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Date: Wed, 10 Apr 2013 10:01:20 -0500
From: Dan Williams <dcbw@...hat.com>
To: Oliver Neukum <oliver@...kum.org>
Cc: Ming Lei <tom.leiming@...il.com>,
Elina Pasheva <epasheva@...rrawireless.com>,
Network Development <netdev@...r.kernel.org>,
linux-usb <linux-usb@...r.kernel.org>,
Rory Filer <rfiler@...rrawireless.com>,
Phil Sutter <phil@....cc>
Subject: Re: [PATCH 1/2 v4] usbnet: allow status interrupt URB to always be
active
On Wed, 2013-04-10 at 15:58 +0200, Oliver Neukum wrote:
> On Wednesday 10 April 2013 08:54:43 Dan Williams wrote:
> > > The refcounting is very good. Just don't mess around with "force"
> >
> > That's easy to do if the helpers aren't used for suspend/resume, which
> > is what I had previously in my v2 patches until Ming suggested that I
> > use the helpers there. I can go back to that approach if you'd like, it
> > is a bit less complicated at the expense of sprinkling the interrupt urb
> > submit/kill code around more widely.
>
> If you introduce a third helper like "forcibly_stop_interrupt" or something,
> I'll be perfectly happy. Just don't use flags which completely alter behavior.
>
> Regards
> Oliver
Do you mean something more like this? If so, I'll go ahead and do the
formal submission. Thanks!
Dan
---
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..f903beb 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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