Merge branch 'dma_rmb_wmb'

Merge branch 'dma_rmb_wmb'

Alexander Duyck says:

====================
Replace wmb()/rmb() with dma_wmb()/dma_rmb() where appropriate, round 2

More cleanup of drivers in order to start making use of dma_rmb and dma_wmb
calls.  This is another pass of what I would consider to be low hanging
fruit.  There may be other opportunities to make use of the barriers in the
Mellanox and Chelsio drivers but I didn't want to risk meddling with code I
was not completely familiar with so I am leaving that for future work.

I have revisited the Mellanox driver changes.  This time around I went only
for the sections with a clearly defined pattern.  For dma_wmb I used it
between accesses of the descriptor bits followed by owner or size.  For
dma_rmb I used it to replace rmb following a read of the ownership bit in
the descriptor.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>