libertas USB: don't set surpriseremoved flag

We found a deadlock in the handling of command failures/reset conditions.
For example:

 1. Two commands are in the queue.
 2. The first command is sent, but causes a timeout, which kicks off an
    asynchronous device reset
 3. The second command is queued (but not yet sent to the hardware)
 4. The device reset kicks in, causing the if_usb disconnect handler to
    set the "surprise removed" flag to be set as the device disappears
    from the bus. This causes lbs_thread to stop processing things
    ("adapter removed; waiting to die"), not processing any further
    commands, leaving the second queued command "in the air", causing a
    deadlock.

Fix this by removing the surpriseremoved flag setting in if_usb. I can't
see any reason why this needs to be done so early. lbs_remove_card will set
this flag at an appropriate time - i.e. after all pending commands have
been completed or cancelled, avoiding this deadlock.

Signed-off-by: Daniel Drake <dsd@laptop.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/libertas/if_usb.c b/drivers/net/wireless/libertas/if_usb.c
index cd3b0d4006189b1ee07ae00a689f4d82a1dad5d0..92b6885d49a2278eb399e3c5cc503387b6f710f8 100644 (file)
--- a/drivers/net/wireless/libertas/if_usb.c
+++ b/drivers/net/wireless/libertas/if_usb.c
@@ -309,7 +309,6 @@ static void if_usb_disconnect(struct usb_interface *intf)
        cardp->surprise_removed = 1;
 
        if (priv) {
-               priv->surpriseremoved = 1;
                lbs_stop_card(priv);
                lbs_remove_card(priv);
        }