usbnet: allow status interrupt URB to always be active

Some drivers (sierra_net) need the status interrupt URB
active even when the device is closed, because they receive
custom indications from firmware.  Add functions to refcount
the status interrupt URB submit/kill operation so that
sub-drivers and the generic driver don't fight over whether
the status interrupt URB is active or not.

A sub-driver can call usbnet_status_start() at any time, but
the URB is only submitted the first time the function is
called.  Likewise, when the sub-driver is done with the URB,
it calls usbnet_status_stop() but the URB is only killed when
all users have stopped it.  The URB is still killed and
re-submitted for suspend/resume, as before, with the same
refcount it had at suspend.

Signed-off-by: Dan Williams <dcbw@redhat.com>
Acked-by: Oliver Neukum <oliver@neukum.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/linux/usb/usbnet.h b/include/linux/usb/usbnet.h
index da46327fca17..f18d64129f99 100644
--- a/include/linux/usb/usbnet.h
+++ b/include/linux/usb/usbnet.h
@@ -56,6 +56,8 @@ struct usbnet {
         struct sk_buff_head     done;
         struct sk_buff_head     rxq_pause;
         struct urb              *interrupt;
+        unsigned                interrupt_count;
+        struct mutex            interrupt_mutex;
         struct usb_anchor       deferred;
         struct tasklet_struct   bh;
 
@@ -248,4 +250,7 @@ extern int usbnet_nway_reset(struct net_device *net);
 extern int usbnet_manage_power(struct usbnet *, int);
 extern void usbnet_link_change(struct usbnet *, bool, bool);
 
+extern int usbnet_status_start(struct usbnet *dev, gfp_t mem_flags);
+extern void usbnet_status_stop(struct usbnet *dev);
+
 #endif /* __LINUX_USB_USBNET_H */