commit 448b4482c6713c5b62828622b7bf46900ff9569b
author Andrew Lunn <andrew@lunn.ch> Wed May 06 01:09:56 2015 +0200
committer David S. Miller <davem@davemloft.net> Sat May 09 16:05:54 2015 -0400
tree 083fb1fc9545bce1eeb716bfa2963630d5258c11
parent 16fe24fc43e8d32b76030c79c151c7db691865f6

net: dsa: Add lockdep class to tx queues to avoid lockdep splat

DSA stacks an Ethernet device on top of an Ethernet device. This can
cause false positive lockdep splats for the transmit queue:
Acked-by: Florian Fainelli <f.fainelli@gmail.com>

=============================================
[ INFO: possible recursive locking detected ]
4.0.0-rc7-01838-g70621a215fc7 #386 Not tainted
---------------------------------------------
kworker/0:0/4 is trying to acquire lock:
 (_xmit_ETHER#2){+.-...}, at: [<c040e95c>] sch_direct_xmit+0xa8/0x1fc

but task is already holding lock:
 (_xmit_ETHER#2){+.-...}, at: [<c03f4208>] __dev_queue_xmit+0x4d4/0x56c

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(_xmit_ETHER#2);
  lock(_xmit_ETHER#2);

To avoid this, walk the tq queues of the dsa slaves and set a lockdep
class.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>