tracking down a bug that turned out to be a free_iob() used where I
needed a netdev_tx_complete().  This left the freed I/O buffer on the
net device's TX list, with bad, bad consequences later.

Also fixed the bug in question.

makes it easier to put the generic allocation code into infiniband.c

using entirely our own code.

fixed; still using a quick hack-up just to be able to pass through
data.