[PATCH] USB: Make hub driver use usb_kill_urb()

This is a rerun of as278, updated to match the current source.  It changes
the hub driver, replacing calls to synchronous usb_unlink_urb() with
usb_kill_urb() and removing the machinery formerly needed to synchronize
the status URB handler with the rest of the driver.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/usb/core/hub.c

@@ -234,18 +234,11 @@ static void hub_irq(struct urb *urb, struct pt_regs *regs)
 	int i;
 	unsigned long bits;
 
-	spin_lock(&hub_event_lock);
-	hub->urb_active = 0;
-	if (hub->urb_complete) {	/* disconnect or rmmod */
-		complete(hub->urb_complete);
-		goto done;
-	}
-
 	switch (urb->status) {
 	case -ENOENT:		/* synchronous unlink */
 	case -ECONNRESET:	/* async unlink */
 	case -ESHUTDOWN:	/* hardware going away */
-		goto done;
+		return;
 
 	default:		/* presumably an error */
 		/* Cause a hub reset after 10 consecutive errors */
@@ -268,20 +261,17 @@ static void hub_irq(struct urb *urb, struct pt_regs *regs)
 	hub->nerrors = 0;
 
 	/* Something happened, let khubd figure it out */
+	spin_lock(&hub_event_lock);
 	if (list_empty(&hub->event_list)) {
 		list_add_tail(&hub->event_list, &hub_event_list);
 		wake_up(&khubd_wait);
 	}
+	spin_unlock(&hub_event_lock);
 
 resubmit:
 	if ((status = usb_submit_urb (hub->urb, GFP_ATOMIC)) != 0
-			/* ENODEV means we raced disconnect() */
-			&& status != -ENODEV)
+			&& status != -ENODEV && status != -EPERM)
 		dev_err (&hub->intf->dev, "resubmit --> %d\n", status);
-	if (status == 0)
-		hub->urb_active = 1;
-done:
-	spin_unlock(&hub_event_lock);
 }
 
 /* USB 2.0 spec Section 11.24.2.3 */
@@ -612,7 +602,6 @@ static int hub_configure(struct usb_hub *hub,
 		message = "couldn't submit status urb";
 		goto fail;
 	}
-	hub->urb_active = 1;
 
 	/* Wake up khubd */
 	wake_up(&khubd_wait);
@@ -640,7 +629,6 @@ static unsigned highspeed_hubs;
 static void hub_disconnect(struct usb_interface *intf)
 {
 	struct usb_hub *hub = usb_get_intfdata (intf);
-	DECLARE_COMPLETION(urb_complete);
 
 	if (!hub)
 		return;
@@ -649,12 +637,16 @@ static void hub_disconnect(struct usb_interface *intf)
 		highspeed_hubs--;
 
 	usb_set_intfdata (intf, NULL);
-	spin_lock_irq(&hub_event_lock);
-	hub->urb_complete = &urb_complete;
+
+	if (hub->urb) {
+		usb_kill_urb(hub->urb);
+		usb_free_urb(hub->urb);
+		hub->urb = NULL;
+	}
 
 	/* Delete it and then reset it */
+	spin_lock_irq(&hub_event_lock);
 	list_del_init(&hub->event_list);
-
 	spin_unlock_irq(&hub_event_lock);
 
 	/* assuming we used keventd, it must quiesce too */
@@ -663,14 +655,6 @@ static void hub_disconnect(struct usb_interface *intf)
 	if (hub->has_indicators || hub->tt.hub)
 		flush_scheduled_work ();
 
-	if (hub->urb) {
-		usb_unlink_urb(hub->urb);
-		if (hub->urb_active)
-			wait_for_completion(&urb_complete);
-		usb_free_urb(hub->urb);
-		hub->urb = NULL;
-	}
-
 	if (hub->descriptor) {
 		kfree(hub->descriptor);
 		hub->descriptor = NULL;
@@ -803,7 +787,7 @@ static int hub_reset(struct usb_hub *hub)
 
 	/* Attempt to reset the hub */
 	if (hub->urb)
-		usb_unlink_urb(hub->urb);
+		usb_kill_urb(hub->urb);
 	else
 		return -1;
 

drivers/usb/core/hub.h

@@ -188,8 +188,6 @@ extern void usb_hub_tt_clear_buffer (struct usb_device *dev, int pipe);
 struct usb_hub {
 	struct usb_interface	*intf;		/* the "real" device */
 	struct urb		*urb;		/* for interrupt polling pipe */
-	struct completion	*urb_complete;	/* wait for urb to end */
-	unsigned int		urb_active:1;
 
 	/* buffer for urb ... 1 bit each for hub and children, rounded up */
 	char			(*buffer)[(USB_MAXCHILDREN + 1 + 7) / 8];