Messages in this thread | | | Date | Mon, 2 Aug 2021 20:34:11 +0100 | From | Salah Triki <> | Subject | Re: [PATCH v2] bluetooth: bcm203x: update the reference count of udev |
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On Sun, Aug 01, 2021 at 08:01:06PM +0200, Marcel Holtmann wrote: > Hi Salah, > > > Use usb_get_dev() to increment the reference count of the usb device > > structure in order to avoid releasing the structure while it is still in > > use. And use usb_put_dev() to decrement the reference count and thus, > > when it will be equal to 0 the structure will be released. > > > > Signed-off-by: Salah Triki <salah.triki@gmail.com> > > --- > > Change since v1: > > Modification of the description > > > > drivers/bluetooth/bcm203x.c | 4 +++- > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/bluetooth/bcm203x.c b/drivers/bluetooth/bcm203x.c > > index e667933c3d70..547d35425d70 100644 > > --- a/drivers/bluetooth/bcm203x.c > > +++ b/drivers/bluetooth/bcm203x.c > > @@ -166,7 +166,7 @@ static int bcm203x_probe(struct usb_interface *intf, const struct usb_device_id > > if (!data) > > return -ENOMEM; > > > > - data->udev = udev; > > + data->udev = usb_get_dev(udev); > > data->state = BCM203X_LOAD_MINIDRV; > > > > data->urb = usb_alloc_urb(0, GFP_KERNEL); > > @@ -244,6 +244,8 @@ static void bcm203x_disconnect(struct usb_interface *intf) > > > > usb_set_intfdata(intf, NULL); > > > > + usb_put_dev(data->udev); > > + > > usb_free_urb(data->urb); > > kfree(data->fw_data); > > kfree(data->buffer); > > I do not understand this. If this is something broken, then it is broken in > btusb.c as well and that driver is heavily used by all sorts of devices. So > we should have seen bug reports about this. > > Regards > > Marcel > Hi Marcel,
The patch is based on the following documentation of usb_get_dev():
[quote] Each live reference to a device should 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_dev(), in their disconnect() methods. [/quote]
Regards
Salah
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