(Adapted from a very similar change to net/802/garp.c by Cong Wang.)

mrp_pdu_queue() should ways be called with the applicant spin lock.
mrp_uninit_applicant() only holds the rtnl lock which is not enough;
a race is possible because mrp_rcv() is called in BH context:

	mrp_rcv()
	  |->mrp_pdu_parse_msg()
	    |->mrp_pdu_parse_vecattr()
	      |->mrp_pdu_parse_vecattr_event()
	        |-> mrp_attr_event()
	          |-> mrp_pdu_append_vecattr_event()
	            |-> mrp_pdu_queue()

Cc: Cong Wang <amwang@redhat.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid Ward <david.ward@ll.mit.edu>
Acked-by: NCong Wang <amwang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Sparse spotted local function that could be static.
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Initial implementation of the Multiple Registration Protocol (MRP)
from IEEE 802.1Q-2011, based on the existing implementation of the
Generic Attribute Registration Protocol (GARP).
Signed-off-by: NDavid Ward <david.ward@ll.mit.edu>
Acked-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>