[ofa-general] MTHCA driver from OFED 1.3a package

[Roland Dreier]

 > Fatal DMA error! Please use 'swiotlb=force'
 > ----------- cut here  --------- please bite here  ---------
 > Kernel BUG at arch/x86_64/kernel/../../i386/kernel/pci-dma-xen.c:333

What is this bug being caused by?  That is, what is line 333 of
pci-dma-xen.c in your source tree?

 > RIP: e030:<ffffffff802104d2>  <ffffffff802104d2> dma_map_single+0x13f/0x18f

 > <ffffffff883179cf> :ib_ipoib:ipoib_cm_alloc_rx_skb+0x92/0x282

The code that calls dma_map_single in ipoib_cm_alloc_rx_skb() looks
fine to me, at least in the upstream kernel (I don't know what extra
patches OFED might add on).  It is basically:

	skb = dev_alloc_skb(IPOIB_CM_HEAD_SIZE + 12);
	skb_reserve(skb, 12);
	mapping[0] = ib_dma_map_single(priv->ca, skb->data, IPOIB_CM_HEAD_SIZE,
				       DMA_FROM_DEVICE);

and I don't see anything at all wrong with with that.

 - R.