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Subject[ 26/37] bas_gigaset: fix pre_reset handling
Date
3.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tilman Schmidt <tilman@imap.cc>

commit c6fdd8e5d0c65bb8821dc6da26ee1a2ddd58b3cc upstream.

The delayed work function int_in_work() may call usb_reset_device()
and thus, indirectly, the driver's pre_reset method. Trying to
cancel the work synchronously in that situation would deadlock.
Fix by avoiding cancel_work_sync() in the pre_reset method.

If the reset was NOT initiated by int_in_work() this might cause
int_in_work() to run after the post_reset method, with urb_int_in
already resubmitted, so handle that case gracefully.

Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/isdn/gigaset/bas-gigaset.c | 19 ++++++++++++++++---
1 file changed, 16 insertions(+), 3 deletions(-)

--- a/drivers/isdn/gigaset/bas-gigaset.c
+++ b/drivers/isdn/gigaset/bas-gigaset.c
@@ -616,7 +616,13 @@ static void int_in_work(struct work_stru
if (rc == 0)
/* success, resubmit interrupt read URB */
rc = usb_submit_urb(urb, GFP_ATOMIC);
- if (rc != 0 && rc != -ENODEV) {
+
+ switch (rc) {
+ case 0: /* success */
+ case -ENODEV: /* device gone */
+ case -EINVAL: /* URB already resubmitted, or terminal badness */
+ break;
+ default: /* failure: try to recover by resetting the device */
dev_err(cs->dev, "clear halt failed: %s\n", get_usb_rcmsg(rc));
rc = usb_lock_device_for_reset(ucs->udev, ucs->interface);
if (rc == 0) {
@@ -2437,7 +2443,9 @@ static void gigaset_disconnect(struct us
}

/* gigaset_suspend
- * This function is called before the USB connection is suspended.
+ * This function is called before the USB connection is suspended
+ * or before the USB device is reset.
+ * In the latter case, message == PMSG_ON.
*/
static int gigaset_suspend(struct usb_interface *intf, pm_message_t message)
{
@@ -2493,7 +2501,12 @@ static int gigaset_suspend(struct usb_in
del_timer_sync(&ucs->timer_atrdy);
del_timer_sync(&ucs->timer_cmd_in);
del_timer_sync(&ucs->timer_int_in);
- cancel_work_sync(&ucs->int_in_wq);
+
+ /* don't try to cancel int_in_wq from within reset as it
+ * might be the one requesting the reset
+ */
+ if (message.event != PM_EVENT_ON)
+ cancel_work_sync(&ucs->int_in_wq);

gig_dbg(DEBUG_SUSPEND, "suspend complete");
return 0;



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