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@xxxxxxxxxx>
---
NOTE: Oliver already ACK-ed this series, but Ming disagreed about the
mem_flags argument to usbnet_status_start() and consensus seems far away;
given that it's not userspace API/ABI, I'd like to see the series go in.
drivers/net/usb/usbnet.c | 79 ++++++++++++++++++++++++++++++++++++++++++----
include/linux/usb/usbnet.h | 5 +++
2 files changed, 77 insertions(+), 7 deletions(-)
diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index 51f3192..b71ce36 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -252,6 +252,70 @@ static int init_status (struct usbnet *dev, struct usb_interface *intf)
return 0;
}
+/* Submit the interrupt URB if not previously submitted, increasing refcount */
+int usbnet_status_start(struct usbnet *dev, gfp_t mem_flags)
+{
+ int ret = 0;
+
+ WARN_ON_ONCE(dev->interrupt == NULL);
+ if (dev->interrupt) {
+ mutex_lock(&dev->interrupt_mutex);
+
+ if (++dev->interrupt_count == 1)
+ ret = usb_submit_urb(dev->interrupt, mem_flags);
+
+ dev_dbg(&dev->udev->dev, "incremented interrupt URB count to %d\n",
+ dev->interrupt_count);
+ mutex_unlock(&dev->interrupt_mutex);
+ }
+ return ret;
+}
+EXPORT_SYMBOL_GPL(usbnet_status_start);
+
+/* For resume; submit interrupt URB if previously submitted */
+static int __usbnet_status_start_force(struct usbnet *dev, gfp_t mem_flags)
+{
+ int ret = 0;
+
+ mutex_lock(&dev->interrupt_mutex);
+ if (dev->interrupt_count) {
+ ret = usb_submit_urb(dev->interrupt, mem_flags);
+ dev_dbg(&dev->udev->dev,
+ "submitted interrupt URB for resume\n");
+ }
+ mutex_unlock(&dev->interrupt_mutex);
+ return ret;
+}
+
+/* Kill the interrupt URB if all submitters want it killed */
+void usbnet_status_stop(struct usbnet *dev)
+{
+ if (dev->interrupt) {
+ mutex_lock(&dev->interrupt_mutex);
+ WARN_ON(dev->interrupt_count == 0);
+
+ if (dev->interrupt_count && --dev->interrupt_count == 0)
+ usb_kill_urb(dev->interrupt);
+
+ dev_dbg(&dev->udev->dev,
+ "decremented interrupt URB count to %d\n",
+ dev->interrupt_count);
+ mutex_unlock(&dev->interrupt_mutex);
+ }
+}
+EXPORT_SYMBOL_GPL(usbnet_status_stop);
+
+/* For suspend; always kill interrupt URB */
+static void __usbnet_status_stop_force(struct usbnet *dev)
+{
+ if (dev->interrupt) {
+ mutex_lock(&dev->interrupt_mutex);
+ usb_kill_urb(dev->interrupt);
+ dev_dbg(&dev->udev->dev, "killed interrupt URB for suspend\n");
+ mutex_unlock(&dev->interrupt_mutex);
+ }
+}
+
/* Passes this packet up the stack, updating its accounting.
* Some link protocols batch packets, so their rx_fixup paths
* can return clones as well as just modify the original skb.
@@ -725,7 +789,7 @@ int usbnet_stop (struct net_device *net)
if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
usbnet_terminate_urbs(dev);
- usb_kill_urb(dev->interrupt);
+ usbnet_status_stop(dev);
usbnet_purge_paused_rxq(dev);
@@ -787,7 +851,7 @@ int usbnet_open (struct net_device *net)
/* start any status interrupt transfer */
if (dev->interrupt) {
- retval = usb_submit_urb (dev->interrupt, GFP_KERNEL);
+ retval = usbnet_status_start(dev, GFP_KERNEL);
if (retval < 0) {
netif_err(dev, ifup, dev->net,
"intr submit %d\n", retval);
@@ -1430,6 +1494,8 @@ usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
dev->delay.data = (unsigned long) dev;
init_timer (&dev->delay);
mutex_init (&dev->phy_mutex);
+ mutex_init(&dev->interrupt_mutex);
+ dev->interrupt_count = 0;
dev->net = net;
strcpy (net->name, "usb%d");
@@ -1565,7 +1631,7 @@ int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
*/
netif_device_detach (dev->net);
usbnet_terminate_urbs(dev);
- usb_kill_urb(dev->interrupt);
+ __usbnet_status_stop_force(dev);
/*
* reattach so runtime management can use and
@@ -1585,9 +1651,8 @@ int usbnet_resume (struct usb_interface *intf)
int retval;
if (!--dev->suspend_count) {
- /* resume interrupt URBs */
- if (dev->interrupt && test_bit(EVENT_DEV_OPEN, &dev->flags))
- usb_submit_urb(dev->interrupt, GFP_NOIO);
+ /* resume interrupt URB if it was previously submitted */
+ __usbnet_status_start_force(dev, GFP_NOIO);
spin_lock_irq(&dev->txq.lock);
while ((res = usb_get_from_anchor(&dev->deferred))) {
diff --git a/include/linux/usb/usbnet.h b/include/linux/usb/usbnet.h
index 0e5ac93..d71f44c 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;
@@ -246,4 +248,7 @@ extern int usbnet_nway_reset(struct net_device *net);
extern int usbnet_manage_power(struct usbnet *, int);
+int usbnet_status_start(struct usbnet *dev, gfp_t mem_flags);
+void usbnet_status_stop(struct usbnet *dev);
+
#endif /* __LINUX_USB_USBNET_H */
--
1.8.1.4
--
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