Commit 94ef3b63 authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman

[PATCH] USB: Fix khubd synchronization

It improves synchronization with hub_irq() and guarantees that the hub
disconnect() routine doesn't exit until the URB's completion routine has
finished.
parent 74636bf5
......@@ -128,11 +128,18 @@ static void hub_irq(struct urb *urb, struct pt_regs *regs)
struct usb_hub *hub = (struct usb_hub *)urb->context;
int status;
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 */
return;
goto done;
default: /* presumably an error */
/* Cause a hub reset after 10 consecutive errors */
......@@ -150,18 +157,20 @@ 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(&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)
dev_err (&hub->intf->dev, "resubmit --> %d\n", urb->status);
if (status == 0)
hub->urb_active = 1;
done:
spin_unlock(&hub_event_lock);
}
/* USB 2.0 spec Section 11.24.2.3 */
......@@ -466,6 +475,7 @@ 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);
......@@ -484,6 +494,7 @@ static int hub_configure(struct usb_hub *hub,
static void hub_disconnect(struct usb_interface *intf)
{
struct usb_hub *hub = usb_get_intfdata (intf);
DECLARE_COMPLETION(urb_complete);
unsigned long flags;
if (!hub)
......@@ -491,6 +502,7 @@ static void hub_disconnect(struct usb_interface *intf)
usb_set_intfdata (intf, NULL);
spin_lock_irqsave(&hub_event_lock, flags);
hub->urb_complete = &urb_complete;
/* Delete it and then reset it */
list_del_init(&hub->event_list);
......@@ -507,6 +519,8 @@ static void hub_disconnect(struct usb_interface *intf)
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;
}
......
......@@ -172,6 +172,8 @@ 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];
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment