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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>
Daniel Drake 13 年之前
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共有 1 個文件被更改,包括 0 次插入1 次删除
  1. 0 1
      drivers/net/wireless/libertas/if_usb.c

+ 0 - 1
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);
 	}