@@ -564,7 +564,6 @@ static void skel_disconnect(struct usb_interface *interface)
int minor = interface->minor;
dev = usb_get_intfdata(interface);
- usb_set_intfdata(interface, NULL);
/* give back our minor */
usb_deregister_dev(interface, &skel_class);
@@ -265,6 +265,18 @@ static inline void *usb_get_intfdata(struct usb_interface *intf)
return dev_get_drvdata(&intf->dev);
}
+/**
+ * usb_set_intfdata() - associate driver-specific data with the interface
+ * @intf: the usb interface
+ * @data: pointer to the device priv structure or %NULL
+ *
+ * Drivers should use this function in their probe() to associate their
+ * driver-specific data with the usb interface.
+ *
+ * When disconnecting, the core will take care of setting @intf back to %NULL,
+ * so no actions are needed on the driver side. The interface should not be set
+ * to %NULL before all actions completed (e.g. no outsanding URB remaining).
+ */
static inline void usb_set_intfdata(struct usb_interface *intf, void *data)
{
dev_set_drvdata(&intf->dev, data);
USB drivers do not need to call usb_set_intfdata(intf, NULL) in their usb_driver::disconnect callback because the core already does it in [1]. However, this fact is widely unknown, c.f.: $ git grep "usb_set_intfdata(.*NULL)" | wc -l 215 Especially, setting the interface to NULL before all action completed can result in a NULL pointer dereference. Not calling usb_set_intfdata() at all in disconnect() is the safest method. Add documentation to usb_set_intfdata() to clarify this point. Also remove the call in usb-skeletion's disconnect() not to confuse the new comers. [1] function usb_unbind_interface() from drivers/usb/core/driver.c Link: https://elixir.bootlin.com/linux/v6.0/source/drivers/usb/core/driver.c#L497 Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> --- drivers/usb/usb-skeleton.c | 1 - include/linux/usb.h | 12 ++++++++++++ 2 files changed, 12 insertions(+), 1 deletion(-)