[PATCH] IB/ipath: fix a bug that results in addresses near 0 being written via DMA

We can't tell for sure if any packets are in the infinipath receive buffer
when we shut down a chip port.  Normally this is taken care of by orderly
shutdown, but when processes are terminated, or sending process has a bug, we
can continue to receive packets.  So rather than writing zero to the address
registers for the closing port, we point it at a dummy memory.

Signed-off-by: Dave Olson <dave.olson@qlogic.com>
Signed-off-by: Bryan O'Sullivan <bryan.osullivan@qlogic.com>
Cc: "Michael S. Tsirkin" <mst@mellanox.co.il>
Cc: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/infiniband/hw/ipath/ipath_kernel.h

@@ -352,6 +352,8 @@ struct ipath_devdata {
 	/* check for stale messages in rcv queue */
 	/* only allow one intr at a time. */
 	unsigned long ipath_rcv_pending;
+	void *ipath_dummy_hdrq;	/* used after port close */
+	dma_addr_t ipath_dummy_hdrq_phys;
 
 	/*
 	 * Shadow copies of registers; size indicates read access size.