsse: drop redundant device reference

[Linus Walleij]

On Thu, Mar 5, 2026 at 1:49 PM Johan Hovold <johan@kernel.org> 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>

Looks right to me.
Reviewed-by: Linus Walleij <linusw@kernel.org>

Yours,
Linus Walleij

Re: [PATCH] gpio: mpsse: drop redundant device reference

[Bartosz Golaszewski]

On Thu, 05 Mar 2026 13:49:45 +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.
> 
> [...]

Applied, thanks!

[1/1] gpio: mpsse: drop redundant device reference
      https://git.kernel.org/brgl/c/3671411e9073cb06d726dbf10835d158e18f0796

Best regards,
-- 
Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>