On Sun, Jul 25, 2021 at 12:56:37AM +0100, Salah Triki wrote: > Hi, > > On Sat, Jul 24, 2021 at 04:08:02PM -0700, Dmitry Torokhov wrote: > > > > On Sat, Jul 24, 2021 at 10:20:16PM +0100, Salah Triki wrote: > > > Use usb_get_intf() and usb_put_intf() in order to update the reference > > > count of the usb interface structure. > > > > This is quite pointless as the driver will be unbound from the interface > > before interface is deleted. > > From the documentation of usb_get_intf(): > > [quote] > > Each live reference to a interface must be refcounted. > > Drivers for USB interfaces should normally record such references in their > probe() methods, when they bind to an interface, and release them by calling > usb_put_intf(), in their disconnect() methods. > > [/quote] I see. In this case I recommend you submit a patch to the documentation clarifying this, as taking a reference when binding to an interface makes sense when dealing with a secondary interface, but not primary one. See for example drivers/usb/class/cdc-acm.c where it binds to the data interface, but also locates control interface and bumps up reference to that. As you may notice there is only a handful of drivers that use this API, and as I am looking at them most do not actually need to use it. Thanks. -- Dmitry
